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Hi Everyone,
a few preliminary results of my new Nikon LS50ED film/slide scanner...
So far I've scanned in a few rolls of 200 ASA negative film, taken on a Olympus OM2n with a OM 28, OM 50 1.4, OM 135 f2.8, or 'Beraflex' (Sigma) 35 - 75 f2.8 zoom, and the results surprised me a bit.
Firstly I suppose that the results of the scanned film image depends a lot on what is being scanned. So far I've scanned mainly family photos, rock climbing and only a couple of astro photos (and they were evening, not real 'night' photos.) The results also depended a lot on the scanner settings. For most of the scans I used the various anti-scratch, anti-dust and anti-grain filters as these gave very good results with normal photos - but basically almost completely removed any stars or other astro type objects in the photos that had them. Turning all the filters off brought them back. It also decreased the acquisition times from about 5 minutes per image down to less than 1 minute.
But really surprised me was that in many of the 'normal' images, the apparent quality of the photos is often much better than images from my 10.1 MP 40D. I say ‘apparent’ as there are lots of factors to consider when discussing this sort of thing.
Film grain is about 2 um, so in 35 mm film this works out at something like 250 - 350 MP. However the scanner does 4000 x 5000 = 20 MP (in round numbers), so this is the limiting factor – or is it?
Now the silver halide crystals in film is actually ‘digital’ while the pixels in my ‘digital’ camera are actually analogue…. Hey? Well, a crystal gets hit by some photons and changes state (after processing) from no colour to black – with nothing in-between, so it is really binary. A pixel in the dig camera collects photons and gives a linear (more or less) output dependent on the sum of the photons – so is actually analogue… Now what this means is that to get shades or tones of black/colour with film, you need 20 – 50 crystals which effectively reduces the actual resolution of anything other than a monochrome line - or point – image to about 2 – 20 MP.
So to sum up, the image quality results depends a lot on the type of photo taken, but generally speaking for the photos I have scanned in so far, it seem that the film + 30 yo camera/lens combination wins over a 10.1 MP + L-series lens combination. Of course against the film is the fact that the dig is so much more versatile – the other day I took about 50 photos of my 3 YO daughter blowing out her birthday cake candles – hand held, by candlelight with the camera set to 800, 1600 and 3200 ASA. Try and do that with film!
I'll do more astro stuff soom and let people know how it went.
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