kye Posted November 3, 2019 Share Posted November 3, 2019 53 minutes ago, tupp said: Higher resolution is not necessarily the primary advantage of larger formats -- the advantage is the look. Our own @richg101 developed a medium format DOF adapter -- the Forbes 70. He used the OG Blackmagic Pocket (HD) with the Forbes 70, and the images were beautiful and distinct from smaller formats. In addition, or own @Gonzalo Ezcurra made the largest format DOF adapters that I have seen (14"x14" and 20"x20"), and he used HD cameras with it, but the footage was wondrously gorgeous. Any idea where "the look" comes from? That's what we're trying to figure out. Quote Link to comment Share on other sites More sharing options...
Nikkor Posted November 3, 2019 Share Posted November 3, 2019 2 hours ago, kye said: Any idea where "the look" comes from? That's what we're trying to figure out. The look comes from the DOF, it works different with different magnifications. The closer you get to large magnificactions the "dof" variance speed increases. If you shoot at infinity you won't notice much benefits apart from increased resolution and less noise, but as soon as you get close to middle shots you start noticing the difference. The result is that a wide shot on 70mm has the same look as a closeup, so you can show an actor suspended in his surroundings, everything looks very plastic-volumetric. Years ago I made a lot of posts about this but nobody seemed to take them seriously. Quote Link to comment Share on other sites More sharing options...
kye Posted November 3, 2019 Share Posted November 3, 2019 10 hours ago, Nikkor said: The look comes from the DOF, it works different with different magnifications. The closer you get to large magnificactions the "dof" variance speed increases. If you shoot at infinity you won't notice much benefits apart from increased resolution and less noise, but as soon as you get close to middle shots you start noticing the difference. The result is that a wide shot on 70mm has the same look as a closeup, so you can show an actor suspended in his surroundings, everything looks very plastic-volumetric. Years ago I made a lot of posts about this but nobody seemed to take them seriously. I'm very interested in this and would like to get to the bottom of what you're seeing. Is it that a wide angle has a shallower DoF? On smaller sensors shallow DoF on wide-angle lenses is very difficult to do, so that would make sense. Or is it to do with the falloff between what is in focus and what isn't in focus? I'm 100% sure that there's some kind of engineering or physics principle behind what we're talking about, the challenge is figuring out what it is Quote Link to comment Share on other sites More sharing options...
Nikkor Posted November 4, 2019 Share Posted November 4, 2019 1 hour ago, kye said: I'm very interested in this and would like to get to the bottom of what you're seeing. Is it that a wide angle has a shallower DoF? On smaller sensors shallow DoF on wide-angle lenses is very difficult to do, so that would make sense. Or is it to do with the falloff between what is in focus and what isn't in focus? I'm 100% sure that there's some kind of engineering or physics principle behind what we're talking about, the challenge is figuring out what it is There is, dof starts behaving differently the closer you get to large magnifications. I took my time and made the math, no idea were those equations ended up, probably in the Recycling bin. In Praxis and depending on lens quality it makes things Pop and Look volumetric, The differentiation between in Focus and out of Focus is stronger. Another way to say it is that the DOF is denser and then quickly fades away vs. the gradual blurring away from the Focus Point that occurs with small formats. Don't lose your sleep over it, if you like the Look you can buy a baveyes kipon Adapter until you can afford a big sensor camera. Quote Link to comment Share on other sites More sharing options...
kye Posted November 4, 2019 Share Posted November 4, 2019 22 hours ago, Nikkor said: There is, dof starts behaving differently the closer you get to large magnifications. I took my time and made the math, no idea were those equations ended up, probably in the Recycling bin. In Praxis and depending on lens quality it makes things Pop and Look volumetric, The differentiation between in Focus and out of Focus is stronger. Another way to say it is that the DOF is denser and then quickly fades away vs. the gradual blurring away from the Focus Point that occurs with small formats. Don't lose your sleep over it, if you like the Look you can buy a baveyes kipon Adapter until you can afford a big sensor camera. No losing sleep for me. I'm interested in figuring it out in order to learn and build my skillset, and find this stuff absolutely fascinating. I'm thinking I might do some tests and see if I can isolate the variables - is there certain subject matter or situations that will emphasise the effect? You mention closer or mid shots, anything else? Do we need a person in frame, or can a still-life reveal the effect? Quote Link to comment Share on other sites More sharing options...
