faded edges at DVinfo.net

Mike Waddick · May 17th, 2005, 10:19 PM

I was just importing some footage from my xl1s and i noticed the four edges faded. Kind of like there was some sort of shroud showing up in the picture. So i didnt some tests with and without the stock shroud and it didnt seem to make a differnce. So then i went on to testing some more things on a white erase board and noticed that the whole imaged is like hot spoted, the center is bright white, then it fades out to the edges. Is that a common thing? There are some other weird things that happen that are hard to explain.

I was just wondernig is this a natural thing with optics or what. If you want i can take some screen captures to explain what i mean.

Thanks a lot,

Mike Waddick

Jack Smith · May 18th, 2005, 08:12 AM

Doesn't sound right.Do you have your setup levels at default?Is this stock lense?
Do the zebras show even and correct exposure?

Mike Waddick · May 18th, 2005, 05:58 PM

The levels were at default and it is a stock lens. I started looking through my footage its completely noticeable. When i use zebras it does show that the center is more exposed then the edges, but its really hard to tell.

I took some screen captures and also a small video of whats happening. its not white balanced but you still see what i mean.

http://www.atmosphericentertainment.com/xl1/test2.jpg

http://www.atmosphericentertainment.com/xl1/test3.jpg

http://www.atmosphericentertainment.com/xl1/test4.jpg

Here is a short video that is pretty compressed, but you still get the idea of whats happening.
http://www.atmosphericentertainment..../testmovie.wmv

Other things i have tried are removing the shroud, the UV filter but its still there. It seems as though when you zoom in it goes away alittle, but its still present.

Thanks a lot,

Mike Waddick

Jimmy McKenzie · May 18th, 2005, 07:50 PM

Has the camera ever made the trip in to a service depot for cleaning? If you were to email Canon service and describe the symptom, they might be able to recommend a fix. The soft vignetting you are experiencing as shown in the wmv looks like the effect of a step down ring with a filter attached. This could also be at the lens connection. Perhaps you can borrow a different lens and perform a comparison. If the trouble is identical, then explore the idea of having the body serviced.

Rok Furman · November 18th, 2005, 04:26 PM

did you ever solve the problem?

my XL-1 "kit" lens seems to have the exact same problem at wide-open apertures - i know that these small CCDs have problems with apertures lower then ~f4, but the vignetting is too intensive. i just stop the lens down to f4,4 or narrower and it sort of fixes the vignetting.

also, lighting seems to effect this phenomenon a great deal. how did you fix the problem? a new lens or did Canon service the old one?

Don Palomaki · November 18th, 2005, 05:28 PM

It is the nature of ALL lenses to have some light fall off at the edges/corners especially when wide open. For most common types of image content it not noticed, but with a blank field (e.g., a white board) image the corner fall off is very noticeable.

See http://www.vanwalree.com/optics/vignetting.html for an informative discussion of this.

Rok Furman · November 19th, 2005, 04:42 AM

i knew that - but it seemed too intense.

it still didn't bother me that much - a week ago i was shooting this "fashion show" and there really wasn't much light to work with. the ~f2 setting and extra gain worked around it and i got great footage. you're right, the vignetting doesn't really show when shooting these kind of scenes

so you're saying it's completly normal for the XL video lens to show so much vignetting? it's not a problem then, thanks

Don Palomaki · November 19th, 2005, 05:18 AM

It is normal to see some vignetting at the corners with the normal lens when shooting a flat, white screen in auto mode (so that the image is not totally washed out corner-to-corner), expecially when wide open. HOwever, not having seen what you have, I cannot say whether or not your situation is within normal limits.

Rok Furman · November 19th, 2005, 12:53 PM

check out the video of the author of this thread. mine is exactly the same, but it highly depends on the lighting conditions - sometimes it's more, sometimes less intensive.

Emre Safak · November 19th, 2005, 05:18 PM

As Don said, avoid shooting wide open. Lenses typically exhibit more vignetting at wide apertures.

Don Palomaki · November 20th, 2005, 06:56 AM

Looks about like what I would expect for wide open.

