"Dave Sill" wrote in message
...
Neil Harrington wrote:

Those are not described in that way; only compact cameras use the
fractional inch method. Nikon and some other DSLRs mostly use a sensor of
either 23.7 x 15.6 mm or 23.6 x 15.8 mm, in either case roughly the same
as the full APS-C format and often referred to by that term.

...

Whatever it's called, the 2/3 type is the largest sensor generally found
in any digicam. Its actual size is about [6.6] x [8.8] mm.

Other common sizes are 1/1.8 and 1/2.5 -- there are several other sizes
as well, but those appear to be the ones most often used today.

What are the actual physical dimensions of 1/1.8 and 1/2.5 sensors? Do
DSLR sensors really have more than six times the area of a 2/3 sensor?
Wow.

Yep. Compact digicam sensors really are tiny compared to DSLR sensors.

The 1/1.8 type is about 5.32 x 7.18 mm, and the 1/2.5 type is 4.29 x 5.76
mm.

You can find the *approximate* size of any sensor if you know the actual
focal length of the camera's lens and its 35mm equivalence, both best taken
at the long end of the zoom for the sake of better accuracy. Dividing the
latter by the former will give you the digicam's lens factor. Dividing the
diagonal of a full 35mm frame (about 43.2 mm) by the lens factor should give
you the diagonal of the digicam's sensor. However, this is a rough method
(because the camera lens's stated focal length may not be precise) and may
not give you exactly the figures above.

More sensor sizes are given he
http://www.dpreview.com/learn/?/Glos...r_sizes_01.htm


Thanks for the informative article.

You're very welcome.

Neil