Orpington Astronomical Society

Astronomy => Technical => Topic started by: MarkS on Jun 02, 2010, 23:28:14

Title: Canon EOS 400D
Post by: MarkS on Jun 02, 2010, 23:28:14
I'm now the proud owner of a Canon EOS 400D off eBay.  They're going for around £200 secondhand now - for a body only.  The first thing I've done is to switch off the dust vibrator thingy - the last thing I want it to do is to move the dust particles around every time I switch it on - it would ruin my flats!

I'll keep you informed in due course how it compares with the 350D in terms of read noise, sensitivity and dark current.  The pixels are smaller, which is generally a bad thing, but it is just possible this is compensated for by improved read noise and dark current.  One thing for sure - amp glow should no longer be a problem!

Hopefully the CCD is square (i.e. orthogonal) and I can use it to finally calibrate both the Tak and my 350D.
Title: Re: Canon EOS 400D
Post by: Rocket Pooch on Jun 03, 2010, 07:42:15
Hi Mark,

Why does this one not have an Amp glow problem?

Chris
Title: Re: Canon EOS 400D
Post by: MarkS on Jun 03, 2010, 09:13:04

It just happens that the 400D was Canon's first budget DSLR where they eliminated the amp-glow problem - I think the circuitry that causes the amp-glow is switched off during long exposures so it doesn't generate heat.

It still has dark current of course but the annoying "patches" are gone.

Mark
Title: Re: Canon EOS 400D
Post by: RobertM on Jun 03, 2010, 10:24:59
Chris,

You'll find that even our cameras exibit amp glow due to curcuitry on the CCD chip itself.  Fortunately it's imperceptable with a bit of cooling 8)

Robert