Which DSLR?

[Psychobilly]

I have never (to date) used Mirror lockup with the DSLR when they are attached to the scoeps in the obs... and I am not sure how important it is for long exposure DSO work unless there is a bright target in the FOV and your working at longer FL's

Peter...

[Gina]

I've had no amp glow with the 1100D and the EOS Utility (supplied with camera) also allows doing this.

[Yoddha]

Gina, 1100D has native mirror lock function that can be controlled only with USB cable and EOS Utils (APT too ) uses this feature.

In short - all Digic4 cameras can be fully controlled only with a USB cable, all Digic3 cameras needs serial cable only to use mirror locking, all Digic2 cameras needs serial cable to make bulb exposures and to use mirror locking.

LiveView simulation of mirror locking is something that was implemented in APT for the first time (in an astro program) in order to avoid the need of serial cable for Digic3 cameras, but as Perter mentioned it causes significant amp glow in the long exposures. I would suggest this method only for tests or for short exposures (up to 60s) with good pauses to give time to the processor to cool down.

[Magnum]

They eliminated Amp glow from the 400D onwards, and I can confirm that my 400D shows no Amp glow even with 30 min exposures.

If you intend to modify it I recommend finding a second hand 400D as it has the extra benefit that the ir filter is only 0.5mm thick ( as apposed to 3mm on previous models) so autofocus still works after I removed it.

Lee

[Gina]

I know I get no amp glow with a 10m exposure with my 1100D at ISO 6400 but the noise starts to show. Amp glow is the problem with long exposures without cooling - amp glow isn't. Later I'm thinking of a couple of mods - removal of IR filter and Peltier cooling. I believe a lot can be done with this camera before I spend a grand or so on an astro CCD camera.

[Gasman]

Hi guys

Very interesting post and relevant to me also. Ok so with £550 ish to spend do you a) Get the Canon 550 and remove the filter rendering it not much use for daytime pics but excellent for astro or Put the £550 towards a astro specific camera such as the Atik 314? I know they are over a grand at the moment but - decisions, decisions??.

I could really do with a decent daytime camera, does removal of the infrared filter really affect daytime shots and conversely does leaving the infrared filter in spoil astro shots? Sorry but never had a dslr before

Regards

Steve

[osbourne one-nil]

I'm certainly not going to bother removing the IR filter to start off with. To my mind, there are plenty of pretty things to take photos off and go "ooooo" at without worrying about that. Another way of thinking about it is even if you did remove the IR filter, you have a camera capable of taking daytime photos still - try doing that with an Atik!

What I still cant get my head around is does an 1100D's low pixel sensor really offer some benefit over the 550D's higher pixel count?

[Moondogg]

Well, in the world of daytime photography, bigger pixels (and thus lower MP count) are preferred by many, as you will effectively be receiving more photons per pixel. This should equate to lower noise. That's the reason the impending 5dMk3/5dX will not have any more pixels than the incumbent, apparently.

This may make a difference in DSO work, where we are talking about capturing single photons.

However, the new Canon sensor technology called Gapless Micro Lenses, should help the efficiency in all Canon cameras released after the 500d.

[osbourne one-nil]

Erring towards the 550D then. Oh, I just need to buy one!

[Gasman]

So if the infrared filter is removed (which I assume is not something you can do yourself??) can an infrared filter be obtained that can be screwed onto the lenses?. I used to use a screw on uv filter with my old Olympus slr so not sure if infrared can done the same?? I suppose that would then give the best of both worlds for using the Canon??

Steve

[Gasman]

Well just checked and yes you can get the infrared filters so maybe that would tick all the boxes for an all round astro/daytime camera?

Steve

[osbourne one-nil]

That sounds a very good idea!

Been looking on Ebay and you can get 550Ds and 600Ds for almost half the price that you pay in the UK. They're Hong Kong imports, and badged differently (EOS Kiss or something) but are brand new and there's consistently good feedback. I don't know though.....I just don't know.

[Gina]

The cameras I've looked at on eBay make no mention of software so I would think this is probably not included.

[Psychobilly]

The driver and software is likely to come with the software... I have bought a few DSLRs and L series lenses of ebay... They are grey imports from the US so no UK warranty the warranty "offered" was via the seller...

Seeing as I was going to mod the cameras and loose the warranty anyway it didnt bother me so I went for the cheaper "canon refurbed" option...

This might not suit everyone though...

Peter...

[jasperuk]

I picked up a reconditioned T12 (550D) for £319 off ebay, canon refurb arrived in A1 condition

[osbourne one-nil]

Well, in the end I've plumped for an 1100D (body only) and a 50mm f1.8 prime lens and a 28mm f2.8 prime, for a total of around £570. My thinking was that for not much more than the 600D body-only, I was getting a camera arguably as suitable for astrophotography, which I'd feel relaxed about modifying and dedicating to this cause, smaller and lighter than a 600D or 60D, and two lenses superior to the kit lens normally supplied with these things.

[Psychobilly]

Congrats I will be suprised if your dissapointed with any if those bits of kit...

Peter...

[osbourne one-nil]

Thanks - being an Ipswich fan, I'm very easily pleased, so it can't fail really.

At some point I imagine I'll treat myself to a nice 200mm or so prime lens, but seeing as I like widefield stuff, and it's far easier in terms of tracking, etc, I thought those two would give me plenty to be getting on with.

[Psychobilly]

I pointed my new arrivals at the sky tonight on a static tripod...I can't wait to see what they will do on a tracking mount with the moon out of the way..

[Gina]

Good choice IMO