Re: Depth of field difference between APS-C and full frame

Roger N. Clark (change username to rnclark) wrote:

Paul Furman wrote:

PS I was tinkering around yesterday and discovered I can mount my webcam
to my 35mm lenses. The webcam dissasembles with one screw and the lens
unscrews, then I set up a mount with a drilled out rear lens cap and a
lens shade and wow! 300mm with stacked teleconverters and a 6x crop
factor approx 6mm sensor) gives a 35mm equivalent field of view of 5,000mm with 1.3MP.. holy crap.
http://edgehill.net/Misc/photography/9-22-07-webcam
OK the image quality is crap but 1280x960 would be 7680x5760 at full frame 35mm or 44MP and it does show more detail than my DSLR.

Paul,
Interesting comparison. Congratulations on the adaptation.
It would be interesting to see the same subject shot with the
DSLR and the web cam. What doesn't make sens is the web cam
image is very sharp with stacked TCs, but the DSLR is very
blurry. The test shows the lens combo is sharp, so the
DSLR must be mis-focused.

I've tested quite a few times & it always looks very soft, that's why I was amazed it held up with the webcam. Maybe that was worse weather the day I tested it on the DSLR. A test of the same target the same day would be useful. It is also a whole lot easier to focus on the webcam!

Also note the noise in the web
cam image, probably photon noise limited.

The webcam has a 'low light boost' and very limited dynamic range. The full pixel crop really does look bad. I was trying it on the moon tonight then the clouds came over before I got a shot.

--
Paul Furman Photography
http://edgehill.net
Bay Natives Nursery
http://www.baynatives.com
.

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