08-25-2010, 11:29 AM
[quote name='wim' timestamp='1282735243' post='2146']
The not so great results are actually related to the seemingly better results of sensors with lower MPs. I have argued here on Photozone and on other forums as well, BTW, that with larger MP sensors (from about 12-14 MP on APS-C, and about 17 MP on FF) we start getting MTF results very similar to what we used to get back in the analog days. The usual optical laws start applying again, as artificially limited resolution by the AA-filter applies much less, i.e, the 1/total_resolution = 1/1/lens_resolution (for a specific aperture) + 1/medium_resolution (for a specific sensor or film) formula starts working again the way it used to <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt=':o' />.
Essentially this also means we get "normal" curves again, i.e, the centre resolution is quite clearly curved, with a maximum around 2 or 3 stops from the maximum aperture, sometimes 4 stops, and edge and corner resolution staying behind, more or less in a similar curve, often playing catch-up towards the optimum aperture but often not completely reaching the same levels. Only the best, often most expensive lenses, in short to longer tele FLs, may still show a relatively flat MTF, until diffraction hits. Very likely, we will also find that the best lenses perform best at around F/4, where these, as in the past, are diffraction limited, rather than resolution limited (400-450 lp/mm, optically).
Regarding older designs: I do think that for the best lenses, with newer designs, we will find that they perform clearly better in many cases than their 30+ year old counterparts, due to newer design technologies being introduced. You mention the SMC - Pentax-M 20 F/4: I used to own a SMC Pentax 20 F/4, it's predecessor, and that wasn't too great in the corners, for sure. However, when printing no larger than about 20 cm X 30 cm, it was quite acceptable, and there were very few semi-affordable lenses in the early to mid-seventies which had an AoV like these lenses anyway <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />. If I look now at the newly designed TS-E 17, I am really amazed, over and over again, at the incredible IQ this lens provides from corner to corner, but even, f.e., the 17-40L is better wide open than that old SMC Pentax 20 F/4 <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. The Pentax was about 3/4 months of wages back then, the TS-E is about two months of wages for a similar position these days, and the 17-40L a little over half a month <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.
I am afraid that the smaller designs, actually due to design constraints implied by the smaller sizes, could well all be a little less in IQ, and potentially not very cost effective to manufacture by the larger companies, especially when we are talking about primes, or become very expensive at high quality with less features than the OEM lenses. I reckon this is a niche market, and we do see niche players (to some degree) embracing this market, like Voigtländer, and Zeiss wrt to the dslr lens range.
The older lenses you mention, like the 24 F/2.8s of the OEMs, I am sure wil fare no better either. Those are older designs, and manufucatured a little more cheaply, so I'd expect them to perform more or less as they did in the past on film, namely, good, but generally not as good as their primary, professional counter parts (teh F/1.4 versions). The question is whether that is good enough or not. For many it will be. For the "thrill seekers" amongst us the F/2.8s probably are curiosities, and we would probably want better performance in one way or the other, or maybe even all (aperture, resolution, optical characteristics).
Personally, I would love to have another small camera again (I really loved my Pentax ME, ME Super, and MXs), and small lenses including the relatively light weight that comes with that, but I also know I wouldn't want to miss the IQ of modern lenses and modern cameras, AF, electronic aperture control, wide apertures, variable iso in a single package, great low light capabilities, or Live View anymore. So if we could get all of that in a low weight (and affordable) package, I would likely be one of the first ones to get one of those. It would have to be a significant change in weight and size however, and everything else staying the same <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.
Anyway, just my 2c <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.
Kind regards, Wim
[/quote]
I still have hope ... we'll see during the next 5-6 tests on the NEX ... during the next few weeks ...
The not so great results are actually related to the seemingly better results of sensors with lower MPs. I have argued here on Photozone and on other forums as well, BTW, that with larger MP sensors (from about 12-14 MP on APS-C, and about 17 MP on FF) we start getting MTF results very similar to what we used to get back in the analog days. The usual optical laws start applying again, as artificially limited resolution by the AA-filter applies much less, i.e, the 1/total_resolution = 1/1/lens_resolution (for a specific aperture) + 1/medium_resolution (for a specific sensor or film) formula starts working again the way it used to <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt=':o' />.
Essentially this also means we get "normal" curves again, i.e, the centre resolution is quite clearly curved, with a maximum around 2 or 3 stops from the maximum aperture, sometimes 4 stops, and edge and corner resolution staying behind, more or less in a similar curve, often playing catch-up towards the optimum aperture but often not completely reaching the same levels. Only the best, often most expensive lenses, in short to longer tele FLs, may still show a relatively flat MTF, until diffraction hits. Very likely, we will also find that the best lenses perform best at around F/4, where these, as in the past, are diffraction limited, rather than resolution limited (400-450 lp/mm, optically).
Regarding older designs: I do think that for the best lenses, with newer designs, we will find that they perform clearly better in many cases than their 30+ year old counterparts, due to newer design technologies being introduced. You mention the SMC - Pentax-M 20 F/4: I used to own a SMC Pentax 20 F/4, it's predecessor, and that wasn't too great in the corners, for sure. However, when printing no larger than about 20 cm X 30 cm, it was quite acceptable, and there were very few semi-affordable lenses in the early to mid-seventies which had an AoV like these lenses anyway <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />. If I look now at the newly designed TS-E 17, I am really amazed, over and over again, at the incredible IQ this lens provides from corner to corner, but even, f.e., the 17-40L is better wide open than that old SMC Pentax 20 F/4 <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />. The Pentax was about 3/4 months of wages back then, the TS-E is about two months of wages for a similar position these days, and the 17-40L a little over half a month <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />. I am afraid that the smaller designs, actually due to design constraints implied by the smaller sizes, could well all be a little less in IQ, and potentially not very cost effective to manufacture by the larger companies, especially when we are talking about primes, or become very expensive at high quality with less features than the OEM lenses. I reckon this is a niche market, and we do see niche players (to some degree) embracing this market, like Voigtländer, and Zeiss wrt to the dslr lens range.
The older lenses you mention, like the 24 F/2.8s of the OEMs, I am sure wil fare no better either. Those are older designs, and manufucatured a little more cheaply, so I'd expect them to perform more or less as they did in the past on film, namely, good, but generally not as good as their primary, professional counter parts (teh F/1.4 versions). The question is whether that is good enough or not. For many it will be. For the "thrill seekers" amongst us the F/2.8s probably are curiosities, and we would probably want better performance in one way or the other, or maybe even all (aperture, resolution, optical characteristics).
Personally, I would love to have another small camera again (I really loved my Pentax ME, ME Super, and MXs), and small lenses including the relatively light weight that comes with that, but I also know I wouldn't want to miss the IQ of modern lenses and modern cameras, AF, electronic aperture control, wide apertures, variable iso in a single package, great low light capabilities, or Live View anymore. So if we could get all of that in a low weight (and affordable) package, I would likely be one of the first ones to get one of those. It would have to be a significant change in weight and size however, and everything else staying the same <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />.Anyway, just my 2c <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />.Kind regards, Wim
[/quote]
I still have hope ... we'll see during the next 5-6 tests on the NEX ... during the next few weeks ...