Exposure is altering itself
Hi,
I'm on v8.0.2.33 and having problems with consistent exposure. Shots will sometimes vary between 185 and 191 with the White Balance Tool sampling the same patch (using the grey readout on the right) and the same flash (Broncolor) exposure given. The Histogram moves left or right showing the change. I have ruled out faults on the lens, Canon 5D mk II body, ambient light, computer by process of elimination.
Under the Camera Controls tab there is Metering currently set to Evaluative. As I am shooting tethered on manual, is this likely to have any effect?
Thanks, Neville James
I'm on v8.0.2.33 and having problems with consistent exposure. Shots will sometimes vary between 185 and 191 with the White Balance Tool sampling the same patch (using the grey readout on the right) and the same flash (Broncolor) exposure given. The Histogram moves left or right showing the change. I have ruled out faults on the lens, Canon 5D mk II body, ambient light, computer by process of elimination.
Under the Camera Controls tab there is Metering currently set to Evaluative. As I am shooting tethered on manual, is this likely to have any effect?
Thanks, Neville James
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It's not the software.
Recheck and you'll find either aperture-jitter (test by leaving lens wide open), strobe-jitter (test by leaving strobe off and using a continuous illumination source that uses a heated element (e.g. tungsten), or shutter variation (test by using a shutter speed and ambient light combo which produces no meaningful light in the exposure when the strobe is off).
My guess is you'll find the issue is the lens/camera as Broncolor and Profoto both have very consistent exposure on a normally operating pack. If this is the case you could look into more industrial/professional bodies. If you're doing reproduction work or other similar color critical work you could consider an RCam and a Phase One back for instance: http://www.dtdch.com/page/dt-rcam. With such purpose built systems the aperture and shutter accuracy is very very very good.0 -
Thanks for the speedy response Doug.
I am tied in to Canon as they are supplied by the company I f/lance to, who are cost conscious.
I will try your suggestions but have swapped my Zeiss 50 f/2 for Canon L 50 f1.2 and had the same variation so pretty sure its not aperture related. I also tried with out the transmitter attached to the two bodies I use and still get it on fluorescent strip ambient light (1/10th sec @ f4).
What is that Metering tab all about?0 -
I changed the tether cable and things are looking a lot more stable. Fingers crossed! 0
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