Super Members BTM_Pix Posted November 5, 2019 Super Members Share Posted November 5, 2019 You might want to have a read through this thread @kye It turned into a bit of a bin fire towards the end but useful stuff for you nonetheless. kye 1 Quote Link to comment Share on other sites More sharing options...
kye Posted November 5, 2019 Share Posted November 5, 2019 2 hours ago, BTM_Pix said: You might want to have a read through this thread @kye It turned into a bit of a bin fire towards the end but useful stuff for you nonetheless. Thanks! All the good things in life turn into dumpster fires.... The only way to not offend anyone is to not say anything, and that still offends people but either they can’t hear you or they’re too oppressed by the status-quo to have a voice and be heard Quote Link to comment Share on other sites More sharing options...
User Posted November 5, 2019 Author Share Posted November 5, 2019 36 minutes ago, kye said: The only way to not offend anyone is to not say anything, and that still offends people but either they can’t hear you or they’re too oppressed by the status-quo to have a voice and be heard Amen. Quote Link to comment Share on other sites More sharing options...
kye Posted November 5, 2019 Share Posted November 5, 2019 4 hours ago, BTM_Pix said: You might want to have a read through this thread @kye It turned into a bit of a bin fire towards the end but useful stuff for you nonetheless. Read through a few pages and my brain is already melted. Not from the technical aspects involved, but in trying to understand what people are actually saying. I think that part of the problem is that so many variables are at play that a proper conversation can't be had because people aren't communicating the full picture and are changing multiple variables at the same time. Even the animated gif in the thumbnail thread (showing the Canon camera and shallow DoF) clearly shows that the camera position has changed, which is hopeless - you can't compare the size of the bokeh if you're moving the camera around. All the talk of 'getting closer' in these articles and comments indicates that at least some people are talking about the difference between close/wide and far/tele shots, which is a completely different topic to standing in the same place and comparing setups that have the same FOV and DoF: a small sensor camera/lens setup a large sensor camera/lens setup, and a small sensor camera / large sensor lens with speed booster IIRC I have 55mm, 40mm lenses at home, plus a 0.71x SB for the 55mm, so should be able to do a comparison (55mm x 0.71 = 39mm). I'll see if my brain recovers enough throughout the day to be able to do a test when I get home. heart0less, Adam Kuźniar and tupp 3 Quote Link to comment Share on other sites More sharing options...
EthanAlexander Posted November 5, 2019 Share Posted November 5, 2019 5 minutes ago, kye said: Even the animated gif in the thumbnail thread (showing the Canon camera and shallow DoF) clearly shows that the camera position has changed, which is hopeless - you can't compare the size of the bokeh if you're moving the camera around. Thank you. From that other thread: On 2/22/2017 at 7:33 PM, jcs said: I did those tests- it's not really possible to do perfect equivalence with physical lenses unless all the settings can be exactly matched. In the first example, the only major difference was shadow detail which could be related to ISO... In the second example, maybe I made a mistake or it's still related to optics not really being equivalent. The 'normal' test matches almost perfectly. Brain Caldwell, the optical engineer and inventor of the Speed Booster says the same thing regarding FF vs. MF. That's why he wasn't interested in making a MF to FF SpeedBooster... In any case, the differences are minor and most people couldn't tell the difference. Someone posted computer graphics (ray traced?) examples that matched perfectly, as the math predicted. I'm about to get my first MFT camera so I'm excited to do my own tests vs FF, but it really seems to me that mathematically there's no difference between formats, it just comes down to real-world imperfections and real world availability of manufacturing. For instance, one thing that I think stands out with larger formats is shallow depth of field at wider fields of view: 24mm 1.4s are commonly made for FF cameras, whereas a 12mm f/0.7 doesn't exist to my knowledge so you can't match that look on MFT. It's technically possible it just doesn't get made because the cost wouldn't be worth it.(.64 speed boosting a Sigma 20mm 1.4 would be pretty close though) heart0less, Jonathan422, tupp and 1 other 4 Quote Link to comment Share on other sites More sharing options...
