vignetting on XL1s at DVinfo.net

Donie Kelly · February 26th, 2004, 04:44 PM

Hi all

I was out the other day and got some nice shots but I noticed in one of two that I was getting vignetting ar the edges of the screen.

I have a UV filter on the lens but I doubt that would do it. Maybe I had the ND filter on. Is this the reason for the vignetting?

New enought to this video stuff hence the question. I'm no expert on optics.

Thanks for any insights.
Donie

Jean-Philippe Archibald · February 26th, 2004, 04:52 PM

You should not experience any vigneting even with the ND filter on or a UV filter. Are you using a 72 mm filter or a smaller one with a step down ring?

Donie Kelly · February 26th, 2004, 05:10 PM

Hi Jean-Philippe

I'm using a 72mm filter, screw on type. I was flying at the time in a microlight and was zooming in on the ground from about 1000ft. The vignetting started about 1/3 into the zoom and got progressivly worse as it zoomed in.

I've seen this happen before on another camera but I can't figure out what causes it, would it be anything to do with lighting conditions or the settings on the camera. I think the camera was on full auto at the time becuase the workload was too high for me to control the camera in manual and try to keep my nerves intack in the aircraft..

I noticed when I got back that I moved the exposure control to I think -1.5. Some of the latter parts of the shooting was pretty much underexposed. Would this cause vignetting?

Thanks for the quick reply.
Donie

Bob Fitzgibbon · February 26th, 2004, 06:40 PM

Hi Donie,

I have never experienced vignetting with video. However, having been a still photographer for 40+ years, I had always found that this problem arose most often at wide angle settings which I find rather curious. Didn't you say that it happened when you zoomed in (telephoto)?

With certain cameras, I found that buying step-up rings and using a filter larger than the lens called for solved the problem.
A matte box or rail shade/vignetter with drop in square filters is also good.

This still doesn't answer your question because you are zooming in and not out.

Donie Kelly · February 26th, 2004, 07:14 PM

I've uploaded a clip to my website to show the effect happening. It's 2.7Mbytes and can be downloaded here

Looking at it I can't figure out what is gone wrong here. It is really bad at full zoom as you can see.

Forgive the poor shot but it's the one that shows the effect most clearly...

ps, right click to download and use media player to play it or some player that will play .m2v files.
Donie

Donie Kelly · April 26th, 2004, 09:18 AM

Hi all

I was speaking to Canon tech support about this and they were extremely interested and helpful in trying to find a solution.

However, after studying the clip above and attempting to reproduce it, they have come to the conclusion that the combination of movement and lighting conditions caused the problem. The shot was murky at best and this causes the auto-focus to have serious problems and you'll notice that focus was not achieved.

Basically, they are at a loss to explain the problem 100%. They do not know why the vignetting appeared. I used the camera since and have not noticed the problem.

Donie

Donie Kelly · July 1st, 2004, 06:20 PM

Hi all

I have figured out how to reproduce this problem on demand and I'm wondering if somebody can give it a try to see if it effects other models or if it's just that mine has developed a fault.

Do the test indoors at night with the normal lights on, not too bright, somewhere around bright enough that you use +6db to +12bd gain.

Point the camera at wall and drop the iris down to 2.6 zoomed in. I get vingetting at this point when fully zoomed in, in fact a circle begins to form about 3/4 way in and closes full when I'm fully zoomed in. It's about a 1 or 2 stops in exposure by the looks of it in full zoom.

If you increase the iris to about 4 the problem goes away.

I have switched off and on everything to see if it stops the problem, the stabiliser, ND filter, auto focus. I've also removed the Lens hood and uv filter. None of these make any difference as expected.

Can anybody reproduce this? I'd be intrested to see. Otherwise I must be looking at a faulty lens.

Many thanks
Donie

Jeff Donald · July 1st, 2004, 06:46 PM

Here is the same issue (and solution) on another camera, the GL2. There is nothing wrong with your lens.

