diogenis Posted July 5, 2012 Share #61 Posted July 5, 2012 Advertisement (gone after registration) Good point I was mainly talking about the 200 f/2. The 24 f/1.4 is as good as the Leica though although much bigger. The 85mm is quite good as well....maybe not as good as my 50 Lux though. The correct thing to say about the 24/1.4 ED is that it is good, just not good enough. There is still substantial loss in contrast that is also uniform beginning from 5mm, as opposed to the 'lux which is more or less "even" No matter how good or great the sensor is, it can only record what it sees from it's lens. And we can't, sadly, change the fundamentals of those lenses. You can see the loss: 10-60% and more loss in contrast for stuff that is not in the absolute center area. At best, your sensor will record this loss, but there are also other things happening in the sensor... guessing is one of those things. Edit: and last, if Ming didn't crop the whole image, the model's head is located in the sensor area around 12mm, meaning exactly 50% loss and more for even finer details 60? 70%? Compare this to the APO that it won't lose more than 40% for the finest details (at 12mm) Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/182646-m9-m9m-do-it-yourself-comparison/?do=findComment&comment=2055670'>More sharing options...
Advertisement Posted July 5, 2012 Posted July 5, 2012 Hi diogenis, Take a look here M9, M9M, Do It Yourself Comparison. I'm sure you'll find what you were looking for!
jaapv Posted July 5, 2012 Share #62 Posted July 5, 2012 It depends on the magnification. It is surely not 35-50cm of the normal print, but the nostril from the eye also is like what? 2cm? If you magnify to see pixel for pixel it is zero (well, you see a kind of DOF-like effect induced by the physical dimensions of the pixels themselves. The area where they cannot resolve further detail. Say about 1 cm deep and not influenced by aperture or subject distance). Link to post Share on other sites More sharing options...
diogenis Posted July 5, 2012 Share #63 Posted July 5, 2012 Thanks for that Jaap. I thought it was a lot more, like 10cm you sure 100% it is 0? Link to post Share on other sites More sharing options...
jaapv Posted July 5, 2012 Share #64 Posted July 5, 2012 Yep - DOF is keeping under the resolution limit of the human eye*. If you blow it up to pixel level, you'll be over that limit so DOF will not exist. The "DOF" at pixel level is detemined by the specification of the sensor. The value is determined by the size of the pixel (and a host of aberrations). I have not worked it out - if somebody wants to feel free. My 1 cm stems from casual observation and is open to amendment;).. *rather the acceptance level of eye and brain combined, but that is overcomplicating things in this discussion. Link to post Share on other sites More sharing options...
diogenis Posted July 5, 2012 Share #65 Posted July 5, 2012 Well I would have said 10x as that, but I can not remember anymore. This is what I have found in wiki Cropping Cropping an image and enlarging to the same size final image as an uncropped image taken under the same conditions with a smaller format is equivalent to using the smaller format; the cropped image has less DOF than the original image from the larger format (Stroebel 1976, 134, 136–37). He speaks of less not 0 Link to post Share on other sites More sharing options...
jaapv Posted July 5, 2012 Share #66 Posted July 5, 2012 That is something totally different I fear. The context is the (approximate) constancy in DOF when a subject distance is unchanged. For one thing he is talking about "normal"cropping and enlarging, not about blowing an image up to the resolution limit, secondly this is about film, which has no mathematically fixed resolution limit anyway. Compare Erwin Puts' resolution comparison film<->digital, where you can see film losing resolution gradually and digital starting to pixellate abruptly. Link to post Share on other sites More sharing options...
diogenis Posted July 5, 2012 Share #67 Posted July 5, 2012 Advertisement (gone after registration) I don't know Jaap. I took a photo of a ruler in perspective to show the DoF. At this time there is no sufficient light available, and I used a summilux 50 @f4 and from 80cm. From the initial dof of say 4-5 cms, the full blown mag 100% only lost like 2 cm. The DoF is there. Maybe we need O1af or mjh Link to post Share on other sites More sharing options...
