Quote:
Originally Posted by dugnsuz
Recently sold a 17-85mm EF-S lens - I felt that it was great as a daytime walk around lens (great FL range), but not so good as an astro lens - bit heavy on the distortions.
I have the f4 version of the Canon 70-200mm L lens, very sharp for day and night use. Sharp stars right to the edge of the field. If the lens is going to be used mainly for astro work, save some money and get the non IS version.
The L lenses are superior for astro imaging IMHO. The f4 70-200 is thought to be as sharp as the f2.8 lens, but as you say the aperture difference might swing it for you (67mm v's 77mm). Either way the 70-200mm FL range is great for wide field imaging (not so much 'wide angle'). Attach a 1.4X extender and you've got a very nice 280mm lens. The 2X extender doesn't get such a good rep though!
The f2.8 is a much larger beast than the f4 lens - so a solid method of mounting the larger lens must be factored in too.
Personally I would avoid the 17-85 for astro imaging. Some reviews show the 17-40 L to suffer from barrel distortions. Here's a couple of review links...
http://www.photozone.de/Reviews/Cano...report--review
http://www.photozone.de/Reviews/Cano...report--review
Good luck
Doug
ps...in the 40D signature link below, the Large Magellanic Cloud pic was taken with the 17-85mm lens and the last 2 pics - Southern Cross and Widefield Eta Carina were taken with the 70-200mm f4L. Comparison may help. |
I will likely leave the 17-85mm on the camera when out and about (general and engineering photography) and may wind up getting a different "standard zoom" later. It comes as part of the Enthusiast kit , cheaper to buy that way so it'll do for now.
There are nice Sigma too.
Like EF 50-500mm f/ 4 - 6.3 APO EX DG HSM
http://www.digitalcamerawarehouse.com.au/prod4085.htm (86mm) , bit big to lug about but .... that's not too shabby on aperture.
and the EF 17-70mm f/ 2.8 - 4.5 DC MACRO HSM looks like good option as a standard zoom.
Too bad I can't use my old lenses and telephotos (Minolta manual focus bayonets) on the 40D , I still use the old XD5 , best 35mm film camera I've ever used for astro work , and has lots of life left in still - I'm not likely to retire it or part with my older telephotos and telephoto zooms any time soon ,even if I am planning on startinfg to do digital photography when the 40D arrives.