colonel Posted September 9, 2015 Share #121 Posted September 9, 2015 Advertisement (gone after registration) It has been demonstrated, for instance by lensrentals optical bench tests, that a lens designed for the thick sensor glass of the A7 performs slightly worse without the glass, while lenses designed for film will perform noticeably worse with the thick cover glass. That is probably because the digital lenses have less severe angles of incidence which improve performance on digital but do not affect film. On the other hand, digital lenses are designed with a negative astigmatism in the corners to counteract positive astigmatism caused by the sensor glass. This inevitably affects performance on film or sensors with thinner glass. Yes, best to use lenses on the system they were designed for. That's my mantra anyway ..... Link to post Share on other sites More sharing options...
Advertisement Posted September 9, 2015 Posted September 9, 2015 Hi colonel, Take a look here Leica's organic rendering versus plasticized Sony 7RII. I'm sure you'll find what you were looking for!
viramati Posted September 9, 2015 Share #122 Posted September 9, 2015 Having sold my M I now have the Leica Q, A7rII and A7s. Of the Sony's I find the 'nicest' files come form the A7s those large pixels just seem to perform in a really film way like especially as the iso goes up, they convert beautifully to B&W and to my eye just have a special look. I even find large prints not to be problem due to the film like quality of any 'grain' present. The A7rII is a technological marvel but after a month or so of sitting idly in the safe the A7s is back out again and getting used, I just love it as a camera. The Leica Q has truly superb files but that is a whole different story. Link to post Share on other sites More sharing options...
jaapv Posted September 9, 2015 Share #123 Posted September 9, 2015 Yes, best to use lenses on the system they were designed for. That's my mantra anyway ..... You have a problem then - since Peter Karbe says his lenses are designed to work as well on film as they do on a sensor... Link to post Share on other sites More sharing options...
ravinj Posted September 9, 2015 Share #124 Posted September 9, 2015 Did Peter Karbe also say that his lenses will work fine on SonyA7 series? Link to post Share on other sites More sharing options...
jaapv Posted September 9, 2015 Share #125 Posted September 9, 2015 What do you think? Link to post Share on other sites More sharing options...
tgm Posted September 9, 2015 Share #126 Posted September 9, 2015 What do you think? have a look : http://diglloyd.com/prem/s/LEICA/LeicaM9/lens-ZeissZM-35f1_4-MTF-mirrorless.html?dglyPT=true it is just a question of optics or physics, if you put a piece of glass between the lens and film or sensor, whatever it is, it has an effect at least for large angles. It is not a question of competence of the optics disigner Link to post Share on other sites More sharing options...
ravinj Posted September 9, 2015 Share #127 Posted September 9, 2015 Advertisement (gone after registration) I think Leica lenses suck. What do you think? Link to post Share on other sites More sharing options...
CheshireCat Posted September 9, 2015 Share #128 Posted September 9, 2015 I think Leica lenses suck. What do you think? Oops.. "ravinj" blew his cover. Kazuo has already been informed. Run, man. Ruuun ! Link to post Share on other sites More sharing options...
CheshireCat Posted September 9, 2015 Share #129 Posted September 9, 2015 Let me fix that for you, once again: You have a problem then - since Peter Karbe says his lenses are designed to work as well on film as they do on a sensor that must be specially designed to emulate film, and barely can... But keep trying ! That's fun Link to post Share on other sites More sharing options...
jaapv Posted September 9, 2015 Share #130 Posted September 9, 2015 I guess you didn't read the interview? Mr. Karbe knows less about lens design than you do? Trying what? Twist words? I leave that to you... Link to post Share on other sites More sharing options...
jaapv Posted September 9, 2015 Share #131 Posted September 9, 2015 have a look : http://diglloyd.com/prem/s/LEICA/LeicaM9/lens-ZeissZM-35f1_4-MTF-mirrorless.html?dglyPT=true it is just a question of optics or physics, if you put a piece of glass between the lens and film or sensor, whatever it is, it has an effect at least for large angles. It is not a question of competence of the optics disigner Digiloyd? Hmmm... Link to post Share on other sites More sharing options...
CheshireCat Posted September 10, 2015 Share #132 Posted September 10, 2015 I guess you didn't read the interview? Mr. Karbe knows less about lens design than you do? Trying what? Twist words? I leave that to you... Mr. Karbe knows much more than I do. For this reason, if he said something similar, he must have been talking about the very special sensors in digital M cameras. At this point, a citation of the interview is required. Please provide link. Link to post Share on other sites More sharing options...
dot-me-not Posted September 10, 2015 Share #133 Posted September 10, 2015 Thank you, all. Epic thread. 'Would read again. Link to post Share on other sites More sharing options...
