+RonC Posted June 28, 2020 Share Posted June 28, 2020 (edited) Thinking of selling my ED80 with a Moonlight focuser and FF/Red and getting a 60 mm scope and reducer instead? The reason being that the FOV between my 150PDS and the ED80 are quite close even the Canon 1000dm let alone the Hypercam. I'd like to do some widefield as well as galaxies etc... I have thought about getting an adaptor to use my Hypercam and a 300 mm Tamron zoom lens?? Any comments would be welcome please?? Ron Edited June 28, 2020 by RonC added text Link to comment Share on other sites More sharing options...
Clive Posted June 28, 2020 Share Posted June 28, 2020 Personally I would try to avoid a zoom lens if possible as I feel they have to sacrifice too much (astro image wise) to achieve the zoom range. I'm sure that there are some excellent zoom lenses out there, especially if money is no object, but I'm also sure that, that pound for pound, a fixed focal length would give a better result. Cropping a good quality image taken with a shorter focal length lens may turn out to be better than a poor quality image taken with a longer focal length lens. +RonC 1 Link to comment Share on other sites More sharing options...
+Bino-viewer Posted June 28, 2020 Share Posted June 28, 2020 The Canon EF 200mm F2.8 is well regarded Ron. I have one in my camera case. Not for sale though. You'd be welcome to borrow it and try it out. (£600-£700 new now ; my word they've shot up in price!!) Shout up if you're in the Derby area. +RonC 1 Link to comment Share on other sites More sharing options...
Clive Posted June 28, 2020 Share Posted June 28, 2020 28 minutes ago, Bino-viewer said: The Canon EF 200mm F2.8 is well regarded Ron. I have one in my camera case. Not for sale though. You'd be welcome to borrow it and try it out. (£600-£700 new now ; my word they've shot up in price!!) Shout up if you're in the Derby area. I agree, its a great lens that can be used at full aperture on a crop sensor. It gives me a 6.5 x 4.25 deg fov on my camera. It's baby brother, the 100mm f2 is also good but I think it is no longer manufactured. The Samyang 135mm f2 also seems to get good reviews in the Astro community. Link to comment Share on other sites More sharing options...
+Bino-viewer Posted June 28, 2020 Share Posted June 28, 2020 Correct me if i'm wrong, but with a crop sensor Canon (APS-C ?) you multiply by 1.6x to get the equivalent focal length ? So a 200mm lens becomes 320mm. 135mm becomes 216mm i have a 135mm lens as well....... Link to comment Share on other sites More sharing options...
+Ibbo Posted June 28, 2020 Share Posted June 28, 2020 Have a look at the samyang 135 for wide field. Link to comment Share on other sites More sharing options...
Clive Posted June 29, 2020 Share Posted June 29, 2020 6 hours ago, Bino-viewer said: Correct me if i'm wrong, but with a crop sensor Canon (APS-C ?) you multiply by 1.6x to get the equivalent focal length ? So a 200mm lens becomes 320mm. 135mm becomes 216mm i have a 135mm lens as well....... Yes you are correct, a 200mm lens will give the same FOV on an APS-C sensor as a 320mm would give on a full frame sensor, simply because an APC-C sensor approx 1.6 times smaller in both dimensions than a full frame sensor. +Bino-viewer 1 Link to comment Share on other sites More sharing options...
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