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Forum: Pentax News and Rumors 10-17-2019, 11:41 AM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
That's not *quite* the only option...

... One option is that we can wait *impatiently*. I've been increasingly doing that since they changed their roadmap release date from "Spring 2019" to the vague and open-ended "2019 or later". Before that I was waiting patiently.

... Or we can stop waiting completely and simply leave Pentax for greener fields where we can actually get the FF lenses we need or really want for the photography we love to do.

I hope it comes out before I'm *dead*.
Forum: Pentax News and Rumors 10-02-2019, 07:53 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I formed that view from carefully examining online side by side comparison shots taken under controlled conditions. That includes DP review and Cameraville's image comparison. (














You Tube



) I'm not the only one to draw this conclusion, either. To be clear, I found it to be *very very* slight at most, and likely not noticeable except under highly controlled conditions. I completely agree that it is unlikely to make a real world difference between a keeper or not. I'm very glad you don't see it. That's great news for you. I'm also very glad that some of the tweaks in the mark 2 work for you. The mark 2 looks like it is a really great camera, just like the mark 1 is.
Forum: Pentax News and Rumors 09-17-2019, 05:10 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I'm not interested in profitability nor marketshare, per se. But these do have an impact for what I do care about: whether Pentax can or will be satisfying my photographic needs now or into the future. If revenues decline then the only way to maintain profitability is to cut costs. One of the chief ways to cut costs is to cut R&D. It's fairly easy to stay profitable if you are not paying people to do R&D or to develop cutting-edge technology, and are just ticking along selling a few cameras with a minor "upgrade" every few years (such as the K-1ii). There is no doubt in my mind that Pentax could remain profitable without entering the mirrorless FF market, but that does nothing to suggest that Pentax will be able or willing to cater for my needs or the needs of some others shooting FF.



I'm fairly new to Pentax, and I only became aware of their explicit refusal to follow the rest of the market into mirrorless least year. That was a bit disappointing for me, but I didn't get into Pentax because I assumed it would go mirrorless. I did get into Pentax assuming that modern FF lenses that satisfy my needs would be in place nearly four years after launch, so my expectations exceeded reality on that score. I was informed that lens support for Pentax FF is weak, but I hoped to make do with the older glass until the relevant modern lenses appeared. In part, my needs have shifted, so I'm not *blaming* Pentax - its a "no fault" divorce that I'm considering.



It really is a case of "what have you done for me lately", and what that portends for the future. I entered into the Pentax realm with the K-1 two years ago. And I did so because it really was and is a great camera. Yes - that showed effort and imagination and it was in some ways ground-breaking. It was exciting to work with such a great camera. The k-1ii, for *my* needs, was a step backwards, not forwards. It's still intrinsically a great camera, but only because it is hardly any different from the original. The obvious lack of effort and imagination that went into the mark ii is indicative, to me, of the future, and is corroborated by the painfully slow development of new lenses. Maybe the mark iii, if it ever appears, will show a return to the effort and imagination of the original. We can hope. But I'm not very hopeful and how many years will that take anyway? Meanwhile, we have to wait for lenses to dribble out after extended delays if at all.



I don't view it as a mistake - it was the best I could afford at the time and I have loved shooting with my K-1. It would be hard to sell the gear I've loved using. But you could be right about changing being the best solution.

Thanks for your comments.
Forum: Pentax News and Rumors 09-14-2019, 06:05 AM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I think that (and the rest) is a fair point. Probably volume rather the failure to go to mirrorless is the major factor here.
Forum: Pentax News and Rumors 09-14-2019, 05:54 AM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I think it is a sad day for Pentaxians because it means that there will be fewer lens options going into the future than otherwise. If you think that is not something to be sad about, then I donít know what to say.

It is also a signal that Pentaxís unwillingness to embrace mirrorless has real world consequences that makes Pentaxians more dependent on Pentax for their lenses going forward. Maybe you will never want new third party glass. Maybe you already have everything you need. But Iíd like to see the options expand rather than decrease going forward, and Im sure I canít be alone in that.

Whether Nikon and Canon are acting desperately or the market is shrinking is irrelevant to my point. The rise of Sony in the FF market is rooted in their FF mirrorless cameras. Nikon and Canon and Panasonic and Fujifilm and Olympus and Leica and Sigma and... well, you get the picture... have recognized the market is shifting toward mirrorless and are playing catch-up whilst trying to defend their market share in the context of the obvious trend that Sony has led. I donít know whether Pentaxís decision will be good for them in the long run or bad. They probably decided they are too far behind in the relevant technology or donít have the resources to compete in the increasingly mainstream mirrorless market as perhaps they once could. Maybe they will carve out a position producing a good lens and a nice camera once in a while that will satisfy an increasingly isolated and dependent clientele.

But maybe the sadness I feel is not in any way representative of others. If so, Iím glad. Maybe it is just *my* needs that are not being fulfilled by Pentax. Maybe it is because I shoot FF and the K-1ii showed just how little effort and imagination they were willing to put into FF development. (It really was a disappointment for me and, for my needs, was actually inferior to the K-1 because of the baked in noise reduction slightly softening base iso and weaker battery life.) And maybe it is just that with Sigma gone there is one fewer possible source for the new top notch lenses I really want to satisfy *my* needs: a 70-200mm f4, a new but fairly compact ultra wide prime circa 14mm, an ultrawide zoom that is not a brick and has a filter thread e.g. 16-35mm, so I can use my existing filter system, a TC that works properly on all FF glass.
Forum: Pentax News and Rumors 09-11-2019, 02:45 PM  
Finally confirmation from Sigma
Posted By Socrateeze
Replies: 89
Views: 6,844
Errm, well, personal financial limitations to one side, there are always other options than just living with it. For some of us there is the option - costly as it may be - to move to a different system. In my case, that will likely be Sony, because I no longer have much faith in future lens support at full frame from Pentax or anyone else now.

