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Forum: Pentax K-3 III
05-19-2021, 12:25 AM
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Yes. Nobody expects the maths police.
Here we can assume from context that you are using the integers 1 and 3, which are defined with infinite precision. A vertical sensor size stated to be for example 15.5mm is not necessarily defined that precisely. Its likely not 15.50000000mm, but some value between 15.45 and 15.55mm. The pixel pitch stated earlier of 3.76um for example does not fit exactly in 15.5mm. But we have no way to know if that number is precise either.
Definitely. Apologies for that, I can't help it.
I agree with all of that. I was also one of those people stating that the sensor size is slightly different. Not 1.5 to 1.54 different though, the crop factor of the original K-3 was closer to 1.53.
However, I think my point is still valid, especially in cases where a lens has known focus breathing. To restate that point (at the risk of being somewhat obnoxious): you can apply a crop factor of 1.54, or maybe 1.5, but unless you know well how your lens behaves, and what its focal length is as a function of distance, its not that useful. The exact effective focal length will likely be different. But as long as you take the number with a grain of salt and don't expect your 100mm to become 'exactly' 154mm regardless of the circumstances, its fine.
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Forum: Pentax K-3 III
05-17-2021, 02:20 AM
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Looking at the sensor size, the K-3 used to indeed be around 1.53x, but the new sensor is very slightly smaller (if the numbers from imaging-resource are precise), so now the crop factor is very slightly higher.
The crop factor is also not the same for the horizontal and vertical axis for either the K-3 or K-3 mark III btw, which makes determining an accurate crop factor a bit tricky.
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Forum: Lens Clubs
04-09-2020, 11:04 PM
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Well, I have the gear, but not the skill to do either the camera or lens justice. I am enjoying it though, part of the reason I got it is its close up ability, and it does not disappoint.
I shot does image of a rock on one of my first outings with it (it being the zeiss 25mm/2.8)
 [url=https://flic.kr/p/2iGHqeW]
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Forum: Pentax News and Rumors
03-25-2020, 05:01 AM
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This is nothing new right? I'd argue that all lenses without aperture ring could already not be used on a lot of older cameras. Lenses are not always backwards compatible, but cameras are, and pentax keeps doing that. That way we can keep using our (sometimes large) collection of pentax glass, while occasionally updating the camera. Updating a camera once every very many years is a much more financially feasible solution to users than having to change all lenses by changing the mount completely.
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Forum: Lens Clubs
03-14-2020, 06:33 AM
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Hello all, this is not strictly ZK news (but rather ZS news). Fujiya in Japan (a shop in Nakano, Tokyo) is apparently selling off some of their stock. They are currently selling new Zeiss distagon 25/2.8 in ZS mount (M42) including a K&F mount converter of your choice for just under 50000 yen, or 463USD or 416 Euro (today they were out of converters though, but I took that as an excuse to buy the pentax genuine converter instead). As far as I can tell, that is far under even used prices.They won't sell internationally, so if you are not in Japan, you'd have to use one of these intermediate companies to order and ship for you. Maybe it is still worth it? In any case, I'm quite excited to be joining the pentax-zeiss owner club!
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Forum: Pentax News and Rumors
10-27-2019, 02:54 AM
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I agree with the sentiment, and of course everyone would be happier if new lenses would come out faster. I'm personally also not in the market for the new 50/1.4 or 85/1.4, thats simply beyond my budget (plus I want my kit to be at least somewhat portable).
However, the earlier statements: 'this currently looks like blackmail to Pentax users', 'why we have no choice in Pentaxland' and 'I feel that the Pentax far inferior to canikoson' I cannot absolutely not agree with.
The first two are simply objectively false. The situation in no way resembles blackmail. Pentax is not telling us to buy the 50mm/1.4 or it will send pictures of us with a mistress (or the male equivalent) to our spouses. That is an example of what blackmail would be. Also, we do have choice in pentax land. We might not currently have the choice that you want, but thats a completely different statement. The last statement is an opinion, so it might be true for you. Its not true for me. Canon sells nothing that I want. They don't have a K-1 or KP, their cameras are generally not as good at dynamic range or high iso, and their lenses are usually huge. The cameras are also often not as nicely built, and more bulky.
