Dark corners on footage? at DVinfo.net

Rich Sheikh · May 9th, 2006, 08:06 AM

Would someone please explain to me why I'm getting dark spots in the corners of my video footage. I'm using a one chip Sony camera and the only thing on the lens is a UV filter. I do zoom in sometimes. Here is a short movie and you can see what I mean about the dark spots in the corners.
http://homepage.mac.com/richsheikh/weddingday/

Rich

Glen Elliott · May 9th, 2006, 08:34 AM

I'm unable to view QT where I'm logging in from but from your description what your describing is lense vignetting.

http://www.vanwalree.com/optics/vignetting.html

Mike Oveson · May 9th, 2006, 08:38 AM

Looks like slight vignetting from the UV filter. The lens is wide enough (or the filter sticks out far enough) that it is barely getting into the corners of the imaging area. On a regular TV you wouldn't even notice these because of the overscan. And even on this clip online it was difficult to pick out, certainly not a big distraction.

Richard Wakefield · May 9th, 2006, 09:19 AM

Hi there, I can certainly clarify that you won't see those minor black areas on TV screens as I get those from my new wide-angle lens! I knew I should have bought the Sony-branded one instead! :)

You could always crop the movie slightly if you're worried about the way it looks in websites.

Just out of interest, I've noticed that some clips that are posted (as with yours) show scenes dissolving but with the end frame remining static! is that deliberate? Each to their own obviously, but I find it distracting, does anyone else? Sorry I really don't mean to offend, I'm just curious?

Francois Camoin · May 9th, 2006, 09:20 AM

I wouldn't have noticed the vignetting if you hadn't pointed it out, but what I'd do is shoot a white wall at full wide zoom with and without the UV filter. That way you'll find out if it's the filter or the lens itself. If it's the filter you might try a photo store—I think there are thinner filters available that might solve your problem.

Martin Mayer · May 9th, 2006, 10:58 AM

Quote:

Originally Posted by Richard Wakefield

Just out of interest, I've noticed that some clips that are posted (as with yours) show scenes dissolving but with the end frame remining static! is that deliberate? Each to their own obviously, but I find it distracting, does anyone else? Sorry I really don't mean to offend, I'm just curious?

I think you'll find that's how iMovie does cross-dissolves - it removes the need for handles on the clips, but causes the out-going frame to freeze during the dissolve - which you may find OK, you may not...

Richard Wakefield · May 9th, 2006, 02:08 PM

Ah, that explains it! I'm not familiar with iMovie...I can also see that would make sense for quickening edit times too.
Oh, and sorry for deviating from the vignetting thread!

John C. Chu · May 9th, 2006, 03:02 PM

There are two types of dissolves in iMovie...one is the straight cross dissolve..and the other is the "overlap" where the last frame from the previous clip is "frozen" and then fades while the new section comes in.

Depends on what you want.

Sometimes you want to "freeze frame" a moment and make it linger.

Rich Sheikh · May 9th, 2006, 03:09 PM

Thanks everyone, I don't believe its IMovie because I've used that cross desolve many times within other movie projects and don't have that problem. It seems to happen when I zoom in while shooting. Thanks to you all, I now suspect vignetting from the UV filter. I'll try a test and see what happens.

Martin Mayer · May 9th, 2006, 04:17 PM

Quote:

Originally Posted by Rich Sheikh

Thanks everyone, I don't believe its IMovie because I've used that cross desolve many times within other movie projects and don't have that problem. It seems to happen when I zoom in while shooting. Thanks to you all, I now suspect vignetting from the UV filter. I'll try a test and see what happens.

I wasn't suggesting iMovie was resonsible for your vignetting - rather that it was responsible for the cross-dissolve behaviour Richard Wakefield had noticed.

I think it's the UV filter too. Simple question - are you always at the widest zoom setting when it occurs? If so....

Rich Sheikh · May 9th, 2006, 04:21 PM

You know, I'm not sure. I'll run that test also. Thanks

May 9th, 2006, 08:06 AM	#1
Rich Sheikh Regular Crew Join Date: Oct 2003 Location: San Diego Posts: 34	Dark corners on footage? Would someone please explain to me why I'm getting dark spots in the corners of my video footage. I'm using a one chip Sony camera and the only thing on the lens is a UV filter. I do zoom in sometimes. Here is a short movie and you can see what I mean about the dark spots in the corners. http://homepage.mac.com/richsheikh/weddingday/ Rich

May 9th, 2006, 08:34 AM	#2
Glen Elliott Wrangler Join Date: Apr 2003 Location: Philadelphia, PA Posts: 2,898	I'm unable to view QT where I'm logging in from but from your description what your describing is lense vignetting. http://www.vanwalree.com/optics/vignetting.html __________________ Glen Elliott Cord 3 Films

May 9th, 2006, 08:38 AM	#3
Mike Oveson Major Player Join Date: Jan 2006 Location: Ogden, UT Posts: 349	Looks like slight vignetting from the UV filter. The lens is wide enough (or the filter sticks out far enough) that it is barely getting into the corners of the imaging area. On a regular TV you wouldn't even notice these because of the overscan. And even on this clip online it was difficult to pick out, certainly not a big distraction.

May 9th, 2006, 09:19 AM	#4
Richard Wakefield Major Player Join Date: Feb 2006 Location: Surrey, UK Posts: 680	Hi there, I can certainly clarify that you won't see those minor black areas on TV screens as I get those from my new wide-angle lens! I knew I should have bought the Sony-branded one instead! :) You could always crop the movie slightly if you're worried about the way it looks in websites. Just out of interest, I've noticed that some clips that are posted (as with yours) show scenes dissolving but with the end frame remining static! is that deliberate? Each to their own obviously, but I find it distracting, does anyone else? Sorry I really don't mean to offend, I'm just curious?

May 9th, 2006, 09:20 AM	#5
Francois Camoin Regular Crew Join Date: Mar 2006 Location: Salt Lake City, Utah Posts: 29	I wouldn't have noticed the vignetting if you hadn't pointed it out, but what I'd do is shoot a white wall at full wide zoom with and without the UV filter. That way you'll find out if it's the filter or the lens itself. If it's the filter you might try a photo store—I think there are thinner filters available that might solve your problem.

May 9th, 2006, 02:08 PM	#7
Richard Wakefield Major Player Join Date: Feb 2006 Location: Surrey, UK Posts: 680	Ah, that explains it! I'm not familiar with iMovie...I can also see that would make sense for quickening edit times too. Oh, and sorry for deviating from the vignetting thread!

May 9th, 2006, 03:02 PM	#8
John C. Chu Major Player Join Date: Sep 2003 Location: Rego Park , NYC Posts: 665	There are two types of dissolves in iMovie...one is the straight cross dissolve..and the other is the "overlap" where the last frame from the previous clip is "frozen" and then fades while the new section comes in. Depends on what you want. Sometimes you want to "freeze frame" a moment and make it linger.

May 9th, 2006, 03:09 PM	#9
Rich Sheikh Regular Crew Join Date: Oct 2003 Location: San Diego Posts: 34	Thanks everyone, I don't believe its IMovie because I've used that cross desolve many times within other movie projects and don't have that problem. It seems to happen when I zoom in while shooting. Thanks to you all, I now suspect vignetting from the UV filter. I'll try a test and see what happens.

May 9th, 2006, 04:21 PM	#11
Rich Sheikh Regular Crew Join Date: Oct 2003 Location: San Diego Posts: 34	You know, I'm not sure. I'll run that test also. Thanks