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03-26-2020, 01:54 PM   #46
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QuoteOriginally posted by Wildbunch Quote
Exactly, especially at 210mm the difference is high. And this is visible in the sample shots as well, the picture (@210mm F4) of the lock on the fence is very soft.
There have been times when I've noticed their sample photos are of sub-optimal quality, e.g. using too slow of a shutter speed for moving subjects. The shutter speed for the photo of the lock is 1/100s, so it could be too slow for critical sharpness, or there is shutter-shock involved... or the sharpness of the lens @ 210mm is closer to "poor" than "very good".

03-26-2020, 02:00 PM - 1 Like   #47
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QuoteOriginally posted by luftfluss Quote
Less-than-expected sharpness plus greater-than-expected CA usually leads me to suspect a very slightly misaligned element, or subtle focusing error.
I suspect the former. I am wondering if manufacture without the VC stuff has resulted in assembly challenges not present for the Tamron version.


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03-26-2020, 06:53 PM   #48
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QuoteOriginally posted by luftfluss Quote
It is interesting that Ephotozine measures the sharpness of the Tamron 70-210/4 on the 36MP Nikon D810 as being higher than the new Pentax 70-210/4 and the DFA* 70-200/2.8, both of which were attached to a K-1 (36MP).

Both Pentax models also had a greater amount of CA.

Pentax has always been lower than Nikon with the same lens and sensor than Nikon. But CA can be an indication of a misaligned lens, That could be an issue. Personally I suspect Pentax thinks about other factors besides absolute resolution. Regardless of the test chart scores, Pentax images do very well on DxO and other places that look at finished images after processing. even at sites like optimal limits Pentax bodies typically produce weaker results with the same lens on absolute sharpness scores, I've shown that folks can't tell the difference for the most part between K-1 and K3 images, with a difference of 8 MP and a resolution difference of around 800 lw/ph. So the 2 or 3 hundred lw/ph difference between Pentax and Nikon doesn't impress me as a terribly meaningful factor.

Last edited by normhead; 03-27-2020 at 05:29 AM.
03-27-2020, 08:11 AM   #49
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QuoteOriginally posted by stevebrot Quote
I suspect the former. I am wondering if manufacture without the VC stuff has resulted in assembly challenges not present for the Tamron version.


Steve
I would assume VC adds complexity and increases tolerances, not reduces them... ?

03-27-2020, 08:40 AM   #50
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QuoteOriginally posted by normhead Quote
Pentax has always been lower than Nikon with the same lens and sensor than Nikon. But CA can be an indication of a misaligned lens, That could be an issue. Personally I suspect Pentax thinks about other factors besides absolute resolution. Regardless of the test chart scores, Pentax images do very well on DxO and other places that look at finished images after processing. even at sites like optimal limits Pentax bodies typically produce weaker results with the same lens on absolute sharpness scores, I've shown that folks can't tell the difference for the most part between K-1 and K3 images, with a difference of 8 MP and a resolution difference of around 800 lw/ph. So the 2 or 3 hundred lw/ph difference between Pentax and Nikon doesn't impress me as a terribly meaningful factor.
Re: Pentax lower resolution scores, I know that to be true when comparing the K-5 vs Nikon D7000, because the K-5 reportedly has a slightly stronger AA filter, but now that we're dealing with filterless sensors that shouldn't be an issue.

I agree with you that the slight differences in scores is not "terribly meaningful", but it does pique my interest, especially because various sites (like DPR) note that the K-1's sensor is at the top of the class for resolving details. Also, the CA performance is odd. In fact, I took a quick stroll through Ephotozine's lens reviews where the K-1 was used, and found that CA scores were generally a bit higher than similar lenses tested on similar cameras, in addition to the resolution figures being a bit lower.

Lenses tested on the K-3, like the DA 16-85 and DFA 150-450, performed superbly.
03-27-2020, 10:57 AM   #51
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QuoteOriginally posted by bdery Quote
That 14g is almost assuredly the mount, nothing more. To use this to conclude that they are different lenses is, shall we say, a bit easy...
Not quite : this diagram shows that basically the magnets and the black pieces do add up to non stabilized lens.

