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Forum: Pentax SLR Lens Discussion
07-12-2023, 05:36 PM
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Is it just because of the wider FOV or the image quality?
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Forum: Pentax SLR Lens Discussion
07-12-2023, 05:35 PM
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How does it compare to the 70/2.4 (on APSC)?
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Forum: Pentax SLR Lens Discussion
07-12-2023, 04:45 PM
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If you were to rank these three lenses in terms of the "special" (pleasing, bokeh, micro contrast, etc.) image they produce, what would it be, in the order of increasing "specialness"? What's special about each lens?
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Forum: Photographic Industry and Professionals
03-10-2023, 09:08 AM
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Most of us seem to be surprised by how quickly prices of used photo gear are falling.
I am in the opposite camp: I am shocked by how slowly those prices are falling.
To me it seems that photographic gear should be depreciating faster than cars and phones, because:
1.these are "wants" and not "needs", unlike cars and phones.
2.it is impossible for an average Joe to asses photographic gear for hidden damage. It is a lot easier to asses a used car ($80 trip to the mechanic), and a lot easier to repair if there is an issue (there are about 10 mechanic shops within walking distance of me. How many camera repair shops are there on the CONTINENT? I am aware of one).
I never pay more than 30% of the original price (that's for mint condition items) for any used photo gear. If there is any issue whatsoever I do not pay more than 20%. Here are more reasons why:
1.When I buy new items with electronics inside, I am already at least 2 generations behind (gear in the upper price range is 1 generation ahead, and the new model that's almost ready for release is 2 generations ahead of what I am ready to buy). "Used" means I am even more behind technologically. Don't tell me old cameras and lenses photograph just as well as the latest model (Pentax AF-C anyone? SDM?); or that it's the biomass behind the viewfinder and not the gear that matters, and even a pinhole can produce masterpieces (I have shot with pinhole. It is amazing what a simple hole can produce. I can also walk pretty amazingly, but that does not replace my car). How much would a phone cost when it is 2 generations behind? At best, 20% of the original price.
2.What about those cameras "with 100 shutter actuations" in "new" condition? My question is "Why did the seller shell out over $1000 and never used it?" Is it because he all of a sudden "lost interest"? Yeah, sure. My suspicion is it is because he dropped the camera and knows that AF/shutter/etc. is likely not working the way it should, and might fail completely at any moment. I do not even consider those.
3.I can neither return the item, nor produce the original receipt for warranty. That must cost something.
4.I am paying for shipping and transaction costs; something that is baked into the retail business model.
5.Photo gear market is very close to a perfect free market, meaning that the primary driving forces are supply and demand. What about the supply and demand? The camera market is rapidly shrinking, meaning there is excess supply and very little demand.
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Forum: Pentax SLR Lens Discussion
04-27-2021, 07:04 AM
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I focused via the viewfinder because this is how I focus while taking shots other than "bills on a wall". I am interested to find out what lens I should use when focal distances overlap.
I was debating this with myself and decided to put all widest apertures into the same pile because when I don't have enough light, I open up the aperture to the widest, whatever it happens to be on that lens. If the aperture is there, it should perform.
Agree, but if a lens fails miserably at sharpness, then nothing else matters.
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Forum: Pentax SLR Lens Discussion
04-27-2021, 06:57 AM
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I have also tested 7 lenses at 50mm (yet to "publish" :)), and 18-55 was the worst performer there.
16mm is why DA16-85 sells so well! This is also why I bought it instead of 20-40 it in the first place.
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Forum: Pentax SLR Lens Discussion
04-27-2021, 06:52 AM
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But FAJ is voted multiple times as the worst Pentax lens ever in another thread, and I have to agree. In my experience, it is a pretty bad lens. I disagree with the whole idea of "sweet spot" of ff lenses on a cropped format. If you take a bad image and blow it up x1.5... I don't see how it may become good.
Yet, it is recommended above 20-40 Limited in another thread for its wide angle. My surprise here is that DA16-85 is doing so badly at the wide end, which is its selling feature. What is the point of a lens with wide angle capability if it does so badly at those FL?
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Forum: Pentax SLR Lens Discussion
04-27-2021, 06:50 AM
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There is a little breathing, but I don't think it affects the outcome. While FL may not be exactly the same, they are very close.
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Forum: Pentax SLR Lens Discussion
04-26-2021, 10:00 PM
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I did! I just have to process the images.
To me, the question is How did it do so well wide-open! It is a cheap kit lens. Here it is against the Sigma and FAJ:
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Forum: Pentax SLR Lens Discussion
04-26-2021, 07:17 PM
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Right, but even DA18-55 (which is a CHEAP lens) outperforms DA16-85.
(I do not understand these EXIFs. These images were saved from Excel.)
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Forum: Pentax SLR Lens Discussion
04-26-2021, 05:53 PM
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I would be glad to upload any combinations of images. Let me know what you would like to see for yourself (there are too many to upload all of them).
Here is and example at 16mm wide open.
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Forum: Pentax SLR Lens Discussion
04-26-2021, 05:39 PM
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I have tested 4 lenses at a wider end with some unexpected results.
Method:
I photographed a banknote in the center of the frame with different lenses at different focal distances. In each shot the banknote has the same size on the sensor (i.e. I moved the camera relative to the subject to keep the image same size on the sensor). The lenses were mounted on a KP, on a tripod, shot with a 2-sec. timer, in DNG. Images were looked at 200% magnification in Lightroom and compared side by side for sharpness, resolution, and contrast. I did no image processing (like sharpening), other than occasional minor exposure correction to compensate for changing lighting conditions. Then they were ranked relative to each other for each FL and each f-stop, i.e. for each stop there were four positions: 1, 2, 3, 4 (higher number = better IQ). Corollary: IQ at different f-stops cannot be compared in terms of absolute quality. At times, it was very hard to tell the difference in IQ and I admit that sometimes difference between adjacent ranks is very subjective. When one looks at extremes end in IQ, the difference is rather obvious.