tupp Posted November 5, 2019 Share Posted November 5, 2019 4 hours ago, kye said: Even the animated gif in the thumbnail thread (showing the Canon camera and shallow DoF) clearly shows that the camera position has changed, I don't think that the tester moved the camera -- the tester was using a single zoom lens and he simply zoomed to change the focal length and then cropped into the image to change the sensor "size." On the other hand, in doing so, the entrance pupil of the lens might have moved forwards/backwards. The problem with such a test (other than the fact that the tester is using the exact same zoom lens for a comparison) is that he didn't test separate optics made for different size formats. 4 hours ago, kye said: I have 55mm, 40mm lenses at home, plus a 0.71x SB for the 55mm, so should be able to do a comparison (55mm x 0.71 = 39mm). That won't work -- it's an almost identical scheme to the above mentioned test in which the tester used a single lens zoomed to different focal lengths. To do the test properly, you have to use two different lenses -- one designed for a smaller format and one designed for a larger format. I would also suggest the the two lenses that you choose to test should be made for two formats of extremely disparate sizes. Comparing a M4/3 lens to an APS-C lens might show a difference that is too subtle for most to perceive, and likewise when comparing lenses made for APS-C and full frame. To make the difference obvious to most people, it would best to compare, say, a lens made for 16mm film to one made for 4"x5" film. By the way, I made those animated gifs, because I could see the subtle yet important differences between the two images that evidently escaped most viewers when the photos were presented one above the other. Even after gifs were posted, some folks could not see the slight, telling differences in focus and DOF, to my dismay. So, you have to hit people over the head to demonstrate a difference. Here is a photo taken with a camera that has a 14"x17" film plane. Aside from the peculiar contrast (it's a tintype), do you think that this look (especially from the focus/DOF) can be duplicated on a Blackmagic Micro Cinema Camera? If you could achieve an identical extremely shallow depth of field with a lens made for M4/3, that girl's shoulders would be a completely blurry mush. 4 hours ago, EthanAlexander said: I'm about to get my first MFT camera so I'm excited to do my own tests vs FF, but it really seems to me that mathematically there's no difference between formats, it just comes down to real-world imperfections and real world availability of manufacturing. I love M4/3, but there are general differences in the look of different formats that do not involve "imperfections." By the way, at what point was it declared that lenses for larger formats have more "imperfections" than those made for smaller formats? Please not that the "equivalence principle" and the depth of field formula are correct in finding the two mathematical limits (front and back) of depth of field. However, neither of these notions account for how the focus rolls off outside of these front and back limits, nor do the equivalence principle and DOF formula describe any variances might occur within their two mathematical limits. There are variables that affect focus that generally increase/decrease depending on the format size for which the optics are designed. For instance, it is easier to put more lines of optical resolution into larger formats. The smaller the format, the more difficult it is to squeeze in the same number of optical resolution lines. When a lens gets near the practical limits cramming lines of resolution into a smaller area, it must certainly affect the look of the focus, which influences how the DOF looks/rolls-off. Quote Link to comment Share on other sites More sharing options...
cpc Posted November 5, 2019 Share Posted November 5, 2019 Historically, the reason for using larger formats was resolution. When the change to widescreen happened, the need for higher horizontal resolutions came naturally. You need more negative in order to cover the wide screen without reducing vertical resolution. But with film stocks getting better and better, this was less of a necessity. Optically, larger sizes can do fine with technically worse lenses because you need less lpmm for the same (perceived) microcontrast after magnification. As a result, larger formats generally have better delineation which promotes a feeling of three dimensionality in the image. Of course, actual FOV has little to do with format size, and perspective entirely depends on viewpoint (camera to subject distance). Anamorphic does have peculiarituies though, since only one FOV (usually vertical) matches the spherical equivalent and the other axis' FOV is wider than nominal. Quote Link to comment Share on other sites More sharing options...
Adam Kuźniar Posted November 5, 2019 Share Posted November 5, 2019 I must've read this page at least twice and I still don't quite get what are we even discussing now. That being said I always hated math so maybe that's why I don't get it. Quote Link to comment Share on other sites More sharing options...
Video Hummus Posted November 5, 2019 Share Posted November 5, 2019 Coming from a non-expert, non-industry professional. What I notice first in a large format video is the shallow DoF in wide shots and a slightly more pronounced separation of things in the frame. But there was probably so many more variables of directors choosing an Alexa 65 over a large format film camera. When I watch a movie I would rate what it was shot on at the very bottom. In Hollywood they always go for that last 10%. I would put the size of the sensor in your camera in that 10%. Would I have enjoyed The Revenant less if it was shot on S35? No fucking way. Its the last 10% of that film. Good luck trying to put your finger on what exactly it is about large format. I think it’s a moving target. Jonathan422 1 Quote Link to comment Share on other sites More sharing options...
androidlad Posted November 5, 2019 Share Posted November 5, 2019 From a pure technical point of view, 50% of the 65mm mojo is the shift in relationship between FOV and perspective - a 50mm lens mounted on Alexa 65 has a wider 35mm FOV but maintains a 50mm perspective - often described as some kind of grandness or panoramic quality: capturing more without the wide angle look. The other 50% is of course the shallower DOF. Quote Link to comment Share on other sites More sharing options...