Lindolfi Posted July 12, 2012 Share #68 Posted July 12, 2012 Even when pixelsize would not be limiting and (due to sufficient magnification), the resolution of the human eye would not be limiting, there still is the diffraction limit of the lens opening. In the case of 50mm at f/4 at a distance of 0.8 meter the diffraction limit gives a DOF of 4.8 mm. (pixelpitch of the M9 masks a DOF of about 4 mm in that case, so 4.8 mm is still a real limit even when pixels are taken into account) In "normal" but still demanding conditions (print size of 60x40 cm, viewing distance 25 cm) the DOF is 9 mm The more traditional DOF of focal length of 50mm at f/4 at distance of 0.8 m is about 50 mm Link to post Share on other sites More sharing options...
jaapv Posted July 12, 2012 Share #69 Posted July 12, 2012 Thanks for the exact numbers, Bert Link to post Share on other sites More sharing options...
120 Posted July 16, 2012 Share #70 Posted July 16, 2012 ... this is about film... the d.o.f. the poster is referring to is a geometric notion--has nothing to do with the properties of film Link to post Share on other sites More sharing options...
120 Posted July 16, 2012 Share #71 Posted July 16, 2012 Even when pixelsize would not be limiting and (due to sufficient magnification), the resolution of the human eye would not be limiting, there still is the diffraction limit of the lens opening. In the case of 50mm at f/4 at a distance of 0.8 meter the diffraction limit gives a DOF of 4.8 mm. (pixelpitch of the M9 masks a DOF of about 4 mm in that case, so 4.8 mm is still a real limit even when pixels are taken into account) In "normal" but still demanding conditions (print size of 60x40 cm, viewing distance 25 cm) the DOF is 9 mm The more traditional DOF of focal length of 50mm at f/4 at distance of 0.8 m is about 50 mm In the version I have seen of this, you still use the "traditional" d.o.f. as you called it, when it dominates the diffraction-limited d.o.f. I have also seen a couple of versions where the diffraction is accounted for by one wholesale formula. Not wishing to wade through it all, can you give a source? Link to post Share on other sites More sharing options...
batmobile Posted February 4, 2015 Share #72 Posted February 4, 2015 Coming back to this a long time later and comparing a Sony A7R with 35mm FE Sonnar and Leica Monochrom with 35mm Summarit-M, I have my own conclusion. After uprezzing the MM files to the same size as the A7R files and shooting both at f5.6, here are my observations: The A7R is clearly sharper on centre at 100%. At 50% you cannot remotely see any difference, which would equate to almost or entirely invisible differences with very large prints. At the edges, the Monochrom is visibly sharper than the A7R and 35mm Sonnar (by about the same amount as we see on centre). The Sonnar is very good at the edges compared to most lenses out there, but the Summarit-M/MM combo is essentially perfect. Most of this disappears at 50%, once again. My overall impression is that the MM produces the more perfect looking file overall. The losses in the centre don't seem to matter as much as the gains on the edges 'perceptually'... somehow.... but I cannot see any of this mattering in reality. It really is a dead heat. But.... I very clearly prefer the MM files 'look'. It is different... a bit more organic and regardless of processing, the A7R file ends up looking more digital, as Ming Thein found with the D800 MM comparison. For old school film users, the MM is likely to feel much closer to home. My conclusion: The A7R with a cracking 35mm prime (and mine is an excellent copy) does not steal any meaningful lead over the Leica MM, IMHO. Overall, I would take the Monochrom files every time, simply because of the peerless uniformity with wider focal lengths and the 'look'. That said, the A7R is capable of wonderful things and I certainly love mine. Leica Monochrom files uprez so much better than anything I have used before that it punches miles above its MP weight. With the best 24mm lenses available for both systems (24mm f3.8 Elmar, anyone?), I would expect the Leica to start pushing very meaningfully ahead (possibly until Zeiss gives us a 24mm Loxia). At 50mm and up, however, from experience I can say that the A7R is able to make its pixels count from corner to corner, whether with the stunning 55mm FE or adapted Leica M lenses. I have a feeling that with the next generation of 50MP cameras, the MM is going to stay up there with them, because the corners and edges will hold them back. At 50MP the centre is going to be well ahead of the 18 MP Monochrom, but without amazing as yet unreleased lenses (at wider than 50mm at least), one has to wonder if the gains on centre will be useable for certain applications, as such magnifications will only reveal edge deficiencies. Sure, lots of pixels has benefits well beyond resolution, but still. P.S I own both and have since the release of the A7R. I am invested in both systems and so have no axe to grind. Link to post Share on other sites More sharing options...
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