General > General Technical Chat
Just because technology can do something, doent meant its always right
2N3055:
--- Quote from: tggzzz on June 20, 2022, 12:36:57 pm ---.....
If you want to, say, have multiple documents visible simultaneously even though you can only perceive one at any given instant, then higher resolution might be useful.
--- End quote ---
Larger size screen is useful.
I have 34" Samsung 34J550 UWHD 21:9 in front of me... I don't use dual monitor setup anymore...
It has 3440x1440 pixels.. cca 110 DPI . I cannot see individual pixels without magnifying glass.
Going more than that is stupid. It brings nothing. Once you get at approx. 100-120 DPI more important would be contrast, dynamic range, color calibration and viewing angles.... Ironically, those can be better optimized if pixels are bigger....
tooki:
--- Quote from: tggzzz on June 20, 2022, 12:36:57 pm ---I've seen two picture technologies that stand out from the rest.
35mm stereoscopic pictures on 100ASA slide film, i.e. about 5000x3000 pixels per eye. It is necessary to have the maximum possible depth of field, since people's eyes wander around the scene scene looking for details. If they can't focus on the details, it is uncomfortable.
Showscan movies, which I saw in the late 80s. They were much superior to the IMAX movies in the neighbouring theatre, and I saw the Showscan movies a several times. It is difficult to determine the resolution, but it was a 65mm image on 700 film, projected at 60fps. As far as I can tell, that equates to a resolution of around 5000x2500 pixels, but the high frame rate will improve the apparent resolution.
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IMAX has over three times the area of a frame as Showscan. So in terms of actual resolution, there’s no contest. The apparent increased sharpness of Showscan could be due to the fact that at 60fps, it means the slowest shutter speed possible is 1/60s, as opposed to 1/24s of regular 24fps film. That means less motion blur. (Of course you can use a faster speed when shooting, but you’re limited on the slow end.)
If we take your estimate of 5000x3000px for standard 35mm still photography (36x24mm) and extrapolate it to Showscan and IMAX, we get around 5920x3552px for Showscan and 10355x6213px for IMAX. (35mm movie film frames are much smaller than 35mm still photography frames.)
tggzzz:
--- Quote from: tooki on June 20, 2022, 02:52:05 pm ---
--- Quote from: tggzzz on June 20, 2022, 12:36:57 pm ---I've seen two picture technologies that stand out from the rest.
35mm stereoscopic pictures on 100ASA slide film, i.e. about 5000x3000 pixels per eye. It is necessary to have the maximum possible depth of field, since people's eyes wander around the scene scene looking for details. If they can't focus on the details, it is uncomfortable.
Showscan movies, which I saw in the late 80s. They were much superior to the IMAX movies in the neighbouring theatre, and I saw the Showscan movies a several times. It is difficult to determine the resolution, but it was a 65mm image on 700 film, projected at 60fps. As far as I can tell, that equates to a resolution of around 5000x2500 pixels, but the high frame rate will improve the apparent resolution.
--- End quote ---
IMAX has over three times the area of a frame as Showscan. So in terms of actual resolution, there’s no contest. The apparent increased sharpness of Showscan could be due to the fact that at 60fps, it means the slowest shutter speed possible is 1/60s, as opposed to 1/24s of regular 24fps film. That means less motion blur. (Of course you can use a faster speed when shooting, but you’re limited on the slow end.)
If we take your estimate of 5000x3000px for standard 35mm still photography (36x24mm) and extrapolate it to Showscan and IMAX, we get around 5920x3552px for Showscan and 10355x6213px for IMAX. (35mm movie film frames are much smaller than 35mm still photography frames.)
--- End quote ---
I suspect that 70mm film is faster than 100ASA, so the grains will be larger, and hence reduced spatial resolution.
I presume that persistence of vision will reduce the perceived grain size via the optical equivalent of dithering.
I guess those two effects cancel out to some degree, hence my guess at 70mm film's resolution.
60fps will definitely improve the perception of motion. ISTR Trumball determining that are dimknishing gains in producing movies at more than 66fps, hence Showscan's 60fps.
tooki:
--- Quote from: tggzzz on June 20, 2022, 03:08:08 pm ---I suspect that 70mm film is faster than 100ASA, so the grains will be larger, and hence reduced spatial resolution.
--- End quote ---
I don’t know where you’d get this idea, nor the notion that motion picture film doesn’t come in an array of speeds. The emulsion doesn’t care what size film stock it’s coated onto.
Anyhow, at least today, the only remaining manufacturer of motion picture film, Eastman Kodak, makes 65mm camera film* in the same ISOs as 35mm: 50, 200, 250, and 500. (Observe that none of these come even distantly close to the high ISOs modern digital cameras can capture cleanly.) The data sheets (one per film speed) — and thus the specs — are identical for all film sizes it comes in, from 8mm through 65mm.
As an aside, no wonder 70mm movies are so rare, and 60fps 70mm even rarer: at 24fps, a 1000 foot reel’s runtime is just under 9 minutes and costs around $1500, according to the price list I’m looking at. So at 60fps, that’s just three and a half minutes! (35mm is less than half the cost.) The intermediate film is even more expensive, but print film is massively cheaper.
*camera and intermediate films are 65mm, print film is 70mm.
tggzzz:
--- Quote from: tooki on June 20, 2022, 05:34:53 pm ---
--- Quote from: tggzzz on June 20, 2022, 03:08:08 pm ---I suspect that 70mm film is faster than 100ASA, so the grains will be larger, and hence reduced spatial resolution.
--- End quote ---
I don’t know where you’d get this idea, nor the notion that motion picture film doesn’t come in an array of speeds. The emulsion doesn’t care what size film stock it’s coated onto.
--- End quote ---
Of course it doesn't care; the photo-chemistry is the same.
My suspicion is based on looking at the single frame of 70mm film in my possession.
--- Quote ---Anyhow, at least today, the only remaining manufacturer of motion picture film, Eastman Kodak, makes 65mm camera film* in the same ISOs as 35mm: 50, 200, 250, and 500. (Observe that none of these come even distantly close to the high ISOs modern digital cameras can capture cleanly.) The data sheets (one per film speed) — and thus the specs — are identical for all film sizes it comes in, from 8mm through 65mm.
As an aside, no wonder 70mm movies are so rare, and 60fps 70mm even rarer: at 24fps, a 1000 foot reel’s runtime is just under 9 minutes and costs around $1500, according to the price list I’m looking at. So at 60fps, that’s just three and a half minutes! (35mm is less than half the cost.) The intermediate film is even more expensive, but print film is massively cheaper.
*camera and intermediate films are 65mm, print film is 70mm.
--- End quote ---
Thanks for the hard numbers. It appears that my suspicion was pretty accurate, despite your snide comment.
For my 35mm stereoscopic slides I had to use 64ASA film, in order to minimise[1] the visible grain. Only one speed you mention is slightly slower (~1.3 times) than that, the others being ~3, ~4, ~8 times faster.
One day perhaps I'll digitise them to try to see the relative grain size.
[1] not eliminate. With stereoscopic slides the grain is more visible for several reasons: you are looking at the film without projection optics, the natural tendency to closely examine all parts of the scene, and grain structure manifesting itself as depth structure.
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