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noone

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  1. I will always have a soft spot for Pentax but they are history and toast.

    Ricoh saved it as a brand from total oblivion and Ricoh is a big enough company that it can exist as a pimple on the arse as long as it does not lose too much money.

    I have had a M42 Spotmatic SLR (still have it and a K mount film camera actually) a couple of other film K mount cameras, an IST*D, K100D and Kx DSLRs and a Pentax Q and loved them all....Thing is that my little Sony RX100 iv is probably better than all of them.

    The K100D and the Q both died prematurely probably because I over stressed the IBIS.

    The Q was a lot of fun and if I came across a cheap one I would buy it in a heartbeat (but not particularly looking).

    Do not forget, Pentax tried the mirrorless APSC route with the K-01 in 2012 but that used the K mount so was very niche in a brand that had already become very niche in itself so maybe 1% of a brand that had about 5% of the market at the time and has gone backwards..

    I would only buy another DSLR IF it was cheap enough, FF and Canon and just to use my existing Canon mount EF AF lenses.

    The only Pentax I would consider is that cheap Q if it hit me in the face in the likes of a pawn shop or charity shop.

    The Pentax 1.7x AF adapter was worth the price of entry to K mount (probably still is for some people).

     

  2. 59 minutes ago, tupp said:

    This should read:  "Once again, I have repeatedly suggested that it is NOT the sensor size itself that produces general differences in format looks..."

    Great so you DO you think the sensor size has nothing to do with any difference so we do agree!   

    Of course if you do not agree with that, you would be able to prove it with science since you cannot prove it with photos (as any differences in photos taken with systems not identically scaled can be explained by difference in the systems.).

     

    Now unless you CAN provide something (ANYTHING) showing how  (often tiny) differences in photos  could not even remotely be explained by differences in the equipment, I think we have gone several pages too far and I am out Really really really this time).

     

  3. Not car racing but i think the same would apply as bike racing and years ago even a little with harness racing  and greyhound racing.

    If possible, I would get on the exit side of a corner and facing them as they come out of it.

    That way they are going slower and it also means you can use a shorter lens, then walk back a bit and do the same with a longer lens like your 600.     Closer to the corner will be almost head on.

    Good luck with it!

    What do you think of the 600?   

  4. 8 hours ago, tupp said:

    Well, I certainly appreciate your thoroughly addressing each one of my points and your giving a reasonable explanation of why you disagree.

     

     

    You mean, do I have any evidence other than all the photos, video links, and references that I have already provided in this thread, which you have largely avoided?

    Sigh!    I do not need to address each point as I disagree with YOUR (no one else its seems) theory that you have shown NO, zero, nil, zilch nix, NOTHING in evidence to support  other than saying there are (often tiny) difference so it MUST be because of the sensor size difference.

    That article explains things pretty well to me and I can not understand how YOU can not understand that ANY difference in a system can explain very tiny differences in photos while at the same time you think those differences are explained by sensor size difference without a shred of evidence why ?

    The fact that this amounts to many many pages of yes, no, yes, no is reason enough to end it now.

    This thread should be locked.

  5. 1 hour ago, tupp said:

    It's not a good read on this at all, as most of the information given is irrelevant.

     

    Furthermore, many of the conclusions of this paper are dubious.

     

     

    How is "sensor quantum efficiency" relevant to optical equivalency?

     

     

    How is "read noise" relevant to optical equivalency?

     

     

    Lens aberrations are absolutely relevant to optical equivalency and DOF/focus.

     

    According to Brian Caldwell, aberrations can affect DOF and lenses for larger formats generally have fewer aberrations.  Hence, the refractive optics of larger formats generally influence DOF differently than lenses for smaller formats.

     

    Keep in mind that the DOF/equivalency formulas do not account for any effects of refractive optical elements, yet optical elements can affect DOF.

     

     

    Again, this property is not really relevant to optical equivalency and DOF/focus.

     

     

    This property is not really relevant to optical equivalency and DOF/focus.

     

     

    Only one of these six factors (aberrations) that you and the paper present are relevant to optical equivalency and DOF/focus.  So, why is this paper quotee/linked?

     

    On the other hand, here is a choice sentence from he paper that immediately follows your excerpt:

     

    There are other similar passages in that paper suggesting differences in image quality between different sized formats.

     

    If the intention of quoting/linking that paper was to assert that it is difficult to get an exact match between two different lenses made by two different manufactures, I  once again direct you to Shane Hurlbut's test in which he compared two different lenses made by two very different manufacturers (Panasonic and Voigtlander), that exactly matched in regards to the softness/bokeh of the background, with only a slight difference in exposure/color.

