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Canon G10 (1 Viewer)

ostling41

ostling41

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Those of us who have tried digiscoping with the Canon G7 or G9 are well aware of the difficulty imposed by the design of the 35-210mm lens. The entrance pupil of this lens moves aft when the lens is zoomed to the telephoto end of the range. Significant vignetting results.

Virtually all the cameras good for digiscoping have a zoom lens wherein the entrance pupil moves forward during zooming. This allows using the lens at a mid-range telephoto setting without vignetting, just what is needed for most bird photography.

The G10 has a new lens, a 28-140mm. Does it display the same "adverse" pupil movement as the 35-210mm? If not, we might have a real contender for a good digiscoping camera, with RAW.

This can be determined by anybody who has seen a G10 in a camera store. I await a report.
 
ostling41 said:
Those of us who have tried digiscoping with the Canon G7 or G9 are well aware of the difficulty imposed by the design of the 35-210mm lens. The entrance pupil of this lens moves aft when the lens is zoomed to the telephoto end of the range. Significant vignetting results.

Virtually all the cameras good for digiscoping have a zoom lens wherein the entrance pupil moves forward during zooming. This allows using the lens at a mid-range telephoto setting without vignetting, just what is needed for most bird photography.

The G10 has a new lens, a 28-140mm. Does it display the same "adverse" pupil movement as the 35-210mm? If not, we might have a real contender for a good digiscoping camera, with RAW.

This can be determined by anybody who has seen a G10 in a camera store. I await a report.
Click to expand...
Hi,
My friend has a Canon G9 camera and he uses it for digiscoping and has vigneting problem that he can not remove. He let me tries with my KOWA 88mm straight scope. I try and can not remove the vigneting problem also.
VIGNet.jpg
What I suspect that the zoom of the camera G9 is not enough to pull in the bird. Is that correct? I also wish to buy Canon G10 for digiscoping but now afraid that it has the same "happening" like G9.

Just found this link about information of G10...
http://www.birdingonthe.net/mailinglists/DIGI.html#1224405906

Thank you.
 
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Allan,
I've looked at the G10 in the store. The lens is the worst for digiscoping I've seen. When zoomed it disappears at a great rate of knots into the camera (so it appears anyway). You would need a lot of Eye-relief to get a vignette-free image.
A shame as it's a wonderful camera otherwise.
Wait for the Panasonic Lumix G1 with the 25/2.8 Pancake lens.
Neil.
 
Neil said:
Allan,
I've looked at the G10 in the store. The lens is the worst for digiscoping I've seen. When zoomed it disappears at a great rate of knots into the camera (so it appears anyway). You would need a lot of Eye-relief to get a vignette-free image.
Click to expand...

Neil,

You may be right. The zooming behaviour you observed for the G10 is the opposite of what happens on the G9, where zooming extends the lens but retracts the entrance pupil. It is the retreat of the entrance pupil from the front of the lens which necessitates having high eye-relief.

I have just acquired a Panasonic Lumix LX3. Of course, I didn't buy if for digiscoping. Like the G10, the 24-60mm lens of the Lumix retreats rapidly into the body when zoomed out to 60mm. The entrance pupil, however, stays close to the front of the lens. I have found that the LX3, when used at 60mm equivalent, can digiscope without vignetting, and without high eye relief. I'll post a report on that in a different thread.
 
Err, pardon me if this is a somewhat obtuse question (what was that saying again.. there are no stupid questions, only stupid people?), but how does the entrance pupil of a lens retract when the lens moves forward?

Not sure I quite follow - it appears to me that the front element of the lens is pretty much where the entrance pupil would be, no? Or are you referring to a second element/group which moves backwards?

Vandit
 
vkalia said:
Err, pardon me if this is a somewhat obtuse question (what was that saying again.. there are no stupid questions, only stupid people?), but how does the entrance pupil of a lens retract when the lens moves forward?
Vandit
Click to expand...

The entrance pupil in a complex lens may be further aft than the front lens element. In the case of the G9 it is quite evident that the entrance pupil retracts during the zooming, while the outermost lens element goes out -- you can see it happening.

The entrance pupil is a lot more obvious if you can take the lens off the camera, and hold it up to the light. You can't do this on the G9, but you can still see the smallest diameter of what is covering the sensor. That is the entrance pupil. You'll see this on whatever digital compact you own.

You can see the exit pupil of a lens, too. For example, hold up a pair of binoculars, and look at the eyepiece. That small bright spot is the exit pupil -- it will be much smaller than the diameter of the eyepiece lens, and typically at an axial distance not coincident with the outermost glass surface.
 
Last edited:
ostling41 said:
The entrance pupil is a lot more obvious if you can take the lens off the camera, and hold it up to the light. You can't do this on the G9, but you can still see the smallest diameter of what is covering the sensor. That is the entrance pupil. You'll see this on whatever digital compact you own.
Click to expand...

Ah right, the secondary lens element may be smaller and so is the limiting factor. Got it, thanks.

V.
 
I am new to digiscoping and this forum. Hello. I've tried using the G-10 with an Swar ATS 80. Could anyone tell me what settings you have found are best for this combination?
 
squillae said:
I am new to digiscoping and this forum. Hello. I've tried using the G-10 with an Swar ATS 80. Could anyone tell me what settings you have found are best for this combination?
Click to expand...

The G10 vignettes a lot with normal lenses so you need an eyepiece with very long Eye Relief. You could try selecting Digital zoom 2x from the Menu which will help with the vignetting but will detract from resolution a little. Try it out.
Also Aperture Priority and Spot Metering is the way to go.
Neil
 
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