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Canon A95 manual focus distance setting.

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Old Saturday 3rd December 2005, 11:20   #1
robert s
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Question Canon A95 manual focus distance setting.

I was wondering why at 2ft the camera and the scope seem in sync with one another. I`ve been taking almost all my shots at infinaty setting and focusing with the scope. But last week I focused with the scope first on a tree then put the camera to the scope and had to adjust focus with the scope again . Then I put up the center zoom helper that zooms in closer so you can fine tune the focusing and put the manual focus on and found the are in sync at 2 ft.I was wondering would I get any advantage with depth of field by leaving it at that setting.
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Old Friday 9th December 2005, 22:20   #2
john-henry
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Quote:
Originally Posted by robert s
I was wondering why at 2ft the camera and the scope seem in sync with one another. I`ve been taking almost all my shots at infinaty setting and focusing with the scope. But last week I focused with the scope first on a tree then put the camera to the scope and had to adjust focus with the scope again . Then I put up the center zoom helper that zooms in closer so you can fine tune the focusing and put the manual focus on and found the are in sync at 2 ft.I was wondering would I get any advantage with depth of field by leaving it at that setting.

Robert, I can't quite understand your thread. It's obvious you shoot in Manual Focus and at infinity, and focus the scope before fitting the camera, which would be the normal method. I then get a bit lost when you say you used the zoom magnifier and then turned to MF - you have to be in MF to use the magnifier, are you talking about being in Macro mode, refocusing the scope then going into MF?
I was quite interested to read your thread as I have found something I just can't get my head around - focus the scope on a subject and put the camera on the scope, now switch to Macro and the subject looks, and is, out of focus, now refocus through the screen until it looks sharp and take a picture, the picture is in focus and sharp even though the scope is not in focus.
I have always believed digiscoping is taking a picture of what the scope is seeing but it's obviously not so clear cut as that.
I know Macro is autofocus but how can it take a sharp picture when the scope is not in focus!!!
As they say its got me passing water horizontally.
Anyway I can see from your threads you enjoy experimenting a bit so have a play around with this one and see what you think.
I'll also carry this on into MF and see what happens although I'm not sure if it will be useful in the field or not..

Regards

john

PS I'm using a Canon A95 and the older Swarovski AT80HD.
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Old Saturday 10th December 2005, 02:35   #3
robert s
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Question A little clearer . (maybe)

I almost always focus my shot through the lcd screen. I have the camera on manual and set at infinaty.Works fine almost all the time. Well I thought nothing of it for awhile. Then one saterday I focused on a tree first . Then I put the camera up to the scope. I figured it should be in perfect focus but it wasn`t. So I put it on macro and adjusted the focus until it matched the scopes focus. Which was 2 ft. according to the lcd scale ( not sure how accurate the scale actually is) . I was just wondering why this was so . I got excellent results at the infinaty settings.

Last edited by robert s : Saturday 10th December 2005 at 02:40. Reason: Smily screw up
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Old Saturday 10th December 2005, 09:03   #4
Neil
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Quote:
Originally Posted by robert s
I almost always focus my shot through the lcd screen. I have the camera on manual and set at infinaty.Works fine almost all the time. Well I thought nothing of it for awhile. Then one saterday I focused on a tree first . Then I put the camera up to the scope. I figured it should be in perfect focus but it wasn`t. So I put it on macro and adjusted the focus until it matched the scopes focus. Which was 2 ft. according to the lcd scale ( not sure how accurate the scale actually is) . I was just wondering why this was so . I got excellent results at the infinaty settings.
.

I've always focused the scope first,attached the camera (with adapter) and then found that the scope need a slight re-focus. I assumed that the focus point of the lens was just a bit further away then with my eye to the eyepiece. I sometimes give the focus a little extra tweak before putting the camera on if I don't want to waste any time re-focusing and sometimes in bright light I have trouble seeing whether the subject is in focus anyway. The camera Auto Focus in Macro Mode does a good job for that last little bit, much better than if I try and focus manually. Neil.
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Old Saturday 10th December 2005, 09:24   #5
iporali
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Quote:
Originally Posted by john-henry
I have always believed digiscoping is taking a picture of what the scope is seeing but it's obviously not so clear cut as that.
I know Macro is autofocus but how can it take a sharp picture when the scope is not in focus!!!
John,

There is no absolute "in focus" with the scope. It is the eye or the camera that determines whether the image is sharp or not: both the eye and the camera can compensate "misfocused" scope - the camera even more than the eye. I am not sure about the macro setting of the A95, but quite often "macro focusing range" does not reach infinity, which means that in this case "in focus" of the scope is out of camera's focusing range. The camera is practically set to be near-sighted - and it can be corrected by over-focusing the scope.

