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Old September 29th 04, 03:06 PM
Ken Alverson
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"Dick" LeadWinger wrote in message
...
In the early days of digital photography, it was said that something
equivalent to 35mm file was some time out in the future. Are we there
yet? What digital resolution would be equivalent to 35mm film?


It depends who you ask and how you compare. Film grains can be very small,
but all the grains of film are a specific color (based on their layer in the
film) - shades of color are created by many grains of film clustering
together. In a digital photograph, there are discrete pixels which are
relatively large, but each pixel can take on one of many shades, based on the
amount of light that hits it.

You can test how thin a line each can resolve, but that test is biased toward
film, since you can use a few small grains to represent a line, while a
digital camera might be able to resolve more discrete shades of color in the
same area, but not as fine a detail.

It's kind of like comparing VHS tapes and MPEG compressed video. The nature
of the artifacts you see when you get close and nitpick the image are
different, so you can't really say that one bitrate of MPEG is equivalent to
one recording speed of VHS, because the difference is subjective.

Many people would agree that a 6.x megapixel image with low noise is roughly
equivalent to 400 speed negative film. Both can be blown up to about the same
size before you start to notice flaws without actually looking for them.

Low speed slide film easily beats 6.x megapixel images, I'm not sure if anyone
has compared slide film to the more recent 10+ megapixel cameras.

Ken