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Old 18-10-2010, 05:44 AM
Martin Pugh
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Martin Pugh is offline
 
Join Date: Nov 2006
Location: Canberra, Australia
Posts: 1,247
Thanks for the additional comments there. Useful indeed, since I did have a heater belt on it. I will remove it next time out.

I kind of expected things not to be perfect of course, but the results were just rubbish.

While the 85mm might be a great portrait image, I cant understand why it would not be good for astrophotography given the MTF curves.

Doug - I did see your initial tests before I bought the 85mm, and almost opted for that same lens, but I wanted to keep the cost down a little, as this is not my main line of astrophotograhy. So, the 85mm lens, with the reviews it had, was just $386.

I do not use Liveview for focussing. I connect to the camera from within Maxim, draw a crop around a bright star, and then take continuous 1 second images using the "View Large Statistics" menu item. I continue to focus until I reach the lowest achievable FWHM I can. Of course, doing this by hand is not perfect either.

I assume that to stop these lenses down, you can only do it via software or external aperture mask. I do not see any physical adjustment on the lens itself.

I will take some daytime shots with the 85mm lens and post them for comment, then I will stop the lens down some more and post some nightime shots also for you DSLR experts to analyse.

thanks for the links and help

appreciate it very much.

Martin
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