If, back in the 1920s, you could have been the decider of the 35mm format ...

[Helge]

Sure, on the back, but what about the front of the emulsion? If the glass were on the front and the back was secured by a metal pressure plate, the introduction of "in focus" dust would have had the ready potential to be rather profound. And "telling" people to be "careful" would not be the same as telling them to imagine themselves as ants who can see dust as giant boulders. - David Lyga

Again, not worse than the problem with dust on sensors.
There is still the potential for dust in the film plane.
So the problem is not completely foreign in our world.

Rollei made the flat glass back work, even if it’s not remembered as their greatest triumph.
But that was shoehorned into an existing design.

If the whole system was based on it, it would be possible to make it pretty smooth and carefree.

Alternatively, have a small vacuum cylinder or barometric can that sucks the film onto a finely holed plate half a second before exposure.
Sounds complicated and Contax like, but could be made simply.

 

[Helge]

It would have brought additional challenges with flare and light piping. I know because I tried.

The flat glass back on the Rolleiflex did it with few or no optical problems.
So certainly it’s possible.

 

[David Lyga]

David.
You are analyzing the mid-points on the edges, when it is the corners that create the challenge.
Draw a diagonal line from corner to corner on a 24mm x 36mm frame. That line is ~43.3 mm long, and is the minimum diameter of a circle of coverage that minimally covers the 24mm x 36mm frame.
Now draw a diagonal line from corner to corner on a 36mm x 36mm frame. As that frame is taller, the diagonal ends up being longer - ~50.9 mm long, and is the minimum diameter of a circle of coverage that minimally covers the 36mm x 36mm frame.
When you compare the distances between the exact centre of the frame and the outermost corners (not edges) the distance on a 24mm x 36mm frame is about 8.8mm closer than on a 36mm x 36mm frame.
EDIT: I now see that others have help you clarify your quandary. Oh well!

You tried, Matt, but my stupidity beat you to the punch! - David Lyga

 

[Sirius Glass]

As for frame format, it’s not just two cinema frames stuck together. The shape of the 35mm format was not randomly selected, but based upon the painters principle of the Golden Mean. There have been other frame shapes such as those introduced by Robot and early Nikon rangefinder cameras. Some APUG members will be able to list more attempts at different frame shapes by other 35mm camera makers. All failed at the market place because not only is the 35mm frame the most pleasing, but also allows some wiggle room for other frame shapes.
Nevertheless, being what were then called 35mm miniature cameras, film quality then did not allow the same flexibility for choosing the desired final frame shape from a more square like format as, say, a Rolleiflex or Super Ikonta B or larger cameras.
As for sprocket holes. As mentioned above, they are needed on both sides to insure film stability at the gate. 16mm movie film can get away with sprockets only on one side because width of film is much smaller. Smaller gauge Minox film needs no sprockets.
We sometimes forget, especially with high end equipment, that we are dealing with precision instruments.

Barnack stuck two frames together for convenience of his work, there was no consideration of the Golden Rectangle nor any other rule. See below.

If it is, it is not at all apparent to me.

Looking at the illustration on the right of Wikipedia page describing the golden rectangle.
The 35mm frame is nominally 36x24 so, a=24 and b=12.
and, (a+b) / a = 36/24 = 3/2 and a/b = 24/12 = 2
3/2 ≠ 2 ≠ 1.6180339887...

Have I misunderstood something?

No, you nicely proved what I stated above. Don't look at the man behind the curtain! There are no Golden Rectangles here.



Note Bene: No Golden Rectangle were injured nor killed in the making of this posting.

 

[Wallendo]

I would just use one row of smaller perforations. I find it interesting that 35mm film, like 120 film could support a large number of image ratios, yet this ability, other than a few half-frame cameras was never exploited.

I like the 1.5:1 ratio, it just seems to fit in better with the way I shoot (A lot of my Yashica Mat photos haver a lot of empty sky).

Amazingly, despite all the film formats specifically designed for still photography, the clunky 35mm format, with all its wasted space, has outlived almost all of them.

