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Forum: Pentax K-1 & K-1 II
07-08-2016, 09:04 AM
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:lol: i didn't look at any of the af pics, but given the rhetoric that constantly gets posted by some people on this forum, i suspect that there is more to the dpr discussion than what we are reading in this thread...
the community needs to post up their own *credible* k1 af data.
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Forum: Pentax K-1 & K-1 II
07-08-2016, 08:28 AM
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i've had some epic arguments with rishi, he's a smart guy, and overall he's done more good at dpr than all of the mods/admins put together.
i would suggest that rather than bemoaning the dismal state of affairs at dpr, the pentax community publish their own sets of af tests, using the same criteria that dpr did.
it sounds like a lot of that testing has been done already, just need to present it somewhere.
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Forum: Pentax SLR Lens Discussion
07-07-2016, 05:15 PM
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lol... i suspect that people have already reached the bottom of this discussion, you can't make it any worse.
and no, for the record the ink cost argument isn't very convincing :D
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Forum: Pentax SLR Lens Discussion
07-07-2016, 04:15 PM
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the o.p. didn't mention any specific focal length, so he clearly wasn't asking for a comparison between specific 50mm lenses, like you are doing... stop trying to confuse the intent of the thread with misinterpretations of what it's about.
---------- Post added 07-07-16 at 04:29 PM ----------
:lol: he did state: "I can see a point in the future when I may go FF"
so if equivalence doesn't matter, why did pentax rate the lens for aps-c use? even sony has both a fast 50 and a slow 50 for ff, it's not like a slow 50 should cut into the sales of fast 50's.
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Forum: Pentax SLR Lens Discussion
07-07-2016, 03:58 PM
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i don't think you are trolling, but at this point i'm convinced that english must be a second language for you.
why do you keeping failing to understand the implications of that? stop pretending that sensor size doesn't matter... i'll explain it once again, per the link: " Total Light = Exposure · Effective Sensor Area. The same total amount of light will fall on the sensor for equivalent photos but, for different formats, this will necessarily result in a different exposure on each format, since the same total light distributed over sensors with different areas will result in a lower density of light on the larger sensor."
your claim that "the amount of light per square millimeter is the same" is disingenous, it's not the same with equivalence, because the differences in sensor sizes must be compensated for with differences in exposure.
sure a 50-watt bulb puts out the same amount of light regardless of what size of sensor takes the pic, but that doesn't mean that sensors of different sizes will use the same camera settings to capture the same pic... quite the opposite in fact.
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Forum: Pentax SLR Lens Discussion
07-07-2016, 03:10 PM
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no, it's you who are confused and wrong, despite all the factual link information that's been posted.
correct, no one ever claimed otherwise... what you fail to understand is that it's the effective focal length(aka angle of view) that was proven to change with sensor size... at least othar got that part right, i'm kind of shocked that you don't know better.
don't tell us how p&s cameras have an equivalence rating, then turn around and claim that there is no such thing as an equivalence rating for aps-c cameras... the same exact principles apply in both cases.
totally wrong, you are confusing aperture with exposure... "Aperture is the size of the opening in the lens." Aperture in Photography Defined | explora it's a physical measurement of size, period.
aperture size is like focal length, it can't be changed, but like focal length, the effect of aperture size is altered with sensor size, which you yourself admitted with your correct post on the sensor-sized differences in the onset of diffraction(wrt aperture numbers on the aperture ring).
once again you contradict yourself... a 50mm ff lens on ff is also a 50mm lens on p&s cameras, so why do the manufacturers put equivalence ratings on p&s lenses... hint: it's to prevent people like we have in this thread from getting confused, lol
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Forum: Pentax SLR Lens Discussion
07-07-2016, 08:14 AM
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wrong... you need to read the link i posted.
---------- Post added 07-07-16 at 08:41 AM ----------
i agree that the lens itself doesn't change, but the effect is not the same, as you admitted, the fov is different, and i'm here to tell you that the aperture numbers on the aperture ring are therefore also effectively wrong.
you claim no disadvantage, then admit that there is a difference, and argue semantics about what the word "disadvantage" really means.
if you want to claim that everything being wrong is not a disadvantage, you are certainly welcome to your opinion... i do agree that with ff lenses on crop, we get used to everything being wrong, but my point is, lets not lose sight of what the truth really is.
that's another contradiction, and it's not correct because the total light falling on different sensor sizes is different... you can't have it both ways... "Saying "f/2 = f/2 = f/2" is like saying "50mm = 50mm = 50mm". Just as the effect of 50mm is not the same on different formats, the effect of f/2 is not the same on different formats... Total Light = Exposure x Effective Sensor Area, and it is the total amount of light falling on the sensor, as opposed to the exposure, which is the relevant measure."
that's why the aperture numbers are wrong.
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Forum: Pentax SLR Lens Discussion
07-06-2016, 06:28 PM
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that's what i gave him, disadvantages with putting ff glass on a crop sensor... 1)the focal length is wrong, 2)the aperture numbers are wrong, 3)the point of visible diffraction doesn't match the aperture number, etc.
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Forum: Pentax Full Frame
07-06-2016, 02:47 PM
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the field curvature characteristics are displayed in the photos, so it's best seen on a comparison basis with other lenses of similar focal lengths... here is an explanation of sorts: photo technique magazine » Field Curvature
it can get complicated with lenses that have a donut-shaped focus field(aka wavy field curvature), wherein the far edges and the center 1/3rd are the sharpest parts of the picture.
i think that he was referring to this: "Pentax also implemented a built-in flower shaped hood which cannot be removed"
Pentax SMC-FA 31mm f/1.8 AL Limited - Review / Test Report |
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Forum: Pentax SLR Lens Discussion
07-06-2016, 02:32 PM
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no need for equivalence? gee, maybe you'd better email cambridge in colour and tell them that their calculator is all wrong.
in a word, no: "Neither the focal length nor the f-ratio of a lens change as a function of sensor (for example, a 50mm f/1.4 lens is a 50mm f/1.4 lens, regardless of the sensor behind the lens). However, the effect of both the focal length and the f-ratio on the visual properties of the photo very much depend on the sensor, and scale in direct proportion to the size of the sensor.
