Does anyone have a comparision of 4x5 films vs. digital in terms of resolution? THX, Jay

-- Jay Gafney (gaff@attbi.com), June 04, 2002

Answers

Sure. Several scanning backs for 4x5 cameras roughly equal film in resolution. The one I saw demonstrated; the Phase One Powerphase produced a 350MB file during a four minute time exposure. These devices have been on the market for many years and are used commonly in pre-press and other production applications. They are essentially a high-resolution scanner in the shape of a 4x5 film holder.

However, if you mean the sort of digital camera that works like an SLR, there really is no comparison. The Fuji S2 (for example) doesn't even approach the resolution of a 35MM image.

The brand new Kodak DCS Pro back for medium format cameras is rated at 16Megapixels, so it should be able to at least equal a drum scan from a 35MM slide. (I have seen the results from this too, and for my tastes, it's the best thing yet - astonishing!)

If resolution is your goal, large format - be it pixels or grains - will always win.

-- Brian Yarvin (brian@brianyarvin.com), June 04, 2002.

Are you asking how many pixels a digital camera would have to have in order to equal 4x5 film in resolution?

There is no exact answer to this question because randomly positioned film grain and periodic pixels are different. Back-of-the-envelope calculations suggest anything from several tens of mega-pixels to around 200 megapixels. If you are thinking of color and want 48 bits per pixel (16 bits per color), then you need to multiply the pixel size by 6 bytes per pixel to obtain the file size.

Some estimates based on scanning film are given by R. N. Clark: http://www.clarkvision.com/imagedetail/index.html and http://www.clarkvision.com/imagedetail/film.vs.digital.1.html

-- Michael Briggs (MichaelBriggs@EarthLink.net), June 04, 2002.

Resolution, Shmesolution. I think you need fewer pixels from direct digital capture to get the same image quality as film. I use a Dicomed Field Pro scanback - an older generation back that produces 130mb 8 bit output (it will also output 16 bit) using a 4x5 film insert. Because of low noise and no grain, I can interpolate without much image degradation - not that I need to very often. It is the equal of 4x5 drum scanned, in my opinion.

Oh, and I'd rather use a Fuji S2 (judging from the samples I have seen) than a 35mm camera any day.

Film degrades image quality in many ways that are avoided with digital capture - including film grain, film flatness problems, and scanner (even drum scanner) degradation.

Not all pixels are equal.

Just my two pennyworth - Q

-- QDB (sales@barleigh.com), June 05, 2002.