     

    So, a more exact match can be achieved than what we have seen so far in "equivalency tests."  In addition, we can compare the actual DOF, instead of seeing how closely one can match an arbitrarily soft background set at some arbitrary distance, while relying on lens aperture markings and inaccurate math entries.

    I Disagree!

    Got ANY shred of evidence to support your case?

     

  6. What system?   What focal length would you like?

    Is that the total diameter or just of the aperture? (a 50mm f2 lens has a diameter of 25mm or about 1 inch but that is not taking into account the rest of the lens).

    If it IS just the aperture then easy to work out, just divide the focal length by the f stop regardless of system but be sure to use the ACTUAL focal length and not the equivalent one for smaller sensors (a 50mm f2 lens on a Pentax Q is going to be a super telephoto but on a large format camera it is going to be a wide angle).

    If you mean the total width of the lens, then you would be restricted to progressively smaller systems and ones that are smaller than most system mount diameters. 

     

  7. This is as good a read on this as any.

    https://www.spiedigitallibrary.org/journals/optical-engineering/volume-57/issue-11/110801/Equivalence-theory-for-cross-format-photographic-image-quality-comparisons/10.1117/1.OE.57.11.110801.full?SSO=1

    "Nevertheless, real world IQ differences (including total image noise) will inevitably occur in practice even when equivalent photos are taken. These will arise due to differences in the underlying camera and lens technology, such as:

    • sensor quantum efficiency;

    • read noise;

    • sensor pixel count;

    • lens aberrations;

    • JPEG tone curve; and

    • image processing.

    In other words, since the total light received by each format is the same when equivalent photos are taken, it is factors such as those above that explain real-world cross-format IQ differences rather than format size. These factors will be discussed further in Sec. 4."

  8. 1 hour ago, tupp said:

    It is doubtful that any of the equivalency tests presented so would be accepted by "scientists" as a valid DOF/equivalency comparison.

     

     

    In regards to your claim in this thread that it is impossible to exactly match the focus between two lenses of the same focal length made for the same format from different manufacturers, I have already linked a comparison conducted by Shane Hurlbut in which the focus matches precisely -- much more exactly than any equivalency comparison presented here.

     

    So, we probably can get a significantly closer match in a DOF equivalency test than what we have seen so far.

     

     

    This is false, as exemplified by the Shane Hurlbut test mentioned above.

     

    That might work, especially if one likes to do things the hard way.  Not sure what the point is regarding low element numbers.

     

     

     

    Sorry Tupp but I disagree and that is why there is no point discussing it with me.

    Again, if anyone wants to ask about this, they are MUCH better off asking in a photography science/technology forum.

  9. I love Sony clearzoom.

    The thing is it is VARIABLE so even a very fast prime becomes a 2x zoom with little loss of image quality.

    Most recent (if not all) Sony digital cameras have both clear image zoom and digital zoom (clearzoom is to 2x, digital zoom is to 4x).

    I do not know what (or if) there is a difference between clearzoom and digital zoom at and below 2x.

    Sony cameras give the option of optical only, clear image zoom or digital zoom.

    I usually have my A7s set to be able to use clear image but my RX100iv most of the time is set to optical only.

    Towards 2x clearzoom CAN have that digital zoom look sometimes but it also comes in handy for using smaller format lenses that do not cover FF.

    I have the A7s set so I can use it on the fly and including for video.      Looking for a better remote control that will let me use it (my current cheap remote is not great using it).

    I did not mind ETC on the GX7 but it was not something I used often.

    I think the A7siii does not allow clearzoom in 4k video??  Did I see that?

  10. Just looked at the EXIF for my Sigma 150 2.8 macro in Canon EF mount adapted to my E mount camera and it reports as being an 18-280 3.5-6.3 lens (everything else that matters is correct). 

    I THINK (no evidence either way) it is correcting vignetting slightly.

    Mine is an older first generation A7s so I do not think it corrects as many things as newer cameras but again, that is yet to be confirmed.

  11. 2 hours ago, Jay60p said:

    A few thoughts on this topic:

    1) I would have expected this equivalency theory would have been tested more reliably by still photographers at the numerous

    photography forums long ago. They use a much wider range of format sizes than the video people here at EOSHD.

    If not, it could be there is just too many variables to control, or no consensus on the methods to use.

     

    2)  I would suggest using a 4x5 sheet film camera (8x10 is at $15 a shot!) and limit the test to manual lenses.

    Mount all lenses on a 4x5 lens board and take a 4x5 shot for each, to be scanned for viewing.