Now if you were to state: the canon lens ecosystem seems superior to the pentax one, I guess quite a few people might agree. But thats not what you said at all.
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Forum: Pentax News and Rumors
01-07-2020, 09:38 PM
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If 'legitimate rhetoric technique' means it can win a debate in some cases (i.e., its an effective technique) than so are most fallacies.
Whether that definition works or not, both ad hominem and fallacies, regardless of efficiency are bad form, and do indeed take away from your own credibility even if the rest of your arguments are convincing.
(To go ad absurdum: if one wants to convince another person to do something they don't want to do, threats of violence or actual violence are an extremely effective technique. That doesnt mean they should be employed)
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Forum: Pentax News and Rumors
10-28-2019, 03:02 AM
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I still think the lens I suggested to you before, the FA* 80-200/2.8, should give you what you want. Its not as compact as a 70-200/4 should be, but judging by the reviews on this site, it is as good as you can expect a zoom to be. Its also a 2.8 lens that goes for a used price in the range I'd expect a new full-frame 70-200 to be, although I'd be happy to be pleasantly surprised.
I'm a prime guy myself, and as far as prime lenses go, there are a lot of old lenses that definitely do match the capabilities of the K-1. With zooms it seems that modern designs do often offer some improvements, but there are a few highly regarded older zooms out there as well.
Maybe I am wrong, but I do not remember pentax promising a complete new range of beginner, intermediate and pro lenses covering all the usual primes and zooms in both f/4 and f/2.8 and f/3.5-5.6 within a few years. The fact that you expected that is not pentax' fault.
Have a look around at what kind of pictures people manage to make with the K-1. Leave out the very expensive lenses, and you'll see that people still manage to make stunning photographs with the K-1.
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Forum: Pentax News and Rumors
12-04-2019, 06:02 AM
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This lens does not compete with the 100mm DFA WR. As far as I understand, it has no focus ring. The distance is set completely by the magnification. The DFA WR can be used for many things, this thing starts where the working range of the DFA ends. The DFA, at its shortest working distance is 1:1 macro. This lens does 1:1 macro as its minimum, up to 5:1 macro. In other words, The biggest you can get something to appear in-frame with the D-FA is the smallest you can get it with this.
Unlike the D-FA, this won't do landscapes, portraits, or studio photography. Only 1:1 and higher magnification macro.
---------- Post added 12-04-2019 at 03:04 PM ----------
I dont see why that depends on in-camera focus stacking. This lens, especially at higher magnifications, will need focus stacking even more than the 100mm, as the depth of field will be smaller. Getting a large depth of field needs focus stacking in either case.
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Forum: Pentax News and Rumors
12-12-2019, 12:52 AM
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Yes, its always a lot easier to build a device with new technology you have not developed and have no in-house experience with than it is to improve existing technology to get better performance. Much easier. For sure. Its like printing money.
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Forum: Pentax News and Rumors
12-02-2019, 03:19 AM
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Some people seem to keep claiming that for the camera to turn up in summer 2020, which has not been confirmed, would be a delay from some earlier possible release date. I don't understand where this comes from. Ricoh / Pentax never stated the camera would come out earlier, as far as I know.
Similarly, while it might come out earlier than June 2020, it could also come out later. If so, people will probably complain about the 'delay' even more. There is no delay as long as the camera does not come out later than an official date. Such a date does not exist.
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Forum: Pentax News and Rumors
11-02-2019, 04:08 AM
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Its not a fact, it's an opinion.
It is a fact there are lenses. It is a fact that according to the opinion of some people, there should be lenses that are not there.
In order for it to be a fact that lenses are lacking, there would have to be a non-opinion standard about what constitutes as a 'lack' in a lens lineup. No such standard exists, its just based on opinion. What some people might perceive as a sparse or lacking lineup is sufficient and complete for others. Hence opinion, not fact. If you were to state: 'some lenses I want cannot be bought new from pentax', that would also be a fact. That does not directly translate to 'the pentax system suffers from a lack of lenses'.
