Howard writes: : Thinking about Karl's comments below, and the article, I realise that I : must never make "big" prints - from my old D100 or even really, from my : new D80.... =-O : : Now I accept the maths totally. Can't argue! : But I do make those size prints, and visually I swear that the A3 prints : I have made from my D100 are far far better than the same size prints I : have had made from my older 35 mm Nikons, in terms of colour fidelity, : lack of noise sharpness and detail. Algorithms can do amazing things - no doubt about that! ;) : But visually, I would rather look at an A3 print from my old D100 than : one from my 35 mm Nikons or FD Canons. And that is comparing it to f=50 : standard lenses on film cameras with 100 ISO film. : Just as everyone complains about image noise in today's digital cameras, : have a look at the grain from similar ISO films. Are they really that : much different? Or worse? Perhaps someone in the group can answer that. : But the D100 produces surprisingly low noise A3 enlargements even at ISO : 800 whereas I'd never dare make an A3 print using ISO 800 colour films. : Has anyone in fact compared high ISO digital images to high ISO film : results? Just as no two films of the same ISO were never alike, no differing digicams can produce the same levels of noise. In fact the noise levels vary dramatically in relation to the subject being shot and the level of illumination falling on it. A test - similar to what anyone would do when testing a film, and easily done with the convenience of digital - shoot a white card (or better yet, a sliver of white perspex) underexposed from a number of stops to over a number of stops. crop out a portion of the image and enlarge it to the point where the pixels are visible so you can *see* the variation in colours .. or save it and do a colour count to see how many discrete colours are present. Do this at a couple of ISO's too.. Anyone who's shot neg film will know that the greater the level of exposure, the greater the colour saturation - the colour will 'block up' becoming more uniform, more consistent and ultimately a *whole lot* less 'grainy'.. to the point that aside from lowered resolving power due to grain size, a 400 ISO neg film can easily replicate the results of a 50 ISO film :) digital behaves similarly sometimes but not always - it depends on the sensor, the heat generated (long exposures = more heat = more noise.. counter to the way film behaves) the algorithms etc etc etc.. But as to how 'good' an image looks, that's different. If we discuss resolving power (not on-axis!) it becomes apparent that for digital to replicate 35mm 100 ISO film you'd need a 35Mp camera.. that's mathematically definable and limited by the physical number of sensors in a given area and the frequency of the sample rate - but that's resolving power and not the 'look'. I have some shots taken with a 16mm camera and 400 ISO film that look fantastic - they 'look' great. Horribly inaccurate of the scene (they resolve very little!) but they look good. There are some 3200 ISO 35mm shots I only print 4 feet long because they look great that size. I remember seeing a A0 print taken by a guy in Perth years back, he was probably the first to buy a Pro digi-SLR and he was SO proud of his 2Mp camera :) Looked great, fantastic colours - magnificent subject. Good thing the detail interpolated up in an almost vector-like manner, and much better than any shot he could have done with film which would have revealed many of the imperfections in the subject he was hoping to eliminate. Perfect for what he was after.. which was a look. not detail. Which is why the publisher of the magazine spoken of in those pages refuse to use anything smaller than 4x5 - and certainly not digital. Too little detail, and that's for a magazine publication. I'm sure they could interpolate the image up, hit it with Neatimage, sharpen the results and have something that 'looks' fantastic, but that's not the only thing they're after. As to colour, my work with the herbarium guys, medical photographers and geologists has found them arraying themselves with a battery of cameras to allow themselves to obtain the most accurate colours for the many and varied situations they encounter - different cameras for different subject (colours). Much as film shooters used different films for different subjects. digital and film are certainly different in both the mechanism and method of use, and each has it's strengths and weaknesses but one thing digital does well is give instant results. k
