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palerider
member
Reged: 06/19/08
Posts: 69
Loc: Rancho Cucamonga, CA
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I've been fooling around the last couple of nights to see what kind of imaging is possible with a digital camera. I found this in another post that pretty much describes the same issue I'm having when trying to achieve focus.
Quote:
With my new scope William Optics Megrez 72.
I'm trying to take astro images afocal.
Just a regular digital camera attached to a Hyperion 17mm.
I can not focus on the moon. This is what I have in line.
Telescope-diagonal-Hyperion-camera-can't focus on object
telescope-Hyperion-camera- still can't focus
Utilizing manual focus on the camera also.
Can someone lead me into the right direction.
I have a Stellarvue SV102ED, 2" WO diagonal, a 17mm Hyperion eyepiece, and a Panasonic FZ-7 camera. The camera is coupled directly to the Hyperion with a 52mm/43mm step down ring. The camera lens is VERY close to the Hyperion. I focus the image in the eyepiece, lock the focuser, and then attach the camera. Zoom in, zoom out, manual focus, auto focus, yada, yada. Nothing works. When I remove the camera, the image is still in focus in the eyepiece.
I know this can be done with the Hyperion 17mm because I've seen several photos others have posted, a couple even used a Panasonic FZ-20 which is very similar to my FZ-7. So, I'm doing something wrong. Just can't figure out what it is. Maybe the lens is actually too close to the eyepiece?
I'd appreciate any thoughts on the subject. Thanks.
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Charlie Hein
Postmaster
Reged: 11/02/03
Posts: 6534
Loc: 26.06.08N, +80.23.08W
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Disable autofocus for starters, it'll definitely be a problem. Also, either keep the diagonal in place or replace it with an extension tube. You eyepiece must be able to come to focus and this can't happen without the extra length that the diagonal (or an extension tube) will supply.
Having the eyepiece as close to the lens of the camera as possible is a good thing. That's not likely to be your trouble. I'd definitely start out with the zoom all the way out, it's going to be easier to work with and will also give you a much brighter image.
Does your camera have an "infinity" focus position? The camera needs to be at infinity focus for this to work properly. If there's no explicit "infinity" setting then try focusing the camera manually on a distant object before attaching it to the eyepiece. You may need to mark the focus ring (or whatever focuses the camera) to know where the "infinity" focus point actually is.
Once you've got that all together then you should be able to use the focuser on your scope to bring the projected image into focus. It shoudn't take a large amount of travel to bring the Moon into focus either if you started with the EP focused visually.
I started out in astrophotography shooting afocally with my digicam. It works pretty well as long as whatever you're shooting is pretty bright...
Charlie
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Weston CSC:
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palerider
member
Reged: 06/19/08
Posts: 69
Loc: Rancho Cucamonga, CA
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Quote:
Disable autofocus for starters, it'll definitely be a problem. Also, either keep the diagonal in place or replace it with an extension tube. You eyepiece must be able to come to focus and this can't happen without the extra length that the diagonal (or an extension tube) will supply.
Ok. Never thought about disabling autofocus. I can set the camera to Manual focus and still use Spot Metering for exposure. And, I do leave the diagonal in place.
Quote:
I'd definitely start out with the zoom all the way out, it's going to be easier to work with and will also give you a much brighter image.
Good point. I've done it just the opposite up until now.
Quote:
Does your camera have an "infinity" focus position? The camera needs to be at infinity focus for this to work properly.
Yes, I can set "Infinity" in Manual Focus Mode.
Quote:
Once you've got that all together then you should be able to use the focuser on your scope to bring the projected image into focus. It shoudn't take a large amount of travel to bring the Moon into focus either if you started with the EP focused visually.
I can get razor-sharp focus in the eyepiece. The problem I have is getting the image focused on the camera LCD. I'll try your suggestions tonight. Thanks for your help.
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microbes
Pooh-Bah
Reged: 12/12/04
Posts: 1192
Loc: Romulus, Sector 12
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Charlie hit the nail on the head:
Quote:
The camera needs to be at infinity focus for this to work properly
If you lock the camera on infinity as long as the eyepiece is focused visually (and you don't have 20/200 vision) you should be focused.