    This way the camera does not change, the sensor does not change, no digital transformations are done in camera.

    The different lenses would have different size image circles in the 4x5s, so would be of different resolutions,

    but that should not effect the depth of field comparisons much.

     

    I did look at the SLR primes with the Turbo II speedbooster. It shrinks the first fringing seen, but it includes more of the edges of the

    image circle, with more CA, so overall the fringing looked the same. It really is not a big problem, in video it will never be noticed unless

    you look for it, it's more of a problem in still photos.  I use these SLR primes for stop-motion and time lapse, where you don't want any

    communication with the camera that changes the lens settings.

     

    Here is a review of my favorite Fuji lens that includes comments on the in-camera corrections (CA, vignetting, distortion) for anyone

    unfamiliar with this: https://opticallimits.com/fuji_x/887-fuji1024f4ois?start=1

     

    My question is, what about the third party lenses? Do the mirrorless cameras generally apply in-camera corrections to

    Sigma, Tokina, Tamron, that come in their lens mounts?

     

     

     

     

    1) Equivalence theory HAS been tested and is accepted by the majority of photographers and scientists.      Most accept it even though no one has done an EXACT match (IE the photos LOOK very similar but someone will always point out a tiny difference) to the satisfaction of SOME but the deniers have never shown evidence that it is wrong either.

    The problem in getting an EXACT match is you would have to scale the equipment for an EXACT match and that would be near impossible.       To the point the EASIEST way might be to build from scratch very simple low element number formulas that test this (but may not be great images).

    There ARE science and technology forums on photography on various sites, so much better to ask in those rather than old format warriors on a video forum.

    2) Nah, it would work for me but there will still be tiny system differences (lens formula ETC) that way which again to me would easily explain tiny difference in the photos but not others.

    Remember, focal reducers do not change cameras, they change lenses so everything else still applies (some lenses have been MADE by tacking a focal reducer group onto an otherwise different lens).

    Third party lenses CAN apply corrections but it depends.

    Sony for example opens its mount to other manufacturers and M43 is an open mount too (they have to sign confidentiality agreements.

    Canon and Nikon do not and the likes of Sigma have to reverse design.

    Even my Canon EF lenses on my A7s  report the EXIF but the lenses get recorded as different Sony lenses so it MIGHT be correcting things but doing it as if it is a different lens though it still might be doing it right.

    Then again, most of my Canon lenses are older that need less correction (or none).

    In camera correction is not necessarily a bad thing as it means they can make lenses better in other areas (or cheaper or both).

    My old Canon EF 20-35 2.8 L is probably better corrected than its great great great grandson (the 16-35 2.8 L iii) but the newer lens is a MUCH better lens.     I would love to do a comparison to see how they both go adapted to my Sony but the cost to experiment is far to high.

    Olympus M43 lenses are some of the MOST corrected in camera and yet they are still extremely nice (yet not so long ago the 43 DSLR lenses were made large enough to cover APSC (at least in some cases) and would hardly have needed any correction.

    Sony E probably corrects for vignetting which probably explains why DXO  often shows FF E mount lenses with the F stop and T stop being the same.

  12. Using the .13 crop factor would actually mean it IS very doable to "match"  (enough to satisfy me anyway) with a 600mm f9 (or even f8) 8x10 lens to M43.

    Using .13 instead of .15 as the crop factor, you would need about a 39mm f1.2 lens for the f9 or an f1 lens for the f8. (again though, we do not know what it actually was).

    A 40mm 1.2 would give a close enough photo. but you could even use an existing Kipon 40mm f0.85 (a lens for both M43 and APSC formats) and keep the change!

    Just found that interesting and I would love to see someone do a direct comparison (between an 8x10 camera anyone got a digital back that size with a 600mm f8 lens who also has M43 with a Kipon  40 f0.85?   Great! I look forward to the tests).

  13. Interesting.

    It seems there is disagreement on the crop factor of 8x10 format.

    Some sites say .15x (600mm would be 90mm equivalent) some say .13x (600mm would be 78mm equivalent).   I guess you would never get an exact match due to the different aspect ratios.

    crop factor calculator sites give 78mm though so I am happy to go with 78mm equivalent if it matters as that does not change anything (differences being down to optics, not sensor size)..

  14. 13 hours ago, tupp said:

     600mm 8"x10" lens is more like an 80mm FF lens (or like a 40mm M4/3 lens).

     

    I wrote a very long post replying (and mostly disagreeing) to all your individual points but have just deleted it as there is no point continuing.

    All I will say is this..

     The crop factor to FF for an 8x10 camera is .15 which means it is a 90mm  equivalent lens.