 

[Helge]

I would just use one row of smaller perforations. I find it interesting that 35mm film, like 120 film could support a large number of image ratios, yet this ability, other than a few half-frame cameras was never exploited.

I like the 1.5:1 ratio, it just seems to fit in better with the way I shoot (A lot of my Yashica Mat photos haver a lot of empty sky).

Amazingly, despite all the film formats specifically designed for still photography, the clunky 35mm format, with all its wasted space, has outlived almost all of them.

Not true.

There is square Robot frames and the various wide formats like Xpan and Widelux.
There is also Viewmaster and Stereo Realist frames which both have their own custom formats.

I bet there are others I’ve forgotten about.

There has even been cameras made to shoot on unperforated film in square format, just like I suggested.

 

[David Lyga]

Amazingly, despite all the film formats specifically designed for still photography, the clunky 35mm format, with all its wasted space, has outlived almost all of them.

In fairness to the truth, the 'clunky' format did not survive wholly on its own merits but, rather, primarily from intense pressure from photo finishers, especially from Kodak who did not wish to compromise the status quo. - David Lyga

 

[Murray Kelly]

If the intention really was to test film and lenses then the 18 x 24 would be bettered by a 24 x 24 format. The fly in the ointment would be sprocket hole spacing. However my square format 35mm cams seem to have it worked out OK.

 

[Donald Qualls]

Given there's some space between frames, a 24x24 frame should work with a 6-perf advance (18x24 is 4-perf, 24x36 is 8-perf).

I just this morning ran across a reference to 235 film as well -- standard 24x36 frame, implying perforated film, but it was sold in a paper-leader spool to spool format, like 220. I think I prefer cassette -- even with 1930s cameras, they're easier to load than a 35mm paper leader (I've loaded just enough 828 to call myself experienced with that size).

 

[moofy]

~ 33.9 * 24 mm. So the diagonal is proportional to the square root of 2 and they could be printed on A paper sizes without cropping. While we're at it, make sheet film the same thing.

 

[BradS]

~ 33.9 * 24 mm. So the diagonal is proportional to the square root of 2 and they could be printed on A paper sizes without cropping. While we're at it, make sheet film the same thing.

Do you mean the aspect ratio? 33.9 /24 ≈ sqrt(2)
The diagonal of a square is exactly proportional to sqrt(2).

 

[moofy]

Yes. Aspect ratio.

 

[albada]

You'd need to have some rebate, for handling and edge protection (828 has about 1.5 mm on the non-perf side, 127 has 2mm or so on each edge, 120 is 3mm edge rebate). So you'd wind up with about 32x32 or 33x33 at most on a 35mm strip.

For years, I have bemoaned the large amount of wasted space on 35mm film. A larger negative brings finer grain, so I'm all in favor of a 33x50 frame (leaving 1mm of rebate along each edge). 33x50 has almost twice the image-area as 24x36, reducing grain accordingly. Just use non-perforated film. Problem solved.

Mark Overton

 

[AgX]

In the Karat, Rapid, SL systems the manufacturers of cameras and films could have left out one of the perforation lines (as being unused anyway) and design the respective cameras for a bit bigger frame. But then there would be the trouble with yet another format at enlarging.
Seemingly they did not find that worthwhile.

And with the second perforations line they keep that silver (from the holes) in house...

 

[Donald Qualls]

Unperfed film, 33x50 frame, and a friction driven length-counter advance (like used in many 120 cameras), plus a paper head and tail to simplify loading (or a cassette system like the one 35mm has now) could have been a nice improvement over 828 or 35mm -- but it would have had to start no later than 1930 to have a chance to beat out the cine double perf film selected by Barnack and Leitz and picked up on a competitive basis by Zeiss. As it is, we have only one non-perfed roll size still in common use (you can still buy 46mm film strips if you're a 127 addict, but it's hard to get spooled 127 film and it's expensive -- actually cheaper to cut down 120 and respool it).

