new 50mm Eta Carina widefield image

[tornado33]

Hi all
Its 2 x 5 mins ISO 800, 50mm f1.8 canon lens stopped down to f4.5 with 2 inch Baader UHCS filter sitting on front .Modded EOS 350D camera, piggybacked on my 10 inch Newtonian.
Larger image here
http://www.users.on.net/~josiah/baad...5uhcssmall.jpg
Scott

[h0ughy (David)]

I lost count after 10, gee there are lots of stars there! nice shot!

[astroboy]

Very nice image Scott .
Does the 50mm need to be stopped down to F4.5 to get good star images at the corners or is it a vignetting issue with the filter.

Zane

[ving (David)]

lordy! how many stars in that pic????
dave you are right... I tiik off my shoes and got up to 22 and theres more still

great shot!

[tornado33]

Many thanks all
Yes, Zane, if I shoot with lens wide open at f1.8 I get some comatic stars near the edges, however with the UHCS filter on the coma isnt too bad it must be because the UHCS blocks a lot of the UV and deep blue that might otherwise lead to chromatic abberations and coma. Focussing is a bit of a pain, sometimes I can be lucky other times Ive got to take dozens of test images to get it spot on. The latitude is tiny, moving the focus ring a fraction of a mm makes a noticable change. I love the old film lenses that manual focus, the focus is much finer, whereas the EOS lenses are really made for AF with manual put on as an afterthought.
I get no noticable vignetting with the uhcs filter at all even though its slightly smaller then the UV cover filter. I do, however, with the zoom kit lens that came with the 300D camera.
Scott

[astroboy]

Good tip about the lens focusing , I was thinking of buying one of the Canon 50mms but probably better off sticking with the Nikon MF lenses ( I bought an adapter for Canon EOS ) the focusing is difficult enough as it is.

Zane