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Dirt Cheap Astronomy
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palerider
member
Reged: 06/19/08
Posts: 69
Loc: Rancho Cucamonga, CA
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I just came in from an hour long photo session. The good news is that I was able to get a couple of decent shots with the moon in focus, but nothing to write home about. Manual focus was set at infinity, 1x zoom, spot metering on, image stabilization off. The moon was focused and centered in the eyepiece, but I still got pretty severe vignetting. When I tried to zoom in to compensate, the moon turned into a blob and ultimately disappeared from the LCD totally at 12x. The only way I could get it focused was at 1x. I gotta think part of the problem is a mismatch between the eyepiece and the camera lens.
I have seen lenses made specifically for digital cameras, like the WO DCL-52, and I've read a couple of excellent reviews of it along with some very good sample photos. Maybe that's what I need. I thought I'd try my 17mm Hyperion first to see what kind of results I could get with what I've got. The saga continues.
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microbes
Pooh-Bah
Reged: 12/12/04
Posts: 1192
Loc: Romulus, Sector 12
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Quote:
but I still got pretty severe vignetting
Using an eyepiece with long eye relief will help with that. The longer the better.
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Dirt Cheap Astronomy
Voyager 114X900 Newt EQ2 * Sky Chief 60X700 EQ1 * Cometron 62X300 EQ1
Sears Ultra Wide 7X50 Binos * Vintage 16X50 Binos EQ1
Books, Barlows, Eyepieces, Camera Adaptors & Other Esoteric Junk.
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palerider
member
Reged: 06/19/08
Posts: 69
Loc: Rancho Cucamonga, CA
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Quote:
Using an eyepiece with long eye relief will help with that. The longer the better.
Not much I can do about that with the 17mm Hyperion. When the rubber eyeshield is removed, the adaptor threads on the eyepiece are virtually flush with the glass.
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ccs_hello
Carpal Tunnel
Reged: 07/03/04
Posts: 2779
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FZ7 has a big front lens. I.e., large entrance pupil.
Basically this type of design is the most difficult type for afocal imaging without seeing optical vignetting.
Clear Skies!
ccs_hello
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G Smith
member
Reged: 11/22/07
Posts: 29
Loc: Central Ohio, USA
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OK, we can quickly help you solve the problem. First of all, check out my shot of the moon
www.ohiobirds.org/forum/viewtopic.php?id=518
This was made with a 10 inch Dob., a Canon A-550 camera, and a 30mm eyepiece. See also the picture of the camera and 2 inch attached metal tube.
I tried to check out the Hyperion 17mm, but it looks like it is made in BOTH 1 1/4 and 2 inch, so that did not help. First of all, it is very difficult to use a FZ camera for digiscoping unless you use a 2 inch eyepiece with a perhaps 1.4 inch diameter eye-lens and 20 mm eye-relief. The optical system is just too big. I have a FZ-30 and a 50, fine cameras, but not for digiscoping. My favorite is a Canon A720 8 meg. A better and newer favorite is the Canon A650, which is a 12 meg. These are very sharp cameras.
You can tell in 15 seconds if a camera and eyepiece are compatible for digiscoping. You do not need the telescope, just the eyepiece and camera. Hold the eyepiece in front of the camera and close to the lens, pointing at some light. Looking at the viewing LCD you should be able to cover it with light. (NOT an image) Many times up to 1.5 zoom will help. I do not like to use any more than that.
My system is very simple and precision made, my fabrication. A bayonet mount filter holder attaches to the camera. A 2 inch diameter by about 5 inch metal tube attaches to the filter holder. An Orion Expanse 20mm eyepiece is positioned inside the tube near the camera lens. This 2 inch tube fits into the 2 inch focuser of the scopes. The A650 also has a bayonet mount, but the filter holder may be a bit larger. Again, see picture address above.
Yes, certainly get that diagonal out of there. Keep the camera on auto focus. It will not focus from scratch. You have to manually bring the focus close and then it should focus automatically and give you the indication. Do use care that the lens does not extend to touch the eyepiece under any conditions, this can damage the camera or cause a lens error. You will want to use a time delay on the camera, which will let the vibration settle before the shot.
I also attach a microscope objective ( a 4X Lomo Plan) to the open end of the 2 inch metal tube to take microscopic shots of snow crystals and small bugs. See my web site www.naturepics1.com Get back to me if you want. Good luck, Gene Smithhill1@Embarqmail.com
Edited by G Smith (08/20/08 01:04 PM)
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