The relative lack of modern lens support, especially at full frame, has long been a significant (almost the only) downside of Pentax when compared with other manufacturers. It was the main thing that caused me to have some second thoughts when I bought the K-1. But the K-1 was the best thing I could get at that price-point and it is a wonderful camera. I thought I could live with the paucity of modern lenses because there was just about enough third-party lens support and just about enough Pentax lenses to get me up and running, but I expected full-frame lens support to continue apace. A few nice primes have emerged, but things have become intolerably slow (e.g., the D-FA 70-200mm f4) and it seems to me that Ricoh have other priorities (such as the wonderful GR III and other aps-c cameras) - and good luck to them! After all, it seems to be working to some extent since Pentax have increased its market share from almost nothing to slightly more than almost nothing. We're soon coming up to four years since the K-1 was announced, and we still have no 70-200mm f4, no FF teleconverter, etc., and the refusal to embrace mirrorless at full-frame - which is central to Sigma's decision, it seems - means that some of us see the writing on the wall and will jump ship.

It's sad.
Forum: Pentax News and Rumors 09-11-2019, 01:59 PM  
Finally confirmation from Sigma
Posted By Socrateeze
Replies: 89
Views: 6,844
All very interesting points and very good questions.
Forum: Pentax News and Rumors 09-11-2019, 01:48 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
So I read now that Sigma will no longer produce K-mount lenses. Will this increase the pressure on Ricoh to deliver more lenses, such as the D-FA 70-200mm f4? I'm not hopeful. Is it a portent of Pentax's ultimate demise? Quite possibly. With the demise of almost the last (and the last major) third-party lens manufacturer for K-mount, Pentax users are even more at the mercy of Ricoh and their apparently lackadaisical approach to lens development than ever before.

It might be worth noting that the reason underlying Sigma's decision seems to be Pentax's refusal to embrace mirrorless cameras whereas Sigma - rightly in my view - believes that "mirrorless is the future". (That's not a judgement on the objective merits of mirrorless over DSLR - just a claim about market trends.)

It's a sad day for Pentaxians.
Forum: Pentax News and Rumors 08-27-2019, 06:19 AM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
Thanks for trying to provide some evidence, but I think you're misreading the text and the graphs. To use your analogy, you are adding 1 and 1 and getting 3 (or at least 2.5). Let me explain...

Firstly, the quote from Lenstip: "From our point of view it would be difficult to get anything better....". This refers to their (then) new ability to compare Pentax lenses with other lenses with similar size and resolution sensors, not to the quality of the lens. You might seem to think that that phrase was evaluating the Pentax lens as "difficult to get any better", as is possibly suggested by you putting it in bold and then saying that "This is in sync with" the ePhotozine review, which is a very positive review of the lens.

Secondly, the MTF graph showing the sharpness of the Pentax as being in line with that of the Canon on the Lenstip webpage is *for the centre of the image*. If you check the MTF graph later in the review (Pentax smc D FA 100 mm f/2.8 Macro WR review - Image resolution - LensTip.com) you can see this to be the case. That matters because if you then compare the MTF charts you cite comparing the Canon with the Sony, you can see that the Sony is in fact *better* than the Canon at the centre of the image (by a relative measure of 0.6 for the Canon compared to 0.65 for the Sony for 50lp/mm). It follows that if you were to transfer the Sony to the original comparative Canon/Pentax MTF chart you would see the Sony as scoring *better* than both the Canon *and the Pentax*, not worse.

And the comparison between the Canon and Pentax is also not quite fair, either. The Canon 50D has 15 effective megapixels, whilst the Pentax K-5 has 16 effective megapixels. That not a huge difference, but it does mean that since the lenses resolve with equal sharpness on those cameras, that the Canon lens is actually a bit sharper, at least at the centre, than the Pentax lens.

Now the MTF charts comparing the Sony with the Canon certainly suggest that the advantage of the Sony is more towards the centre of the image, but that advantage is lost to the Canon towards the edges. Kudos to Canon for its superior edge sharpness, and kudos to Sony for its superior centre sharpness! Which, then, is the better lens? Well, on sharpness, it depends on whether centre sharpness is more important to you than edge sharpness. And before you overinterpret the MTF charts even more, remember that the poorer performance of the Sony at the edges than the Canon is not as important on the crop sensors used in the Lenstip article because they crop out most of the edge superiority of the Canon over the Sony.

So what we've learned from Lenstip is that if the DxO marks carry similar information we should expect similar scores from the Pentax and the Canon for the same lenses and bodies as Lenstip uses for their comparison. So let's look at the the DxO marks and what do we see?:

DxO mark for sharpness for the Canon EF 100mm f/2.8L Macro IS USM on the Canon 50D: 8

DxO mark for sharpness for the Pentax smc D FA MACRO 100mm F2.8 WR on the Pentax K-5: 8

Well, quelle friggin' surprise!! Exactly the same! Precisely what you'd expect given the Lenstip measurements! Ironically, far from undermining the suggestion that DxO marks contain information about relative sharpness, the Lenstip MTF graph actually corroborates it!

