jaapv Posted September 20, 2019 Share #41  Posted September 20, 2019 Advertisement (gone after registration) To which may be added that the convention of a COC being 0.03 mm was established well before WWII. The films were thick and blurry compared to present-day ones and even far more so compared to a high-res sensor, the standard print size was 6x9 (cm!) All this adds up to present-day DOF being considerably more narrow than it used to be. A reasonable COC to assume for a 24MP sensor and an A4 print would be 0.01 mm. Maybe this has given rise to today's fad of shallow-focus photography.  Link to post Share on other sites More sharing options...
Advertisement Posted September 20, 2019 Posted September 20, 2019 Hi jaapv, Take a look here depth of field of APS C Sensor. I'm sure you'll find what you were looking for!
lct Posted September 20, 2019 Share #42  Posted September 20, 2019 We may well pick a small or large CoC value if we wish so but the ones chosen by Leica are 0.03 and 0.02mm respectively for FF and APS-C cameras. Those interested will find those values in the exif data of their raw files if they own an M10, an SL or a CL at least. Link to post Share on other sites More sharing options...
lct Posted September 20, 2019 Share #43  Posted September 20, 2019 (edited) 19 minutes ago, jaapv said: A reasonable COC to assume for a 24MP sensor and an A4 print would be 0.01 mm. With such a CoC value we could not focus accurately any Noctilux anymore. Edited September 20, 2019 by lct Link to post Share on other sites More sharing options...
jaapv Posted September 20, 2019 Share #44 Â Posted September 20, 2019 If you need to depend on DOF to focus a Noctilux, you are misfocusing all the time. Critical focus only exists in the plane of focus. DOF is "acceptable" out-of-focus. The whole point of using a Noctilux is to have your point of interest in critical focus with the rest of the image fading away in beautiful bokeh. Eye-lash portraits. Link to post Share on other sites More sharing options...
lct Posted September 20, 2019 Share #45 Â Posted September 20, 2019 2 minutes ago, jaapv said: If you need to depend on DOF to focus a Noctilux, you are misfocusing all the time. Critical focus only exists in the plane of focus. DOF is "acceptable" out-of-focus. RF accuracy is based on CoC as well. There is no free lunch... Link to post Share on other sites More sharing options...
jaapv Posted September 20, 2019 Share #46  Posted September 20, 2019 17 minutes ago, lct said: We may well pick a small or large CoC value if we wish so but the ones chosen by Leica are 0.03 and 0.02mm respectively for FF and APS-C cameras. Those interested will find those values in the exif data of their raw files if they own an M10, an SL or a CL at least. They are not "chosen by Leica" They are a convention used throughout the industry, as I said, dating back to the 1930-ies. Link to post Share on other sites More sharing options...
jaapv Posted September 20, 2019 Share #47 Â Posted September 20, 2019 Advertisement (gone after registration) 3 minutes ago, lct said: RF accuracy is based on CoC as well. There is no free lunch... Partly correct. It is based on the resolving power of the human eye. As a virtual optical system it has no COC. That has two results: Leica will do tolerance-matching on the camera+lens for a Noctilux and the lens is more accurate on the SL. Link to post Share on other sites More sharing options...
lct Posted September 20, 2019 Share #48 Â Posted September 20, 2019 1 minute ago, jaapv said: They are not "chosen by Leica" They are a convention used throughout the industry, as I said, dating back to the 1930-ies. Then Leica chose to use that convention. But they don't have a clue about DoFÂ of course . Link to post Share on other sites More sharing options...
jaapv Posted September 20, 2019 Share #49  Posted September 20, 2019 <sigh>... Leica narrowed the tolerances for M lens focusing dramatically since the introduction of digital Ms and has been refining their rangefinder considerably ever since for this very reason. Link to post Share on other sites More sharing options...
