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Digital equivalent of a legacy 35mm movie camera
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Jun 22, 2022 14:16:48   #
Alphabravo2020
 
I've been reading on filmmaking recently and was wondering what digital sensor would be required to film a typical 35mm 1.85:1 movie from the 70s/80s.

I guess I'm asking what sensor size and dpi would be adequate for projection onto a cinema screen and represent the original resolution assuming frames are cropped to 1.85:1 or 16:9 (no anamorphic lenses).

TIA

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Jun 22, 2022 14:34:18   #
User ID
 
Alphabravo2020 wrote:
I've been reading on filmmaking recently and was wondering what digital sensor would be required to film a typical 35mm 1.85:1 movie from the 70s/80s.

I guess I'm asking what sensor size and dpi would be adequate for projection onto a cinema screen and represent the original resolution assuming frames are cropped to 1.85:1 or 16:9 (no anamorphic lenses).

TIA

Most cameras of the last few years are more than capable of that.

No matter how great the cinematography, a film movie is just a bunch of half frame (single frame) still images. Most modern cameras are the equivalent of full frame (double frame), so no hey problemo.

(DPI ?!? Thaz graphic arts. Not at all related to motion picture. Theres no answer for that.)

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Jun 22, 2022 14:40:04   #
CHG_CANON Loc: the Windy City
 
Repeat after me: there are no dots in pixel-based images.

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Jun 22, 2022 15:01:12   #
therwol Loc: USA
 
User ID wrote:
Most cameras of the last few years are more than capable of that.

No matter how great the cinematography, a film movie is just a bunch of half frame (single frame) still images. Most modern cameras are the equivalent of full frame (double frame), so no hey problemo.


The frame size matters for quality. A full frame camera will tend to produce better looking video than a consumer grade camcorder shooting at the same resolution. Those have tiny sensors. But the other factor is the resolution itself. On some of these new cameras, you can shoot 1080p, 4K and 8K and have a choice of screen formats. Where do you cross the line to the quality of projected 35mm film? I don't know the answer, but I can tell you from experience that digital projected movies are getting better all of the time. At the same time, and I don't know how long this will last, many major motion pictures are still shot on film and digitized for release. All 37 of the pictures listed here were shot on real film in 2021. They even list the film and equipment used. Surprised?

https://www.imdb.com/list/ls085159107/

If they're shooting on film and transferring to digital, it tells you that the resolution of the film equals or exceeds the resolution of the digital.

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Jun 23, 2022 01:08:07   #
Wallen Loc: Middle Earth
 
Alphabravo2020 wrote:
I've been reading on filmmaking recently and was wondering what digital sensor would be required to film a typical 35mm 1.85:1 movie from the 70s/80s.

I guess I'm asking what sensor size and dpi would be adequate for projection onto a cinema screen and represent the original resolution assuming frames are cropped to 1.85:1 or 16:9 (no anamorphic lenses).

TIA


Films have a different way of recording light compared to digital sensors so a direct comparison would be very subjective. It rely on randomly distributed photosensitive chemicals, which to some degree, are also random in size. Meaning, film does not have a set DPI like digital sensors which is composed of an exact repeating matrix.

Image sharpness is another example where comparison may come into issues because digital sensors has problems that does not apply to film. If we film a diagonal line, the digital matrix can show this as a jagged steps in low dpi and a moire in high dpi. The same does not apply to film. It will just show a change in fuzziness but never the jagged steps or the moire.

If the question is "What DPI is enough to create a good experience in the silver screen?", that is still subjective. More to that, the size of the screen and the distance of the viewer will greatly affect the experience.

Back then we were using 800x600dpi digital projectors for training. From 10ft away, a horizontal image of 5ft on the wall was acceptable for watching videos. That is only about 13.33dpi.

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Jun 23, 2022 07:14:12   #
Schoee Loc: Europe
 
Wallen wrote:
Films have a different way of recording light compared to digital sensors so a direct comparison would be very subjective. It rely on randomly distributed photosensitive chemicals, which to some degree, are also random in size. Meaning, film does not have a set DPI like digital sensors which is composed of an exact repeating matrix.

Image sharpness is another example where comparison may come into issues because digital sensors has problems that does not apply to film. If we film a diagonal line, the digital matrix can show this as a jagged steps in low dpi and a moire in high dpi. The same does not apply to film. It will just show a change in fuzziness but never the jagged steps or the moire.

If the question is "What DPI is enough to create a good experience in the silver screen?", that is still subjective. More to that, the size of the screen and the distance of the viewer will greatly affect the experience.

Back then we were using 800x600dpi digital projectors for training. From 10ft away, a horizontal image of 5ft on the wall was acceptable for watching videos. That is only about 13.33dpi.
Films have a different way of recording light comp... (show quote)


Your projector was 800x600 pixels, not dpi. As you said yourself it made a 5ft image which is only 13.3 dpi.

