35mm vs 120 Film: What’s the Difference?

If you are getting into film photography, the difference between 35mm and 120 film can seem more confusing than it really is. The names do not help: 35mm is an actual measurement, 135 is another name for the same familiar cartridge format, and 120 is a historical format number that has almost nothing to do with the physical width of the film.

The practical difference is much easier to understand. 120 film gives you a much larger negative than 35mm film, which can produce finer-looking grain, more detail, and smoother enlargements. In return, you usually get fewer photographs per roll, larger cameras, and a noticeably higher cost per frame.

Neither format is automatically better. Choosing between 35mm vs 120 film is really about deciding which set of compromises fits the way you want to photograph.

What Do 35mm, 135, and 120 Actually Mean?

Let's clear up the terminology first, because this is where a lot of the confusion starts.

35mm film is approximately 35 millimetres wide from edge to edge, including the perforations running along both sides. The actual image recorded by a standard 35mm still camera is smaller, normally around 24 × 36mm, which gives the familiar 3:2 rectangular frame.

You will also see this format called 135 film. In normal still photography, 35mm and 135 refer to essentially the same thing: the familiar light-tight cartridge used by most 35mm SLRs, rangefinders, and point-and-shoot cameras. The number 135 does not mean the film is 135mm wide; it is simply the format designation.

120 film is different. Despite the name, the film is not 120mm wide. The strip itself is roughly 61mm wide, and "120" comes from Kodak's historical numbering system for roll-film formats rather than from a physical measurement.

So the easiest way to remember it is:

• 35mm — approximately the physical width of the film strip
• 135 — the format name for the standard 35mm cartridge
• 120 — a historical roll-film designation, not a measurement

That means 135 vs 120 film and 35mm vs 120 film are basically two ways of describing the same comparison.

35mm vs 120 Negative Size

Negative size is the biggest technical difference between the two formats. A standard 35mm frame is about 24 × 36mm, while 120 film can create several larger frame sizes depending on the camera.

This is an important point: 120 is the film format, not the image size. A roll can be used by cameras that produce 6×4.5, 6×6, 6×7, 6×9 and a few less common formats. Those names refer approximately to the dimensions of the negative in centimeters.

The exact dimensions and frame count can vary slightly from one camera to another, but the pattern is simple: the larger each frame becomes, the fewer photographs fit on one roll of 120 film. If you want to go deeper into the different cameras that produce these frame sizes, the beginner's guide to medium format film cameras covers 645 systems, TLRs, 6×7 cameras, folders, and medium-format rangefinders in more detail.

Does 120 Film Have Better Image Quality Than 35mm?

In comparable conditions, the larger negative of 120 film gives it a genuine image-quality advantage. This does not necessarily come from a better emulsion, because many film stocks are available in both 35mm and 120. The difference is simply that the same scene is recorded across a much larger physical area.

A 6×6 negative has more than three times the surface area of a standard 35mm frame, while 6×7 is larger again. When both negatives are enlarged to the same final size, the medium-format frame needs much less magnification, so grain appears smaller and fine detail is easier to preserve.

This is the main reason medium format vs 35mm can look noticeably different in larger prints or high-resolution scans. Medium format often has a smoother, more detailed appearance, especially in skin, skies, fine textures, and gradual tonal transitions.

That does not mean every 120 photograph will automatically be sharper. Focus accuracy, camera movement, lens quality, exposure, development, and scanning can easily matter more than format size if something goes wrong.

Grain Looks Different, Even With the Same Film

One of the most obvious differences in a 120 vs 35mm film comparison is grain. The important detail is that the grain itself is not necessarily smaller in the 120 version of a film stock.

If you shoot the same emulsion in both formats, the basic grain structure remains related. What changes is how much you need to enlarge the negative to reach the final viewing size. A 35mm frame needs much more enlargement than a 6×6 or 6×7 negative, so its grain becomes more visible as well.

Film speed still matters too. A slower ISO film generally gives you finer grain than a faster stock, regardless of whether you are shooting 35mm or 120. If the relationship between ISO, available light, grain, aperture, and shutter speed is still a little unclear, the guide to what film ISO really means explains it without getting unnecessarily technical.

That is why 120 photographs often look smoother and cleaner even when both images were shot on the same ISO film. Medium format can make relatively fast film look surprisingly refined, while 35mm tends to show more of the texture that many people associate with the classic film look. Personally, I do not see visible grain as a disadvantage; it is part of what I like about 35mm, especially when the texture works with the photograph instead of distracting from it.

120 Film Can Have Different Aspect Ratios

With 35mm, the frame shape is mostly standardized. The usual 24 × 36mm negative gives you a 3:2 aspect ratio, which is what most people imagine when they think of a traditional 35mm photograph.

120 film is much more flexible because the camera decides how much of the roll is used for each frame. A 6×6 camera produces square photographs, while 6×4.5 and 6×7 create different rectangular proportions. A 6×9 negative is wider again and can feel closer to the proportions of larger sheet-film formats.

This affects composition more than you might expect. A square 6×6 frame encourages a different way of arranging subjects than the longer 3:2 rectangle of 35mm, while 6×7 is popular partly because its proportions work beautifully for portraits and traditional print sizes.

So when comparing 35mm vs medium format, you are not only choosing a larger negative. You may also be choosing a completely different frame shape.

Depth of Field and the Medium Format Look

Larger film formats also change the focal lengths you use to achieve the same field of view. A 50mm lens is considered roughly normal on 35mm, but a 6×6 camera needs something around 75–80mm to give a broadly similar perspective.

Because medium format typically uses longer focal lengths for equivalent framing, it can produce shallower depth of field at similar aperture settings. This is one reason medium-format portraits can have such strong subject separation while still keeping a natural-looking perspective.

