Focusing a Canon A590 (1 Viewer)

[yornotelppa]

I recently pulled an old telescope out of the closet to try my hand at digiscoping. I also recently purchased a Canon A590 on clearance sale to use with the telescope. I've successfully coupled the camera to the telescope which by the way appears to be a old Meade ETX 90 but the only markings to identify it are on the bottom and don't mention any model number but just 90mm F=1250 f/13.8.

Camera and telescope

Camera and telescope

I've been having limited success focusing the A590. I've tried letting it autofocus in the normal and macro setting neither is 100%. Though normal seems to work more often then macro.

I've tried the manual focus mode also but with the lower resolution display screen of the A590 I wasn't having much luck and gave up on manual focus.

Though I realize that this is a bird forum and I too want to eventually "shot" birds, my examples here will simply be my first attempt to take pictures at something that was both interesting and didn't move too fast!

Moon but not in good focus

Moon in better focus

These were taken with a 25mm eyepiece. I've got a 32mm eyepiece ordered and it will arrive in the next couple of days. Though I don't think that the 32mm eyepiece will solve my focus problems, hopefully it cut down the magnification a little and make the Meade a little more "manageable".


Any suggestions or directions on getting a handle on focusing the A590 would be very much appreciated.

Roy

 

[obelix]

You have to bear in mind that the LCD is the 590IS weakest point. I use the following method:

- zoom in until it goes into digital zoom. Zoom in to the max, half press the release button and adjust the focus on the scope. Then zoom out to around 70 - 100 mm (2 - 3 times optical zoom), then take the picture. A release cable (as sold by srb griturn) will help you reduce vibration.

If zooming 2 -3 times is too much for the object you want to photograph, try the above, but using macro instead of normal focus.

Hope this helps,

Paul

 

[yornotelppa]

Paul, thanks for the suggestions. I just got my 32mm eyepiece yesterday and so hopefully today I'll get a chance to try it out. I'll try the methods you suggested.

I guess the bottom line is that you can't successfully use the camera's auto focus consistently? I wonder what the problem is. I can get it to "go green" for me some of the time but the majority of the time no luck on auto focus. And this is with the same subject and the same framing.

Thanks again for your input.

Edit: I just re-read your post and realized that you were talking about focusing the telescope. I'm not having a problem focusing the telescope but getting the camera to focus instead. Also on the release cable, I've made a USB cable shutter release to use with the CHDK software.

 

[obelix]

Edit: I just re-read your post and realized that you were talking about focusing the telescope. I'm not having a problem focusing the telescope but getting the camera to focus instead.

Yes and no. What I meant is this: after zooming in, you half press the release button. That makes the camera (auto)focus on the subject. Then you can see if the subject is good in focus, and adjust it using the scope (!).

Using this method has improved the quality of my photos. You can see my pics using this link on a dutch digiscoping site. I hope you can see the improvements (photos at the bottom are the oldest).

Paul

 

[Thing]

Roy,

If the A590 is anything like the A560 (which I use), it may be worth trying the method I have found to be best.

Firstly, ensure that the macro setting is on and secondly do not use any zoom! Optical or digital.

This may result in vignetting, but the quality of the image improves no end although you will need to crop on the computer...

I have also found the most crisp images by dropping the ISO to 80 and using the spot rather than elavuative setting. The exposure may need tweaking with the AWB setting, but that is bound to be particular to what you have on the end of it I reckon.

I've got this working on an 8 x 30 monocular and a 30 x 75 drawscope.

Worth a try?

 

[Thing]

And I should have said that this is in the manual setting, not the auto...

 

[yornotelppa]

obelix and Thing,

Thanks to both of you for taking the time to give suggestions. I really appreciate that.

It's early afternoon here in Dallas, TX and though it suppose to get close to 100 degrees again today I think that I'm going to drag out my stand and camera/telescope and try out the new 32mm eyepiece with both the techniques you've described and see how it goes.

Thanks again,

Roy