25mm f/1.4 on mFT (4/3) is equivalent to 31mm f/1.8 on 1.6x (Canon APS-C), 33mm f/1.9 on 1.5x (APS-C for everyone else), and 50mm f/2.8 on FF (FX), where "equivalent to" means:"
Equivalence |
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Forum: Pentax SLR Lens Discussion
07-05-2016, 06:30 PM
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the only true comparisons are at an equivalent field of view, dof, distance, etc., so yes, you chop out edge weaknesses with a ff lens on crop, but what happens to edge quality with the equivalent lens on crop?
if 28mm ff shot at f/2 = 18mm crop shot at f/1.3 Digital Camera Sensor Sizes: How it Influences Your Photography
which lens is going to be the hardest and most expensive to design? forget the difficulty of 18mm at a fast f/1.3 aperture, keep it simple, which lens will generally have the least amount of distortion?
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Forum: Pentax SLR Lens Discussion
07-05-2016, 11:08 AM
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that was interesting, thx for the link... wish that he would have used a 36mp camera instead of a 16mp camera for the landscape pics.
---------- Post added 07-05-16 at 11:10 AM ----------
lol... he didn't provide any evidence either way, but it would be interesting to see how they all compare.
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Forum: Digital Processing, Software, and Printing
07-03-2016, 05:31 PM
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costco for 20x30 is the best option, by far, you can proof the images on your monitor using the downloadable printer profiles, as was mentioned earlier, and also print smaller size test pics beforehand, to verify the processing.
unfortunately 20x30 is the biggest size they have, and even their lustre paper is pretty reflective.
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Forum: Pentax SLR Lens Discussion
07-02-2016, 12:18 PM
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exactly... in both shots of the cat sitting on the patio, the grass two feet in front of the cat is clearly in better focus, than the area next to where the cat is sitting.
why is it that no one else on this forum can see what we see in those pics? it's really obvious.
the o.p. could easily trim the af point compensation in the camera, using those pics at 100% view in the lcd, as the determining factor.
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Forum: Pentax SLR Lens Discussion
07-01-2016, 10:01 AM
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make sure to evaluate the sharpness using live view for focusing, not af.
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Forum: Pentax Full Frame
07-01-2016, 09:55 AM
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filters would be a problem, and i don't recall seeing anyone post solutions for it.
i think that pentax owners are a bit spoiled when it comes to legacy glass for landscape shooting, because it leads one to believe that canikon/minolta/konica/oly/etc. made just as many lenses that had just as good field curvature characteristics, but that's actually not the case.
minolta slow 28mm lenses all suck, their legacy 35mm primes are nice mechanically, but have mild wavy field curvature and weak corners... i've had four oly wides, all but one were decentered, and the good 28/3.5 that i just got has weak corners that never fully clean up... etc.
fa31 looks like it does a lot of things really well, i think that it's overpriced only because modern technology has created some incredible alternatives, many of which are not available in k-mount.
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Forum: Pentax SLR Lens Discussion
07-01-2016, 09:15 AM
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i like those action photos: Photos of "Power and Speed". I love my K-1!: Pentax SLR Talk Forum: Digital Photography Review
sony owners get the same b.s. comments about shooting action... you can't do this, you can't do that, it's only good for landscapes, blah blah :confused:
when someone starts whining like that, it just proves that they don't know how to use a camera.
---------- Post added 07-01-16 at 09:21 AM ----------
lol... it's star wars technology! :D
if they can turn out better q.c. than what samyang is offering, those lenses could be a real home run.
i thought that it was ironic that here we are in a thread about no 3rd party glass for pentax, when in fact it's sony that's getting the cold shoulder with these lenses, not pentax.
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Forum: Pentax SLR Lens Discussion
06-30-2016, 09:15 PM
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they are offering it in canikon and pentax mounts so far, but not sony.
made in korea tho, i wonder if it's just a rehashed samyang.
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Forum: Pentax Full Frame
06-30-2016, 09:22 AM
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Forum: Pentax K-1 & K-1 II
06-29-2016, 02:12 PM
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lol... if i added all of the time i wasted watching his videos, my rebate request would probably be rejected :D
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Forum: Pentax K-1 & K-1 II
06-29-2016, 09:58 AM
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10 minutes of my life that i'll never get back, lol
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Forum: Pentax SLR Lens Discussion
06-29-2016, 09:42 AM
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Forum: General Photography
06-29-2016, 09:13 AM
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Forum: Pentax SLR Lens Discussion
06-29-2016, 08:45 AM
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if everything is functional, that nikon package will easily pay for the whole batch, well done.
fwiw, there are some threads about nikon glass on pentax bodies, it would interesting to see how it compares to the a50/1.4 you got.
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Forum: Pentax SLR Lens Discussion
06-29-2016, 08:36 AM
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i've had some great experiences there also, i think the key is to identify the sellers who know how to look at lenses... sometimes they will say that the blades work, no fungus, etc... one of the oregon sellers knows camera lenses, and the prices that his store gets reflect that.
some of the sellers there don't know anything, one time i got a minolta 50/1.4 that had all of the aperture blades rusted together :confused: tore it down, cleaned it up, replaced the blades, turned out well.
when dealing with legacy glass, being able to do rudimentary disassembly and cleaning can make a huge difference.
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