Re: [ATM] Lens grinding for a digicam.

[Dominic-Luc Webb <dlwebb@canit.se>]

Many people use Oslo software for design (www.sinopt.com) If you
are not actually into optics, maybe I can offer some small tidbits.

I find that modern CCD cameras already have remarkably good optics
compared to older cameras. I tried replacing lenses of even the
cheapest CCD webcams, like the Philips USB webcam, and the image was
not noticably improved when replaced with expensive Nikkor or
Hasselblad objectives.

The Canon A70 is rated with an ISO of at highest 400, so this
is not a very sensitive camera. Compare to the Nikon D70 which
can do ISO 1600 and some others that can do 3200. You will
get a fainter image with a teleconverter. You may want to
consider the trick I once tried to deal with this. Buy a used
300 mm focal length telephoto for a 35 mm camera. Ebay has many.
You could spend your time and money on an appropriate adapter
and a fitting to connect to a tripod, etc. These lenses have larger
aperture than the mini CCD lenses, so they fetch more photons to
direct to the CCD. Hopefully the color will be acceptable. I noticed
that different lenses give images with different colors, shades,
contrast, etc, so you may end up wanting to manipulate colors after
the exposure, or maybe try filters, etc. I am not clear how to deal
with this issue, maybe someone else on the list.

Dominic-Luc Webb

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