Quote:
Originally Posted by gregbradley
I am not so sure about a faster aperture 50mm from Pentax. I have a 55mm 6x7 lens and it needs to be stopped down so any gain from faster F ratio you probably can't use anyway.
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This lens is f/2. I had to stop it down to f/5.6 It seems that all my Pentax lenses perform better at the f/5.6 mark. but the lens aperture is really tiny. Something wider would be great. Ross brought an old Pentax 100mm 6x7 at the last meeting and it was as big as a small SCT
I even had its own carry bag, with shoulder strap
Quote:
Originally Posted by gregbradley
A Nikon or Canon 50mm F1.8 may be the go though. I have used a Nikon 50mm F1.8 and it seemed sharp wide open. I had the Canon equivalent and I tested both against each other and they seem identical in terrestial shots.
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I never tried any other make than Pentax because of my adpaters and back focus. I wanted to keep it simple that's why I built up the selection on the same models M Primes.
Quote:
Originally Posted by RobF
The problem for imagers going with a QHY9 image train is the focal length of canon lens versus Pentax though Greg. Those extra few mm of backfocus make sorting adaptors easier. I suspect your 6x7 has even more backfocus to play with. You pretty well have to take the outer window off a QHY9 to fit a canon on, which is doable of course, just not ideal.
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When I use the QHY9 with those lenses I always remove the nosepiece. I insert the Ha filter inside the lens adapter. I also have two dessicant plugs that I microwave and recharge each time I use the camera. I'm always worried about secondary reflections with the nosepiece like the 8.
Quote:
Originally Posted by RobF
Mark, those are inspiring shots for sure. I just love how you make this look so easy. Hoping weather allows me some Barnard's loop fun this year, but the Cygnus area shot is one I wouldn't have though of. Qld Astrofest one of the best Northern horizons I see up here, but always seems a shame to shoot Ha at a dark sky site |
Nothing to it mate. Just practice. If you nail the focus that's 99% of the job. At 50mm I go by the numbers as the stars are two small to see any definite patterns. From 100mm onwards I confirm focus one way or the other with a small bathinov. Then stick the whole lot in socks.
Yeah , cygnus would be good value for you brissie guys. Nab a few extra degrees up
