squarenegs Posted July 3, 2010 Share #61 Posted July 3, 2010 Advertisement (gone after registration) "Any lens, irrespective of focal length, and at a given aperture and ratio of reproduction on the sensor, will produce the same d.o.f." Lars is correct, full stop. Try it. Take a 21mm lens and a 100mm lens for example, both set to the same aperture. Shoot a subject, a portrait say, and render your sitter at the same size in the image frame with both lenses; the same "ratio of reproduction". Both lenses will exhibit the same depth of field. DOF is independent of focal length. Geez, for some reason there are far better lensmen/women than I who don't understand this piece of grade eleven physics. Best regards to all on the Forum Sam An old man still clutching his TOPCON. Quote Link to post Share on other sites More sharing options...
Advertisement Posted July 3, 2010 Posted July 3, 2010 Hi squarenegs, Take a look here Accuracy of depth-of-field scale of lenses on M8. I'm sure you'll find what you were looking for!
ampguy Posted July 3, 2010 Share #62 Posted July 3, 2010 Yes Steve. I have in fact focused on a subject, and found the results acceptable Also, yes. I have, in practice, focused on infinity, and found f2, 20 metres, 50mm perfectly acceptable. I don't want to sound funny, but have you actually done this in practice and found the results acceptable? At f2? With a lens of 50mm or longer? I only mention this because you don't mention focal length or aperture, both of which have an effect on perceived DOF. Quote Link to post Share on other sites More sharing options...
01af Posted July 3, 2010 Share #63 Posted July 3, 2010 "Any lens, irrespective of focal length, and at a given aperture and ratio of reproduction on the sensor, will produce the same d.o.f." Lars is correct, full stop. He is not. As simple as that. And you aren't either. Quote Link to post Share on other sites More sharing options...
ampguy Posted July 3, 2010 Share #64 Posted July 3, 2010 Well, that is why these forums are so nice, they are informative! M8 users print at whatever sizes they like. Maybe M9 users print larger or smaller. The point is, is that the DOF scales on a Leica lens is going to be equally accurate/inaccurate on an M9 vs an M8, and possibly an APS-C (RD1, NEX, etc.), and depending on perception, and specific lens, u4/3. Give it a try, it's a fun way to spend an afternoon. Okay. Didn't know that M8 users always print everything 1.33× smaller than M9 users do. Quote Link to post Share on other sites More sharing options...
mjh Posted July 3, 2010 Share #65 Posted July 3, 2010 "Any lens, irrespective of focal length, and at a given aperture and ratio of reproduction on the sensor, will produce the same d.o.f." Taken literally this statement is true – specifically, the depth of field will always be zero, i.e. there is no such thing as a depts of field; there is just a plane where everything is rendered sharply and everything else is unsharp. The very concept of depth of field assumes there is a circle of confusion defining an acceptable degree of unsharpness. But then the depth of field depends on the circle of confusion so conveniently missing from the statement above. To maintain that DOF doesn’t depend on the sensor size it doesn’t even suffice to assume that photographers would stick to smaller print sizes when using smaller sensors (not that there was any evidence in support of this assumption), because the photographer and his or her preferences don’t really matter. It is the viewer that counts. Formulas for depth of field generally assume that the typical viewing distance is proportional to the print size, so even if M8 photographers did indeed opt for smaller prints, these prints would typically be viewed from a shorter distance, neutralizing this effect. Yes, there are exceptions to this rule, but I am not aware of a better rule describing how images are typically viewed. Quote Link to post Share on other sites More sharing options...
01af Posted July 3, 2010 Share #66 Posted July 3, 2010 To maintain that DOF doesn’t depend on the sensor size ... Michael, you didn't get the point here. This is not about how DOF depends on sensor size (or film size), but how DOF depends on focal length, assuming constant film/sensor size. For some reason, it has become a common misconception that DOF would depend on reproduction ratio alone rather than on focal length and distance (all other things being equal). Quote Link to post Share on other sites More sharing options...
Guest mc_k Posted July 4, 2010 Share #67 Posted July 4, 2010 Advertisement (gone after registration) ... DOF depends on focal length... This assumes you don't know the viewing conditions. Some here may reach a different conclusion than you because they started from different assumptions. Again, there is more than one formula for depth of field. Quote Link to post Share on other sites More sharing options...
DWatts Posted July 10, 2010 Share #68 Posted July 10, 2010 I much prefere to listen to a Leica person than a nobody on a forum ! ! ! Quote Link to post Share on other sites More sharing options...
DWatts Posted July 10, 2010 Share #69 Posted July 10, 2010 I much prefere to listen to a Leica person than a nobody on a forum ! ! ! Quote Link to post Share on other sites More sharing options...
mjh Posted July 10, 2010 Share #70 Posted July 10, 2010 I much prefere to listen to a Leica person than a nobody on a forum ! ! ! You also like to listen to yourself, don’t you? Quote Link to post Share on other sites More sharing options...
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