Strange iris behaviour....

O

Ogrus

Well-known member
I had to shoot on the run a musician, so I had no time to manually do anything. I popped on full auto and noticed as i was shooting the musician that auto iris would change f-stops constantly, giving a light noticeable stobe effect, but only if it was a wide shot. It was a cloudy rainy day. I'm wondering if the autoiris on the hmc40 is that sensitive to not settle ad one f.stop. I did'nt notice a huge light change while shooting

Any opinions?
 
I haven't experienced anything like that. Did you have face-detection on, and were the faces being ccovered/uncovered by the clouds or anything?
 
I never seen this one before, but then again, I like to use manual iris a lot. It sounds like the auto-iris is picking up on some change in lighting.

Maybe the best solution is to zoom into the subject before you shoot, let the auto-iris find the setting, switch to manual iris mode, and then shoot the video. When you can't do that, shoot and switch to manual iris while shooting.


Bob Diaz
 
Barry_Green said:
I haven't experienced anything like that. Did you have face-detection on, and were the faces being ccovered/uncovered by the clouds or anything?
Click to expand...

Face Detection was on. If clouds were covering/uncovering i didn't notice it. I will be shooting again this friday and will see before hand if the strange behaviour (or extreme sensitivity) happens again
 
Yeah, ive definitely learned not to trust the auto iris. It's all over the place. I think you'll have good luck doing what Bob said. =)
 
To me it looks like a camera malfunction; you may want to have Panasonic check this out.


Bob Diaz
 
I would say that is far from normal behavior and you need to have your camera serviced. Auto-iris will "hunt" a little bit and can certainly be affected if a lighter or darker object moves into the shot, but it shouldn't swing wildly like that just sitting on a static shot. If I had to guess, I'd say maybe the mechanical iris blades in the lens are sticking a little and the auto-exposure system has to overcompensate to get them moving.

- Greg
 
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