CheshireCat Posted September 10, 2015 Share #134 Posted September 10, 2015 Digiloyd? Hmmm... Maybe Dr. Brian Caldwell (lens designer at Coastal Optics, now Jenoptik) is more to your taste: http://www.lensrentals.com/blog/2014/06/the-glass-in-the-path-sensor-stacks-and-adapted-lenses Link to post Share on other sites More sharing options...
lct Posted September 10, 2015 Share #135 Posted September 10, 2015 Having sold my M I now have the Leica Q, A7rII and A7s. Of the Sony's I find the 'nicest' files come form the A7s those large pixels just seem to perform in a really film way like especially as the iso goes up, they convert beautifully to B&W and to my eye just have a special look. I even find large prints not to be problem due to the film like quality of any 'grain' present. The A7rII is a technological marvel but after a month or so of sitting idly in the safe the A7s is back out again and getting used, I just love it as a camera. The Leica Q has truly superb files but that is a whole different story. Does the A7s have less smearing problems on wides in borders and corners at infinity? Just curious. Link to post Share on other sites More sharing options...
CheshireCat Posted September 10, 2015 Share #136 Posted September 10, 2015 Does the A7s have less smearing problems on wides in borders and corners at infinity? Just curious. Since the sensor cover glass is part of the optical system, it is reasonable to expect that its thickness is the same for all E-Mount cameras. And if the thickness is the same, then the smearing is the same. However, given the lower number of pixels, it will be less noticeable when pixel-peeping. Link to post Share on other sites More sharing options...
Adam Posted September 10, 2015 Share #137 Posted September 10, 2015 Let me fix that for you, once again: You have a problem then - since Peter Karbe says his lenses are designed to work as well on film as they do on a sensor that must be specially designed to emulate film, and barely can... But keep trying ! That's fun We are talking about refraction right? I do not think one can make an overarching statement that a sensor barely emulates film as far as refraction unless there is concrete data. For each lens aperture, the data has to reflect the comparison between refraction in gelatin with refraction by different types of glass in front of a sensor (and maybe within it). This requires measuring the cumulative effects of refraction by each layer of film (accounting for different types of film) But that is not the end though. I suspect that after measuring the light paths through the lens and layers of film and comparing them with the light paths through different types of sensor glass, one needs to factor in the differences between pixel and crystal behavior due to size, properties, etc. I doubt that this is an easy task. I am sure people at Leica have tried hard to measure these things. Maybe they could answer how close can you create a sensor that mimics behavior of film with Leica glass. If they know, they never shared the info. However, judging by the fact that there are no specific Leica lens advertised separately for film and digital, I presume Leica thinks their current lens perform well enough on both. Without concrete numbers it is baseless to claim that glass in front of a sensor prevents us from having lens that behave comparably on film and on digital as far as the effects of refraction. I think there is a very useful comment from Mike Brassey below the mentioned text by Dr Caldwell http://www.lensrenta...-adapted-lenses Link to post Share on other sites More sharing options...
uhoh7 Posted September 10, 2015 Share #138 Posted September 10, 2015 You have a problem then - since Peter Karbe says his lenses are designed to work as well on film as they do on a sensor... Always a problem when you let others do all the thinking and talking, because pretty soon you just can't tell when they are putting you on. LOL "work as well on film as they do on a sensor..." a sensor? What sensor? If fact Leica has gone out of their way to give us sensors as close to film as they can manage. The thinnest stack of any digital sensor is.........the M8. Then comes the M9 and we have seen what can go wrong with thin cover glass there. Then is the 240, which does at least seem stable. If you think Karbe is giving you his real thoughts on designing and the digital issues, well you are naive. It's a complex issue that's not going to be vetted in public for all sorts of reasons. NDA not least. All that said, I am a huge fan of Karbe. Link to post Share on other sites More sharing options...
viramati Posted September 10, 2015 Share #139 Posted September 10, 2015 Does the A7s have less smearing problems on wides in borders and corners at infinity? Just curious. The A7s can be slightly better on certain lenses and I presume this is due to the large pixels and lower pixel count as Cheshirecat has mentioned. Corner sharpness is certainly not as good as the leica M with leica lenses. The only real difference between the A7rII and previous A7's is the lack of colour cast towards the edges which has been put down to backlight sensor. Link to post Share on other sites More sharing options...
jaapv Posted September 10, 2015 Share #140 Posted September 10, 2015 Always a problem when you let others do all the thinking and talking, because pretty soon you just can't tell when they are putting you on. LOL "work as well on film as they do on a sensor..." a sensor? What sensor? If fact Leica has gone out of their way to give us sensors as close to film as they can manage. The thinnest stack of any digital sensor is.........the M8. Then comes the M9 and we have seen what can go wrong with thin cover glass there. Then is the 240, which does at least seem stable. If you think Karbe is giving you his real thoughts on designing and the digital issues, well you are naive. It's a complex issue that's not going to be vetted in public for all sorts of reasons. NDA not least. All that said, I am a huge fan of Karbe. I am well aware of the optical properties of a planparallel piece of glass. That is nothing new. However the behaviour of Leica wide angles on Sony sensors strongly suggests that Leica is looking for solutions in sensor design, not lens design. This would appear sensible as no two sensors are the same as you point out, nobody knows where sensor design will end up ( Leica designs lenses to last decades) and they have to try and optimize their sensors for heritage lenses anyway. That makes Peter Karbe's statement the simple truth, not spin. Being about the only remaining maker of film cameras might influence this as well. Link to post Share on other sites More sharing options...
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