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Problem: Einsteins f/stop and camera aperture
https://paulcbuff-techforum.com/viewtopic.php?f=8&t=3406
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Author:  sdegan [ Thu Feb 16, 2012 11:43 pm ]
Post subject:  Problem: Einsteins f/stop and camera aperture

Hi,
I am not sure what is wrong, but the following is what happens with the Einstens and my cameras. There is always a gap between the light f/stop reading and the aperture I have to set on the cameras. For example: if the Einsteins output reading is 5.6'2 I have to set the camera with an aperture of about f/8 (i.e. stepping down about 2/3-1 f/stop) to have proper image exposure. I thought that the light level measured by the light meter should match the aperture setting on the camera e.g. light reading f/8 and set the camera aperture to f/8 (or close +/-0.2 f/stop) as well. If I set for the matching values the final image is way to overexposed indicating that the Einsteins are firing too much light.

A final note: Cyber Commander readings quite well match with the Sekonic values.

What am I doing wrong?

Thanks for any suggestion.

Author:  ltwimberly [ Fri Feb 17, 2012 12:51 am ]
Post subject:  Re: Problem: Einsteins f/stop and camera aperture

Make sure you aren't standing between the strobe and the meter when you take your readings. If you do you'll block some of the light and the reading will underestimate the actual output.

Make sure there's no global offset programmed into the CC and that you have the ISO and shutter speed set correctly on the CC. But if your readings are comparable to another meter then it probably has more to do with technique.

Also, opinions vary on whether to point your meter toward the light source or toward the camera. Either can give you useful information. In light of what you're describing, you might want to try pointing the meter toward the light instead of towards the camera. That will tend to push you towards underexposure.

Author:  BDP [ Fri Feb 17, 2012 1:57 am ]
Post subject:  Re: Problem: Einsteins f/stop and camera aperture

also, be sure that you have set the ISO on your meter to match the setting on your camera. If you are metering at ISO100, but your camera is at ISO200, you would see a stop overexposure (about what you are reporting)

Author:  Technical Support [ Fri Feb 17, 2012 10:00 am ]
Post subject:  Re: Problem: Einsteins f/stop and camera aperture

BDP wrote:
also, be sure that you have set the ISO on your meter to match the setting on your camera. If you are metering at ISO100, but your camera is at ISO200, you would see stop overexposure (about what you are reporting)


This is my first thought too. If you have a CyberCommander that closely matches a Sekonic, then the settings issue would be in the camera, or there is a similar offset dialed into both meters.

You can see the ISO value of the CC in the upper right corner, and it can be changed by going to SETUP>FLASHMETER>LEFT JOYSTICK up or down to change.

Author:  BigIronCruiser [ Fri Feb 17, 2012 4:27 pm ]
Post subject:  Re: Problem: Einsteins f/stop and camera aperture

If you're shooting Nikon, the camera probably defaults to ISO 200, while the CC defaults to 100. You should also note that The CC resets to 100 each time the batteries are removed.

Author:  sdegan [ Wed Feb 22, 2012 1:33 pm ]
Post subject:  Re: Problem: Einsteins f/stop and camera aperture

Hi All,
After more testing I think I have found the problem. I used to take a reading of strobe 1, 2 and 3 without taking the 'All' reading. In other words I was not taking the reading of all lights at the same time. I will do more testing but I think that was the problem with the different aperture of the strobes compared to the f/stop in the camera.
Many thanks for helping.

Author:  Technical Support [ Wed Feb 22, 2012 4:56 pm ]
Post subject:  Re: Problem: Einsteins f/stop and camera aperture

That'll do it. If any two lights hit the same place, thier additive light should be measured, or you will get a discrepency between the meter reading on the commander and the exposure in the camera. Depending on the ratio between one light and the next, the discrepency can vary significantly.

Author:  sdegan [ Wed Feb 22, 2012 10:46 pm ]
Post subject:  Re: Problem: Einsteins f/stop and camera aperture

Many, many thanks for helping!

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