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EX1 Exposure issue when changing gain setting

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David Ice
EX1 Exposure issue when changing gain setting
on Dec 1, 2008 at 1:32:19 am

Please forgive me if I'm a dunce or not getting something obvious, but I seem to be having an issue when changing the gain settings. I normally use, say, -3db for outdoor. All is fine. But if I up the sensitivity to, say, +6db due to lower light, it seems like the auto iris (which I must use occasionally) doesn't compensate. The images are quite overexposed. On my old FX-1, if you switched from 0db to +18db, the exposure would automatically compensate. While it does seem to compensate mechanically in the EX-1 (the iris ring does move) it still seems to me that when I up the gain, the resulting images go one or more f-stops overexposed.

Any ideas? Thanks!

Other than this, I've been delighted with the images I've gotten from this camera! The blu ray discs are incredible!

David Ice
harpdude@cox.net



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Don Greening
Re: EX1 Exposure issue when changing gain setting
on Dec 1, 2008 at 8:08:24 am

I just did a little test for you and turned my auto iris switch to on, pointed the camera to a table lamp then switched from -3 gain to 0 gain. My EX changed the exposure from F4.8 to F5.6 in about a half second. Automatically. The zebra bars present after the gain change were pretty much the same as before the change, telling me that the EX auto-iris function compensated adequately.

- Don


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Tom Parke
Re: EX1 Exposure issue when changing gain setting
on Dec 1, 2008 at 7:41:12 pm

Your LCD monitor may be adjusted too bright. I believe Don's description of the zebra confirms that his camera is working as expected. The only way for you to tell without question is to hook up to an external monitor that is properly calibrated.

Tom

Tom Parke
ProScan DP

Tom Parke
ProScan DP


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Stephen May
Re: EX1 Exposure issue when changing gain setting
on Dec 2, 2008 at 9:36:40 pm

When I first began using my EX-1 I noticed that it was very easy to get hot spots especially in skin tones while all other aspects of the exposure looked good. If I iris'd down to get rid of the bloomed skin tone or other hot spots, the image looked a little dead.

I started to use the picture profile settings to reduce the highlighted areas and that worked out pretty well. I thought this might be useful to you if the hot spots are just here and there like mine.
-s

Stephen May
Keystone Media Productions
Freelance Videographer


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Paul Coolahan
Re: EX1 Exposure issue when changing gain setting
on Jun 10, 2009 at 11:19:13 pm

Thanks for that post Stephen. I have exactly the same problem.
I would have thought that the EX1 would be able to handle these hot spots
without resorting to a specific setting in picture profile.
When I drop my gain down to -3 for outdoors it does not make a lot of
difference. Does anyone have any solution apart from the PP.

Thanks Paul


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David Ice
Re: EX1 Exposure issue when changing gain setting
on Jun 11, 2009 at 5:05:18 am

Hi Paul,

I did discover that on the Picture Profile setting, I had somehow nudged the exposure compensation up to +1....how I'll never know. I put it back to -.5, and it seemed to help.

BUT....I just got my camera back from Sony. I realized a month ago that, to my horror, the auto iris was only sporadically working. In other words, you powered on the camera, and it would work for 30-60 seconds. Then it seemed to freeze, and no matter how the lighting changed or what I panned to, it would be locked. Sony had to totally replace the lens...fortunately under warranty.

So check to see if your iris does automatically work after an extended period of time. In my case, it was easy to miss and deceiving....if I changed the gain control immediately after powering up, it compensated. If I was fiddling around with stuff and changed the gain later, it would not compensate. And some shots (i.e. filming a play or a show) would suddenly and suspiciously be over or under exposed--because the auto iris froze up.


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