Differences in Film Perfs?

T

tommygdawg

Well-known member
Hey all,

I should start this off by saying that this question is coming from a guy who's never touched film (I'd love to if I had the money). I've always had an interest in it. I've heard a number of DP's talking about the perfs in film, 2 perf, 4perf, etc. I know that this is essentially the number of perforations on the side of a single frame of film, but what I don't understand is the practical application and difference. From what I gather via Google, basically using less perforations is essentially like cropping the film, correct? Does this mean that all films shot with spherical or aspherical (ie not cylindricals) lenses are shot in 1.33 and simply cropped to the whatever aspect ratio is desired, ie 1.77, 1.85, etc.? I'm kind of confused here, any input would be greatly appreciated!

Thanks!
 
35mm is more legacy than anything, that's really old.

not cropping the film, just using less film per frame.

http://www.panavision.com/sites/default/files/2Perf Explained.pdf

in super 35 or s35mm, 3perf can get you a 1.85 image, 2perf can get you a 2.35 image.

with the 1.85 aspect ratio, you have some headroom (above and below the 2.35 aspect ratio) for vertical corrections, or you could choose 1.85 aspect ratio for the film. 2 perf is less forgiving but can cost you less film, lab costs...etc, to get a digital file.
 
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just a note, in the pdf, they are using 2.4 aspect ratio as the standard extraction area, but 2perf and 3perf can have the same width at 3.35 aspect ratio.
 
tommygdawg said:
Hey all,

I should start this off by saying that this question is coming from a guy who's never touched film (I'd love to if I had the money). I've always had an interest in it. I've heard a number of DP's talking about the perfs in film, 2 perf, 4perf, etc. I know that this is essentially the number of perforations on the side of a single frame of film, but what I don't understand is the practical application and difference. From what I gather via Google, basically using less perforations is essentially like cropping the film, correct? Does this mean that all films shot with spherical or aspherical (ie not cylindricals) lenses are shot in 1.33 and simply cropped to the whatever aspect ratio is desired, ie 1.77, 1.85, etc.? I'm kind of confused here, any input would be greatly appreciated!

Thanks!
Click to expand...

If shooting a very wide aspect ratio, say 2.40:1, with spherical lenses on s35mm format, you could shoot with a 4-perf camera and then crop in post, but you would be throwing away much of the frame. Instead you can save film and money by using a modified camera that shoots 2 perf. Instead of cropping the 2.40:1 frame out of a regular frame, you can capture more frames per roll of film by just shooting the area you intend to use. Make sense?
 
Thanks guys!

Ryan Patrick O'Hara said:
If shooting a very wide aspect ratio, say 2.40:1, with spherical lenses on s35mm format, you could shoot with a 4-perf camera and then crop in post, but you would be throwing away much of the frame. Instead you can save film and money by using a modified camera that shoots 2 perf. Instead of cropping the 2.40:1 frame out of a regular frame, you can capture more frames per roll of film by just shooting the area you intend to use. Make sense?
Click to expand...

Mostly, it basically means that the frame size is vertically smaller on 2-perf? I guess my confusion comes from the fact that I was somehow imagining that widescreen in film is literally wider, not just essentially cropped. So, what if you're shooting with anamorphic lenses? Do you shoot on 4-perf?
 
Yes, anamorphic would be shot on 4 perf. The advantage is getting that wide aspect ratio but using way more negative for a cleaner image than just cropping or shooting 2 perf.
 
Yes, two perf has the same width as 4-perf, but less height. This is for people who are shooting a wider aspect ratio. Shooting with anamorphic lenses makes more sense most of the time, as you don't lose the resolution of cropping, which is how you get a widescreen aspect ratio when using spherical lenses.

So yes... you would not shoot 2-perf with anamorphic lenses unless you wanted some insane aspect ratio well beyond what is typically used.

The reasons to use 2-perf over anamorphics would be to use spherical lenses and still get 2.40:1, save money, get longer takes from the same length of film, and etc. Sometimes it's money reasons, sometimes it's aesthetic reasons.
 
Thanks for clearing that up! So, shooting with an anamorphic lens on 4perf film will get you a 2.39 aspect ratio? I guess I'm assuming the lens has a 1.33 squeeze, if this is the case then wouldn't you get only a 1.77 image? I think I read that 4-perf has an aspect ratio of 1.33, or is that wrong?
 
tommygdawg said:
Wouldn't that give you a 2.66 aspect ratio, though?
Click to expand...

Roughly, yes. You are right about that, but when shooting on film, the film negative will almost ALWAYS need a projection mask of some sort or an extraction of the aspect you want from the negative. I can't think of many common aspect ratios which are natively achieved from the negative without needing extraction of some sort. Even when shooting s35mm two-perf, you still must do your 2:40 extraction from the negative, as 2-perf aperture is actually slightly wider aspect than 2.40:1.

As mentioned, this will have less resolution than using anamorphics, but it will use 50% less film than 4 perf and thus each roll of film will last 2x as long for those long takes! You'll also be able to use spherical lenses which can be less to rent, smaller is size and weight and/or also have a faster t/stop for those low light shoots. I love anamorphics, but instead of using a huge Hawk, if the final product does not need to be top quality in terms of resolution or apparent grain, you can shoot 2-perf with Ultra Primes, Panchro/i's, or other lens sets. Those lenses will perform much better even at wide open, will weigh less, and likely be less to rent, when compared to top notch ana's.
 
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