03-28-2020, 04:33 AM   #52
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QuoteOriginally posted by tibbitts Quote
I would assume VC adds complexity and increases tolerances, not reduces them... ?
What replaces the mechanism for the moving component and its mount would determine that. The simplest way to deal with it would be to remove the drive controller and fix the mechanism at the central position. The ideal way would be to manufacture a new mount. I have no idea which Ricoh opted for, but if I were the design lead, I'd be proposing the latter. On the other hand, the former may even be the cheaper option, given that Tamron would be making far more of its own branded lens, than Ricoh would be making Pentax-branded versions.

03-28-2020, 11:06 AM   #53
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QuoteOriginally posted by normhead Quote
So the 2 or 3 hundred lw/ph difference between Pentax and Nikon doesn't impress me as a terribly meaningful factor.
Yes, the differences are insignificant. You wouldn't notice them in the gestalt of looking at an entire image. I'm wondering if these slight differences in resolution at long distances at the long end of the lens might be a consequence of Pentax's attempt to tweak the Tamron lens so that it renders better. Could it be that in an attempt to make the lens render in a more Pentax way a bit of resolution has been lost at longer distances? In my experience, my non-Pentax lenses do tend to be a little sharper at longer distances than my Pentax glass.

I was looking at some of the images over at ephotozine taken with this lens and they had one image of duck that was reasonably sharp, but featured a nicely rendered beak — very life-like and tactile. Maybe the Tamron wouild render that beak just as well, but without a comparison shot, how do we know? Pictures of distant cell towers and roofs and other trivial objects only provide a partial glimpse of what a lens can do. I want to see the kind of images I would use the lens for, were I to acquire it. Only then could I determine whether the lens is up to snuff.
03-28-2020, 11:50 AM - 1 Like   #54
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QuoteOriginally posted by northcoastgreg Quote
Yes, the differences are insignificant. You wouldn't notice them in the gestalt of looking at an entire image. I'm wondering if these slight differences in resolution at long distances at the long end of the lens might be a consequence of Pentax's attempt to tweak the Tamron lens so that it renders better. Could it be that in an attempt to make the lens render in a more Pentax way a bit of resolution has been lost at longer distances? In my experience, my non-Pentax lenses do tend to be a little sharper at longer distances than my Pentax glass.

I was looking at some of the images over at ephotozine taken with this lens and they had one image of duck that was reasonably sharp, but featured a nicely rendered beak — very life-like and tactile. Maybe the Tamron wouild render that beak just as well, but without a comparison shot, how do we know? Pictures of distant cell towers and roofs and other trivial objects only provide a partial glimpse of what a lens can do. I want to see the kind of images I would use the lens for, were I to acquire it. Only then could I determine whether the lens is up to snuff.
I once downloaded files from Imagine Resources in a "discussion"with the famous Ian over the meaning of the 150 lw/ph between a 24 MP K-3, and a 24 MP D500. Even pixel peeping you had to believe there was a difference to see it. There as a little bit of teeny tiny barely noticeable fuzz that if you squinted really hard even pixel peeping looked little bit softer. To him it was a significant difference making it worth his while to buying a D500. To me it was barely visible if you were sitting in the right spot, looking directly at a particular part of the image and would have been easy to overlook if you weren't engaged in a stupid argument, oops I mean discussion. Pixel peeping a K-3 is the same as looking at a 60 inch print done at a real 109 dpi on my computer.

It made practically no difference even at 60 inches across. So it doesn't even have to be when looking at the entire image. Even pixel peeping it makes no practical difference. Unless you have specific part of the image that is too small to be resolved by 2700 lw/ph yet large enough to be resolved by 2850 /lw/ph, with in this case was some print black on white, and the odds of that happening are probably somewhere in the order of 5% (a lot less if you conser that not every part of photo must be razor sharp to be enjoyed) and the lack of detail was not noticeable on feathers, cloth swatches etc. anything but very fine printing. And IR were set studio shots they put every camera through. Your odds of producing two shots in real life that were in any way different would be remarkably low unless you used the worst lens you own. I have an FA 28-200 and an FAJ 18-35 that would be soft reproduced at 60 inch that reproduced at 36 inches would be absolutely as good as my best lens.