It is easy to exaggerate this into a mythical "medium format look," but there is nothing magical happening. Aperture, subject distance, focal length, background distance, and composition still matter. The larger format simply gives you a different set of optical relationships to work with.

You Get Far More Photographs From 35mm

A standard 35mm roll usually gives you 24 or 36 exposures, while a roll of 120 may give you anywhere from around eight to sixteen frames depending on the camera.

That changes the way you shoot. With 36 exposures available, it is easier to photograph variations of the same scene, react quickly, or keep a roll in the camera across several days. There is more room to experiment without thinking too much about every press of the shutter.

With 120, you are much more aware of the number of frames remaining. Twelve photographs on a 6×6 camera or ten on 6×7 can disappear quickly, especially when each roll also costs money to buy, develop, and scan.

I would not say that this automatically makes medium format more thoughtful or "serious." It simply creates a little more friction, and that naturally changes the rhythm of shooting.

35mm Cameras Are Usually Smaller

The larger negative of 120 film requires a larger camera to hold it, so medium format vs 35mm also becomes a question of portability.

A 35mm SLR, rangefinder, or compact camera can be relatively small and easy to carry all day. Even with a couple of lenses, a complete 35mm setup can fit into a modest shoulder bag without becoming too annoying.

Medium-format cameras vary enormously. Some folding cameras are surprisingly compact, and certain 645 systems are manageable, but cameras built around 6×6 or 6×7 negatives can become substantial pieces of equipment. Add interchangeable lenses, film backs, or a prism finder and the weight increases quickly.

For travel, street photography, casual everyday shooting, or any situation where you want the camera with you rather than specifically going out to photograph, 35mm is usually the easier format.

Loading 35mm and 120 Film Is Different

35mm film is straightforward because it comes inside a light-tight cartridge. You open the camera, pull out the leader, attach it to the take-up spool, close the back and advance to the first frame.

120 film has no protective cartridge around the roll. Instead, the film is attached to backing paper and wound around a spool. You place an empty spool on the take-up side of the camera, insert the new roll, thread the backing paper into the empty spool and advance until the camera's start marks line up correctly.

It sounds more complicated than it really is. After you have loaded a few rolls, the process becomes routine, although you do need to keep a finished roll tightly wound and secured before removing it from the camera.

The larger difference is simply convenience. A 35mm cartridge feels almost foolproof, while 120 asks you to pay a little more attention every time you load and unload.

Metering With Older Medium Format Cameras

One practical difference is that many older medium-format cameras do not give you the same built-in metering convenience as later 35mm SLRs. Depending on the camera, you may need a handheld meter, phone app, metered prism, or simply enough experience to judge the available light yourself.

That should not put you off 120 film, but it is worth considering when choosing your first camera. If you end up with a completely mechanical medium-format body without a meter, learning the Sunny 16 rule gives you a surprisingly reliable way to estimate daylight exposure without adding another device to the bag.

35mm vs 120 Film Cost

The price of the film itself does not tell the whole story. Even when a roll of 120 costs roughly the same as a roll of 35mm, you may only get ten or twelve photographs instead of 36.

That makes the cost per frame substantially higher with medium format. Development prices can also differ between labs, and high-resolution medium-format scans may cost more because the files are larger and require more scanning time.

The camera system matters too. Medium-format equipment ranges from inexpensive vintage folders to very expensive professional systems, just as 35mm cameras range from cheap point-and-shoots to collectible rangefinders.

For most people, though, 35mm remains the more economical way to shoot film regularly. Medium format becomes easier to justify when the larger negative or the specific camera experience is something you genuinely want.

Is 120 Better Than 35mm?

If "better" means maximum image quality from a piece of film, then 120 generally has the advantage. A larger negative gives you more usable information, finer-looking grain, greater enlargement potential, and access to larger formats such as 6×6 and 6×7.

But photography is rarely about maximizing one specification. A 35mm camera that you actually carry everywhere can produce far more meaningful photographs than a large medium-format system that stays at home because it is inconvenient.

The two formats also encourage different behaviour. 35mm works particularly well when you want speed, portability, experimentation, and plenty of frames. Medium format suits a slower process where image quality, larger negatives, and the physical experience of the camera are part of the reason you are shooting.

35mm vs 120 Film: Which Should You Choose?

Choose 35mm film if you want:

• smaller and lighter cameras;
• 24 or 36 photographs per roll;
• lower cost per frame;
• faster and more spontaneous shooting;
• a huge range of cameras and lenses;
• visible film grain as part of the look.

Choose 120 film if you want:

• a substantially larger negative;
• finer-looking grain and more detail;
• better potential for large prints and high-resolution scans;
• formats such as 6×4.5, 6×6, 6×7, or 6×9;
• fewer frames and a slower shooting process;
• the experience of using a medium-format camera.

For someone completely new to film photography, I would usually recommend starting with 35mm. It is cheaper per frame, easier to load and carry, and 24 or 36 exposures give you much more room to experiment while you are still learning. If you are at that stage and have not chosen a camera yet, the guide to the best film cameras for beginners covers several affordable 35mm options ranging from fully manual SLRs to cameras with automatic exposure.

Once you are comfortable with exposure and already know what you enjoy photographing, 120 becomes much more interesting. It is not simply "better 35mm"; the larger negative changes the cameras, composition, grain, depth of field, cost, and pace of the whole process.

That is ultimately the difference between 35mm and 120 film. Both can produce beautiful photographs, but they encourage you to make them in slightly different ways.

And if the names still seem unnecessarily confusing, remember the simple version: 35mm describes the approximate width of the film strip, 135 is the standard format designation for the familiar 35mm cartridge, and 120 is a historical name for the wider roll film used by medium-format cameras. The 120 definitely does not mean 120 millimetres.