dxomark.com website seems to have relevant numbers, see for example Nikon lens mentioned by Sturm Flut: https://www.dxomark.com/Lenses/Nikon/AF-S-Nikkor-24-70mm-f-2.8G-ED-mounted-on-Nikon-D750__975 https://www.dxomark.com/Lenses/Nikon/AF-S-Nikkor-24-70mm-f-2.8G-ED-mounted-on-Nikon-D7100__865
Interestingly enough on D810 number is higher than on D750 even though sensor's physical dimensions are the same, probably due to the absence of optical low-pass filter: https://www.dxomark.com/Lenses/Nikon/AF-S-Nikkor-24-70mm-f-2.8G-ED-mounted-on-Nikon-D810__963 On Sun, 24 Feb 2019 13:32:54 +0100 Florian W <flo.wern...@gmail.com> wrote: > Thanks for the details Simon. > > I also thought about it a bit and had a reasoning similar to yours, that > basically something designed for a specific acquisition chain will probably > perform worse on an acquisition chain farther from its spec. > > However thinking about it more deeply, 2 things are still boggling my mind. > > 1 This reasoning is mixing description of digital features with analog ones > . A lens quality and specs is not defined by MP resolution (rather by like > purity of the glass, glass curvature homogeneity, CoC, TCA, and so on). > > 2 Some of the lenses we're talking about were developed and (partially) > targeted to FF cameras having a sensor with less MP than a current APS-C > (for example in Canon, the 6D is a 2012 FF with 20MP). > > If the reasoning is valid, a lens released at times of FF with 24MP or > higher wouldn't be a good match to the previous cameras with less MP. Which > doesn't seems to be the case. > > What I mean by this is that at some point, to ensure a lens will perform > well on FF cameras that will be released the following decade, one can > assume that the optical manufacturing quality is probably one order of > magnitude above the quality required to fit the current camera sensor > capabilities. Maybe explaining why you can see problems in older lenses. > > Please feel free to point any mistake in this reasoning. > > Maybe are we lucky enough that someone working in the optical lenses or > cameras industry is part of this mailing list and provide us some insights > about it :) > > Florian Wernert > Software engineer INSA > In-training Neuroscience researcher > https://www.linkedin.com/in/wernertflorian > > > > Le sam. 23 févr. 2019 à 18:12, Sturm Flut <sturmf...@lieberbiber.de> a > écrit : > > > Hi, > > > > Am 23.02.19 um 16:34 schrieb Florian W: > > > Thanks for your answers guys. > > > > > > Simon, I'm curious to know why to you it's not the best idea ? > > > > (oversimplifying it a bit) > > > > Full-frame lenses are designed to deliver their full sharpness across > > the whole full-frame image circle. If I put a full-frame lens on my > > APS-C D7100, I am basically expecting it to deliver 24 megapixels within > > the smaller APS-C image circle the sensor is cropping out. That means I > > expect the lens to deliver about 24*2,25 = 54 megapixels over the whole > > full-frame image circle. Which not that many standard lenses will do. > > > > If put my standard 24-70/2.8 on a Nikon D850 and (let's say) it only > > delivers 40 megapixels of actual resolution instead of the ~46 the > > sensor wants, that's not going to be a catastrophe. If I put it on a > > camera with a lower resolution sensor, e.g. the 24 megapixel sensor in > > the D750, there is zero problem. But if I put the same lens on the > > D7100, the cropped area will only get around 40 / 2,25 = 17 megapixels. > > That's suddenly 30% less than what the sensor needs. And not every lens > > will even deliver these 40 megapixels. Good APS-C and especially > > Micro-Four-Thirds lenses are expensive and hard to make because they > > have to be very sharp within the smaller image circle. > > > > Prime lenses are usually sharper to begin with, so with your 50/1.8 and > > 28/2.8 it might not be that much of an issue. But I can clearly see the > > problem with my 24-70/2.8, and especially with the good old 70-300/4.5-5.6. > > > > cheers, > > Simon > > > > ___________________________________________________________________________ > darktable developer mailing list > to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org > ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
