Upgrading Astrophotography Camera

As far as I know the chip size in the 300d and 350d is the same, otherwise the focal reduction ratio of 1.6 would be different on each camera.

Jed,

The chip size between the EOS 300d and 350d is NOT the same! The former has a 6.3 megapixel array whereas the latter has an 8.0 megapixel array (10% larger for each dimension). Similarly, the focal length multiplier is 1.6x for the former and 1.4x for the latter.

Anthony.

The focal length multiplier is 1.6 for both.

In fact (and I found this surprising) the sensor is physically smaller on the 350D:

Comparison 300d versus 350d

Doesnt this mean you actually get a smaller field of view compared to the 300D at the prime focus of a scope,

The focal length multiplier is 1.6 for both.

In fact (and I found this surprising) the sensor is physically smaller on the 350D:

Comparison 300d versus 350d

The ONLY explanation remaining then is that they are using a smaller pixel on the 350D than on the 300D?!

Doing some quick calculations using my AP160 as an example, we have:

AP160 + EOS 300D = 43.4 x 65.0 arcmin FOV .... 1.25"/pixel
AP160 + EOS 350D = 42.2 x 63.3 arcmin FOV .... 1.10"/pixel

I am staying with my EOS 300D!

Anthony.

Doesnt this mean you actually get a smaller field of view compared to the 300D at the prime focus of a scope,

Dave,

Yes, it does by virtue of the fact that the smaller chip (due to the smaller pixel) now covers less sky and, hence, for the lower arc-sec/pixel above.

Since the digital EOS is a great camera for deep-sky work, it seems to be a step backward by going to a lower arc-sec/pixel.

Thoughts?

Anthony.

PS. Jed, thanks for alerting me about the smaller chip. I knew about the increase in the size of the pixel array by 10% in each dimension but I did not know that they simultaneously downsized on the pixel itself (from 7.4 to 6.4 microns) which not only effectively wipes out the larger pixel array (with respect to the number of pixels) but they went overboard and negated the larger pixel array.