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Home: Inactive Forums: Underwater Video:
Strange vignetting problem with amphibico

bullshark
Novice

Feb 22, 2006, 9:30 AM

Post #1 of 8 (2052 views)
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Strange vignetting problem with amphibico	Can't Post

Hi, I have a sony TRV33 housed in an Amphibico Divebuddy. When using the 120° wide angle lens I get intermittent vignetting on the right corners.

It only happens at depth below 20', and even then only seems to happen when going through burst of current. I tried to make it happen in my pool, applying sideway force to the lens, no go, I get no vignetting.

There's also some play betwee the locating pin of the camera mounting plate and the camera hole, so I tried both side play position before tighting the camera down, no difference.

I tried shaking the housing underwater, doesn't make the vignetting appears. Only happens at depth in 60°f water in high current situation. Since I do 98% of my diving in those conditions, it's a major problem.

Help?

(This post was edited by bullshark on Feb 23, 2006, 1:17 PM)

steve
User

Feb 22, 2006, 1:08 PM

Post #2 of 8 (2041 views)
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Re: [bullshark] Strange vignetting problem with amphibico [In reply to]	Can't Post

Have you called Amphibico and asked about this problem? If they are aware of it you you might find that they have a solution for you.
On the other end, if you are outputting to tape in post production than it is very likely that the vignetting falls outside your action safe barriers and thus will not be seen anyway. I have never heard of vignetting that occurs due to depth. So that one is a new one for me.-Steve
www.worldfilmsandtravel.com

bullshark
Novice

Feb 22, 2006, 2:09 PM

Post #3 of 8 (2037 views)
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Re: [steve] Strange vignetting problem with amphibico [In reply to]	Can't Post

In Reply To

Have you called Amphibico and asked about this problem? If they are aware of it you you might find that they have a solution for you.

Not yet no. I'm kind of weary of them, the last time I went to see them it was for a reflection problem on a flat port. They told me, of all thing, that I had the "nightshot"switch on and that was causing the problem... On all my footage, which included about 20 dives; even more troubling, I had some shot mid level (half in the water, half in the air), which only displayed the reflection problem on the underwater part: what then, I must have had the nightshot switch only halfway to cause this. Crazy

Anyway, what it come to is that they basically said it was my fault and that I was stupid and their equipement were perfect. So no I don't really want to call them, or buy anything from them anymore. And I still have the reflection problem when using the flat port, so aside from being called stupid, I never got my problem solved.

In Reply To

On the other end, if you are outputting to tape in post production than it is very likely that the vignetting falls outside your action safe barriers and thus will not be seen anyway. I have never heard of vignetting that occurs due to depth. So that one is a new one for me.-Steve

I'm baffled too.
And yes the vignetting is outside the action safe area and it doesn't show on a CRT TV, I'm wondering if it would show on a LCD or plasma TV thought.

(This post was edited by bullshark on Feb 22, 2006, 2:13 PM)

steve
User

Feb 22, 2006, 4:09 PM

Post #4 of 8 (2033 views)
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Re: [bullshark] Strange vignetting problem with amphibico [In reply to]	Can't Post

Yes, I have heard that Amphibico's attitude is not the best. Thats why I stick to Gates housing, their quality and service is excellent. If you put the sequence onto a DVD than you just might see the vignetting, not sure,you will simply have to give it a try one as well as for 16X9 displays.
www.worldfilmsandtravel.com

bullshark
Novice

Feb 23, 2006, 7:12 PM

Post #5 of 8 (1984 views)
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Re: [steve] Strange vignetting problem with amphibico [In reply to]	Can't Post

I was able to replicate the problem somehow.

If I turn the camera "steady-shot" ON.

And push the camera a little out of perfect alignement using the free play in the locating pin.

And immerse in water.

And then shake the housing fast, similar to the kind of buffeting one can get in high current going through obstacles (more like a vibration than shake actually).

Then I get the kind of vignetting I was talking about. The vignetting doesn't follow the "shake" thought, it just kind of slowly drift in and out of the visor.

I'm at a lost trying to explain the phenomenon thought. Anybody has any ideas? Is the camera faulty?

I should probably dive with steady-shot off, but in the kind of condition I'm diving in, it would mean a lot of my footage would be unuseable due to too much camera shake.

steve
User

Feb 23, 2006, 7:20 PM

Post #6 of 8 (1976 views)
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Re: [bullshark] Strange vignetting problem with amphibico [In reply to]	Can't Post

It sounds to me more of a problem with your cam being set in the housing sturdily so that buffetting should not move it out of alignment as you put it. I don't believe the steady shot should have anything to do with it. My 2cents-Steve
www.worldfilmsandtravel.com

bullshark
Novice

Feb 24, 2006, 2:44 AM

Post #7 of 8 (1957 views)
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Re: [steve] Strange vignetting problem with amphibico [In reply to]	Can't Post

No, for it to happens, all of the condition I pointed above must be present; it's not a "or" but an "and".

Beside, I don't know if you've seen how a camera is attached inside an Amphibico housing, but once secured it is impossible that it moves, even slightly.

I've posted an example of what occurs, in this shot I'm moving backward in a high buffeting current, then I bump my shoulder and vignetting gets extreme then slowly resides.

208 kb wmv example

Anybody with any suggestion to fix this?

steve
User

Feb 24, 2006, 7:16 PM

Post #8 of 8 (1931 views)
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Re: [bullshark] Strange vignetting problem with amphibico [In reply to]	Can't Post

For whatever reason, the movie will not open on my G5. You're right, I have no practical experience with Amphibico, it just seemed to me that if you were able to shake the housing around, thus producing the vignetting that perhaps it was because the cam was not seated firmly enough. Sorry if I have not been able to be helpful here.-Steve
www.worldfilmsandtravel.com