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Kentari
scholastic sledgehammer
Reged: 11/19/06
Posts: 794
Loc: Belgium
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Hi all,
It's been a while since I posted an image... This is a result of the First Light evening with my "brand new" 10 year old EF 300 f/2.8 L USM I managed to get last month. I consider it a bargain, but that new 40D will have to wait a little longer now  .
The start of the session turned out to be a bit more exciting than expected. I put the lens on my modified 20D and I couldn't reach focus. No matter what I tried, it just stayed very fuzzy. Removed the IDAS filter, no change... In the end I desperately put my non modified 20D on the lens and it all worked just fine. So I focused and started a sequences of images to worry about the seemingly wasted modded 20D. Other lens on the body, same problem... Sensor busted? Hmm, no... then it should be sharp on the focus screen... Focus screen busted: no, looks Ok. Focus at infinity with the lens: sharp... Puzzling... Wait... There's a diopter control next to the viewfinder. Ah... fixed. Pheew...
The Image
Tech Info:
Canon EOS 20D (not modified)
EF 300 f/2.8 L USM at f/2.8
60x 30s at ISO 1600
Processing in Iris and PS CS2
Unguided on Losmandy GM8
Larger version and more info
Clear skies,
Koen
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Darkstar 355 f/5 Dobsonian
Orion UK 8" f/4.5 Newtonian and WO ZS 80 FD on Losmandy GM8
Canon 20D DIY mod with Baader filter
A bunch of lenses: 10-22mm f/3.5-4.5, 17-40mm f/4, 50mm f/1.4, 70-200mm f/2.8, 300mm f/2.8
www.koenvangorp.be
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Buzzer
professor emeritus
Reged: 07/21/07
Posts: 673
Loc: Long Island, NY
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That's a great shot. It is amazing how long this thing is hanging around, Andy
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TMB 92ss
Orion 8" F/4 Newt
FLI ML 8300 Mono FLI CFW 2-7
Mini Borg 50 Guidescope
Celestron CGE Mount
Orion Starshoot Autoguider
http://buzzer.zenfolio.com/
"I THINK THE WEATHERMAN NEEDS MORE EXPENSIVE EQUIPMENT"
WANING CRESCENT OBSERVATORY
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Andrew Welsh
Carpal Tunnel
Reged: 03/28/06
Posts: 2511
Loc: Rochester, NY
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Lucky dog! I want a 300/2.8! Nice pickup though. I suppose I could sell my 40D, 135L and 400/5.6L and find a used 300/2.8 non-IS lens.... as soon as I sell my car I'm picking up either a 200/1.8, 200/2 IS (if it's just as sharp) or 300/2.8 can't decide though.
This pic helps me to decide, because it looks pretty sharp and flat across the sensor. Does it have round stars? I can't really tell with your full size image if the stars are slightly triangular due to tracking or the lens.
Otherwise, nice image, especially considering the near full moon!
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LX200 8" classic, f/10, Meade eq. wedge, .63x FF/FR
Canon 40D and 5DMkII, unmodified
Canon EF 200/2L IS, 300/4L non-IS, 100/2.8 Macro, 50/1.4, 85/1.8, 35L, 24L, 16-35L and Peleng 8mm fisheye
Orion Apex 102mm (4") Mak-Cass
Pimped out with accessories and bling
My DSLR Astrophotography Webpage and photo bucket with full equipment list
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Lord_Vader
Vendor - Aries
Reged: 07/25/06
Posts: 140
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Quote:
Lucky dog! I want a 300/2.8! Nice pickup though. I suppose I could sell my 40D, 135L and 400/5.6L and find a used 300/2.8 non-IS lens.... as soon as I sell my car I'm picking up either a 200/1.8, 200/2 IS (if it's just as sharp) or 300/2.8 can't decide though.
This pic helps me to decide, because it looks pretty sharp and flat across the sensor. Does it have round stars? I can't really tell with your full size image if the stars are slightly triangular due to tracking or the lens.
Otherwise, nice image, especially considering the near full moon!
Get an older Canon FD 400/2.8 L !
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Kentari
scholastic sledgehammer
Reged: 11/19/06
Posts: 794
Loc: Belgium
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Andrew: I couldn't fully test it yet. Mostly thanks to the lousy weather we've been getting for the last 3 months and of course the holidays didn't help either.
I can't say for certain that it is sharp across the entire field. Centre sharpness is really outstanding. The lower left and upper right corners are equally sharp, with an assymmetric diffraction pattern. Upper right is a tad less sharp and lower left is noticably less sharp, but acceptable. Since I see a similar behaviour with my 70-200 I have good reason to believe this is mostly because of misalignment of the sensor rather than the lens. Once the skies clear up again, I will perform further tests.
I don't think you could go wrong with any of the Non-IS L primes...
As for getting an older FD lens. Well, you'll need to find the FD to EF adapter (with lens) too then, which is even more rare. Or get it modified by a skilled person...
Koen
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Darkstar 355 f/5 Dobsonian
Orion UK 8" f/4.5 Newtonian and WO ZS 80 FD on Losmandy GM8
Canon 20D DIY mod with Baader filter
A bunch of lenses: 10-22mm f/3.5-4.5, 17-40mm f/4, 50mm f/1.4, 70-200mm f/2.8, 300mm f/2.8
www.koenvangorp.be
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