> > On 12 Feb 2004 at 13:18, Nenad Djurdjevic wrote: > > > I am sure this question has been asked before but what would be the > > megapixel equivalent of a 35mm colour slide? I have heard about 9 > > megapixels. Anyone know any better? > > It's all in the interpretation, if you would like the scan to resemble direct > digital image capture then you need to scan at resolution somewhat under the > films average grain size. However if you wish to utilize all the available > information stored in a fine grain film then scanning at 5400 DPI will get you > close. The resultant file would be approximately 39 megapixels or a 234MB file > at 16 bits per pixel.
Yep. Insert the usual caveats about using a good prime lens, a rigid camera support, etc., etc. A 2700dpi scan (around 10 megapixels) doesn't pull all the information out of film such as Fuji Provia 100F, and I can produce good images hand-holding (or using a monopod). The next step up (the 4000dpi of the next generation of home scanners, and of the old Kodak Pro Photo CD scans) roughly doubles the number of pixels. I've had some of my images scanned at 2700dpi and at 4000dpi, and there is definitely more image detail to be found in the higher-resolution scans. Much beyond 4000dpi the gains begin to tail off. It's hard to tell exactly where, because the high-resolution scans generally come from better scanners; a 4000dpi scan from an Imacon or a Leaf scanner tends to look better than a 4000dpi scan from a Nikon Coolscan. One final thing to bear in mind, of course, is that the DSLRs pixel count is inflated - a 10 megapixel scan from a slide has individual R/G/B samples at each pixel position. I wouldn't expect a 10MP digital camera to produce images that match even 2700dpi scans from a 35mm slide in the matter of fine detail, although the all-digital image would have other advantages.
