Guide · Medium format

Medium Format Film Basics: 120 Film, Frame Sizes and the Cameras That Use Them

Hold a medium format negative up to the light next to a 35mm frame and the appeal is obvious. It's big. Detail, tonality and that gentle falloff from sharp to soft all come easier when there's more film to work with.

Medium format can also feel confusing at first: numbers like 6x4.5 and 6x7, rolls with paper backing, cameras that open in odd ways. This guide untangles the basics so you can choose a camera and a format with confidence.

What "medium format" actually means

Medium format sits between 35mm and large format sheet film. In practice, when people say medium format today they almost always mean cameras that take 120 roll film. The film is roughly 6cm wide, wound on a spool together with an opaque paper backing that protects it from light and carries printed frame numbers.

The width of the film is fixed. The length of each frame is set by the camera. That's why you see descriptions like 6x6 or 6x7: the first number is (roughly) the film's usable width in centimetres, the second is the frame's length along the roll. The actual image areas are a little smaller than the nominal figures.

Frame sizes compared

Exact counts can vary by camera, so check the manual for the one you're looking at. Bigger isn't automatically better: a 6x9 gives you fewer chances per roll and larger cameras, while 6x4.5 is more economical and often lighter.

The main camera styles

Twin-lens reflex (TLR)

Two stacked lenses, a waist-level finder and usually a 6x6 frame. TLRs are relatively simple, quiet thanks to their leaf shutters, and often the most affordable route into medium format with a good lens. Most have fixed lenses. Our guide to identifying a TLR by visible clues helps if you're trying to pin down an unfamiliar model.

Medium format SLR

Often modular: body, lens, viewfinder and film back are separate pieces. That means you can swap backs mid-roll or change viewfinders, but it also means more parts to check. Lenses may have leaf shutters or the body may have a focal-plane shutter, depending on the system. Some are big and heavy; others are designed to handle more like an oversized 35mm SLR.

Medium format rangefinder

Larger rangefinder bodies, often 6x7 or 6x9, prized for being lighter and quieter than an SLR of the same format. Some take interchangeable lenses; others are fixed.

Folding cameras

A lens on a bellows that folds flat into the body. Folders can be wonderfully compact for their negative size, and many shoot 6x9 or 6x6. They're also older on average, so bellows, shutters and lens alignment need extra attention. The site's folding and bellows collection covers their history.

Loading 120 film without tears

120 film catches out almost everyone once. A few habits help:

1. Load in subdued light, never direct sun. The paper backing protects the film, but light can creep in at the edges if the roll is loose.
2. Keep tension on the roll as you thread it, so it stays tight on the spool.
3. Line up the arrow or start mark if your camera uses one, or follow the frame-number window if it uses the paper backing numbers.
4. Move the empty spool from the old roll to the take-up side; you need it for the next roll.
5. After the last frame, wind on until the paper tail passes through, then seal the roll tightly with its tape. A loosely wound finished roll is a common cause of edge fogging.

What to check before buying medium format

Everything in a general film-camera inspection applies, plus format-specific points:

• Film backs: on modular systems, confirm the back matches the body, the dark slide is present and inserts smoothly, and the frame counter advances and resets.
• Frame spacing: uneven spacing or overlapping frames point to a worn advance mechanism. Ask for a scan of a developed roll if possible.
• Leaf shutters: test every speed. Slow speeds that drag are common on older lenses.
• Bellows (folders and some SLRs): shine a light inside in a dark room and look for pinholes, especially at the corners of the folds.
• Folder struts and lens standard: the lens should lock out square and firm. A wobbly standard ruins sharpness.
• Interlocks: modular cameras have interlocks that prevent shooting with the dark slide in or removing a back mid-roll. If something won't fire, the cause may be an interlock rather than a fault, so check the manual.
• Spool and film type: make sure the camera takes 120, not 620 or a rarer roll size, unless you're happy to respool.

For a fuller walkthrough of shutters, seals and glass, use a general inspection checklist and add the items above.

Running costs and research

Medium format uses more film per picture, and lab development and scanning prices vary widely, so check current rates at labs near you before you commit to a format. Because frames per roll differ so much between 6x4.5 and 6x9, the cost per frame differs too. That's worth thinking about before you choose a camera.

When you research what a camera is worth, compare like with like: the same body with the same lens, back and finder. A modular camera listed "body only" is a very different thing from a complete kit. Completed sales are the most honest guide.

You'll also want somewhere sensible to store negatives once they come back from the lab.

Choosing your first medium format camera

The bottom line

Medium format slows you down, and that's half the point. Twelve frames feels limiting until you notice that you thought harder about every one of them.

Frequently asked questions