What is the resolution of film?

Does 35mm film have a maximum resolution?
What pixel dimensions would a digital picture have to be to be equivalent to a picture on an average trusty-brand SLR camera?
Thank you very much in advance.:slight_smile:

I’m pretty sure that 35mm film is analog, which means it has no effective resolution, any more than a pencil drawing has a resolution.


In terms of useful resolution the latest 5-6 megapixels cameras are pretty much toe to toe with the better 35mm SLRs for virtually any standard photography up to 11x 14 prints. The latest 11 and 14 megapixel cameras go well beyond that and compete with the large format cameras.

See www.dpreview.com for more info

This camera the Canon EOS 10D is hailed as setting the standard for 6 megapixel cameras and is regarded by some as being as good as or superior to almost any 35mm SLR on the market.

Having said that the comparison is still a bit apples and orangish because film is analog and there are still some specialized imaging applications that film can do that digital will be at pains to duplicate cost effectively for the near future.

Well, yes, it absolutely does have a maximum resolution. Film emulsions sare composed of fine grains of a silvber halide. Faster films have larger grains and lower resolution than fine-grained slow films. However it’s difficult to specify the resolution in the same terms as digital cameras. For standard 200 ASA film it would probably be somewhere in the gigapixel range.

Astro, the resolving power of film cameras is mostly dependant on the film, not the camera. Granted, optics do also play a role here.

You won’t get a lot of agreement on this question. While 6mp DLSR cameras are a good substitute for 35mm film that does not mean they equal 35mm film.

All pixels aren’t created the same either. A DLSR has a physically bigger CCD than a prosumer camera with a 2/3 CCD and because of that has less noise, particulalry at high ISO values, and a wider tone latitude. So my 5mp Dimage 7 has the same effctive pixels as a 6mp Nikon D1x but that does not mean it can produce the same image. Ihad an opportunity to try a D1H and under some conditions it produces better images than the Dimage 7 with half as many pixels.

This is kind of a self cancelling issue. Lower ISO values in film and digital produce less grain/noise and higher numbers produce more.

D’oh! Someone asked almost this same question about 25 days ago (I see now.) I’m sorry about that!

Thank you for your patience and not swearing at me.:slight_smile: I’m new.

See http://www.imx.nl/photosite/technical/Filmbasics/filmbasics.html to get you started.

If it means anything, my 2.0 megapixel Kodak Easyshare CX4200 says “39 mm (Equiv)” on the lens cap.

Troy, that’s the lens, not the resolution. It just means that your lens is the equivilent of a 39mm lens on a 35mm camera.

I remember seeing a quote of 20 megapixels to be the minimum equivalent resolution of 35mm film. Obviously, this is an estimate. I’ve personally scanned old wallet-sized prints and blown them up to 8x10, and they looked great (after some manual dust removal); film has just an amazing resolution compared to (most) digitial cameras.

FWIW, when doing digital effects for movies, the film is digitized at various resolitions from 1k^2 up to 4k^2. I’d love to hear what resolutions are used for the latest imaging such as Lord of the Rings : TTT or Matrix: Reloaded; my guess would be they would tend use something close to HD (1920x1080) res just for convenience, but that’s just a guess.

Also, film has much greater dynamic range than CCD digital captures. Anyone who’s noticed that TV soap operas look a bit ‘flat’ compared to a commercial or prime time series are noticing this difference; the soaps are filmed on video, the others on film.

So, what about dpi? What dot-per-inch resolution does a digital photo print need in order to fool the eye and become indistinguishible from a traditional photographic print?

Probably too many variables to say – it depends on the photo content, what size you’re printing it at, and how picky you are.

For example, my 4mp camera produces images that are 2272x1704 pixels. At 11x8.25, that would be 206.545 dpi. When printed, this looks acceptable to me for some shots, and utterly inadequate for others.

At 3x5", the same shot would be 454.4 dpi, which to me is indistinguishable from film.


My camera’s resolution is only 1600x1200, i.e. 1.92mp, and I’ve got some stunning 10"x8" pics from it, using my cheap Epson inkjet printer – even when I’ve cropped the original image down to maybe half its area. . It helps that it’s a decent camera, with quality optics, of course.

This means I’ve been getting decent pics from around 100dpi of image data. To improve the print, I upsample the picture to at least 200 dpi using my photo editing software - this obviously doesn’t add detail, but it does prevent an obvious pixellated appearance.

You can get around a 40 meg file out of a scanned 35mm slide.

14 MP is, for practical purposes, as good as 35mm film, even better at low ISO speeds (see Popular Photography & Imaging’s review of the new 14MP Kodak DSLR for more info. I can’t find my copy, but I think it was May 2003).

DPI: 200 pixels per inch is the most the eye can see. As long as your camera puts out more than that, the pixels won’t be visible at 200 ppi. If you don’t have 200 ppi worth of information and use Photoshop to make it 200, it’ll look grainy, because you can’t add information that wasn’t there – it just makes what is there bigger.
I’ll stick with my 4x5 film camera, which works out to something like 187MP digital equivalent :smiley:

Although the Nikon D1* that I use at work is nice, for prints 8x10 and under, and newspaper reproduction…

*— yes, the original unlettered 1999 model (now the D1h, except the h has a few performance modifications). Cheapass small-town newspaper won’t buy us newer ones (except for the chief photog. He has a D1x.)