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Jun 23, 2022 10:16:23   #
User ID
 
therwol wrote:

.................... All 37 of the pictures listed here were shot on real film in 2021. ........,.

https://www.imdb.com/list/ls085159107/

If they're shooting on film and transferring to digital, it tells you that the resolution of the film equals or exceeds the resolution of the digital.


Nope. Choice of film or digital is not for image quality. The IQ of both media are equal. Labor cost for motion picture can be phenominal. Film is faster and easier to use. Time is money, huge money.

In the overall budget of a major shoot, the *material* cost of using film is a minor concern.

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Jun 23, 2022 11:18:19   #
Wallen Loc: Middle Earth
 
For clarification, I used the term wrong in explaining the monitor, which should be PPI.

Dots are resolution in print and Pixels are for detectors or monitors.

But I deliberately used the term dots to compute and represent the projectors capability as a printer painting a wall to level the answer to the question, and since using the pixel count will be a misnomer because there are many pixels contributing for each dot.

Back then, in a digital projector, the color pixels are premixed into a dot of light and that dot is projected.
The 800 dots actually has 800red, 800blue & 800green pixels mixed with the projection lamp.

It can be computed as DPI:
800dpi / 5ft = 160 dots per feet
160/ 12=13.3333 dpi.

The projector is using 13.33 dots to light up and show data for every inch of the projection on the wall.

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Jun 23, 2022 11:24:31   #
therwol Loc: USA
 
User ID wrote:
Nope. Choice of film or digital is not for image quality. The IQ of both media are equal. Labor cost for motion picture can be phenominal. Film is faster and easier to use. Time is money, huge money.

In the overall budget of a major shoot, the *material* cost of using film is a minor concern.


Just wondering something. There is time involved in processing film, editing it and doing a digital transfer. I do realize that in reality the shots are done on both simultaneously, which allows for preliminary edits, but wouldn't shooting entirely digital actually save some time?

Perhaps 5 years ago, I learned of a couple of things when listening to the BBC in the UK (while on vacation). Computer special effects at that time were a mature business that relied heavily on film for the end result. I don't know if that has changed. Second, some directors insisted on shooting their masterpieces on film. With the improvements in digital in the past 5 years, I wonder if they're just stuck in the past, like people who still buy DSLRs in 2022.

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Jun 23, 2022 11:46:25   #
User ID
 
therwol wrote:
Just wondering something. There is time involved in processing film, editing it and doing a digital transfer. I do realize that in reality the shots are done on both simultaneously, which allows for preliminary edits, but wouldn't shooting entirely digital actually save some time?

Perhaps 5 years ago, I learned of a couple of things when listening to the BBC in the UK (while on vacation). Computer special effects at that time were a mature business that relied heavily on film for the end result. I don't know if that has changed. Second, some directors insisted on shooting their masterpieces on film. With the improvements in digital in the past 5 years, I wonder if they're just stuck in the past, like people who still buy DSLRs in 2022.
Just wondering something. There is time involved ... (show quote)

You may be right about directors stuck in the past. Tach moves very fast so five years is a long time. Likewise editing film is faster than digital but given advances in computer power and therefor speed, what was true last year may be reversed next year.

Finally, just speculation but I wonder about the unions involved. Thinking about parallels to classic example of having a fireman on a diesel locomotive.

But the main point is that the operations and finances of motion picture are so complex that you cant infer that film has any IQ advantage simply by observing that it remains in use. And most certainly, there is no correlation between still photo and cinema as pertains to IQ.

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Jun 23, 2022 11:46:44   #
burkphoto Loc: High Point, NC
 
Alphabravo2020 wrote:
I've been reading on filmmaking recently and was wondering what digital sensor would be required to film a typical 35mm 1.85:1 movie from the 70s/80s.

I guess I'm asking what sensor size and dpi would be adequate for projection onto a cinema screen and represent the original resolution assuming frames are cropped to 1.85:1 or 16:9 (no anamorphic lenses).

TIA


Nearly all of the 4K capable mirrorless cameras already exceed the requirements.

A good choice would be the Panasonic Lumix GH6 (Micro 4/3) or Lumix S1H (full frame). Both are top quality video cameras *made for* filmmakers. They also double as great still cameras.

1.85:1 is very close to the DCI 4K resolution of 1.9:1 (4096 x 2160 pixels). The Lumix models do a great job with DCI 4K.

The GH6 has a 25MP sensor. It uses all the width of the sensor in most capture modes. It downsamples from that to 4K or DCI 4K, but can also record in "open gate" mode, where it records 5.7K video in 4:3, with or without anamorphic processing.

Compared to film stocks of the 1970s, the sensors in the GH6 and S1H are light years ahead. So is the entire digital filmmaking process. You can put an ENTIRE camera system and a computer to edit with in a backpack. Oh, you might want to add more lighting, sound, and monitoring equipment, but you can carry the essentials on your back and stuff it under an airline seat. Compare that with the 1970s, when it took an army of creators to make films!