Rok Furman · November 20th, 2005, 06:57 AM

that's all i needed to hear :)

thanks a bunch, Don

May 17th, 2005, 10:19 PM	#1
Mike Waddick Tourist Join Date: Nov 2004 Posts: 2	faded edges I was just importing some footage from my xl1s and i noticed the four edges faded. Kind of like there was some sort of shroud showing up in the picture. So i didnt some tests with and without the stock shroud and it didnt seem to make a differnce. So then i went on to testing some more things on a white erase board and noticed that the whole imaged is like hot spoted, the center is bright white, then it fades out to the edges. Is that a common thing? There are some other weird things that happen that are hard to explain. I was just wondernig is this a natural thing with optics or what. If you want i can take some screen captures to explain what i mean. Thanks a lot, Mike Waddick

November 18th, 2005, 05:28 PM	#6
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,487	It is the nature of ALL lenses to have some light fall off at the edges/corners especially when wide open. For most common types of image content it not noticed, but with a blank field (e.g., a white board) image the corner fall off is very noticeable. See http://www.vanwalree.com/optics/vignetting.html for an informative discussion of this. __________________ dpalomaki@dspalomaki.com

November 19th, 2005, 05:18 AM	#8
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,487	It is normal to see some vignetting at the corners with the normal lens when shooting a flat, white screen in auto mode (so that the image is not totally washed out corner-to-corner), expecially when wide open. HOwever, not having seen what you have, I cannot say whether or not your situation is within normal limits. __________________ dpalomaki@dspalomaki.com

November 20th, 2005, 06:56 AM	#11
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,487	Looks about like what I would expect for wide open. __________________ dpalomaki@dspalomaki.com

May 18th, 2005, 08:12 AM	#2
Jack Smith Major Player Join Date: Nov 2003 Location: ontario Posts: 445	Doesn't sound right.Do you have your setup levels at default?Is this stock lense? Do the zebras show even and correct exposure?

May 18th, 2005, 05:58 PM	#3
Mike Waddick Tourist Join Date: Nov 2004 Posts: 2	The levels were at default and it is a stock lens. I started looking through my footage its completely noticeable. When i use zebras it does show that the center is more exposed then the edges, but its really hard to tell. I took some screen captures and also a small video of whats happening. its not white balanced but you still see what i mean. http://www.atmosphericentertainment.com/xl1/test2.jpg http://www.atmosphericentertainment.com/xl1/test3.jpg http://www.atmosphericentertainment.com/xl1/test4.jpg Here is a short video that is pretty compressed, but you still get the idea of whats happening. http://www.atmosphericentertainment..../testmovie.wmv Other things i have tried are removing the shroud, the UV filter but its still there. It seems as though when you zoom in it goes away alittle, but its still present. Thanks a lot, Mike Waddick

May 18th, 2005, 07:50 PM	#4
Jimmy McKenzie Major Player Join Date: Jan 2004 Location: Waterloo Ontario Posts: 721	Has the camera ever made the trip in to a service depot for cleaning? If you were to email Canon service and describe the symptom, they might be able to recommend a fix. The soft vignetting you are experiencing as shown in the wmv looks like the effect of a step down ring with a filter attached. This could also be at the lens connection. Perhaps you can borrow a different lens and perform a comparison. If the trouble is identical, then explore the idea of having the body serviced.

November 18th, 2005, 04:26 PM	#5
Rok Furman Regular Crew Join Date: Nov 2005 Location: Maribor, Slovenia Posts: 25	did you ever solve the problem? my XL-1 "kit" lens seems to have the exact same problem at wide-open apertures - i know that these small CCDs have problems with apertures lower then ~f4, but the vignetting is too intensive. i just stop the lens down to f4,4 or narrower and it sort of fixes the vignetting. also, lighting seems to effect this phenomenon a great deal. how did you fix the problem? a new lens or did Canon service the old one?

November 19th, 2005, 04:42 AM	#7
Rok Furman Regular Crew Join Date: Nov 2005 Location: Maribor, Slovenia Posts: 25	i knew that - but it seemed too intense. it still didn't bother me that much - a week ago i was shooting this "fashion show" and there really wasn't much light to work with. the ~f2 setting and extra gain worked around it and i got great footage. you're right, the vignetting doesn't really show when shooting these kind of scenes so you're saying it's completly normal for the XL video lens to show so much vignetting? it's not a problem then, thanks

November 19th, 2005, 12:53 PM	#9
Rok Furman Regular Crew Join Date: Nov 2005 Location: Maribor, Slovenia Posts: 25	check out the video of the author of this thread. mine is exactly the same, but it highly depends on the lighting conditions - sometimes it's more, sometimes less intensive.

November 19th, 2005, 05:18 PM	#10
Emre Safak Trustee Join Date: Feb 2004 Location: Brookline, MA Posts: 1,447	As Don said, avoid shooting wide open. Lenses typically exhibit more vignetting at wide apertures.

November 20th, 2005, 06:57 AM	#12
Rok Furman Regular Crew Join Date: Nov 2005 Location: Maribor, Slovenia Posts: 25	that's all i needed to hear :) thanks a bunch, Don