AC130: Vignetting - is this inherent?

A

amendegw

Active member
I've been noticing vignetting on my AC130. Is this something that is inherent to the camera? Or should I return the camera for repair? The following is a frame capture plus a YouTube video. Full Zoom In and OIS=on.

AC130-Vignetting.jpg


Edit: YouTube does a poor job of depicting the problem. Original footage is here: http://www.jazzythedog.com/sharing/00138.zip

Thanks,
...Jerry
 
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I haven't seen this on my 160, but the way the vignette moves around makes me think it has something to with the OIS. Was it on while you were shooting?
 
Hi Jerry

I'm guessing you were on a tripod for the shot as it's reasonably steady for full telephoto. I think they recommend not using OIS on a tripod. Anytime you pan, you're confusing the OIS, which is designed to remove hand held camera movement in relatively static shots. I don't have any specific knowledge on this, but I would suggest trying a test on sticks with OIS on and off. I always turn OIS off when I'm on sticks.

Cheers

John
 
John,

Thanks for the theories, but here's another test. Handheld, full Zoom and OIS off.

AC130-Vignetting-OIS-off.jpg

Vignetting is not as apparent as above, but it's still there.

...Jerry

Edit: I did some further testing and this only occurs at full zoom in.
 
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Jerry

Interesting, did the vignetting move around like it did in your previous test, or is it static in the frame?

John
 
John,

I didn't notice much movement of the vignette. I held the camera as still as I could in this last test. Obviously, at 22x & no OIS the tree branches still jumped about a bit.

...Jerry

PS: As an aside, in another thread I started here, I can't see a whole lot of stabilization even when turning OIS on at 22x.
 
Hi Jerry

I did some quick and dirty tests today, panning back and forth on a washed out cloudy sky with OIS on and off and I can confirm that I saw minor vignetting at full telephoto with OIS on. Mostly while the camera was moving, once I stopped moving the camera, the OIS settled down and the vignetting mostly disappeared.
I also tested the OIS and it does improve the stability at 22X. But I would never expect OIS to be much help with a 600mm equivalent lens.

Cheers

John
 
John,

Thanks so much for your testing (I was hoping someone would confirm what I saw). So, it sounds like it's not just my camera, but all AC130's.

Also, I might mention that I tried another test, this time indoors, full open and no ND filters. This time I could not see any vignetting. However, I'm not sure how important that finding is as if it's repeatable outdoors in the sky when the iris is closed down, then it's a problem.

...Jerry
 
I wonder if it is an issue with the iris? What f-stop do you first see the vignetting and does it always happen at that f-stop or does it change?
 
Gecko,

Issue with the iris? Good question, I've just spent an hour trying to get a good test on this and have failed. When I point the camera at the sky, it goes to fully closed iris and recommends full ND. I've tried shooting some solid white cardboard, but just can't get the light right where I can open the iris and still get the correct exposure. If others can test this, I'd love to see their results.

...Jerry
 
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jchristie said:
I was around f8 when I saw the vignetting

Cheers

John
Click to expand...


That was a mistake. In his book on the AC130/AC160, and here on this forum, Barry Green has made it clear to not go smaller than f/5.6 with these camcorders. Image quality simply suffers too much.

This may be another good reason to avoid using f/8.
 
Well, you may get some softening of the picture but not vignetting. I've shot F11 with the 250 and there was no vignetting. There's a problem with this camera if it is actually vignetting.
 
LanceOregon said:
That was a mistake. In his book on the AC130/AC160, and here on this forum, Barry Green has made it clear to not go smaller than f/5.6 with these camcorders. Image quality simply suffers too much.

This may be another good reason to avoid using f/8.
Click to expand...

Hi Lance

My test wasn't very scientific, I put the camera on auto, pointed it at a white sky and panned the camera back and forth handheld. The disturbing thing is that the vignetting moves as you move the camera. It's definitely the OIS lens elements trying to catch up with the movement. I don't know how often it will be an issue in my day to day shooting as I'm usually on sticks or hand held static shots. Try the test yourself at 5.6 and see what results you get. I don't have Barry's book in front of me right now, but I believe his recommendation has more to do with diffraction affecting softness over the whole picture area and not vignetting

Cheers

John
 
Your right, Barry was talking about diffraction. But if the camera is vignetting with OIS off, how can it be the OIS? This is something entirely new and you're the only one I've heard this from. Has to be a manufacturing problem. You need to send it in to Panasonic service.

Only other thougt I had is if you had a filter on the camera like a polarizer?
 
Hey! It's not just John. I started this thread and I've got the problem as well. Here's a screen grab from today's shoot.

AC130-Vignetting-Duck.jpg

I'd love to see others attempt to duplicate this problem.

...Jerry
 
amendegw said:
Hey! It's not just John. I started this thread and I've got the problem as well. Here's a screen grab from today's shoot.

View attachment 49217

I'd love to see others attempt to duplicate this problem.

...Jerry
Click to expand...

That's so weird. I'm about to leave for a shoot, but I'll try it with my 250 tomorrow just to see. But you guys need to send these stills and clips to Panasonic. That's not normal.
 
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