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Old Aug 10, 2003, 9:27 AM   #11
Join Date: Jun 2002
Posts: 1,139
Default Some facts to consider.....

With film, enlargement potential is nearly always determined by the appearance of grain because film is resolution "rich."

With digital enlargement potential is almost never determined by "grain" (noise) but is nearly "always" resolution limited.

What does this then mean as far as print size potential? It simply means that when enlargements are made from digital captures, the core issue becomes whether or not there were "sufficient" photo receptors per unit of geography in the frame to allow interpolation algorithms to correctly reproduce the available detail in the image.

This situation is largely determined by the field of view. A small field of view means that the available resolution is vested in a small area and the enlargement potential is great. I've made incredibly sharp prints of 100 inch and larger size on the horizontal aspect from 3 megapixel captures. I've also "failed" at making sharp 16x20's from rock steady perfectly exposed landscapes made with wide angle with my 11 megapixel 1DS.

The difference in the above scenarios were simply that in the former case (low resolution large print) the subject was a head and shoulders portrait which didn't "challenge" the available resolution and in the latter case the subject was a huge field of view detailed landscape which would not have been satisfactory had I shot it with my medium format film cameras.

So in the very elemental sense, the "subject" does greatly affect the potential in that the field of view or amount of subject per degree of frame is very important.

Some day there will probably be field of view "tables" which can give a reasonable expectation of print size "success" per megapixel, but at present it's pretty much "seat of pants" experience. In the film world it's much easier because the resolution per film type doesn't change and one simply selects a larger frame platform when the grain monster rears its ugly head. With digital, we really need all the resolution we can get and the more we have, the more versatility we can expect under a wider set of circumstances.

In my experience, for all practical purposes six megapixel pro level sensors are an adequate replacement for 35mm color film and transparency. They are superior for enlargement of small field of view captures and inferior for wide angle landscape prints larger than 8x10. Eleven megapixel pro level sensors are an adequate replacement for 645 size MF film and transparency for most situations. They are superior for enlargement potential for small field of view captures and somewhat inferior for large field of view enlargements over 16x20.

This then leaves the consumer camera with 1.5 to 5 or 6 (new Fuji) somewhere between equal to 35mm color film or transparency for small fields of view - or inferior for large field of view. The advice I have is "don't challenge the resolution" and you will be exceedingly happy with even a two megapixel camera.

The "rule of thumb" is buy all the resolution you can afford if your photography leans toward landscapes and large prints. Buy all the lens you can afford (10X optical stabilized zoom, etc.) if you want to maximize the probability of success for wildlife, etc. Don't expect too much success from enlargements made from crops of small portions of your frame if you intend to print large.

Best regards,

Lin Evans is offline   Reply With Quote

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