dem331 Posted February 17, 2023 Share #41 Posted February 17, 2023 Advertisement (gone after registration) 30 minutes ago, jaapv said: I'm not convinced that you used the same aperture. I don't know how I can show you the EFIX data. I actually used F2.2 on the 35mm and and f2.8 on the 180mm, but that only reinforces what I am saying. I just looked it up in LR (not for the Contax obviously) I really think that some of you guys, who actually know a lot more about optics and digital sensors than me, (and this is not false modesty), are so caught up in the "perspective only depends on where you are standing and is independent of focal length" mantra (which is a true mantra), that you fail to see that the different focal length changes things in the image that have nothing to do with perspective, and probably have something to do with that "widely misunderstood" concept of depth of field. I am happy to be disproved but I am not hearing any convincing argument. Quote Link to post Share on other sites More sharing options...
Advertisement Posted February 17, 2023 Posted February 17, 2023 Hi dem331, Take a look here How can you appreciate 100MP without cropping?. I'm sure you'll find what you were looking for!
pgk Posted February 17, 2023 Share #42 Posted February 17, 2023 Think about it this way: if depth of field varied on focal length then all that we would need to do would be to build wideangle short focal length lenses with great coverage and crop them for vast depth of field. Hasn't happened because unfortunately it doesn't work like that. Quote Link to post Share on other sites More sharing options...
dem331 Posted February 17, 2023 Share #43 Posted February 17, 2023 54 minutes ago, pgk said: Think about it this way: if depth of field varied on focal length then all that we would need to do would be to build wideangle short focal length lenses with great coverage and crop them for vast depth of field. Hasn't happened because unfortunately it doesn't work like that. Thanks for your reply. I think that probably the reason this has not been done is that the film and digital sensors have not been good enough to make this magnitude of cropping feasible from IQ perspective. Also not everyone wants depth of field. Quote Link to post Share on other sites More sharing options...
dem331 Posted February 17, 2023 Share #44 Posted February 17, 2023 Look at these two files, the first taken with my SL24-90mm at 24mm f4, focus point on top white flower cropped to 90mm. Second file zoomed in to 90mm, no other changes. 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! Quote 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/366574-how-can-you-appreciate-100mp-without-cropping/?do=findComment&comment=4689273'>More sharing options...
dem331 Posted February 17, 2023 Share #45 Posted February 17, 2023 Another example, exactly the same, all f4, first 24mm cropped, second 90mm 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! Quote 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/366574-how-can-you-appreciate-100mp-without-cropping/?do=findComment&comment=4689275'>More sharing options...
dem331 Posted February 17, 2023 Share #46 Posted February 17, 2023 What is happening here? (@jappv , sorry if they are just grab shots, but I think they illustrate the point.) You can actually just see this effect quite easily by zooming in on the back screen of the SL2 on the 24mm photo. Quote Link to post Share on other sites More sharing options...
Einst_Stein Posted February 17, 2023 Author Share #47 Posted February 17, 2023 Advertisement (gone after registration) 3 hours ago, dem331 said: A very good question that is not that easy to answer. I would say no, unless you crop the FF image and use the same focal length and aperture for both images, and even then it will depend on the properties (pixel densities or whatever, which I don’t fully understand) of the sensors. One thing that surprises me is that people that are very keen on shooting at f0.95 or f1.0 are also keen to use extreme crops to explain the need for a 100mp sensor. Why cropping? Because the much too narrow DOF? So, say, cropping 50mm f1 to mimic 100mm f2 or f1.4? If so, the motivation is the lack of 100mm f2 or f1.4? Anyway, we all agree the value of 100mp is for cropping, nothing else yet. Quote Link to post Share on other sites More sharing options...
dem331 Posted February 17, 2023 Share #48 Posted February 17, 2023 2 hours ago, Einst_Stein said: Why cropping? Because the much too narrow DOF? So, say, cropping 50mm f1 to mimic 100mm f2 or f1.4? If so, the motivation is the lack of 100mm f2 or f1.4? Anyway, we all agree the value of 100mp is for cropping, nothing else yet. For me 100mp has no value. I can accept it may have to others. 1 Quote Link to post Share on other sites More sharing options...
01af Posted February 17, 2023 Share #49 Posted February 17, 2023 vor 21 Stunden schrieb pgk: Depth of field will be the same at the same aperture for a long focal length lens or an equivalent crop from a shorter focal length lens. No, it won't be the same. Instead, the cropped image with shorter focal length will show more depth-of-field ... see examples posted by Enrique dem331 above. . vor 21 Stunden schrieb pgk: Depth of field is a rather widely misunderstood concept. You don't say ... 2 Quote Link to post Share on other sites More sharing options...
