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Cyber commander light meter
http://www.paulcbuff-techforum.com/viewtopic.php?f=8&t=4354		 Page 1 of 2
Author:  alp [ Wed Feb 12, 2014 12:10 pm ]
Post subject:  Cyber commander light meter
I've been trying to confirm my suspicion that my CC meter is reading "hot" and after some testing I think it is.

What I have done is set up an Einstein with a medium softbox firing at a grey card (18%). Camera is set to ISO 400, 1/250, f11 (also tried f8). Using Lightroom, captured image of card, adjusted WB, selected part of the image and the RGB values are not as expected (50% for the way LR works) but are indeed "hot."

Adjusting the CC settings I went all the way to +4.0, which seems a bit extreme. Once I hit 4.0 I stopped trying as the power levels were getting close to minimum.

What are the typical adjustment values for the CC?

I have a pdf showing my test results: Let me know how to attach it if needed.
Author:  Technical Support [ Wed Feb 12, 2014 12:31 pm ]
Post subject:  Re: Cyber commander light meter
What version of firmware are you using?

Do your CC settings match the camera (i.e. ISO)?

If you go into the SET UP screen> FLASHMETER, in the upper right corner, you should see "CAL" with a value underneath. What is that value?
Author:  alp [ Wed Feb 12, 2014 12:49 pm ]
Post subject:  Re: Cyber commander light meter
CC firmware is the latest.

Settings match between camera and CC flashmeter settings.

The flash meter CAL adjustments I started with were 0 and I changed them to drive the LR RGB values to something appropriate. So this went from 0 to +4.0. ISO was 400, 1/250, f11 and f8. Tries ISO 100 just to see and there was not much difference in the RGB values.
Author:  Technical Support [ Wed Feb 12, 2014 3:11 pm ]
Post subject:  Re: Cyber commander light meter
It sounds like the Cyber Commander may have lost calibration. Please bear with me as I research this.

By the way, just to be sure, by "the latest" firmware, you mean v.50?
Author:  alp [ Wed Feb 12, 2014 3:17 pm ]
Post subject:  Re: Cyber commander light meter
Technical Support wrote:
It sounds like the Cyber Commander may have lost calibration. Please bear with me as I research this.

By the way, just to be sure, by "the latest" firmware, you mean v.50?



Yes, Version 50.
Author:  Technical Support [ Wed Feb 12, 2014 6:30 pm ]
Post subject:  Re: Cyber commander light meter
Ok, I am going on the assumption the calibration was lost. You can give us a call at your convenience tomorrow (or whenever) and we can walk you through re calibrating. To do this on your end, you will need another flash meter and a light. Please ask for David.
Author:  alp [ Wed Feb 12, 2014 6:32 pm ]
Post subject:  Re: Cyber commander light meter
Technical Support wrote:
Ok, I am going on the assumption the calibration was lost. You can give us a call at your convenience tomorrow (or whenever) and we can walk you through re calibrating. To do this on your end, you will need another flash meter and a light. Please ask for David.


I do not have another meter. Is there another way? I have a shoot this weekend.

Any idea why is might have lost calibration?
Author:  alp [ Thu Feb 13, 2014 12:38 pm ]
Post subject:  Re: Cyber commander light meter
alp wrote:
Technical Support wrote:
Ok, I am going on the assumption the calibration was lost. You can give us a call at your convenience tomorrow (or whenever) and we can walk you through re calibrating. To do this on your end, you will need another flash meter and a light. Please ask for David.


I do not have another meter. Is there another way? I have a shoot this weekend.

Any idea why is might have lost calibration?


OK, while waiting I went outside and metered the sun. Had to apply +0.5 to get a Sunny-16 reading. This was stable across multiple ISOs and shutter speeds. Will try a different body in a while.
Author:  Luap [ Thu Feb 13, 2014 7:08 pm ]
Post subject:  Re: Cyber commander light meter
Sunny 16 is not at all accurate. can vary by 2 f stops depending on conditions.

I would do this: Meter something white - like printer paper - with CC meter. Shoot a picture at 2f smaller aperture number than indicated, then -1f, then 0f, then +1f, then +2f. Using histograms, RAW or straight Photoshop, determine which shot is closest to 100% white (255-255-255).

If, for instance, the -1f shot is closest, do the meter calibration adjustment in CC to -1f. In other words, trial and error adjustment of the CC meter calibration until pure white metering produces pure white shot, at the indicated CC aperture.

Crude, but should get you in the ballpark. CC calibration is rarely more than 1.7f off if it has lost its calibration. Since you're shooting at ISO400, are you sure the CC is set to ISO400?

I can safely tell you if you are using any softbox at 10', you should get very close to f5.6 at ISO100 and f11 at ISO400 (at full 160WS power) - maybe a tad less than this - perhaps 3/10f less.

Perhaps not a great method, but I've tested softboxes at 10' at 640WS ISO 100 and invariably get about f8+7/10.

You didn't say how far the softbox was from the test card?

Also, firmware 50 does cause the CC to lose it's factory calibration. They have a fix for this, but I don't know if it's online yet of not. TECH???
Author:  Technical Support [ Fri Feb 14, 2014 10:39 am ]
Post subject:  Re: Cyber commander light meter
For clarification, the update to v.50 can cause the meter to lose calibration. Units shipped with v.50 will still be calibrated.

We are working on instructions to re-calibrate the CC in the field, but this will require a second light meter.
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