Hi
is it my turn to inject my opinions yet? ;p
Originally i wanted to do another one of my long digital vs film 'thesis' but i'm getting a bit tired of that. Those who hang out here long enough know my stand - i'm a pro digital person. The D30 wielding friend that CK mentioned is me. We have done numerous real world comparisons, shot from ISO 100 to 1600, in a variety of situations.
Without going too much into the nitty gritty details (again! we need some kind of FAQ for this!), the clean grainless and noiseless files of digital clearly surpasses any major wins in resolution film has. By using our good old eyeballs, examining prints of different sizes, the digital output exhibits superior color reproduction, color accuracy in mixed lighting conditions without the distraction of grain. Grain in film when viewed up close turns details into muddy pools of slush, especially at high ISO, while the digital files retain detail just as well as at ISO 100.
Film does have more resolution (more on this later); however, how much of that is contained in the grain, and how much of the details can be resolved
visibly without being masked by grain?
My own subjective judgement of image quality - the print has to resemble as closely as possible what the eye sees at the time of light capture. And in the real world, there is no grain.
You can either take my word for it, or perform the tests yourself. ANd pls, no consumer digital camera output - use a real 35mm based, digital SLR for your comparisons. Our tests uses no theoritical, mathematical formulas or MTF charts. Visual inspection of big prints at high magnifications and normal viewing distances shows that digital is at least as good as 35mm film, if not more so. Show those prints to layman in blind tests, and their conclusions do not differ.
With the advent of true 6 megapixel digtal SLRs, i'm afraid the game is over for 35mm film (where image quality is concerned).
http://www.luminous-landscape.com/d60-first.htm
I have a few high resolution D60 files with me right now (shot by another friend who owns a D60). I cannot disagree with that article's conclusion. If the D30 is good, the D60 brings quality to another higher level (caveat: with good lenses)
Now, let's move on to something more interesting.
Vadium brought on the topic film resolution in terms of lp / mm. (line pairs per mm). Since black and white TMAX film is mentioned, let's talk about black and white processing. Document films like Kodak Technical Pan, Agfa Copex Rapid AHU, Maco Orthopan 25 and several others, do indeed have resolution figures of 350 to 600 lp/mm according to the manufacturer's datasheet. BUT let us point out the caveats:
The given resolution is measured on negatives that have been developed to the extremely steep characteristic curve needed for halftone (black-white) reproduction in special developer chemicals.
Also, the resolution figures have been produced by contact printing a glass plate with finely etched black/white lines with the emulsion. For very fine structures an even finer pattern can be used, again on a glass plate, with a chromium layer in which the patterns are etched.
How many of us actually develop our own black and white film, let alone adhere to stick standards to achieve the highese possible image quality?
Secondly, the resolution of very fine detail is limited by optical aberrations and the limiting value of diffraction. A lens that is diffaction limited is so well corrected in its optical aberrations, that only the diffraction of light does influence the quality of the image.
Thirdly, the viewing medium. Laying even 200 lp/mm of image quality into the best photographic paper is at best a tough job for even the best printers. And the contrast of the paper - different papers are going to give you different results. So how do we translate that supposedly 150 lp/mm of TMAX 100 into a high quality print? To view slides as they are meant to be viewed, at close to quality given by figures on manufactuers' MTF charts, you need VERY good loupes, with well calibrated lightboxes.
A chain is as strong as its weakest link. Every step in the imaging chain degrades the reproduction of the original object.
The taking lens is the obvious candidate as optical aberrations do reduce the accurate reproduction of the object. Less wellknown are the accurate focus and the movement of the camera body. Then the film emulsion adds to the degrading of the image, not only by contrast reduction and grain pattern, but also scattering of light in the emulsion. Then we have the exposure and development, which also introduce effects of reduction.
Then we have the enlargement lens and the conrast of the paper. At every stage there are many factors to control.
What am i trying to point out here? The theoritical resolution power of film at even 150 lp/mm is highly overrated. With digital, assuming good photo taking techniques, the imaging chain is simplified simplified, from taking lens (diffraction limited) to imaging sensor (CCD or CMOS), you cut away the many variables inherent in film.
The outout of the CCD or CMOS IS the negative and print both at the same time. This is a unique concept - in film, you still have to worry about nudging the last ounce of image quality from a negative. Not so with digital, unless u're alluding to the idea of processing RAW files from digital cameras. They are not quite the same thing.
Taking into account all of the above, assuming similar techniques, the actual resolution of a digital SLR output may not be that far from the resolution of film. True, the ultimate resolution of film is going to be higher, but grain, no matter how fine, distracts from the overall apparent image quality. Just look at pictures with clear blue skies for an example.
to be cont'd....