Your Guide to Film Flatness

When your film is inside your camera, you want it to be sitting flat. If it’s not, you’re in for some trouble. Some blurry trouble.

Let us explain…

An example of losing sharpness across an image Image courtesy of Caroline Tran

“Film flatness” is the term used to describe when part of your film image loses sharpness, even when other areas of the image that are on the same plane are clear and crisp, and it has nothing to do with the focus in your lens… It’s caused when the film is not lying flat on the pressure plate within your camera. This happens predominantly with medium format film, but it can happen in 35mm film cameras, too.

Let’s say you take a shot of a bridal party that's standing all in a row on the same focal plane, but one person appears out of focus. Then your film wasn’t sitting flat within your camera. Yikes!

An example of film flatness (left part of the image) Image courtesy of Caroline Tran

More often than not, this is caused by a faulty insert. But it can also occur if you leave film sitting in your camera and it becomes kinked around the insert, causing it to no longer sit flat against the insert.

Film flatness can happen on just one shot in your roll or it can be recurring—but chances are that if you’re seeing it more than once, it’s an issue with your insert.

The best way to prevent film flatness is to check out your camera. The bottom take-up spool in your medium format camera should not turn both ways, it should only roll forward. This is what keeps the film taut inside the camera body.

The bottom take-up spool from a medium format film camera

While it is super rare, a negative can “pop” during the scanning process and produce a similar result to true film flatness. How do you tell the difference? If the problem was in your camera, the negative will show the out-of-focus areas—if not, then the lab can rescan your film.

Don’t be fooled—lack of aperture control and missing your focus is commonly mistaken for film flatness. Shooting at f/2 with a very narrow plane of focus can look similar to film flatness because there is very little wiggle room for focus at that aperture.

But, remember that film flatness will show different levels of focus for items sitting on the same plane, while missing your focus results in all the items being blurry.

Example of film flatness affecting the subject on the far left Image courtesy of Caroline Tran

So, what do you do if you're getting film flatness on your images? You can usually pinpoint the problem by testing each insert you have to see which one is having the issue.

Shoot something flat in your test, like a textured wall or a tablecloth with a pattern—anything that sits entirely on the same focal plane and will have an element that you can use to detect changes in focus. Then, you’ll be able to easily see if some areas of the image are blurry.

You can also preemptively plan how to tackle film flatness when it occurs. Here’s how photographer Rebecca Yale does it:

"I actually have four camera backs, and I change out the whole back when shooting, not just the insert. I have assigned each back a letter (A,B,C,D), and as I shoot, my assistant labels the roll with the corresponding letter.

I put it all in a spreadsheet, so now if I get film back and see an issue, I can know exactly which insert is causing the problems and send it off to be fixed.”

Once you figure out which of your inserts is causing film flatness, you’ll want to get it repaired or replace it all together.

Find a reputable camera repair shop in your area and look forward to some perfectly-taut film!

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