Resolution Comparison: Film vs. Digital

[photophorous]

Is there any kind of direct comparison between megapixels and film size? In other words, how many megapixels do I need to have the resolution of 35mm film or medium format? I know there are a lot of other factors in play, but I'm looking for a basic relationship, assuming all other conditions are equally good. Can someone explain?

Thanks!

[Franglais]

Is there any kind of direct comparison between megapixels and film size? In other words, how many megapixels do I need to have the resolution of 35mm film or medium format? I know there are a lot of other factors in play, but I'm looking for a basic relationship, assuming all other conditions are equally good. Can someone explain?

Thanks!

The comparison between film and digital is a little difficult because film has grain whereas noiseless digital is a "clean" image which can be enhanced much more than a film image to make it look better even if the true resolution is less.

I find that the 6Mpix image from my D70 is at least as good as what I get from 24x36 film. From what I read, the 11Mpix image from the original Canon 1Ds was at least as good as medium format.

Does that help?

Charles

[racingpinarello]

Is there any kind of direct comparison between megapixels and film size? In other words, how many megapixels do I need to have the resolution of 35mm film or medium format? I know there are a lot of other factors in play, but I'm looking for a basic relationship, assuming all other conditions are equally good. Can someone explain?

Thanks!

Film would provide more resolution, BUT, to get equal results you would need a drum scan. So it's not an easy comparison.

Last time I checked those scans are still very expensive and not cost effective for most of us. I'm sure if you measured the resolution of the scan to a digital camera it would give you a base comparison, but to get that resolution would be painful.

Loren

[Michael Fanelli]

Is there any kind of direct comparison between megapixels and film size? In other words, how many megapixels do I need to have the resolution of 35mm film or medium format? I know there are a lot of other factors in play, but I'm looking for a basic relationship, assuming all other conditions are equally good. Can someone explain?

Thanks!

Unfortunately, there is no comparison that makes any sense. Digital and film are totally different methods of recording an image. Pixels are not equivalent to grain. An excellent article to read is:

http://www.luminous-landscape.com/essays/clumps.shtml

For me, my old 3 MP Canon G1 matched or exceed 35mm film up to 8x10. My Rebel out performs 35mm at every size. Of course, if you like the "film look", no editing really gets it right. Film is already legacy, only large format still has the advantage. FWIW, there is more to photography than the technical details.

[photophorous]

Thanks everyone. I think I get the idea. Good article, Michael. Now I just need to sell my soul. Only $4999.00. Any takers?

Paul

[Photo-John]

I've been seriously thinking about writing an article called, "Resolution - The Real Story", or "The Truth About Resolution." My first serious digital camera was the 4-megapixel Canon EOS 1D. I still have it and I'm still making money with it. I think enlargements from the 1D look better than anything I was getting with slide film, excellent scans, and the LightJet printer. I've made prints up to 24x36 from slides and from the 1D and I definitely think the 1D images are better.

As far as what you need to spend, the 13 megapixel EOS 5D will be available in a month or so. Get your pre-order in!

[darkman]

There's definately lots of symantics, definitions, and confusion about this subject on the web.

My simple take is film has higher resolution while digital has higher MTF's. In other words, with 100iso film (assuming comprable formats, lenses, etc ect) at the resolution limit I could tell, barely, that two seperate lines exist. The contrast between the lines will be low. This resolution limit is beyond what most digital cameras can do.

Conversely, digital by it's very "pixel" nature has high mtf's right up to it's resolution limit (from a simplistic standpoint ignoring the bayer patter, it takes two pixels to make line pair) Thus, at it's resolution limit the lines still have high contrast between them. If you take this resolution limit, in lp/mm, and compare it with film, you will find the lines are much cleaner looking because of the higher contrast between the lines. This tends to be the reason while digital looks better to the eye in many cases. It's also what helps it to print large.

In terms of pure resolution, measured in lp/mm, the 1dsII @17Mp is about the same as 100iso color negative film. The MTF values will be higher for the 1dsII though creating a cleaner looking image. I recall reading something once that in terms of pure resolution, it would take about 22Mp on 35mm format to equal a good slide film.