I wanted to try out the DSLRs on my Kowa 823 telescope. There are two ways of taking photos through a telescope:
- Replace the eyepiece with an adapter (which usually connect to the camera via a T-mount)
- The same way as a compact camera - i.e. photograph the image that the telescope's eyepiece produces by pointing a camera with a normal lens mounted at the eyepiece.
Since I already have the LCE adapter for my Coolpix 4500 (which is essentially a bucket shaped piece of metal which slips over the eyepiece of the scope and has a hole surrounded by a 28mm filter thread to fit to the camera lens - see). So, if I can find a suitable lens for the DSLR which will successfully form an useful image, I just need a way to mount it on the 28mm thread of the LCE adapter. After some Internet searching, it seemed that a 50mm lens was often mentioned as suitable - and I have a Zuiko 50mm f1.8 lens from a defunct Olympus OM1 film camera (whose metering system gave up the ghost in the dim and distant past). I have an adapter to mount Olympus lenses on the Canon DSLR (bought for a few quid off eBay) and it did indeed form and image (without any vignetting!) when held against the scope's eyepiece. It has a 49mm filter thread, so a 49 - 28mm step-down ring solves the mounting problem.
|LCE adapter, 49-28mm step-down ring, 50mm lens, Olympus to Canon EOS mounting adapter|
|Canon EOS 60D mounted on Kowa 823 telescope|
|Car number plate - the red line shows the height of the inside of the letter "L" which is 64mm high|
|100% crop - 500mm|
|Coolpix 4500 - min zoom to avoid vignetting|
|Coolpix 4500 - max optical zoom|
|Canon EOS 60D,/Zuiko 50mm mounted on Kowa 823 telescope|
Just like with the Coolpix, the whole setup is quite cumbersome and it can be quite difficult to find the subject, because the field of view is so small. Focusing is also a problem. The auto focus system won't work of course - since the scope and 50mm lens do not have focus motors. Even focus confirmation is not possible because the Canon need a lens aperture of f5.6 or wider for its auto focus system to work. I don't know what the effective aperture of the scope setup will be - but its a lot smaller than f5.6! The live-view mode and articulating LCD screen of the 60D is a tremendous help here.
I will be interested to try it out for real next time I am in a hide somewhere and have a subject that isn't moving very much!