Donie Kelly · July 2nd, 2004, 03:07 AM

Now I understand!! Great thread. I will work around the limitation. It's nice to know about this stuff. Thanks

Donie

February 26th, 2004, 04:44 PM	#1
Donie Kelly Regular Crew Join Date: Jan 2004 Location: Ireland Posts: 159	vignetting on XL1s Hi all I was out the other day and got some nice shots but I noticed in one of two that I was getting vignetting ar the edges of the screen. I have a UV filter on the lens but I doubt that would do it. Maybe I had the ND filter on. Is this the reason for the vignetting? New enought to this video stuff hence the question. I'm no expert on optics. Thanks for any insights. Donie

February 26th, 2004, 04:52 PM	#2
Jean-Philippe Archibald Trustee Join Date: Sep 2003 Location: Saguenay, Québec, Canada Posts: 1,051	You should not experience any vigneting even with the ND filter on or a UV filter. Are you using a 72 mm filter or a smaller one with a step down ring? __________________ Jean-Philippe Archibald http://www.jparchibald.com - http://www.vimeo.com/jparchib

April 26th, 2004, 09:18 AM	#6
Donie Kelly Regular Crew Join Date: Jan 2004 Location: Ireland Posts: 159	Canon Response Hi all I was speaking to Canon tech support about this and they were extremely interested and helpful in trying to find a solution. However, after studying the clip above and attempting to reproduce it, they have come to the conclusion that the combination of movement and lighting conditions caused the problem. The shot was murky at best and this causes the auto-focus to have serious problems and you'll notice that focus was not achieved. Basically, they are at a loss to explain the problem 100%. They do not know why the vignetting appeared. I used the camera since and have not noticed the problem. Donie

July 1st, 2004, 06:20 PM	#7
Donie Kelly Regular Crew Join Date: Jan 2004 Location: Ireland Posts: 159	Raising this again Hi all I have figured out how to reproduce this problem on demand and I'm wondering if somebody can give it a try to see if it effects other models or if it's just that mine has developed a fault. Do the test indoors at night with the normal lights on, not too bright, somewhere around bright enough that you use +6db to +12bd gain. Point the camera at wall and drop the iris down to 2.6 zoomed in. I get vingetting at this point when fully zoomed in, in fact a circle begins to form about 3/4 way in and closes full when I'm fully zoomed in. It's about a 1 or 2 stops in exposure by the looks of it in full zoom. If you increase the iris to about 4 the problem goes away. I have switched off and on everything to see if it stops the problem, the stabiliser, ND filter, auto focus. I've also removed the Lens hood and uv filter. None of these make any difference as expected. Can anybody reproduce this? I'd be intrested to see. Otherwise I must be looking at a faulty lens. Many thanks Donie __________________ Macbook Pro 2.0Ghz and Canon XL2

July 1st, 2004, 06:46 PM	#8
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Here is the same issue (and solution) on another camera, the GL2. There is nothing wrong with your lens. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

February 26th, 2004, 05:10 PM	#3
Donie Kelly Regular Crew Join Date: Jan 2004 Location: Ireland Posts: 159	Hi Jean-Philippe I'm using a 72mm filter, screw on type. I was flying at the time in a microlight and was zooming in on the ground from about 1000ft. The vignetting started about 1/3 into the zoom and got progressivly worse as it zoomed in. I've seen this happen before on another camera but I can't figure out what causes it, would it be anything to do with lighting conditions or the settings on the camera. I think the camera was on full auto at the time becuase the workload was too high for me to control the camera in manual and try to keep my nerves intack in the aircraft.. I noticed when I got back that I moved the exposure control to I think -1.5. Some of the latter parts of the shooting was pretty much underexposed. Would this cause vignetting? Thanks for the quick reply. Donie

February 26th, 2004, 06:40 PM	#4
Bob Fitzgibbon Regular Crew Join Date: Jan 2004 Location: West Simsbury, CT Posts: 30	Hi Donie, I have never experienced vignetting with video. However, having been a still photographer for 40+ years, I had always found that this problem arose most often at wide angle settings which I find rather curious. Didn't you say that it happened when you zoomed in (telephoto)? With certain cameras, I found that buying step-up rings and using a filter larger than the lens called for solved the problem. A matte box or rail shade/vignetter with drop in square filters is also good. This still doesn't answer your question because you are zooming in and not out.

February 26th, 2004, 07:14 PM	#5
Donie Kelly Regular Crew Join Date: Jan 2004 Location: Ireland Posts: 159	I've uploaded a clip to my website to show the effect happening. It's 2.7Mbytes and can be downloaded here Looking at it I can't figure out what is gone wrong here. It is really bad at full zoom as you can see. Forgive the poor shot but it's the one that shows the effect most clearly... ps, right click to download and use media player to play it or some player that will play .m2v files. Donie

July 2nd, 2004, 03:07 AM	#9
Donie Kelly Regular Crew Join Date: Jan 2004 Location: Ireland Posts: 159	Now I understand!! Great thread. I will work around the limitation. It's nice to know about this stuff. Thanks Donie __________________ Macbook Pro 2.0Ghz and Canon XL2