lct Posted September 20, 2019 Share #50  Posted September 20, 2019 2 minutes ago, jaapv said: Partly correct. It is based on the resolving power of the human eye. As a virtual optical system it has no COC. That has two results: Leica will do tolerance-matching on the camera+lens for a Noctilux and the lens is more accurate on the SL. Not sure if math formula can be "partly correct" but fact is that both DoF and RF accuracy are calculated that way. Link to post Share on other sites More sharing options...
jaapv Posted September 20, 2019 Share #51  Posted September 20, 2019 Just now, lct said: Not sure if math formula can be "partly correct" but fact is that both DoF and RF accuracy are calculated that way. Math formula? It is a convention. Link to post Share on other sites More sharing options...
01af Posted September 20, 2019 Share #52  Posted September 20, 2019 (edited) vor 17 Minuten schrieb jaapv: They are a convention used throughout the industry, as I said, dating back to the 1930-ies. They are dating back much further than that, and they are still valid today. The evolution of the human eye hasn't changed that much since then. . vor 6 Minuten schrieb jaapv: Math formula? It is a convention. You pick a maximum size for an acceptabe circle-of-confusion, and then—assuming an ideal lens—it's all math from there. By the way—the depth-of-field tables published in the Leica Camera data sheets do not assume ideal lenses. They are individually calculated for each lens, and so the values may differ slightly. Compare, for example, the d-o-f tables for Noctilux-M 50 mm Asph and Summicron-M 50 mm. Their actual focal lengths are 52.3 mm in both cases, and yet their d-o-f is not the same. At 3 m and f/8, for example, it's 2.354 - 4.150 m for the Noctilux and 2.343 - 4.182 m for the Summicron. The reason is that d-o-f actually depends on more factors than just image format, focal length, distance, and aperture. Edited September 20, 2019 by 01af Link to post Share on other sites More sharing options...
jaapv Posted September 20, 2019 Share #53 Â Posted September 20, 2019 Yep, but the optical recording systems have... Link to post Share on other sites More sharing options...
lct Posted September 20, 2019 Share #54 Â Posted September 20, 2019 (edited) . Edited September 20, 2019 by lct Link to post Share on other sites More sharing options...
lct Posted September 20, 2019 Share #55 Â Posted September 20, 2019 (edited) . Edited September 20, 2019 by lct Link to post Share on other sites More sharing options...
jaapv Posted September 20, 2019 Share #56 Â Posted September 20, 2019 Actually, Mozes carried DOF and COC down the mountain on a stone tablet... IÂ give up. Link to post Share on other sites More sharing options...
01af Posted September 20, 2019 Share #57 Â Posted September 20, 2019 vor 21 Minuten schrieb jaapv: Yep, but the optical recording systems have ... That means the maximum sharpness the systems are able to record has improved. But the degree of blurriness that our eyes will accept as "sharp enough" has not. Link to post Share on other sites More sharing options...
jaapv Posted September 20, 2019 Share #58  Posted September 20, 2019 No argument there. It is the basis of the phenomenon. We are arguing the whole chain, from subject to brain. More like a cone of confusion than a circle of confusion. Link to post Share on other sites More sharing options...
ramarren Posted September 20, 2019 Share #59  Posted September 20, 2019 It's easy to forget just how beautifully the Summilux 35mm v2 lens can render a simple scene. 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! Leica CL + Summilux 35mm f/1.4 v2 (1972 vintage) ISO 2500 @ f/2.8 @ 1/60 enjoy, G 2 1 Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! Leica CL + Summilux 35mm f/1.4 v2 (1972 vintage) ISO 2500 @ f/2.8 @ 1/60 enjoy, G ' data-webShareUrl='https://www.l-camera-forum.com/topic/301631-depth-of-field-of-aps-c-sensor/?do=findComment&comment=3823245'>More sharing options...
jaapv Posted September 20, 2019 Share #60  Posted September 20, 2019 Too much DOF 😡    Link to post Share on other sites More sharing options...
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