Check these out:

https://youtu.be/ooeXkMRnat4 (Jordan Drake's DPReview TV review of the GH6)

https://youtu.be/jUd_I8Z3Iqw (A really good *filmmaker's review* of the GH6)

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Jun 23, 2022 12:36:13   #
Schoee Loc: Europe
 
Wallen wrote:
For clarification, I used the term wrong in explaining the monitor, which should be PPI.

Dots are resolution in print and Pixels are for detectors or monitors.

But I deliberately used the term dots to compute and represent the projectors capability as a printer painting a wall to level the answer to the question, and since using the pixel count will be a misnomer because there are many pixels contributing for each dot.

Back then, in a digital projector, the color pixels are premixed into a dot of light and that dot is projected.
The 800 dots actually has 800red, 800blue & 800green pixels mixed with the projection lamp.

It can be computed as DPI:
800dpi / 5ft = 160 dots per feet
160/ 12=13.3333 dpi.

The projector is using 13.33 dots to light up and show data for every inch of the projection on the wall.
For clarification, I used the term wrong in explai... (show quote)


My point was just that the projector has dots. Not dots per inch. They only become per inch when you project them and that varies by screen distance

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Jun 23, 2022 12:37:46   #
Alphabravo2020
 
therwol wrote:
I wonder if they're just stuck in the past, like people who still buy DSLRs in 2022.


Ouch, that hurt 😝 Seriously though, I appreciate all the comments and insight. From my recent reading it is a bit amazing that analog film and sound are so similar with respect to the limits of fidelity. Apparently it was once thought that 5MP would represent the resolution of 35 mm film. As scanners have improved the equivalent seems to be more like 80MP or maybe higher idk. And b/w film even higher.

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Jun 23, 2022 13:28:45   #
burkphoto Loc: High Point, NC
 
therwol wrote:
The frame size matters for quality. A full frame camera will tend to produce better looking video than a consumer grade camcorder shooting at the same resolution. Those have tiny sensors. But the other factor is the resolution itself. On some of these new cameras, you can shoot 1080p, 4K and 8K and have a choice of screen formats. Where do you cross the line to the quality of projected 35mm film? I don't know the answer, but I can tell you from experience that digital projected movies are getting better all of the time. At the same time, and I don't know how long this will last, many major motion pictures are still shot on film and digitized for release. All 37 of the pictures listed here were shot on real film in 2021. They even list the film and equipment used. Surprised?

https://www.imdb.com/list/ls085159107/

If they're shooting on film and transferring to digital, it tells you that the resolution of the film equals or exceeds the resolution of the digital.
The frame size matters for quality. A full frame ... (show quote)


Most of the folks still using film are doing it for a range of reasons not the least bit related to resolution. Here are a few:

Process — There is a certain ethos of film production that some directors and producers aspire to maintain. They believe it gives their work a look, and perhaps a credibility, that they might not achieve digitally. This may be more important with investors than with audiences.

Speed of process — Using film requires many hands, a lab, and more time than video. That can be an aid in the creative process, even if it is more expensive.

People — Some cinematographers and directors are more comfortable working with film. They grew up with it, and really don't want to move to digital late in their careers. As they "age out" and retire, fewer films will be made with real film, and film manufacturers will close their coating alleys.

Technical limitations — Film is slow (has low sensitivity). It forces the use of auxiliary lighting in most circumstances, both to raise exposure levels and control dynamic range. This has workflow consequences, which can be very positive.

"Look" — Although very subjective, film has a characteristic look that cannot be duplicated exactly with digital means. There is grain, color crossover, and extended dynamic range beyond the 12-15 stops of digital video cameras. That can be important in some situations.

Resolution? A 12MP digital camera has more image resolution than most full frame 35mm films. Super 35 camera aperture is 24.89 mm × 18.66 mm, compared to the standard Academy 35 mm film size of 21.95 mm × 16.00 mm. Full frame 35mm film and digital are nominally 36mm x 24mm. So the film frame is in about the same size class as APS-C digital. The film scanners used to transfer film to digital have higher resolution than the film itself.

One of the companies I worked for was owned by the same conglomerate that owned Consolidated Film Industries in Hollywood. CFI made some instructional filmstrips for us back in the early '80s, and I toured their facilities then. In addition to motion picture film processing and printing, they did lots of special effects work, and they transferred films to video for the television studios and network syndicators. I remember their VP of engineering telling me that most of the films they were transferring to analog video would have to be transferred again when digital imaging came of age. His hope was that the original film negatives would survive in storage that long.

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Jun 23, 2022 13:29:49   #
therwol Loc: USA
 
Alphabravo2020 wrote:
Ouch, that hurt 😝


Okay, I bought a DSLR in 2021 (Nikon D850) but with mitigating circumstances. I'm 70 years old living on retirements income, and because I would have to replace all of my screw drive autofocus lenses to move to a new mirrorless system, I'm not willing to spend that kind of money. I'd rather spend it on travel. I bought what will certainly be the last of the bunch, and that's okay with me.

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