cpc Posted November 5, 2019 Share Posted November 5, 2019 19 minutes ago, androidlad said: From a pure technical point of view, 50% of the 65mm mojo is the shift in relationship between FOV and perspective - a 50mm lens mounted on Alexa 65 has a wider 35mm FOV but maintains a 50mm perspective - often described as some kind of grandness or panoramic quality: capturing more without the wide angle look. The other 50% is of course the shallower DOF. Focal lengths have no "perspective". There is no such thing as "50mm perspective", so you can't maintain this with a 50mm lens on a bigger sensor. Relative sizes of objects depend entirely on the position of the camera. Closer viewpoints will exaggerate perspective and more distant viewpoints will flatten perspective. Hence, some people may say that wider lenses have stronger perspective, which is incorrect. What they actually mean is that with a wide lens you move forward for a similar similar object size in the frame (compared to a longer lens), and this movement forward decreases the camera-subject distance and exaggerates perspective distortion. Surely everyone has seen one of these: EthanAlexander 1 Quote Link to comment Share on other sites More sharing options...
androidlad Posted November 5, 2019 Share Posted November 5, 2019 18 minutes ago, cpc said: Focal lengths have no "perspective". There is no such thing as "50mm perspective", so you can't maintain this with a 50mm lens on a bigger sensor. Relative sizes of objects depend entirely on the position of the camera. Closer viewpoints will exaggerate perspective and more distant viewpoints will flatten perspective. Hence, some people may say that wider lenses have stronger perspective, which is incorrect. What they actually mean is that with a wide lens you move forward for a similar similar object size in the frame (compared to a longer lens), and this movement forward decreases the camera-subject distance and exaggerates perspective distortion. Surely everyone has seen one of these: Correct. But if that’s relevant to what we are discussing here, all films should be shot with just one super wide focal length and just crop in post for different shot sizes. Quote Link to comment Share on other sites More sharing options...
EthanAlexander Posted November 5, 2019 Share Posted November 5, 2019 6 hours ago, tupp said: By the way, at what point was it declared that lenses for larger formats have more "imperfections" than those made for smaller formats? It wasn't. I meant imperfections in real world tests, not larger lenses. 6 hours ago, tupp said: love M4/3, but there are general differences in the look of different formats that do not involve "imperfections." This is why I said "real world availability of manufacturing" - I do believe there is a general "look" that comes from larger sensors, but I think it has more to do with the lenses that are available. The lack of availability of extreme wide angles with super shallow depth of field (such as a 12mm f0.7) is a big reason FF is hard to match with smaller sensors like MFT. It also accounts for the fact that not every sensor is going to deliver the same results for things like dynamic range etc. But in a computer, equivalency is accurate, and we can come close enough in the real world that only minor differences happen. 6 hours ago, tupp said: To do the test properly, you have to use two different lenses -- one designed for a smaller format and one designed for a larger format. The only difference is the size of the image circle that comes out the back. The size of the sensor then determines the field of view. This is why if you're shooting on an APSC camera with a FF 24-70mm 2.8 lens or an APSC 18-55mm 2.8 (two common Canon zooms, for instance), you'll get the same image for the entire overlapped range of focal lengths of 24-55mm. I invite you to test this out yourself and see. Quote Link to comment Share on other sites More sharing options...
cpc Posted November 5, 2019 Share Posted November 5, 2019 4 minutes ago, androidlad said: Correct. But if that’s relevant to what we are discussing here, all films should be shot with just one super wide focal length and just crop in post for different shot sizes. Can't do this if you want constant image quality (noise size, detail and no-crop equivalent DOF). But yes, if you only care about perspective, you can do this. Quote Link to comment Share on other sites More sharing options...
EthanAlexander Posted November 5, 2019 Share Posted November 5, 2019 11 minutes ago, androidlad said: But if that’s relevant to what we are discussing here, all films should be shot with just one super wide focal length and just crop in post for different shot sizes. I know you're being sarcastic, but you're making an invalid point - it's about perspective. The artistic choice comes from deciding how close or far you are from your subject. Roger Deakins, for example, loves 27mm and 21mm on S35 because it's wider than is traditional for a 1-shot which allows him to get closer to people and make the audience feel like they're closer. It doesn't have to do with the FOV, which you could match with a longer lens from far away, it has to do with perspective, which changes when you get closer. People know, even if only subconsciously, how close the camera is to the subject. So whether you're on S35 or FF or whatever, the feeling will be the same if the camera is in the same spot, and then to match the FOV you just use an equivalent focal length (So a 27mm on S35 or a 40.5mm on FF). Quote Link to comment Share on other sites More sharing options...
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