The effect of pixel increases on images

I constructed a small gallery to illustrate the relative differences in
image detail at
different megapixel counts. Comparing the actual cameras is the best
way to do it,
since you will likely buy based on that alone, but the problem with it
is that the cameras, their internal software and the sensors are all
different. There are no two (unfortunately) cameras
that use the same of everything, except for pixel counts on sensors.
That would be an ideal
situation because it would mean you could have 4 meg P&S cameras with
the noise levels of
8 meg DSLRs, simply by cutting down the sensor to a 4 meg pixel count.
But this has
not be done.

What I did was to take images at distances that corresponded to varying
pixel counts.
So (for eg) the image area under the lens for the 3.7Meg equivalent
occupied approx. 1/4
of the size of the 16Meg shot. The lens was set at its highest
resolution
point, f5.6. Only the centre of the image was used for the 100% crops.
Lastly, I used "Smart Interpolation" to upsize the lesser megapixel
count shots until they matched the 16 meg shot size. Very little image
artifacting was noticed, even with relatively
large (3.7meg to 16 meg size) upsizings so the specific details of each
shot are preserved.
The images were taken in RAW, sharpened equally, converted to 16 bit
TIFF cropped and "Smart interpolated" and finally saved as 100% quality
JPEGs.
I used a halogen light source to illuminate the object, tripod mounted
the camera
and used a remote shutter release.

The reason I used close-up shots (2 feet) was to avoid the uncontrolled
aspects of long
distance (landscape) shots, such as exposure variation, etc.

Anyway, the result seems to be that the detail in the lesser megapixel
images is reduced
noticeably and this has resulted in a sharpness degradation as well.
Sharpness and resolution (detail) do not always go hand in hand, I've
seen unsharp shots that had more
detail than some sharp shots, but at a maximum resolution onscreen of
72dpi or so,
the differences are (IMO) very noticeable. At print resolutions of
300dpi, it would be even
more drastic. Now its clear why someone would be willing to pay $7000
or so for that
16 meg Canon!
Here is the gallery:

http://www.pbase.com/andersonrm/uprezing

.

Relevant Pages

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