DSLR vs CP4500 with scope (1 Viewer)

I am a proud owner of Zeiss 85 Fl telescope and want to make more use of it than just birdwatching. I also want to use it as a telelens for bird photography. My idea has been to get a CP4500 camera and an adapter for "digiscoping". But now the DSLR cameras have dropped considerably in prise making them more affordable (i.e. Canon 300D). Zeiss produces camera adapter that would make the scope a 1000 mm F12 lens (+1,6x internal magnification in DSLR).
Is it difficult to get reasonable photos with the DSLR setup? I do not think I have seen a single DSLR+scope picture in the Gallery! Why is that? Is the reach comparable in the two setups?
With the DSLR route I would be able to get me some 300-400 mm lens for the many cases scope photography is just not handy enough!

Hi Gaukur,
I have the Zeiss 85fl , photoadapter and dslr but haven't really put it to much use as yet....it's been very overcast down here and one aspect that you'll notice straight away is that you need plenty of light to get satisfactory results. The main problem is that f12 is a very small aperture and the image in the dslr's viewfinder is very dark with the scope attached, you may have a dslr that's good at high iso speeds but the main problem is trying get the subject perfectly focused with such a dim view.
I'll give it another try next week, hopefully it will be a bit brighter down here (sunday is supposed to be good).
Magnification wise, a dslr with a 1000mm in front of it is a match for digiscoping with a scope eyepiece of 20x.
Look for photos in the gallery by Neil Fifer, I did notice that he had taken some photos with a dslr+swarovski scope... it's nice and bright down there in Australia though.
Regards,
Andy

Andy's hit the nail on the head. In Scotland in winter with a DSLR + fast(F4) 500mm lens + 2x convertor (effectively 1000mm F8 lens) I struggle to get good shots even with ISO 400 setting on a typical Scottish mid-winter day. Those that I do get are a consequence of the image stabilisation function on the Canon lens (I'd imagine the mid-Winter situation in Iceland might be worse -unless you've got snow cover reflecting incident light!!) The slightest movement on a 1000mm effective lens produces image blur. In SLR photography the guide to preventing this is to use a fast shutter speed with the rough rule of thumb being to use the speed closest to the reciprocal of the focal length-in this case 1/1000sec-impossible with an F12 minimum aperture. Image stabilisation will allow you to steal 2-4 stops (> 1/250-1/60sec) depending on the support for your lens. I wouldn't bother with a telescope adaptor & DSLR > better to go for the DSLR + TELE lens if your Bank Manager permits it!!

Thanks for the answers. I did look at Neil's Fifer pictures. He did take some excellent pictures using DSLR and a scope last year, but he really seems to do just about perfectly whatever he uses! I do not understand why shutter speed is more relevant on DSLR than CP4500! Andy, you would do me (and probably many others) a favour by trying this DSLR & scope setup.
I also looked at your pictures in the gallery Steve. Excellent collection! If money was no object I would probably go for Canon 500 F4 IS. But it is far too expensive for me. I have been considering Sigma 500 F4,5 like Andy has, but it is still too expensive for me (and does not have IS)!

Gaukur said:

I do not understand why shutter speed is more relevant on DSLR than CP4500!

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I'm not sure, but my best guess is that it has to do with the mirror slap which is absent on the digcams. I routinely take pictures at shutter speeds below 1/250 with no problem and often get good results even below 1/60 with equivalent focal lengths of 1500mm to 2500mm. And I'm using a tripod and head that many would consider marginal for digiscoping (Manfrotto 3021 and 3130 head).

With digiscoping you almost always have the scope on a tipod, then the camera attached to this. With a DSLR it is the same, if on a tripod you can get down to 1/60 shutter speed. It is only when hand holding that you need the 1/mm length approx shutter speed. If you hand-held a scope + camera together you would need a very fast shutter speed indeed.

You set the shutter speeds for two reasons,
1, to combat camera shake, if on a tripod then not nessasary.
2, to combate the target movement.

This is why a landscape photographer has very long exposures on a tripod (to give large depth of field (due to apature) and no movement).