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Z1u and auto exposure


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#1 Bob Hayes

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Posted 17 February 2006 - 05:46 PM

I was shooting with the Z1u over the weekend. Day exterior. Moving fast I put the expure on auto. The lighting was standard front lit. Auto expsure said on thing but the 70% iris said I should stop down a couple of stops. Why the discrepency.
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#2 Laurent Andrieux

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Posted 17 February 2006 - 06:05 PM

Sorry I don' get this sentence perfectly due to my bad english knowledge

Auto expsure said on thing but the 70% iris


But I've read topics on french forums about such problems with this camera...

Are you sure the zebras were set at 70 % ? They said on this forum that zebras should be set at 100 % on this camera. If someone set it to 100 % before you used it and you thought it was on 70 %... It might explain it ?
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#3 Tim J Durham

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Posted 17 February 2006 - 06:22 PM

I was shooting with the Z1u over the weekend. Day exterior. Moving fast I put the expure on auto. The lighting was standard front lit. Auto expsure said on thing but the 70% iris said I should stop down a couple of stops. Why the discrepency.


There may be a compensator which can adjust the auto-exposure up or down up to 2 stops (so if the AE thinks the scene should expose to f5.6, you can adjust it so if will expose that scene at f2.8 or f16 or somewhere in between). I have an XL-2 and it has that feature. The zebras don't have anything to do with the auto-exposure. They just tell you what in the frame is 70 IRE or above if you set them to 70.
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#4 Laurent Andrieux

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Posted 17 February 2006 - 06:47 PM

The zebras don't have anything to do with the auto-exposure


Sorry, I know they don't

It's because of that sentence (that I didn't understand well) That I thought Bob might have been using them in appreciating his exposure and that they might have confused him, eventually...

Auto expsure said on thing but the 70% iris


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#5 Bob Hayes

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Posted 17 February 2006 - 06:57 PM

My English isn't so good either. I was setting th exposure using auto iris and it doesn't agree at all with Zebra settings.
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#6 Laurent Andrieux

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Posted 17 February 2006 - 07:03 PM

That's what I figured out from your post (funny how about two bad english speakers can understand each other well ! :lol: ).

So don't think it could have been set to 100 % instead of 70 %, that puzzling you ?
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#7 Tim J Durham

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Posted 17 February 2006 - 07:14 PM

My English isn't so good either. I was setting th exposure using auto iris and it doesn't agree at all with Zebra settings.


Were you checking it with a waveform monitor where the zebras were telling you 70 IRE and the waveform was telling you it was something else?
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#8 Laurent Andrieux

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Posted 17 February 2006 - 07:35 PM

I was shooting with the Z1u over the weekend. Day exterior. Moving fast I put the expure on auto.


I guess he certainly was ! :lol: :lol: :lol:
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#9 Lucita Jones

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Posted 14 April 2006 - 02:36 PM

I became aware of the same discrepancy today as I was trying to figure ot me camera`s ASA. I imagined that the autoexposure would give me a reading which at the same time would present zebra at 70IRE. But the autoexposure reading was about one stop darker than the reading with zebra.

What I want is to use a lightmeter (on reflected mode) and to be able to determine how many foot lamberts my camera needs for any given subject to register 70IRE at a predetermined T stop.

I want to use a lightmeter in order to work apart from the camera and the LCD. However, I want to set my lights according to the IRE of the image. I am thinking of lighting to 70IRE and then checking if at 100IRE I get zebra stripes and then reduce light levels as required.

Please if anyone has a similar method, I'd appreciate your advice.

Thanks


LJ
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