01-16-2011, 06:32 AM
[quote name='popo' timestamp='1295115945' post='5538']
For example the model mentioned is 300mm f/5. Not that exciting in photograph lens terms. I guess at astronomical distances you don't usually have to worry about bokeh... so I have no idea what they might do there.[/quote]If it's a mirror design with good contrast then it's likely produce the donuts like normal mirrors. In a lot of cases it's not that bad.
[quote name='popo' timestamp='1295115945' post='5538']
I only did a few test shots on my mirror scope terrestrially. It wasn't practical in any way due to a combination of factors, not least that fixed f/13 is already softened by diffraction and in daytime the air was never that stable! Beyond a few hundred meters or so it gets quite wobbly.[/quote]
Yes, the atmospheric turbulence get in the way of long lens IQ... quite a pain <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />
GTW
For example the model mentioned is 300mm f/5. Not that exciting in photograph lens terms. I guess at astronomical distances you don't usually have to worry about bokeh... so I have no idea what they might do there.[/quote]If it's a mirror design with good contrast then it's likely produce the donuts like normal mirrors. In a lot of cases it's not that bad.
[quote name='popo' timestamp='1295115945' post='5538']
I only did a few test shots on my mirror scope terrestrially. It wasn't practical in any way due to a combination of factors, not least that fixed f/13 is already softened by diffraction and in daytime the air was never that stable! Beyond a few hundred meters or so it gets quite wobbly.[/quote]
Yes, the atmospheric turbulence get in the way of long lens IQ... quite a pain <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />GTW