(It might not be interesting, bu in my opinion for example there is no lack of lenses. Of course a modern tilt-shift, magnifying macro and other niche stuff does not (or at least barely) exist. And for some lenses you have to go third-party or used. I also agree that it would make sense for pentax to sell a wide fast prime to complement the astro-tracer, instead of only the rather bulky and expensive 15-30 (FF) and 11-18(APSC). In practice though, I have the samyang 14/2.8 and am unlikely to buy a second massive wide angle lens even if pentax does make one. Its also very unlikely pentax would make one that can compete on price, and they might have decided that there is not much room in the fast ultrawide market due to Samyang and Irix. I'd also like to see something like a 20mm FF lens, but I'd probably anyway prefer the 20mm/2.8 that already exists, because a possible new one is bound to be much larger.)
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Forum: Pentax News and Rumors
10-26-2019, 05:43 AM
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What a strange choice of words to describe a normal situation. With any company, you can only choose to buy the products they actually offer. That is not blackmail in any way, you are no forced to buy anything. And purely because you might not have the specific choices that you want to have, there is plenty of choice in pentax land, including a very highly reviewed pentax FA*80-200/2.8 that goes for less than what the new 70-200/4 will likely cost.
I dont understand these 'I can't get what I personally want right now, and will therefore ignore there are options and there is progress' type of responses.
EDIT: as an addional point: please don't state 'pentax FF users are looking for / want X' without substantial evidence. Not everyone wants the same thing. As an example, I too am a pentax FF user, but I am not looking for any of the lenses you describe. I shoot nearly only primes and have the ones that I need. Some of the lenses I am thinking about buying include the FA limiteds, which accidentally do not exist outside of pentax land.
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Forum: Pentax News and Rumors
10-16-2019, 04:41 AM
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It might be nice, but its not of much use when not having your tripod with you. When I do bring it, I'm happy to use my ballhead at a 90 degree angle. Alternatively I could purchase an L bracket.
I nearly always carry my camera (K-1) with me, but nearly never bring my tripod, so if longer shots are needed, I improvise with whatever happens to be around. Its great that we don't have to be too careful with these cameras due to dust/water proofing and robust build.
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Forum: Pentax News and Rumors
04-11-2019, 07:48 AM
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Doesnt the accelerator chip sit between the sensor and the main processor? I doubt there is anything that can be done in firmware if that is the case. I think in order to make the accelerator switchable, if Ricoh did not intend to do so right from the beginning, probably the entire board needs to be redesigned.
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Forum: Pentax News and Rumors
04-25-2019, 09:39 PM
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A true lower ISO would require that either there is a lower input, or that the sensor has a capability of detecting lower signals than it currently does.
Here is how I understand digital cameras, please tell me where I go wrong: It seems to me that the current base ISO is the 'full' sensitivity of the sensor, ie, it records what it detects in its full single-pixel dynamic range (in case of an 8-bit sensor (for the sake of simplicity), the camera settings will be such that the brightest parts of the scene will register at near-max values (256). For an 8-bit sensor, the lowest values are ~1, and the dynamic range is basically given by this: the contrast between the highest and lowest value.
Now if we increase the ISO, we collect less light/lower values by changing the camera settings, and adjust by amplifying the signal. In doing so, we also amplify noise. Besides, if we use the full sensor range (0-256), we have 256-intensity steps per colour, but if we collect less light (lets say, for example, 128 steps) and amplify by a factor 2 to get back to the same values, we have less information, because we basically only have the even numbers from 0-256. We will have much less nuance in the colours. I don't entirely believe that this explanation is 100% correct, so if someone knows, please tell me.
If we want to do an attenuation step, we have a similar problem. For ISO 50, if our base or native iso of the sensor is 100, we'd have to set the camera up to massively overexpose and then de-amplify all sensor values. We run into a few problems: the sensor clips at maximum value of 256, so everything above is lost. So after de-amplification, if it was for example by a factor 2, there will be no brightnesses in the raw values above 128. Basically we lose the right part of the histogram. For the other values, we have rounding problems: for a deamplification of factor 2, each 2 histogram bins in the original is collapsed into a single bin post deamplification. So I think we should get very poor / no highlight recovery at all, and a hit in dynamic range.