    We do not know what the aperture was for that photo, I do not know if it would be possible to get the same photo (if it was an F9 or f12 lens then YES, it would be POSSIBLE but you would first have to have a lens of the exact same formula and match the crop exactly which no one is going to do ...again, that is WHY I prefer FF, I can get lenses I can not match with M43.   

    It seems to me

    1) We AGREE that there are lenses available for some systems that are not available for others.

    2) You believe there is a difference between formats to the point if anyone ever does do an EXACT scaled match between formats there would still be a difference in the photos. (I do not).

    Happy to reply further if you ever post a test or a link to a test that DOES match system EQUIPMENT exactly.

     

  15. 22 minutes ago, kye said:

    Why, f4 lenses are sharp wide open, that was your criteria.

    People often make the mistake of judging lenses wide open, but the problem is that not all lenses have the same largest aperture.

    Sometimes the best way to get a lens that's sharp at a particular aperture is to get a lens with a wider aperture than your desired one.

    Kye, sometimes f2 and faster are needed for valid reasons.    The OP stated they needed that so that was ALSO a criteria.

    I agree about most (though not all) lenses are better stopped down.    The few exceptions are usually very expensive.

    Often there is a bit of a myth about slower lenses being better than the faster version of same.

    I would always take a good fast lens over a good slow one unless the size became unmanageable.

    I do sometimes wish my very old A mount AF Sigma 180 5.6 macro lens was in Canon mount or Sony E as I would love to use it from time to time due to its small size (though my Sigma 150 2.8 macro is light years better).

  16. I have had a LOT of 50s and near 50s.

    Very few are what I would consider sharp wide open though it is relative and none of the cheaper ones I have had would be.

    MAYBE used on your camera they would be ok as they are not using the worst part of the lenses.

    The best by far for me is the FE Sony Zeiss 55 1.8 which IS sharp wide open but that is no help to you.

    One cheapy that i had and really liked was the Nikon 50 1.8 AF (non D made in Japan version).

    Maybe any of the Nikon 50 1.8s? would be a reasonable combination of cheap/sharp enough?

    IF you could find one in your price range, the FD 50 1.2 L (not the non L) is sharp in the area in focus at 1.2 and it is better stopped down a little so still fast.

    The same with the Pentax 50 1.2 I had though no asperic elements in the Pentax there is in the FD L (those two might be too dear though.

  17. 5 minutes ago, noone said:

     

    my ancient 85 1.2 (again, no 42.5mm f0.65 lenses which is approaching the limit in air). 

     

    A 8x10 camera with a 600mm lens will probably be something like a 600 f9 Nikon. 

    A 600mm 8x10 f9 lens would be equivalent to about a 90mm 1.4 FF (so about a 45mm f0.7 M43).   If you COULD get a lens to match it  (it IS possible even if there are none) it would yield a very similar photo even without being the exact same lens design.If the lens was 600mm f8, then that would be almost impossible to match with m43 as that would be about a 90mm f 1.2 FF so you would need an aprox 45 f0.65 

     

    Too late to edit 1.2 FF is more like f0.60 M43.

  18. 37 minutes ago, tupp said:

    Trying to get the numbers to precisely match the DOF/equivalency formula is a fools errand.

     

    On the other hand, there is nothing wrong with setting up the test with two camera/lens combinations that match as closely as possible, and then merely adjusting the aperture ring on one of the cameras until the two DOF ranges match by eye.  If the adjusted aperture reads a little off from where the DOF/equivalency formula says it should be, simply make a note of that adjustment and include that note in the test report.

    I would think that this point of this exercise was obvilus by now -- to demonstrate similarities and/or differences between optics made for different formats.

    There are tests that got a close enough match with the equipment.  However, they suffered the maladies that afflict most other tests:

    If you do NOT get things to match exactly there will ALWAYS be a small difference that will just leave SOME to say that because there is a difference the theory does not match the practice and THAT is what makes even trying a "fools errand"

    All the tests to date look close enough for me, if they do not for you, that is your problem and you should be doing the tests to match YOUR theory.

    You think the tests get close enough but then when you see a(often very small) difference you attribute that to a difference between formats instead of between the optics.

    There is no reason you would get a difference in vignetting if you used identical formula lenses to match the crop (IE scaled).

     

    As to your 600mm 8x10 above, 

    That is a very different argument and actually plays into the original question and is again the reason WHY FF is necessary to ME.