Best regards,

Ilkka


ps. Sorry Robert if this didn't answer your question...
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Old Saturday 10th December 2005, 11:49   #6
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Thumbs up Thanks that does answer my question.

I`ll just do what I`ve been doing it works almost all the time. So thanks for your replies.
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Old Monday 12th December 2005, 21:40   #7
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[quote=iporali]John,

There is no absolute "in focus" with the scope. It is the eye or the camera that determines whether the image is sharp or not: both the eye and the camera can compensate "misfocused" scope - the camera even more than the eye. I am not sure about the macro setting of the A95, but quite often "macro focusing range" does not reach infinity, which means that in this case "in focus" of the scope is out of camera's focusing range. The camera is practically set to be near-sighted - and it can be corrected by over-focusing the scope.

Best regards,

Ilkka

Ilkka,
Many thanks for your reply, I'm sorry to say I still can't see how it happens - but it certainly does. It seems to throw away the idea that autofocus uses contrast and edges to obtain a focus as neither of these are present. Looking through the scope it is well out of focus, not just by a "tweak". Also the A95 has an 'in-or out of' focus colour signal and a double bleep to indicate good focus, both of these show a good focus is obtained by the camera and the picture taken confirms this.

I take your point that Macro has a very limited focus range - up to 1.5ft on the A95, I suppose it's just that I cannot see what it uses to produce a sharp image from what it's seeing through the scope, especially as there is so little leeway with normal autofocus.

Regards and best wishes

John
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Old Monday 12th December 2005, 23:56   #8
iporali
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Quote:
Originally Posted by john-henry
I suppose it's just that I cannot see what it uses to produce a sharp image from what it's seeing through the scope
John,

That was exactly my point.

I wish I could explain it better, but I am afraid this is about all I can do. I have an old friend, who is very far-sighted and I am very near-sighted. We often share my scope when we are birding. After looking through the scope my friend said once: "Oh yeah - I have to return this scope to unsharp for you". We both saw the same bird perfectly sharp, but the scope had to be very differently focused (about 8.0 diopters) - not just by a tweak.

You could try to test this with your digiscoping system. Focus the scope on some distinct target which is far from background or any disturbing objects. Take a digiscoped picture (like you normally do) of the target. Then try the same by slightly over- and underfocusing the scope. Now increase the misfocus. If you get sharp images from many focus positions, wouldn't it prove that the scope can be focused on "almost anything" and the camera does its best to maximize the contrast of the subject within "focus rectangle". If you only get a sharp image from "correct" focusing, I'll let someone else to try to explain this .

Best wishes,

Ilkka
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Old Tuesday 13th December 2005, 21:20   #9
john-henry
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Quote:
Originally Posted by iporali
John,

That was exactly my point.

I wish I could explain it better, but I am afraid this is about all I can do. I have an old friend, who is very far-sighted and I am very near-sighted. We often share my scope when we are birding. After looking through the scope my friend said once: "Oh yeah - I have to return this scope to unsharp for you". We both saw the same bird perfectly sharp, but the scope had to be very differently focused (about 8.0 diopters) - not just by a tweak.

You could try to test this with your digiscoping system. Focus the scope on some distinct target which is far from background or any disturbing objects. Take a digiscoped picture (like you normally do) of the target. Then try the same by slightly over- and underfocusing the scope. Now increase the misfocus. If you get sharp images from many focus positions, wouldn't it prove that the scope can be focused on "almost anything" and the camera does its best to maximize the contrast of the subject within "focus rectangle". If you only get a sharp image from "correct" focusing, I'll let someone else to try to explain this .

Best wishes,

Ilkka

Ilkka,
As usual a well thought out reply, with good advice.
I will have a play with your suggestions and see what happens as it's really got me curious.

Regards

John
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