Focusing screens for Canon 50D

[sologuitarist61]

Hi,

I am having trouble trying to focus through my Canon 50D camera (sometimes I cannot use the laptop to focus) and know that there are alternate focusing screens. My scopes are f6 and so the image is dim and hard to focus. Has anyone tried the other screens and can you recommend one that works at f6 or smaller? I have heard the the EF-D is better than the standard screen but cannot find much on the 'net to support this. Does anyone know if this works better through a scope?

Any help would be appreciated positive or negative. Thanks

[GlassWalker]

The default A type focus screen is already optimised for brightness. The D type is the same as the A type, other than the etched lines on it so it wouldn't make any difference. The only other one they do is the S type, but that is optimised for f/2.8 or faster, so it would actually give an even dimmer image on slow optics.

My suggestion is to try to get ball park focus by eye and the existing viewfinder. Then go into live view, and fine tune the focus there. You can "zoom in" to help.

[Tinker1947]

Live View will pick up very dim stars but the focus point on a 10 - 1 focus is in and out of the live view in a quarter of a turn, with the magnification at 10x, better to find a bright star then slew your chosen object....or have a shed load of patience...

[sologuitarist61]

Thanks guys, unfortunately Live View is nor easy when doing solar imaging even with a dark cloth over your head (which I am sure looks very strange!!)

The only thing I was going on was the blurb accompanying the WEX listing, which is the only one i have found which states :-

For Canon EOS 40D and 50D digital SLR cameras, the Ef-D Focusing Screen (Grid Precision Matte) maximises viewfinder brightness and is optimised for use with f/5.6 and slower lenses. It provides a 3-line (horizontal) by 6-line (vertical) grid for easier composition and horizon alignment.

A lot of the reviews on Amazon also seem to state that it gives a brighter image and is better that the one supplied with the camera, but there criteria won't be the same as mine I would suspect. Guess I will just have to get one and try it and put it down to experience if it is no better..

[Quatermass]

Focusing on those tiny screens is a right pain and I used to have a camera with live view as well. I can do it if I have to but focusing with my laptop and backyard eos is 100 times better for focusing and aligning my images, to the point where I am going to get a spare battery for my laptop so I can use it when I am away from an electric supply.