And what about the superior Sony scores? Well, DxO places greater weighting to the centre sharpness over edge sharpness. That would not be my choice, but hey, maybe that matters more to other people than to me. In any case, it is no great surprise that the DxO scores the Sony higher than the Pentax or the Canon on similar resolution sensors, especially on crop sensors that crop out the edges where the Sony would seem to be relatively weaker when compared with than the Canon. Unfortunately, DxO do not test the Pentax lens on the K-1. If they did, I suspect you'd find the Pentax closer to the Sony than the aps-c comparisons might suggest. It's possible that the Pentax macro would even beat the Sony, but that's rather speculative.

And as for the claim that "mirrorless is lighter", I never made any such a blank claim. My claims regarding weight savings refer to specific comparisons of lens sets that I might want with the K-1 vs the a7r4. And the Sony set-up would be lighter for me from between 800g and about 3kg. I wasn't including macro lens in that because I don't tend to carry a macro lens together with my other lenses.
Forum: Pentax News and Rumors 08-27-2019, 02:45 AM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I don't think I did say that testing with anything is better than no testing at all. Whether it is depends, of course, on whether the testing provides any information. On the assumption that it does, then some information is better than no information. My issue lies with your contention that DxO marks provide no information.

Obviously, a "wrong test" leads us to believe false things, and that is (usually) worse than a state of complete ignorance.

---------- Post added 27-08-19 at 09:48 ----------






QuoteQuote:

[/COLOR]You were saying: Sony lenses get consistently better scores than Pentax lenses by DXO mark. I replied: DXO tested Pentax lenses with apsc cameras , and tested Sony lenses with full frame higher resolution cameras. There is nothing to argue about, that's pretty clear, end of story.



What in the above do you think is something I disagree with?

DxO also tested the Sony 90mm macro on aps-c cameras. When tested on similar resolution aps-c sensors the Pentax scored markedly less for sharpness than the Pentax 100mm macro.

---------- Post added 27-08-19 at 09:49 ----------

[/COLOR]





QuoteQuote:

How can DXO have tested the lenses on a Pentax full frame camera while they tested the lens the Pentax K1 did not exist! By the way, I don't know what you are talking about, because it is not possible to get DXO test results of the DFA100 macro with the Pentax K1 since the K1 is not available in the list: Pentax smc D FA MACRO 100mm F2.8 WR - DxOMark



Again, I'm not sure what your point is or why you think I disagree with the above. I never suggested that DxO tested the 100mm macro on a FF camera. Neither did I suggest that they tested it with the K-1.
Forum: Pentax News and Rumors 08-27-2019, 01:31 AM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I'm not sure what you mean by "ad driven tabloid". Do you mean the DxO website? That's where I got my information about their scores.

Okay, so you raise an interesting question about burden of proof. Who has the burden of proof? As a *general* principle, it is with the person making the claim. If someone claims that DxO marks are meaningless, that is a claim and they shoulder a burden of proof for that claim. So there is nothing wrong with me asking people for evidence for such claims - i'm placing a burden of proof on the shoulders of those who make that claim. As I'll argue below, this general principle, however, cannot be extended universally, on pain of radical skepticism.

What burden of proof do *I* have? *At most*, I have a burden to provide reasons for only those claims that I have made. Me asking those who have claimed, for example, that DxO marks carry no information, for grounds for their claim, does not result in any burden of proof for me to establish anything.

But I have made some claims. My first claim was that DxO gave the scores that I said they do. I could provide you with links, but I'm going to assume that that is not your concern. I think what you are asking for evidence for is for my assumption, later made explicit, that DxO marks carry some information (and are therefore not meaningless). Here is my response:

All reasoned argument has to start somewhere with premises (not always explicitly stated, of course) that are not ultimately subjected to further questioning. (In order to get anywhere in an argument, you have to start somewhere.) If you express a belief I *could* ask you for a reason for that belief, then a reason for your reason, and then a reason for your reason for your reason, and so on ad infinitum. The result of demanding that reasons be provided for *any and all* beliefs is to demand something that *cannot* be given and leads to radical philosophical skepticism. (Which is bad!)

Our premises almost always include someone saying something (something on the internet, in a newspaper, on tv, on the news, in Pentaxforums, in a peer-reviewed scientific paper, etc.) The vast majority of the things that we humans believe are based ultimately on the testimony of others, and that requires a large degree of *trust*. Without trust there is almost nothing we could learn about the world. For example, I believe that gold atoms have 79 protons in its nucleus. I believe that only because lots of sources that I trust have said that. I haven't got any personal experience that corroborates that, and neither have even the vast majority of scientists. I certainly have not experimentally tested it. This does not make our beliefs irrational however, for reasons that I'll try to make clear.

The challenge lies in deciding where to place our trust.

In the case of lenses, people here have pointed to, for example, Lensrentals as a source of information about lenses or to MTF charts sourced on the internet. To use those as sources of information requires some trust. One could equally ask the same question there: where is your evidence that Lensrentals actually carried out the tests they say that they did? Where is your evidence that, even if they did carry out those tests, that their instruments work or are well-calibrated? Etc. If one were to adopt such a radical skeptical approach then no one has any reason for anything if it is based on the testimony of someone else - which almost all of what we believe about the world is. I take that kind of radical skeptical approach to be coherent, but also very corrosive for the general enterprise of critical enquiry. In other words, I take it that at some level we have to trust others if we are to have informed opinions - as we desperately need to have - that extend beyond our own immediate and very narrow personal experience.

So I believe that the *default* should be that a speaker sincerely expressing a declarative statement raises the probability of the statement being true. In the absence of grounds for thinking that the statement is either a) false, or b) without epistemic warrant (i.e., without rational justification), it is then reasonable to believe that the person's statement carries information. This is *not* to say that the statement is true - it is simply to say that it raises the probability of the statement being true. (This is related to what is sometimes called the principle of credulity, or principle of epistemic charity.) Very roughly speaking, without getting into to much detail, we should give epistemic credit to testimony *unless* we have grounds to think that the testifier is lying, stupid, or ill-informed. Without that principle we could not learn anything from anyone giving testimony. Since I think we *can* and *do* learn things from testimony, I endorse that principle. I think pretty much everyone does, implicitly.