Lenses tested:
Sigma 10-20mm F4-5.6 EX
Pentax DA 16-85
Pentax FAJ 18-35mm F4-5.6 (the only full-frame lens here)
Pentax DA 18-55mm F3.5-5.6 AL
The lenses were tested at 16mm, 18mm, and 20mm, at f-stop of 4.0 (or whatever the largest f-top is available for that lens), 5.6, and 8.0. Sometimes, a lens had f/3.5, but I plotted it as 4.0.
Results:
---------- Post added 04-26-21 at 05:45 PM ----------
Discussion:
16mm: I was surprised to see Sigma outperform the DA 16-85. Sigma is a budget lens, while DA16-85 is a rather respected lens on this forum.
18mm: Again, Sigma is above all at any f-stop, but an even more surprising result is that wide-open DA16-85 looses to FAJ18-35 and DA18-55, both known as very weak lenses! How come? Any ideas?
20mm: DA16-85 is still struggling a lot. FAJ18-35 is the best at f/8! This is not normal. I must have messed up my test.
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Forum: Video Recording and Processing
03-26-2021, 01:03 PM
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The focusing issues during video recording (using KP in my case) prompt one to use an f-stop with a great DOF. However, DOF for video is probably drastically different from that for stills, since video "resolution" is much lower than photo resolution. When plugging numbers into a DOF calculator, we should probably use a different Circle of Confusion for video. Any idea what it should be? Should one just increase CoC three-fold (6000/1920=3), or is it more involved?
Somewhat related: what DOF calculator are you using? The android DOF calculator that I like does not allow me to select a specific sensor size, but rather lists "Pentax DSLR". I suspect not all "Pentax DSLRs" have the same sensor.
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Forum: Digital Processing, Software, and Printing
03-25-2021, 07:45 AM
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Thank you for the plugin!
I went through my shots and discovered that some of them are tagged appropriately with the lens name. It looks like this worked fine when I was shooting in PEF (and then converted PEF to DNG with Adobe converter; the converted DNG displays the lens), but once I switched to in-camera DNG the lens model stopped being displayed in Lightroom (older lenses are still recorded in DNG). Ironically, I switched to DNG because my Lightroom was not able to read PEFs from KP (even though it has no problem reading PEFs from older cameras).
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Forum: Digital Processing, Software, and Printing
03-25-2021, 06:15 AM
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My Lightroom 4 displays "Unknown" for the lens, but does display focal distance and f-value correctly. This only happens with DA16-85 and DA55-300. The older FA lenses are displayed correctly. I know I have an older Lightroom, but maybe someone knows the fix. Updating Lightroom says "Lightroom is up to date".
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Forum: Pentax SLR Lens Discussion
03-18-2021, 10:32 PM
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I am also thinking that this focal length might be a better fit.
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Forum: Pentax KP
03-17-2021, 06:48 PM
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Then, how do you get PS straight out of camera? I open PS files in Lightroom, and they look identical to non-PS. While, if I "Save As with Image Processing..." with Camera Settings in Camera Digital Utility, I get a file that looks different.
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Forum: Pentax KP
03-17-2021, 05:48 PM
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OOOOOK, so the files do need to be processed outside the camera! It is not obvious at all. I have installed Digital Camera Utility and processed the image of a banknote (without sharpening). I do see the difference now (albeit still somewhat underwhelming). PS image has less noise (that "sharpness" I was talking about before is indeed just noise).
The utility does not have much in terms of sharpening (I have attached a screenshot of its tools). That leaves one with Rawtherapee I guess?
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Forum: Pentax KP
03-15-2021, 04:20 PM
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Maybe I am missing something obvious. Do Pixel Shift images need any processing other than sharpening? I heard that Sony pixel shift needs to be manually processed, but Pentax Pixel Shift is already processed in camera.
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Forum: Pentax KP
03-15-2021, 12:52 PM
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I badly want to see the difference.
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Forum: Pentax KP
03-15-2021, 10:38 AM
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Going through the photos, I have found an area where the PixelShift seems to be sharper, but to be honest this sharpness looks more like noise:
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Forum: Pentax KP
03-15-2021, 10:32 AM
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Thank you for everyone's feedback! I have repeated the test at f4.5, photographing a banknote.
Below are a pair of SOOC photos, followed by a sharpened pair. I still fail to see any meaningful difference.
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Forum: Pentax SLR Lens Discussion
03-14-2021, 07:54 PM
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I have doubt this is a great lens, but the price is getting a little out of control :) I would like to keep it in the $250 budget for a used lens.
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Forum: Pentax SLR Lens Discussion
03-14-2021, 07:47 PM
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Thanks a lot for the link to the comparison! It basically concludes that the three lenses are about the same :)
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Forum: Pentax SLR Lens Discussion
03-14-2021, 07:16 PM
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I would like to get a fast lens for my KP for those situations when it is getting dark, but I am still having am urge to continue shooting without a tripod. I am considering the two lenses above. I like the FA 50/1.4 better because it is faster, but I am eager to learn what others think. I am totally open to other suggestions. The requirements are a fast lens in 24-60mm range, autofocus only.
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