Einst_Stein Posted February 17, 2023 Author Share #50 Posted February 17, 2023 53 minutes ago, dem331 said: For me 100mp has no value. I can accept it may have to others. I am trying to find out what that value would be. 2 Quote Link to post Share on other sites More sharing options...
frame-it Posted February 17, 2023 Share #51 Posted February 17, 2023 7 hours ago, jaapv said: Amen to that! ill just drop this in here: https://www.samyanglens.com/en/product/simulator/lens.php Quote Link to post Share on other sites More sharing options...
pippy Posted February 17, 2023 Share #52 Posted February 17, 2023 Slightly clearer - than my last effort - demonstration showing how Depth of Field can change quite dramatically with f/length depending on various factors. Three similar crops from three different f/l lenses all set to f2. One was a 90mm; one was a 50mm; one was a 28mm. Camera was M Monochrom and was tripod-mounted. Focus was the TINY small white spot of lichen on the middle of the roof-tile just south of centre. Just to make things a bit more interesting I won't say which snap was taken with which lens............ 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! Philip. 3 Quote Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! Philip. ' data-webShareUrl='https://www.l-camera-forum.com/topic/366574-how-can-you-appreciate-100mp-without-cropping/?do=findComment&comment=4689592'>More sharing options...
wizard Posted February 17, 2023 Share #53 Posted February 17, 2023 vor 7 Stunden schrieb jaapv: These grab shots tell us very little. Well, they look pretty conclusive to me, provided the same aperture was in fact used. vor 6 Stunden schrieb pgk: Think about it this way: if depth of field varied on focal length then all that we would need to do would be to build wideangle short focal length lenses with great coverage and crop them for vast depth of field. Paul, I value your opinion very much, but I am not sure if things are getting mixed up here. What I know is that perspective does not change when comparing e.g. a 35mm shot to a 90mm shot taken from the same position. That is, you can 'find' the 90mm shot in the 35mm shot by just cropping the 35mm shot to what the 90mm shows. However, I have so far not heard that depth of field remains the same when comparing the 35mm shot to the 90mm shot. To the contrary, I am pretty sure that depth of field - when comparing shots taken with the same aperture value - will change, as shown in the above sample shots. 4 Quote Link to post Share on other sites More sharing options...
wizard Posted February 17, 2023 Share #54 Posted February 17, 2023 vor 9 Minuten schrieb pippy: I won't say which snap was taken with which lens....... Well, that's pretty obvious anyway 😉. 1 Quote Link to post Share on other sites More sharing options...
Einst_Stein Posted February 17, 2023 Author Share #55 Posted February 17, 2023 If you shoot with 80mm f2.8 on 100mp FF then crop to 24mp, it will look like from a 160mm f11 on 24mp FF, though the image quality per pixel is only 1/4 of a 24MP FF. Will you be satisfied ? Probably not if you have the choice of real 24mp FF with a real 160mm f2.8? Quote Link to post Share on other sites More sharing options...
jaapv Posted February 17, 2023 Share #56 Posted February 17, 2023 1 hour ago, wizard said: Well, they look pretty conclusive to me, provided the same aperture was in fact used. Paul, I value your opinion very much, but I am not sure if things are getting mixed up here. What I know is that perspective does not change when comparing e.g. a 35mm shot to a 90mm shot taken from the same position. That is, you can 'find' the 90mm shot in the 35mm shot by just cropping the 35mm shot to what the 90mm shows. However, I have so far not heard that depth of field remains the same when comparing the 35mm shot to the 90mm shot. To the contrary, I am pretty sure that depth of field - when comparing shots taken with the same aperture value - will change, as shown in the above sample shots. Quite so. The DOF is a different matter in this context. The “unchanged” matter only refers to perspective as I posted way back. 1 Quote Link to post Share on other sites More sharing options...
dem331 Posted February 18, 2023 Share #57 Posted February 18, 2023 13 hours ago, Einst_Stein said: though the image quality per pixel is only 1/4 of a 24MP FF. Why is this? If this is the case it really does take the fun out of cropping. Personally I never crop more than 10-20% of an image even on SL2, and having been a slide shooter all my life, I try not to crop at all. So not attracted by 100mp for cropping. Quote Link to post Share on other sites More sharing options...
dem331 Posted February 18, 2023 Share #58 Posted February 18, 2023 12 hours ago, jaapv said: Quite so. The DOF is a different matter in this context. The “unchanged” matter only refers to perspective as I posted way back. A few other things you posted back then have vanished into thin air. Administrator rights? 😉😂😂 Quote Link to post Share on other sites More sharing options...
Einst_Stein Posted February 18, 2023 Author Share #59 Posted February 18, 2023 5 minutes ago, dem331 said: Why is this? If this is the case it really does take the fun out of cropping. Personally I never crop more than 10-20% of an image even on SL2, and having been a slide shooter all my life, I try not to crop at all. So not attracted by 100mp for cropping. To me, cropping is never the purpose, it is merely a correction, particularly crop for composition, such as crop to square format or fit to 16x9 TV or so. 1 Quote Link to post Share on other sites More sharing options...
otto.f Posted February 18, 2023 Share #60 Posted February 18, 2023 On 2/16/2023 at 4:10 PM, pippy said: hopefully this wee test will be of some use So we only need the 28 on our m11. Cheap Leica! 2 Quote Link to post Share on other sites More sharing options...
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