So far, I have no reason to think DxO are lying, no reason to think that they are stupid, and no reason to think that they are ill-informed, when they make statements about, say, the sharpness of the lenses they test. The same goes for Lensrentals, or ePhotozine, or Optical Limits or Lenstips, etc. I therefore give them epistemic credit and treat their statements as carrying some information. There are, of course, many factors that modulate the reasonableness of crediting their statements with carrying information, and many factors that modulate the amount of information their testimony is likely to carry (such as the number of lenses they say they test), and I strive to take those factors into account.

For analogy, suppose I want to know what the time is and I ask someone and they say: "it's nearly ten". I take it that I now have some reason to believe that it is nearly ten. It may well be that there are better and more accurate sources of information about the time out there, but it would be unreasonable for someone to simply *assume* that the statement carried *no* information about the time without some reason to do with, say, the person's poor sight, their high alcohol levels, their propensity to lie, the recent operational failures of their watch, etc. In other words, they would need some reason if their dismissal of the statement is to be reasonable.

None of this means that DxO marks *are* worth anything. BUT, it does mean that if someone claims that they are not worth anything, then it is reasonable *for me* to ask for the reasons for thinking that.

---------- Post added 08-27-19 at 02:18 AM ----------



Then the test would be worthless. I could equally ask: What if the apparatus LensRentals used was badly calibrated? Then their tests would be useless. How do such possibilities show that the DxO mark should be ignored? Have you grounds to believe that it was not in focus? Have you reason to think that DxO folks don't know how to focus a lens properly? I have no such reason to think such things.






QuoteQuote:

A real test like the camera companies or Roger Cicala does is in a rig just for the lens:

Lens Rentals | Blog

Otherwise you're not testing the lens, you're testing that individual copy of the lens, the camera body, the software algorithm, the subject setup and lighting, and the skill of the individual photographer. It's called controlling variables.



You are testing the lens, but you are not testing *just* the lens. That is, differences in the lens makes a difference to the marks, but it is not the only thing that makes a difference. Claiming, with justification in my view, that Lensrentals is a *better* source of lens information than DxO marks is something I would certainly agree with. But it does absolutely nothing to show that DxO marks should be ignored. All you are saying is that there are other factors that we need to control for before interpreting the marks from any source as a measure of the lens' properties.



Right. And again, none of that shows that the DxO marks carry no information or should be ignored. Have you any reason to think that the DxO testing also used a decentred lens? Could they have? Sure!



Yep, and again....



What you possibly can tell me concerns your experiences of your particular copies of those lenses. Your testimony carries information, but it does nothing to show that DxO marks should be ignored, rather than, say, showing that Pentax lenses vary in their sharpness from one copy of a lens to another.



I love that Pentax lens as well. And those are some good reasons to prefer the Pentax lens over the Sony, imo, all else being equal. What they are not are reasons to dismiss or ignore DxO marks. That there is a lot more to deciding which lens will be best for oneself than DxO marks (or MTF charts, for that matter) is not something I have remotely disagreed with.
Forum: Pentax News and Rumors 08-26-2019, 11:46 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
For a belief to be *rational* it requires evidence (or, more generally, good reasons). If you don't accept that, then we really have nothing further to discuss. *Psychologically*, belief requires nothing more than a *cause* and many causes of beliefs are not good reasons: hypnotism, inculturation, cognitive biases, a bump on the head, marketing - you name it.

I'm interested in having *rational* beliefs, which means that I'm interested in the evidence. So should everyone be, because rational evidence-based beliefs have a greater propensity to be true than irrational ones. (I take it for granted here that truth is of some value.) So when people make claims I have no independent reason to believe are true (or, wrt which I have some reasons to think may be false) I like to ask: why do you think that? What is your evidence? That way I have a greater chance of learning something or being corrected (if I'm mistaken) - I always start out by assuming that the person has some rational basis for their claim, of course. Alas, I'm often disappointed.

Back to DxO. Unless you have grounds to believe that the lens tested is unrepresentative of that lens generally, then you have no basis for rejecting the findings based on that lens simply because it is a single instance of a lens. If I test a piece of chalk for its hardness, then I have some information about the hardness of chalk in general, even though there is some variation. And I can form reasonable opinions about whether, for example, chalk is harder or softer than some other sample of something else.

Merely saying that there is variability (which is true of all lenses, some more than others) merely introduces some degree of uncertainty into the results, insofar as those results purport to be about the lens generally. How much uncertainty it introduces depends on the variability in those lenses. The more known variability there is, the less information is carried in the results from a single instance. Testing more instances of a lens reduces the uncertainty and increases the likelihood of the results being representative, all else being equal (which helps to make lensrentals a valuable source of information). And that is a good thing because it allows the result to convey more reliable information about the lens in general, always assuming the the lenses are selected randomly.

Pointing to the better scores of the Sony lens and saying, in effect: "but that's only one lens and it could be by chance one of the better of a generally inferior lens" is true - it *could* be. Equally, however, it *could* be one of the inferior lenses of a generally better lens, in which case the lens is even more superior to the Pentax than the DxO mark would suggest. How do you pick between these two possibilities? You can't. Independently of any further evidence, there is no reason to suppose the former if more likely that the latter. It *might* be unrepresentative, but one ought not assume that it is unrepresentative simply because there is variation in the population. And it might just as well be unrepresentative to the detriment of the lens than in its favour. The same is true of the tests of the Pentax lens, of course. It could be that the lens tested was a particularly good example of the lens generally, and the Pentax lens is generally worse than the DxO score would suggest.