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Forum: Lens Clubs
04-03-2019, 10:04 PM
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Some sakura blossoms, with the D-FA 100mm WR on the K-1, wide open
 sakura |
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Forum: Pentax News and Rumors
04-11-2019, 10:39 PM
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Wouldnt it be best to be in the situation where writing to the card is as fast as / faster than your maximum shooting speed?
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Forum: Pentax K-1 & K-1 II
04-05-2019, 12:40 AM
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Very interesting. I only got into photography much later (about ten years ago), and for me the reason I started with pentax was low-light capability and small cameras (I started with the k-x, which at the time was good in both ways). The reason I stayed and will stay in the foreseeable future, is that I really like the quirky stuff pentax does: IBIS, astrotracer, AA simulator, pixelshift. The low-light capability of the K-5 for astrophotography is still competitive even now. Native compatibility with old manual small metal lenses and weathersealing are a great pro too.
I might not be the typical customer, but for me the fact that pentax lags in AF and video is way less important than the IQ and IBIS-related tricks they implement before anyone else does. If pentax would not be doing these type of innovations nobody else is looking at, and instead make Nikon-like AF, they would lose customers like me. What I would like, though, is a smaller K-1. But I guess that is at least very very difficult, if not impossible.
To get back on topic: I like that this guy is doing pentax videos, but I find it really hard to stomach his style somehow. I don't know what it is. I have no complaints about the contents of the video. Testing the weather sealing of each camera would be nice, but would probably end up being way too expensive for a small channel, we can't really ask for that.
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Forum: Lens Clubs
06-24-2018, 10:39 AM
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Here is another jumping spider. In the bright sunlight there was today, shooting handheld is fine. This was with a reversed pentax-M 28mm/3.5 set to f/8. The light was bright enough to look through the view finder, although it was still pretty dark. I got lucky with the spider resting in place for about 20 seconds.
I used rawTherapee for some postprocessing and a very slight crop.
jumping spider by virtual arjan
I am still looking to show off my high-magnification setup at some point, but I have no idea what to shoot with it. I usually use it to shoot small chips, but they don't make a very good object photographically, and there is no way I'll manage to shoot anything alive with that setup. Any advice?
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Forum: Pentax News and Rumors
11-14-2018, 03:53 PM
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Well, if you optimize it for efficiency (switch off back LCD, use manual lenses, shoot in reduced resolution JPEG-only) you can get far beyond 1500 shots. I used the K-5 as a timelapse device for a while and could shoot about 4000 pictures (give or take 1000) before having to switch the battery. This was of course within a single day, and under very light circumstances for the K-5. But its battery life is really fantastic, I've never had to switch a battery within 600 pictures under any circumstances (I never used built-in flash though, that might matter).
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Forum: Pentax News and Rumors
10-08-2018, 07:33 AM
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Maybe I don't count as a 'photographer', but handheld night photography is certainly something I do*. Besides. for non-handheld photography, dark AF would be convenient for tripod work too. That said, most of my bright lenses are MF anyway.
*I am a single data point, so this doesnt contribute much to the topic, but neither does your rather questionable statement that handheld night photography is not something photographers do a lot.
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Forum: Pentax News and Rumors
10-05-2018, 09:41 AM
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Well, different people have different opinions. I am fine with the weight of the cameras, I think really good build quality and robustness comes with some weight, and a very rigid frame (magnesium and steel are good, carbon fibre and plastics can be strong but are not as rigid) is probably necessary for the IBIS to function.
On the other hand, I'd really like the cameras to be smaller, closer to film-era sizes, which would allow me to carry more things in my backpack. The compactness of Pentax cameras compared to other brands was one of the reasons (together with low-light capability) that made me decide on pentax when I bought my first 'serious' camera.
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Forum: Lens Clubs
06-27-2018, 07:23 PM
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In my case it was indeed partially just the challenge of getting higher magnification, but also the technology I work with is sub-millimeter sized (with the smallest features about 1um), so precisely small enough to need higher-than-normal magnification.
That said, my setup is nothing sophisticated at all, especially compared to some of the experts on this forum.
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Forum: Lens Clubs
05-28-2018, 11:29 AM
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