Seeing thru the lense

[jr#8]

Hello All, Heres what I'm trying to do. I dable with taking pictures thru a telescope and I cant get focus exactly perfect. When I focus with my eye thru the viewfinder and with the LCD on the camera the images look great. But when I download them to the PC there always out of focus just a little. I would like to be able to view thru the20D camera to a pc screen Via the wire of course. Is there any program out there for free. Heres an example of the moon.

[Fittipaldi]

The software that came with my 20D has a remote capture utility. I haven't used it myself, but I think it's what you're looking for. I can't see how you could get a "live" feed to the PC (given the nature of dSLRs), but it would be useful for taking a shot, refocussing, (repeat) until you've honed in on the desired focus.

Incidentally, I also dabble in astrophotography. I haven't acquired a T2 mount for the 20D yet, so I'm stuck with my 70-200 for now. Here's a picture of Friday's moon (full size crop).

--John.

[Jon]

There's no way to get an image off the sensor before you take the picture. The shutter and mirror are in the way. If you're willing to trial-and-error, you could use Remote Capture to refine your focus. You could alternatively get the Angle Finder C, which alllows a 2+ x magnification of the center of the screen, and focus using that. The 20Da is a specially modified version of the 20D for astrophotography that includes, among other features, ability to view the LCD prior to taking the picture. It's a legitimate Canon version, not an aftermarket mod, and fairly pricey. I doubt many of the replacement focussing screens will help you as they're optimized for larger apertures than you likely have. IIRC, preferred focussing screens for astro are clear center spot or all matte.

[PhotosGuy]

Sounds like cam movement to me.

[Joe C.]

Try using mirror lockup and the remote to minimize vibration.

[Dante King]

how is your diopter set?

[jr#8]

First whats a diopter?. Second there is no f/stop(no lens) the scope is the lens. (2500mm and the f/10 on the scope) That is whats called Eye Piece projection. Where the camera is connected to a T-Ring which is connected to an adapter which holds the EP and then connects to the telescope. The scope is motorized and tracks a given object. So there is no movement from a human stand point. I set the timer on the camera. press the button and walk away. What for a given amount of time and then preview the image. On the LCD the image is great even after zooming in on it. But its still not crystal enough for me. Plus when I have to change the size of the image to post it. It loses some of the clarity also.

[PhotosGuy]

But its still not crystal enough for me. Plus when I have to change the size of the image to post it. It loses some of the clarity also. if you're shooting jpegs you have to set sharpening parameters in the cam's menu.
If RAW, you must sharpen in post processing.
"Diopter" is the wheel next to the viewfinder used to get a sharp image for your eyes before you take the shot.

[Bob_A]

The Canon 20Da is designed for astrophotography, with a partial transmissive mirror and a modified low-pass filter. With the partially transmissve mirror it gives a live preview.

http://www.letsgodigital.org/en/news/articles/story_3405.html

The camera isn't displayed on the canonusa site, but I understand it is available in Japan and the UK.