If your point is simply that there is some uncertainty surrounding the reliability of tests performed on a single instance of a lens, I agree. Uncertainty does not result in an absence of information.

You suggest that the scores listed as tested for lower resolution cameras (such as the NEX-7) were not actually tested on those lower resolution cameras - despite the fact that they say that they were - but were interpolated from scores on higher resolution cameras. What is your evidence for that? (I.e., what is your evidence that they are lying?) And even if they were interpolating, why think that the interpolation is not accurate?

---------- Post added 08-26-19 at 11:51 PM ----------



Thank you. I stand corrected. I'm not sure where I got that from.
Forum: Pentax News and Rumors 08-26-2019, 12:39 AM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I do research MTF graphs, when available. And Lens Rentals is very useful too for the reason you cite. Glad we agree on that.

Again, I'm not basing my decisions exclusively or even primarily on DxO marks. I simply responded to a specific mention by someone else of Sony's macro lens in comparison with Pentax's WR macro and used the convenient expedient of a DxO mark - far more convenient than posting MTF charts or locating links to such - to illustrate a general point about Sony lenses using the example given - i.e., they're very good and the evidence I've seen suggests that the Sony may be even sharper than the Pentax.

I'm operating on the assumption that the DxO marks carry *some* relevant information about the properties and quality of lenses, such as sharpness. Until I see good evidence to the contrary (i.e., evidence that DxO marks carry no relevant information about sharpness, etc.) - and so far, as best I can see, no one has provided any - then that operating assumption remains quite reasonable. And so long as that assumption remains a reasonable one for me to hold, in the absence of equal or greater evidence to the contrary, it is reasonable for me to believe that the Sony macro lens is probably sharper than the Pentax macro lens.

As for you not taking DxO marks seriously, well, that's up to you, I guess. If you have a good *reason* to not take them seriously or to ignore them, please do speak up. If you have evidence that DxO marks carry *no* information, either in general or in this particular case, I'd be keen to hear about it. But until you do present some evidence, I don't have any good reason to take your contention that DxO marks should not be taken seriously, at all seriously.
Forum: Pentax News and Rumors 08-24-2019, 07:39 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
That's not the best comparison, imo. The K-3 has a 24.7 MP sensor without anti-aliasing filter and the Sony a5000 has a 20 MP sensor with an anti-aliasing filter, and as we all know, higher resolution of the sensor makes a huge difference, and lacking an anti-aliasing filter likewise boosts the resolving power of the sensor. So I think similar scores on a sensor with nearly 25% fewer pixels and the encumbrance of an anti-aliasing filter clearly implies, all else being equal, that the Sony 90mm is quite a lot better overall. Of course, that is the overall score you are looking at, and when it comes to sharpness in particular the comparison looks even worse: the Pentax scores 10 on the 24MP without anti-aliasing filter sensor whilst the Sony scores 18 on a 20MP sensor with an anti-aliasing filter! That difference goes in the *opposite* direction of what you might expect if the lenses were equally sharp. That can't be considered a negligible difference, imo.

Perhaps a better comparison might be with the NEX-7 with is, like the K-3, a 24MP aps-c sensor. Here the Sony scores 16 to the Pentax's 10 for sharpness. Similarly, if we compare the scores with the Pentax K-S1 with the Sony a5000 - both are 20MP aps-c sensors with anti-aliasing filters - the Pentax scores 8 for sharpness and the Sony scores 18. That does not look negligible to me.

To reiterate - none of this is me dissing the Pentax lens. I love it. I have absolutely no complaints, not even about the occasional focus-hunting. I'm just making the very minimal claim that in terms of sharpness the DxO scores for the Sony suggest it is the sharper lens. And I'm not even saying that DxO marks are definitive, either. I'm just saying that they provide information that is useful in making comparisons.
Forum: Pentax News and Rumors 08-23-2019, 12:30 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I realize that filter thread size is not the issue. I mentioned the filter thread size because at 95mm the Lee 100 holder will not attach to the Irix 15mm lens with a wide-angle adapter ring. Their wide-angle adapter rings only go to 82mm. With the Irix filter holder it attaches to the hood thread, not the filter thread, placing the filter holder much closer to the front element than would otherwise be possible.

Bottom line: there is no significant vignetting with the Irix 15mm on a FF with the Irix filter holder (at least if you don't use a CPL), so your claim that "100mm filters will only work down to 20mm on FF" is simply *not true*, whatever *your* experience may be. It depends (amongst other things) on the specifics of the filter holder. Based on reports from others, I've reason to believe that it will not vignette at 16mm using the Nisi filter holder. Since you didn't answer my question as to whether you had tried Nisi, I'm guessing you haven't.

As for having to try it and test it, most of us do research online first and some of that research can have value. Not all of it, of course, and much of it is just marketing. We need to be wary of that and your emphasis on that is well-founded. But we don't necessarily have to test anything ourselves so long as we can find reliable and relatively objective sources who have tested it for us. And that, of course, is a tricky task, but it is not an impossible one. I've found credible sources where others claim that using the Nisi filter system it does not vignette at 16mm.