After about 2000 lw/ph, improvements in lw/ph are pretty much for bragging rights, 99.9% of the time. Case in point a Nikon D800 shooting buddy who was dead certain he was getting better images than me with my K-3. He was terribly disappointed, and pulled the famous, "my pictures are better but you have better PP skills than I do " excuse. I thought "If you don't have good PP skills why would you even pay for a D800 and shoot raw. Shoot jpeg man." But he was already hurting... why rub it in?
And he had enough money he could buy whatever he wanted.

Next time out his camera broke 4 days into a 7 day trip and he ended up shooting the rest of the trip with a point and shoot he borrowed from his daughter.

Shooting landscape and pixel peeping Tess and I can't tell the difference between her k-5 and my K-1, same shot, same lens (DFA 28-105) same tripod set up, adjusted for field of view. When I bought the K-1 I was set to tell the world about the huge difference 36 MP makes. Spurred on from years of promotion by jsherman and other D800 shooters. I ended up feeling a little foolish.... but I'm over it now.
I still love my K-1 and am happy to use it for the 2%-3% of the images where it might make a difference. Not a real world difference but a pixel peeping difference, if you can actually find that spot in the photo where it shows up because it won't be every where. Comparing Tess' K-5 and my K-1 I've never actually found such a place, but like other K-1 users, I have to believe it's there somewhere if I look long enough.

Last edited by normhead; 03-28-2020 at 12:09 PM.
03-28-2020, 12:13 PM   #55
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slow write / small clipboard / unreliable accompanying auto focus / rebranded lenses / lenses that still lag behind the canikon series of the same series and in focusing speed and optical quality overall / smaller choice and photo bodies and photo lens / poor third party support both in lenses and lighting, please where, then, is Pentax in the photo world of serious players versus canikosony conglomerates, Pentax turns out to be some exotic that few people play with and send on, and is now owned by Ricoh, e.g. it is issued in small doses / quantities, a little better and a little more expensive but far from the leadership in both photographic and lenses-unspecified exotics, it is not clear to me how each time the reviewers would get the wrong copy for comparison with the competition, reading this forum concludes that "everyone praises your horse" ie Pentax lens is good only if the review is by a forum member or "purebred" pentaxianer, some random reviewers always get a bad copy, this Ephotozine review for DFA70-210 / 4 is nice to read but I don't know if yes i believe her completely the same as those who say Tamron original is better than Pentax packing same optical formula, i have been using Pentax photo equipment as an amateur for 13 years i enjoy it and i am satisfied because i can afford it and have never used anything else (except Ricoh KR-10super and 14 years ago some sony dsc h.. with original wide angle and telefoto conversion), at the end where then is the pentax DFA 70-210 / 4 ED SDM WR compared to the canon / nikonon / sony same lens, not for the money but specifically for optical and autofocus quality only

Last edited by mbukal; 03-28-2020 at 05:05 PM.
03-28-2020, 12:23 PM   #56
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QuoteOriginally posted by normhead Quote
I once downloaded files from Imagine Resources in a "discussion"with the famous Ian over the meaning of the 150 lw/ph between a 24 MP K-3, and a 24 MP D500.
I hope you are not talking about me, I don't think I am famous thou I might be infamous. Its a good thing you bring this up as the D500 is 20 mp not 24.

QuoteOriginally posted by normhead Quote
Even pixel peeping you had to believe there was a difference to see it. There as a little bit of teeny tiny barely noticeable fuzz that if you squinted really hard even pixel peeping looked little bit softer.
I am glad you bring this up at this is the very thing that many Nikon users have said that the difference you see in between 24mp and 20 mp is barely noticeable.