    I simply can NOT match my ancient 300 2.8 with M43 (other than the $35000 plus Arri 150 1.3) or my ancient 24 1.4 (because there are no 12mm m43 f0.7 lenses) or my ancient 85 1.2 (again, no 42.5mm f0.65 lenses which is approaching the limit in air).   No high quality tilt shift lenses either like my favourite 17 f4.

    If I could do what i can with m43 (or Pentax Q) what i can with FF, I would only be using that.

    A 8x10 camera with a 600mm lens will probably be something like a 600 f9 Nikon. 

    A 600mm 8x10 f9 lens would be equivalent to about a 90mm 1.4 FF (so about a 45mm f0.7 M43).   If you COULD get a lens to match it  (it IS possible even if there are none) it would yield a very similar photo even without being the exact same lens design.

    If the lens was 600mm f8, then that would be almost impossible to match with m43 as that would be about a 90mm f 1.2 FF so you would need an aprox 45 f0.65 to even give a similar if not exact photo.

    You have yet to show that there is ANY difference BECAUSE of the differences in sensor size and so far all difference have been because of the optics and not getting an exact match.

    After all if the Moon astronauts had been just 2% off course, where would they be now?

  19. 11 hours ago, tupp said:

     

    By the way, Caldwell also admitted that refractive optics can affect DOF:

     

    Of course he did.    But if you use the same optics in different formats you get the same result...it is not the format that makes the difference it is the lenses.

    To get an exact match to satisfy everyone, 

    You would need to firstly pick your cameras of different formats and get the EXACT crop factor.

    Next you need a lens for one format.
    You would need to know the actual focal length (not just the marked focal length),
    You would need the  diameter and could then work out the exact f stop.

    Using the crop factor to get an exact match, you would then need to do the same for the second format.

    You will also probably need to have the exact same lens formula though to get the same T stop (and take away any possibility of being a difference for other reasons).

    Yeah, it probably IS possible (maybe even easy for some).

    I could not do it in a lifetime though and again, beyond being a academic exercise, what is the point?

    It would HAVE to be done this way because otherwise some will point out (often tiny) differences but those differences .

    So, unless you (or someone else) does THAT, I will always accept that the theory matches the practice and to date, all tests have satisfied me they do.    

    Are there ANY tests that have been done matching equipment EXACTLY? 

  20. 8 hours ago, hyalinejim said:

     

    This implies that you maintain that there is a look inherent to a format, independent of variations between lenses. If so, it should be consistent as format size changes and it should be describable. How does the look of small format compare to the look of a larger format, at equivalent focal lengths and apertures?

    I'm just interested here, as I use DOF calculators to help my understanding when moving between FF, micro 4/3 and speedboosted micro 4/3. But I also see a huge difference in the images posted, which I would not have expected.

     

    When I use my two different FF 24mm lenses both made by Canon but one EF and the other FD (both quite old though), I can often  see almost as big a difference as between my FD 24 1.4 L and my RX100 iv at 24mm equivalent (actually the EF 20-35 2.8 lens is a closer match usually maybe because it fully passes exif to the camera while the FD adapter is dumb).     As with all of these, the small difference are down to many reasons mostly including the lens design but also the settings are usually not exact (IE one 24mm lens might be 24.5 while another might be 23.8mm).     The numbers to get an exact match between an 8,8mm lens on the RX100 and the 24mm on FF I use are aprox and the crop factors used are aprox.     This is why it would be almost impossible to get an exact match and I doubt even Lens Rentals and their optical bench could get one.    Since I very much doubt you will EVER see an exact match, some people will never accept the theory matches the practice and hence discussion like this are pointless (the why /why not use FF or any other format can be a very valid discussion but not the equivalence is real ones).

    Read the other thread linked to earlier and what Dr Caldwell said (he designed the Metabones SpeedBooster as well as one of the highest performance lenses ever).    

    Back to (trying to) be a spectator.

  21. 11 hours ago, tupp said:

    Have you priced an Alexa 65 lately?

     

    If I had the money to buy an C300/Komodo/Ursa-12K, I'd buy an A7s II with an Irix 15mm lens and a shift adapter and build a copy of Zev Hoover's 8"x10" rig.  I'd deposit rest of the money.

    Buy me a Arri master prime 150 1.3 and an adapter to use it on M43 and I will happily compare it to my ancient lowly Tamron 300 2.8 FF.

    As for the rest, in your reply to me above, I disagree

  22. 10 bit is not something that was available on most cameras until quite recently.

    The Canon R5 has it but only in log so for people likely to be more serious about video.

    The A7C is not aimed at more serious video users.

    The recent Sony cameras that ARE and I would imagine any future Sony cameras that are aimed at serious video users will all have 10 bit (as will everyone else).

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