On the other hand you have your personal experience and, like most of us, it makes a lot of sense to place a lot of weight on one's own experience. We can gain from the personal experience of others and I do trust you to report that experience honestly. But honesty is not accuracy. Most people place way too much weight on their own experience, taking themselves to be more objective and reliable than they actually are. Our own experience is partial, in the sense that we have not tested everything, and we have a strong tendency to generalize too quickly from our own experience (as I suspect you may have done with respect to filters systems vignetting below 20mm). We are also all biased in various, usually unconscious ways. It is no surprise, for example, that a lot of people here are biased in favour of Pentax - the same is respectively true on other brand specific forum sites, of course.

Some sites are more objective than others. DxO marks provide some information and I'm aware of no particularly good reason to suspect bias is playing a role in their judgements when comparing Pentax with Sony. That you would not use DxO as a source for lens judgements is not in itself a reason for me to not use it as a source for lens judgements (and, of course, I am familiar with the reviews you linked to - another source I've used for judgements about lenses).

You say that DxO numbers "really don't seem to have much meaning", but it is unclear to me on what objective basis you have drawn that conclusion. Is it because they use a single copy? But is ePhotozine - a source you seem happen to cite - any different on that?

You mention that sharpness will depend on the sensor - and of course that it right, so we can't *directly* compare sharpness figures without taking that into account. But having to take that into account does not result in "meaningless figures". For a given lens, we should expect a 42mp sensor to deliver greater sharpness than a 24mp sensor, all else being equal. But the Sony scores 36 on a 24mp sensor whilst the Pentax scores 10 on a 24 mp sensor. So sensor resolution, per se, is not a critical factor invalidating that particular comparison.

What else might invalidate the comparison? You suggest that the higher score for Sony is because it's on FF, and that DXO "count the whole sensor area, so the score is higher than apsc". This puzzles me, so I'd like to understand your reasoning on that. Why should the fact that the Pentax sensor is physically smaller give it a lower sharpness when they are both 24 mp sensors? If anything, this would seem to me to speak against the Pentax, since, as you've already pointed out, a lens' sharpness drops off towards the edges of the frame and is best at the centre. The Pentax score is taken from only the centre of the image that the lens produces, with the less sharp edges and corners outside the aps-c sensor borders being ignored, whereas the Sony score includes the less sharp edges and corners of the image.
Forum: Pentax News and Rumors 08-19-2019, 01:58 AM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I think that rather depends on the specifics of the filter system. For example, Lee *claims* that with their 82mm wide angle adapter most people use their 100 system down to 16mm, and they implicitly claim that it will be without vignetting unless you are using more than two slots or adding their CPL on the front. In that case you'd have to zoom to 18mm to avoid vignetting. (Of course, this would not work with the threadless Pentax 15-30mm).

In any case, I've used 100mm filters on the Irix 15mm without significant vignetting using their own filter holder, which is specifically designed to be used with the 15mm (which has a 95mm filter thread) - and it works with other lenses via an adapter ring. That works okay until I want to use a CPL with other filters, then it vignettes. Have you tried Nisi? I'm about to try their system which reportedly does not vignette at 16mm even with a CPL (which cleverly sits inside the filter system attachment ring).
Forum: Pentax News and Rumors 08-17-2019, 11:20 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
Thanks. I was actually looking at Sony's 90mm f2.8 Macro G OSS that is 602g and a somewhat eyewatering CAN$1499. But it is also (I believe) ranked by DxO as the sharpest macro they have ever tested! The weight of such a lens is not actually much of a factor for me since if I'm out to take macro I'm rarely if ever out to take landscape (or vice versa). I have Pentax's more recent 100mm macro and I think it is great. No complaints at all! I'm fairly new to macro photography so it is hard for me to imagine the Sony 90mm macro being better, to be honest. Nevertheless, DxO tested the Pentax 100mm on a K-3 and scored it 10 for sharpness, and the Sony on an a7r2 and gave it 42. On the more comparable (24MP) a7R it still clocked up 36 for sharpness, so it looks like the Sony 90mm macro is some genuinely stunning glass. *Sometimes* the grass actually is greener elsewhere.

A lot of this, for me, just comes down to becoming increasingly fed up with waiting for the lens that I need to get on with doing the photography I want to do in the way that I want to do it. Life is finite and I'm acutely aware that the number of years that I can get to the places I want to get to with a FF camera is also finite. Maybe I'm just not a patient enough person.

I take your point about the bag, of course, and and the overall volume of the gear is not likely to be reduced by much, if at all. I *might* try to opt for a lighter tripod in some cases that would not be a realistic option with my Pentax gear. And none of this would be under realistic consideration were it not that I recently received a bit of a financial windfall. I might well decide to hang on to my Pentax gear, as I really do love shooting with my K-1. Most of you are ecumenical, right? ;)

---------- Post added 08-17-19 at 11:28 PM ----------



Yes, that is another additional weight saving that I was not including in my figures. The Sony 16-35mm has an 82mm filter thread and can be used with my regular filter system without vignetting. It's also much more convenient to have one filter system for all my lens.
Forum: Pentax News and Rumors 08-17-2019, 10:18 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I think that a 70-200mm f4 that was light and compact, as "promised", would keep me in the fold by being just enough to make the gains of jumping ship not worth the (extreme) costs. If the optics were top notch (something that remains an unknown, at this time, although I should say that I've never felt disappointed by any of the D-FA or DA glass I've tried). I've been holding out for one since it was first announced, which must be over a year ago now. It feels much longer. So, to be clear, I'm not at all disgruntled with the quality of what there is - it's great glass and a truly great camera in the K-1. But I have recently come into a sizeable chunk of change that makes jumping ship and getting (for me and my needs) a better set-up, a realistic possibility. Had it not been for that I'd be waiting for as long as it takes.

---------- Post added 08-17-19 at 10:29 PM ----------



I am truly delighted to be corrected on that! That is wonderful news!

