Camera for the Web - Comparison
We propose that for all practical purposes, a 2 mega-pixel digital
camera makes images for the WEB that are indistinguishable from images
made from any film camera.
Here is an image shot with my new Leica that we can compare with the
digital camera.
There are 3 versions of this picture. One was taken with the
Powershot S100. There are two versions
of the film based image. First the one above was scanned with the
Canon FS2710. The second was from the Kodak Photo CD done by our local
consumer photo finisher, Wolf Camera.
Here are all three images on one page for
comparison. I suspect you would agree, that there are subjective
differences between the three images, but each seems equivalent to the
other in edged definition, detail, color saturation, and tonal
range. There are differences in color and depth of field.
The CanoScan image is of the highest quality. Here is a small section
of the original scan that image showing the label on the ladder. The
label is clearly a CAUTION sign. This level of detail does not exist
in a 2 mega-pixel image from the S100. However it is lost in the
final image as you can see below. Thus, the there is little difference
between the WEB images from both cameras. Significant detail is lost
as the image is downsized to fit on a WEB page.
By the time the image is converted to the appropriate size for the WEB
the detail captured by the CanoScan is lost. Here is a blow-up of the
labels from each of the final images:
From these blowups, we can conclude that the S100 and the CanoScan
images are of about the same resolution, while the PhotoCD version is
slightly inferior.
These images were made by making a screen print of the blown up images
(500%) in Photoshop and capturing the resulting clip-board image in
Paint. In this way we can see the individual pixels.
Experimental Technique
The S100 image was used as reference. It was taken at the highest
image quality, producing a 2.0 MB file of a 1600 x 1200 image at 72
dpi. The other pictures were matched to this one in terms of picture
coverage (magnification). The full frame was scaled to 500 pixels
high.
The Photo CD image is of relatively poor quality - suitable for WEB
snapshots only. The image was cropped slightly to have the same final
magnification as the S100 image. It was a 760 KB file of a image at 72
dpi. The image 1488 x 992 at 72 dpi. It was cropped to the same
vertical magnification and then scaled to 500 pixels high.
The CanoScan image was a 27.5 MB file of 3888 x 2591 at 2720 dpi,
8-bits/pixel. The image was cropped slightly to have the same final
magnification as the S100 image. This image was scaled in PhotoShop to
500 pixels high ant 72 dpi for the WEB picture.
There are other differences besides the available detail in the
images. This is discussed on the page showing
all three images.
The digital cameras produce images with excellent edge definition, no
grain and loose detail particularly in the shadows and high
lights. Color accuracy can be suspect and dimensional distortion may
exist depending on the model. However, taken by them selves they make
fine images for the WEB with huge benefits in work flow. I wouldn't be
without one.
Last modified: Wed, 07-Nov-01 08:15:31 PST
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