Canon 300D

>Does anyone know if the mirror lock feature (whatever that is ) affects the cameras performance for >astrophotography?

Mirror lock – means that you can set a delay between the mirror flips and diaphragm opens – the purpose of this is to allow the vibrations produced by the mirror flip to die out. This is only/maybe visible a high magnifications and if your camera doesn’t have a sturdy mount.
Now, for DSO this is irrelevant as usually the micro-vibrations last between less then a second and 1-2 seconds. Also dso doesn’t require high magnification so that wont be a problem.
For planetary subject – ie moon and high magnification, because the shutter speed will be reasonable high, wont catch much vibrations either. The again for planetary (except maybe moon) you better go for a webcam(ie toucam) – dslr cameras are ok for dso .
I did test myself with/without mirror lock with my 10d and there was no visible difference. Also, I read on the net different people did the same test and they’ve got the same result – no visible impact.

Larry

Does anyone know if the mirror lock feature (whatever that is :oops: ) affects the cameras performance for astrophotography? (I think it's got something to do with being able to lock the slr mirror in the 'open' position, and prevent vibration when the mirror moves from open to closed, not sure though)

That exactly wat it was for film SLR's anyway. I was considering getting an Olympus OM1 for that very feature but I might just save up for a digital SLR now. Though focusing is my main problem!

From my very limited experience with film astrophotography, the mirror lock would make a big difference. My camera does not have the feature and there is a noticible wobble of stars in the images, though my mount istnt the strongest for the scope so even a slight vibration will be noticable.

The solution I was told was to have a cover (black cloth draped over it ro similar) over the scope, start the exposure, then remove the cover.

Cheers,
~Al

The solution I was told was to have a cover (black cloth draped over it ro similar) over the scope, start the exposure, then remove the cover.

Clever, I like that... The only problem I see is introducing more vibration then the mirror slap, though a black card held within millimeters of the lens could work.

The other thing I noticed with the 300D from reviews is that the viewfinder is darker then the 10D - which could be a problem for focusing.

- John

There is a thread running ok uk.sci.astronomy about this camera at the moment too:
groups.google.com/groups?group=uk.sci.astronomy

Also www.mlunsold.com seems to be working again after a couple of days on the blink.

Cheers,
~Al

groups.yahoo.com/group/digital_astro/message/36455

You will find a lot of threads on digital_astro group on 300d.
The mirror flip for 10d (and I presume same for 300d) is not as bad as I remember on some old film/slr was… you could hear them for miles Also, there you will find a good few pictures with 300d.

As for viewfinder – I would not worry as it’s not useful to get a good focus anyway. The only way to achieve a pinpoint focus with DSLR(10d,300d,etc) is to take shots remotely and adjust focus accordingly – you might want to use focus assistant – written by Chris Venter(version 2 will be released in two weeks – I doing beta testing on it right now)

Larry

Hi Larry,

Have you got a link for the focus assistant guide? You said that version 2 will be released in 2 weeks, ok, is version 1 around somewhere?

Also, thanks for posting the yahoo link... some of the images from there are very impressive.

- John