I imagine that the Ricoh GR III really helped. It is very much a niche camera and a wonderful one at that. And I'm sure that APS-C Pentaxians likely feel less disgruntled than many full-framers might, there being much more DA glass out there. The less than enthralling update of the K-1 did not help, for me at least, to instil long-term confidence in their full-frame ambitions, either. The K-1ii was a terribly unambitious camera, especially given how Pentax has shown in the past that it can lead the way. So I remain skeptical that Pentax has a long-term future in full frame market if it does not embrace mirrorless.

Still, I'm more confident given that information that Pentax is on to a strategy that could work in the medium term at least, developing for the APS-C and niche markets.

Cheers,
Forum: Pentax News and Rumors 08-16-2019, 05:23 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I'm chasing better, not perfect. I could go with the Sony a7R3 and still have a better system *for my needs* within my current financial limitations.

As for weight savings, it is *not* an illusion. Sony equivalent top-tier FF lenses are almost always lighter when compared with their closest Pentax equivalent, sometimes by a *huge* amount. At lower tiers it is more mixed, I agree, but for an equivalent overall top-tier set-up Sony is definitely lighter (note, I say "lighter", not "light"). Sure, if you compare Pentax with recent and massive mirrorless offerings from Canon and Panasonic, youíd have a great point. But *Iím* considering Pentax specifically in relation to Sony. Iím not saying mirrorless FF lenses are intrinsically or even generally lighter than DSLR equivalents. And it is not just the lenses, of course, it starts with the body. Here are the numbers:

Pentax K-1ii: 925g
Sony a7r4: 665g

Pentax 15-30mm f2.8 D-FA: 1040g
Sony 16-35mm FE f2.8 GM: 680g

Pentax 24-70mm f2.8 D-FA: 787g
Sony FE 24-70mm GM f2.8: 886g

Pentax 28-105mm f3.5-5.6 D-FA: 440g
Sony FE 24-105mm f4 G: 663g

Pentax D-FA* f2.8 70-200mm: 1755g
Sony FE f2.8 GM 70-200mm: 1480g

Pentax 150-450mm: 2000g
Sony FE 100-400mm GM: 1395g

If we just consider the body plus ďholy trinityĒ covering 15mm to 200mm lenses this comes to:

Pentax: 4507g
Sony: 3711g

For me, that is a *hefty* 800g difference, equivalent to, say, one or two primes, depending on focal length, speed, and so on.

And it only gets more significant if I want to extend my telephoto range beyond 200mm or even the 250mm that the superb 60-250m DA* offers (such as for wildlife, say) Ė and I do. For zooms, at least, I need to consider the Pentax 150-450mm. But with that I still have to include the 70-200mm or else I have a gap in the focal range I can natively cover. Even opting for the less than top-tier, but more rangy and still quite excellent D-FA 28-105mm still leaves me with no coverage between 105 and 150mm. So to cover the full focal range with best D-FA glass from 15mm to 450mm I would have to carry 6507g!

With Sony, by contrast, I have the option of swapping out a 24-70mm 2.8 *and* the 70-200mm f2.8 for their 24-105mm f4 (like the Pentax close equivalent, very good if not quite top tier - as a tripod using landscape shooter, the slower aperture doesn't impact me much if at all) together with their 100-400mm GM lens for the full focal range coverage Iím looking for. And that comes to 3403g! That is almost *half* the weight for the relatively small sacrifice of 50mm at the top end (which can be readily compensated for by cropping a little from Sony's higher resolution sensor), 1mm at the low end, and with no loss of image quality - arguably, perhaps, even with a gain in image quality. There was a time when Sony lenses were inferior - that time has past.

Money to one side, I can't see why switching to Sony is not clearly the best option for me and my needs. For others with different needs, it can be a totally different story.
Forum: Pentax News and Rumors 08-16-2019, 04:34 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
I appreciate the response. My point about Pentax's long-term future relates to *market share* rather than absolute sales. Yes. I know mirrorless FF sales are dropping too. But the DSLR drop in sales is proportionately larger, is it not? That is, within the FF market there is a shift towards mirrorless and away from DSLR.

To compete in a significantly shrinking FF market a camera manufacturer needs to move with the wants of its potential customer base - ideally, they should move ahead of it (as I think Sony did, at least judging by their hugely increased market share), but that is obviously not easy to do. The alternative survival strategy is to master a niche market, and perhaps that is what FF DSLR is becoming. So unless you can tell me that Pentax's market share is increasing, I think my point stands. Honestly, I'd love to be shown that I was wrong on this.

I thought I had made it clear enough that I am perfectly aware that my needs do not reflect the needs of everyone else or even most people. If I were studio based, for instance, it would be a whole different story.

---------- Post added 08-16-19 at 04:45 PM ----------



Yes, APS-C is lighter, all else being equal. But all else is not equal. Just as medium format is (all else being equal) heavier than FF and smartphones are a whole lot lighter than APS-C. There is always going to be some degree of compromise between quality of image and weight carried. Where one finds the sweet spot depends on each individual and that is dependent on such things as their age and physical fitness in relation to their photographic interests and goals Ė and there is no universal right or wrong answer. It's all a matter of what burdens we are prepared to (literally) shoulder for the gain we are hoping to achieve.

In my case I have a particular standard of image that I am aiming for and I'm seeking the lightest weight where I can still manage to achieve those goals. And for me, that is at FF. For many years I used just a Ricoh GR when out in the backcountry, which imo packs more image quality into a small and light camera than any other I've used. For the quality of image that I now seek in my landscape photography I need the combination of resolution and dynamic range that FF gives me. I'd take medium format if I had the physical strength and resolve, but for me, that imposes too high of a weight burden (not to mention expense).

