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Old 17-10-2011, 06:29 PM
gregbradley's Avatar
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gregbradley is offline
Join Date: Feb 2006
Location: Sydney
Posts: 16,906
I think Phil is right on the money here. I have used quite a few lenses over the years with CCD cameras.

Nikkor 50mm F1.8, Nikkor 180mm F2.8 ED Canon FD 85 and 105mm, on an STL11, a Pentax 67 55mmF4, 165mm F2.8, 300mm F4 and Canon 18-55mm on a Proline 16803.

The Nikkor 50mm was definitely one of the better ones. The bigger the sensor though as you'd expect the tougher it is on the lens.

The Pentax 67 55mm F4 showed quite a bit of coma but cleaned up mostly with 2x2 binning. The 165 though was quite aberration free fully open at F2.8 as is the 300mm on the Proline 16803 which is quite a feat.

I found in an old camera bag a Pentax 50mm F1.2 which I would like to use on my ML8300. The 8300 should not be so demanding on the lens being aberration free but unless you want to do manual focusing you need something with some decent backfocus.

My imaging train with the Pentax 67 lenses is Proline, filter wheel, PDF focuser, Precise Parts adapter, Pentax 67 lens. I notice focus is like a telescope and quite particular and I think it would be hard to adjust manually.

In the case of FLI the 8300 chip is about 22mm inside the body and the Proline 30. I imagine the ST8300 is similar to the FLI in chip placement.

Another way of focusing I have seen is a rubber belt around the focus ring of the lens attached to a wheel run by a Robofocus.

The Canon FD lenses were a bit disappointing but I did a couple of shots that were OK.

You really need ED lenses in there otherwise there will be some chromatic aberration. In the case of the Pentax 67 it is minor and you can process it out mainly being bright stars look magenta.

The 55mm F4 gives a very widefield view with the Proline 16803 so that 2 images would cover 1/2 the Milky Way approximately.

I am beginning to feel a Canon 5D would be the best camera for this type of shot with a nice fast short focal length lens like Phil uses or Alex uses with his Nikon D3

The Nikon 14-24 would be very tempting if you have the budget for it.
I am waiting for the 5D Mark 111 to be released before I get a 5D camera but it may not be that different for wide field images than the current model.

I found this guide to Pentax 67 lenses very helpful:

There was another table I read which listed the backfocus of many different lenses. There are only a few that match this 87mm or so backfocus. The Pentax 67 lenses are fairly plentiful on ebay as are adapters to make them fit Canon cameras.

I am not sure how they compare to Canon L lenses but they are very good for CCD cameras.

So in summary the Nikkor 50mm and the Pentax 67 165mm F2.8 so far have been the standouts. The Nikkor 180mm F2.8 ED as I recall was also good but too long for what you have in mind.

Of course any lens you get for an APS sized sensor you need to multiply the focal length by 1.6 to match a full frame 5D or Nikon D3 etc. Full frame will be wider field for any lens. So when Phil mentions a particular lens his camera is a 5D and the same on your 550D will be a factor of 1.6 less in FOV.


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