09-13-2011, 07:24 AM
[quote name='DTR' timestamp='1315865140' post='11527']
If you used a camera capable of clean high ISOs you could do away with f/2.8 glass, and canon 70-200mm f/2.8 non is is wonderful for a start. There are plenty of manual lenses around 200/2.8 and an odd bargain of 300/2.8 although you really have to hunt for it. Really, upgrade to 5D II or 1DIV (or D3s should you fancy) and you'll have more options.
[/quote]
For astrophotography, high ISO makes a lot less difference than you think. A lower value to maintain dynamic range helps there. Also by using a bigger sensor you will then be subject to the wider border characteristics.
If I were to go f/2.8, I see no reason to get anything other than the 70-200 IS II in the middle ground. The only reason I don't have it yet is I don't really have a use for it. I'm in no hurry to "go large" so will wait for the 5D3 as things have moved on since the 5D2 sensor generation. I used to have a 300/2.8L (non-IS) and that suffered from really bad vignetting even on crop sensor. And besides, I wanted a shorter focal length for this application.
Anyway, I did have one short break in the clouds with the moon far enough off for a quick test of the 135/2. That was a bit of a "wow" moment. Stars in corners remained as tight as the ones in the middle. I think I can get away with using this one wide open, or stopped down to f/2.8 if I need a bit more. I doubt any native f/2.8 lens of a similar focal length will match it there.
If you used a camera capable of clean high ISOs you could do away with f/2.8 glass, and canon 70-200mm f/2.8 non is is wonderful for a start. There are plenty of manual lenses around 200/2.8 and an odd bargain of 300/2.8 although you really have to hunt for it. Really, upgrade to 5D II or 1DIV (or D3s should you fancy) and you'll have more options.
[/quote]
For astrophotography, high ISO makes a lot less difference than you think. A lower value to maintain dynamic range helps there. Also by using a bigger sensor you will then be subject to the wider border characteristics.
If I were to go f/2.8, I see no reason to get anything other than the 70-200 IS II in the middle ground. The only reason I don't have it yet is I don't really have a use for it. I'm in no hurry to "go large" so will wait for the 5D3 as things have moved on since the 5D2 sensor generation. I used to have a 300/2.8L (non-IS) and that suffered from really bad vignetting even on crop sensor. And besides, I wanted a shorter focal length for this application.
Anyway, I did have one short break in the clouds with the moon far enough off for a quick test of the 135/2. That was a bit of a "wow" moment. Stars in corners remained as tight as the ones in the middle. I think I can get away with using this one wide open, or stopped down to f/2.8 if I need a bit more. I doubt any native f/2.8 lens of a similar focal length will match it there.
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.