---------- Post added 08-16-19 at 04:46 PM ----------



The lens road map said it would be a "Spring 2019" release. And it wasn't. When a manufacturer says something about what they will do and when they will do it Ė which is precisely what a lens roadmap does Ė it sets up a reasonable expectation with their customers about when things will happen. If a lens roadmap is not telling us what they will do and when they will do it, then I have no idea what a lens roadmap is for. It doesn't matter whether it is spoken or a lens map or whatever, so long as it is for public consumption to convey information about future actions. In my idiom, saying to your customers that you will do something at a certain time amounts to a promise that you will do something at a certain time. And when they don't, that counts as a broken promise. But lest this get bogged down in semantics, try to keep in mind that my *point* is that it is very frustrating and annoying, whether we call it a broken promise or not.
Forum: Pentax News and Rumors 08-15-2019, 08:41 PM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
Agreed in most respects. Out of frustration with broken promises ("Spring 2019" release) and the interminable waiting for the 70-200 f4, I bought (and modified for full frame) a DA* 60-250mm f4. And it's a *very* fine piece of glass and I'm *very* happy with the images I'm getting - but - and for me it is a very big "but" - it is definitely *heavy*. I've noticed that I am increasingly leaving it behind when I head up a mountain which, as primarily a landscape photographer, I do rather a lot. If I were studio-based it would be a very different story. My reasons for wanting an f4 70-200mm (rather than the otherwise wonderful f2.8) is precisely the reason I'm finding I'm leaving the 60-250mm behind.

And I have to say that the frustration is now sufficiently great that, together with a bunch of other reasons (not least of which, to be frank, is recently coming into some money) I'm now on the verge of jumping ship for the recently announced Sony a7r4. Who wouldn't want - not necessarily need, of course - a 61 MP full-frame sensor? Or 240MP equivalent pixelshift? The Sony set-up ends up almost a kilo lighter for about the same focal range (the 15-30mm is another lovely lens that is a *very* heavy beast, one that I usually don't take, preferring instead an ultra wide prime and then cropping a little as needed). Sony now offers more options in terms of *modern* lenses than Pentax offers and there is zero sign that that will not just get worse over time. Yes, it cannot be denied that Sony lenses exact a hefty price - even heftier than Pentax's best offerings, which is pretty hefty - but their high-end lenses are at least as good now in terms of IQ as what Pentax has available, if not better. (That's my opinion, anyhow, and somewhat subjective, of course.) What will I miss from my Prentax K-1 if I do indeed jump ship? Ummm - a) astrotracer (though I've rarely used it, to be honest), b) a pretty good menu system, c) ummm.... somewhere for my pinky to rest?

And it's a great shame, because Pentax is a noble brand that has produced top-notch and often innovative gear. Its outright refusal to embrace mirrorless in a shrinking global market can only lead to one end. Sigh - sorry - I'm drifting off topic.

Peace.
Forum: Pentax Camera and Field Accessories 05-30-2019, 01:59 AM  
Do non-Pentax batteries really deliver more shots? (D-Li90)
Posted By Socrateeze
Replies: 26
Views: 1,975
Test results:

I just did a test comparing the Newmowa D-Li90 against the Pentax D-Li90 on my Pentax K-1 under controlled conditions. The former claims 2400 mAh and the Pentax claims 1860 mAh. What I did was run the video (FullHD at 60 fps) on a static scene with maximum brightness of the screen until the battery was depleted (in 25 minute chunks since that is the video limit). Here is what I got:

Newmowa: 104.9 minutes
Pentax: 149.2 minutes

Yep - you get what you pay for! The Pentax gave almost 50% more shooting time compared to Newmowa. 2400 mAh is complete BS.

At least the charger I got with it seems to work a lot faster at charging - roughly half the time of the supplied Pentax charger. However, I'll check tomorrow whether the charger (they charge at different amperages) makes a difference to the stored capacity of the batteries.
Forum: Pentax Camera and Field Accessories 05-20-2019, 06:02 PM  
Do non-Pentax batteries really deliver more shots? (D-Li90)
Posted By Socrateeze
Replies: 26
Views: 1,975
Thank you all for the responses. It's clear that there is warranted skepticism regarding the mAh figures for non-Pentax batteries.

What I will do is conduct a controlled test to see how they compare when fully charged. To be honest I ordered them simply as part of a package with their two-battery simultaneous charger as I sometime have limited time between extended outings into the field with which to recharge my depleted batteries.

Cheers.
Forum: Pentax Camera and Field Accessories 05-19-2019, 02:23 AM  
Do non-Pentax batteries really deliver more shots? (D-Li90)
Posted By Socrateeze
Replies: 26
Views: 1,975
Hi,

I notice that some non-Pentax D-LI90 batteries profess to carry more charge than the Pentax batteries. The Pentax D-LI90 says it carries 1860mAh, but the Newmowa D-LI90 I'm looking at for my K-1 says it carries 2400mAh. Can anyone conform or deny that that translates into more shots per charge?

Cheers.
Forum: Pentax News and Rumors 04-29-2019, 02:55 AM  
New zoom 70-200 F4
Posted By Socrateeze
Replies: 1,071
Views: 81,697
When I say "delay" I am referring to the fact that they had said Spring 2019 in the lens road map, but have recently removed that in the latest iteration. Why remove it if it is not now going to be delayed beyond Spring 2019? Technically, I suppose, Spring 2019 lasts until the Summer Solstice in June, but with not so much as a mock-up sighted or a spec sheet leaked it seems highly unlikely that they will keep to their earlier promise.
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