And this is they very same for me with the small difference we see in between a 16mp crop and a 24mp crop, I am much more interested in the flexibility a 36mp FF camera has over a cropped 24mp camera and this is even more true when you are not FL limited.
03-28-2020, 01:08 PM   #57
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QuoteOriginally posted by Ian Stuart Forsyth Quote
I hope you are not talking about me, I don't think I am famous thou I might be infamous. Its a good thing you bring this up as the D500 is 20 mp not 24.



I am glad you bring this up at this is the very thing that many Nikon users have said that the difference you see in between 24mp and 20 mp is barely noticeable.

And this is they very same for me with the small difference we see in between a 16mp crop and a 24mp crop, I am much more interested in the flexibility a 36mp FF camera has over a cropped 24mp camera and this is even more true when you are not FL limited.
I agree there, with 36 mp, you don't have to go through the thing where you crop exactly to your desired framing. With 36 MP you can get close, shot slightly wider than you need and then crop. On a crop in the studio where everything is set up exactly may be different from in the filed, where you may have to grab an opportunity and crop later.
03-29-2020, 06:40 AM   #58
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QuoteOriginally posted by stevebrot Quote
If, indeed, one can actually get a D850 + Tamron 70-210/4 combo for about the same price as a K-1ii + D FA 70-210/4 and one only needs a FF body and that lens. However...B&H says $3595.95 vs. $2775.95 -- advantage Pentax.


Steve
Hi Steve,

Here in Europe the D850 + Tamron 70-210/4 is basically the same price as a K-1ii + D FA 70-210/4 both for around 3000$

More than that, as you can also save on other lenses and accessories in case of D850 of which some are superior optical quality (lenses with11blades vs 9 blades etc)

I really like the K-1 however which is on sale right now too...

The Pentax lenses often have lots (more) of CA, of course curable in post processing , but...
This new 70-210 Pentax lens is very weak at the long end so for me no point of buying it if 200mm is hardly usable.
Better to buy other lens covering that focal range...

Another great option is new Panasonic S1R which is on sale now for about 3500$ together with 24-105 F4 Lens (very good optically) plus original grip and battery included..
Its high res mode is the best in my opinion in most situations, as well as dual image stabilization is great too.
03-29-2020, 07:19 AM   #59
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QuoteOriginally posted by luftfluss Quote
I did a quick look through the Ephotozine site and didn't find an explanation of their testing methodology. How are tested lenses focused?
Autofocus in live view.
For Pentax, they might use outoffocus in live view.
03-29-2020, 07:25 AM   #60
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QuoteOriginally posted by PentaxBro Quote
Here in Europe the D850 + Tamron 70-210/4 is basically the same price as a K-1ii + D FA 70-210/4 both for around 3000$
I note a difference of GBP £126 (currently USD $157) between both combos, here in the UK, the Nikon option being the more expensive one. It's a less compelling price difference advantage for Pentax than in the USA and Australasia - though of course the Pentax 70-210 is still currently selling at release price, being such a new lens. That price will come down.

For those in the UK and Europe who aren't already committed to the Pentax K-mount platform for a variety of valid reasons, the D850 plus Tamron represents excellent value, when considered as a combo in isolation. But you have to look at the overall cost of system ownership. No-one is going to buy just the camera and that one lens. Furthermore, folks who shoot Pentax do so mostly because they want to. As such, even if the D850 plus Tamron is a good option, it won't be for them - because it's a Nikon.

QuoteOriginally posted by PentaxBro Quote
The Pentax lenses often have lots (more) of CA, of course curable in post processing , but...
With respect, I consider that an exaggeration.

QuoteOriginally posted by PentaxBro Quote
This new 70-210 Pentax lens is very weak at the long end so for me no point of buying it if 200mm is hardly usable.
Better to buy other lens covering that focal range...
That's not been the experience of our members thus far.

QuoteOriginally posted by PentaxBro Quote
Another great option is new Panasonic S1R which is on sale now for about 3500$ together with 24-105 F4 Lens (very good optically) plus original grip and battery included..
Its high res mode is the best in my opinion in most situations, as well as dual image stabilization is great too.
It sounds like you're going to be better off with the Nikon or Panasonic, and their respective user forums...
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