A 33x50 frame could have easily competed against 127 half frame -- more compact camera, no harder to load (with a better spool design than 828, or a cassette system) -- and with the films of the day, would have been significantly superior to the 24x36 we have now. Mechanical counters for unperfed film, however, didn't come along for another seven or eight years (my Super Ikonta B is a 1938 design, despite having been built after the War) and the earliest of them were turns-counters, which are less consistent than length counters. That would have required backing paper and a ruby window on the hypothetical camera, making it similar to 828 (which Kodak made easier to use with auto-stop winding working from a single perf per frame), and thus hampered for professional use by roll length (16 is about the limit that will fit 828 spools and 12 was probably closer to the mark with 1930s films, assuming you keep the backing for the full length), the fiddly operation of loading the tiny spools, and needing the ruby window to see how much film you've used/have left. Our hypothetical "133" or "1650" film format would almost certainly have wound up as just another of the relatively obscure roll film formats that vanished over the past century.

 

[NB23]

Ooohhh “golden recrangle”! I like that!

I think a square-ish rectangle is sexier than a longish rectangle, therefore I’d have done 24x32. But then again, I’m also a XPAN nut... so my opinion is worthless.

I will just say that one major PITA are the available standard paper sizes that don’t match the 24x36 format. 5x7? 8x10? 11x14? 16x20?

Ratios are all over the place. Drove me crazy until I decided to bypass this insanity and started to print full frame within the paper. That was my middle finger to the market conventions. Best decision ever also because it forced me to be careful with in-camera composing. I just never ever crop. Solved so many problems all at once.

 

[nosmok]

I took one of my 828 Kodak Bantams and filed the film gate to 28mm x 44mm (same ratio as the old 7x11in format from the turn of the 20th century) to get closer to a 'Golden Mean' frame in a compact format. It's 50% more area than a normal 35mm negative, and you have the benefit of being able to use cut-down 120 backing paper -- the 6x4.5 numbers give you a little safety margin. Like all 828 film, it's tough to scan (if you want a d***tal product) in its correct size. I had much worse luck trying to shave down an Epson scanner film holder from 24 to 28mm than I had filing that film gate.

 

[David Lyga]

It is true that the most successful format of them all wastes more space than any.

A bulk roll of 35mm film has 30,480mm in length and 35mm in width. Thus, its total area is 1,066,800 sq mm.

Optimally, one can hope to get no more than 700 frames (even that is stretching it) from that bulk roll. Each frame has an area of (24 X 36) = 864 sq mm. Thus, the total area of usable image area is (864 X 700) = 604,800 sq mm.

It is a bit mentally distressful to have to acknowledge that the percentage of USABLE film in that bulk roll is only (604,800 / 1,066,800) = 56.69% AT BEST (and usually closer to 50%). Close to HALF the film is wasted. - David Lyga

 

[David Lyga]

(if you want a d***tal product)

Were the asterisks put into place because you had just uttered a profane word? - David Lyga

 

[Donald Qualls]

I took one of my 828 Kodak Bantams and filed the film gate to 28mm x 44mm (same ratio as the old 7x11in format from the turn of the 20th century) to get closer to a 'Golden Mean' frame in a compact format. It's 50% more area than a normal 35mm negative, and you have the benefit of being able to use cut-down 120 backing paper -- the 6x4.5 numbers give you a little safety margin. Like all 828 film, it's tough to scan (if you want a d***tal product) in its correct size. I had much worse luck trying to shave down an Epson scanner film holder from 24 to 28mm than I had filing that film gate.

If you search eBay, there's a seller who makes and offers 3D printed single strip negative carriers for 126 and 110 to fit the Epson scanners (they can be made to fit 4870 and all later models, possibly a few earlier ones). With no cross bars between frames, the 126 carrier will work with 828, since the frame width and offset is the same.

I've used the 120 backing whenever I've cut 828 from 120 -- you'll get extra spacing with the standard cameras, and have to watch the window since the stop finger won't operate, but in my Bantam RF there's a length-counter advance stop (roller on the perf edge film rebate, but without an actual counter), which gets me 18 exposures on a cut down roll instead of 16. I use the (green) window only to know when to continue to wind off the tail.

Were the asterisks put into place because you had just uttered a profane word? - David Lyga

Most like that -- this is, after all, the analog-only section of Photrio...