Paul C. Buff, Inc. Technical Forum

deleted videos since the comparisons were not accurately conducted*

I uploaded an observational video review between the cybercommander's built in light meter vs the sekonic l358. I noticed that the sekonic is consistently more accurate throughout the tests that I conducted which probably attributes that the sekonic is a dedicated light meter and has a larger dome to make sure the light is consistent.

My question though is this: why does the cybercommander freeze up on certain exposures?
these values are f/1.0'2, 1.4'9, f/4.0'4, f/11....etc. once the light meter hits these readings, it seems to not take any more 1/10' stop readings such as 1.4'8, 1.4'7 and just kind of locks up until there is a significant change of light to meter such as the light going to f/4.0'4

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Cybercommander (repaired) vs Sekonic l358
www.youtube.com/watch?v=_KmbNGgNUnY

Ambient light comparison
www.youtube.com/watch?v=lQrOtxNMSBQ

Ok, A few things to try. First, go to SETUP>FLASHMETER. In the upper right corner, you will see the letters "CAL". Beneath that, make sure it is set to +0.0f. Next, go to SETUP>ADVANCED CONFIGURATION>FACTORY CALIBRATION. In the lower left, you will see <>REVERT. Press to the left or right on the left joystick. The screen should read "original factory calibration has been restored". At this point, retry the test.

Another possibility: While the size of the dome in and of itself should not affect metering accuracy, it will affect where the two are positioned relative to each other. The Sekonic is mounted higher, and reaches farther forward than the CC. While the difference in proximity to the light is miniscule, the bracket to which you hae the meters attached may be flagging the light reflecting off the white back drop from the CC, but not the 358. This could make a difference, but I do not think that is the entire problem.

Next, it almost seems as though the CC is not taking a new reading every time the flash fires. It will take a reading, then not take new readings, rather than register a reading at f/1.4'9. To verify the CC is updating, take a series of readings (by itself is fine). Use a power setting that gives you about f/2.8 or so. Alter meter readings, one with the dome in direct line of sight with the flash, one with your hand covering the dome, and repeat of a series of 5-10 readings. The ones with your hand covering the dome should be significantly lower than those in direct line of sight.

And yes, one meter using 1/10f cannot be acurately compared to a meter using 1/3f.

http://www.youtube.com/watch?v=cVJWzHdq ... e=youtu.be

Re-ran the test again this time with the cybercommander butted directly against the sekonic's dome. the results were similar yet the cybercommander continued to freeze up on certain exposures 1.4'9, 4.0'4, and 11 were ones i found that the cybercommander stops metering 1/10 stop changes based on distance.

Yeah, I'm a bit surprised that even at standard studio apertures, the sekonic registers f/8 and the CC registers f/11 - a full stop different. Honestly I didn't even know the CC had a light meter built in to it.

It does seem like the CC light meter is just not as sensitive and precise, but at $180 I'm not complaining that it's not as good as the dedicated lightmeter (only) $300 Sekonic L-358, and even the cheapest Sekonic L-308S is $230. I actually just ordered the L-308S so I'll give it some comparison tests too, noting it's light dome is also a bit smaller. I hope the L-308 is at least within 1/3 stop accuracy, but I don't have a L-358 to compare against.

How does the ambient meter readings compare?

thanks for the ambient suggestion as i just remembered there was a sticky on the pcb forum that suggested that the cybercommander can meter ambient light. I will run a test today.

While there is obviously something amiss on this particular CC, this is by no means representative of Cyber Commander as a product in general. What is going on in these examples are not a product of firmware, nor is it a result of a smaller dome. There is something out of spec in the hardware, or there was some miscalibration in the factory calibration.

Either can be corrected under warranty at our repair facility. However, there is one last remedy the end user can perform.

You will need an f/1 reference and and f/16 reference. These reference points can be determined with the Sekonic during the process. You will then go to the SETUP>ADVANCED CONFIGURATION>FACTORY CALIBRATION screen. Here you see the prompts for f/1 and f/16 in each lower corner. If you press down, the light will fire and the intensity the CC registers will be the respective reference point. The last register will be the one stored. So, you can align the two meters and enter the above screen. Arm the Sekonic and fire the f/1 button. If the Sekonic does not read f/1, back off or get closer as needed until the Sekonic does read f/1. Repeat the same steps for f/16.

If calibrated properly, you should find the CC very close to the Sekonic throughout the range.

If desired, this can be undone by the REVERT command. If you are unsuccessful, we can recalibrate it here.

I gave it a go with the cybercommander this evening so that I had an accurate reading of f/1.0 and f/16 on my sekonic meter. No go. The cybercommander wasn't off after I calibrated but the minute i started scooting back from the f/16 exposure, it would change much faster then the sekonic's exposure. So after about 20 minutes, I reverted the settings back to normal. I'm pulling my hair trying to find out why the cybercommander isn't metering between f/1.4'9 and f/4.0'4, and f/8.0 and f/11. I just worry that if i send the meter in for calibration, it will come back with the same issue of getting exposure locked at f/1.4'9 and f/4.0'4 respectively until there is a increase in light change to jump to the next default. Maybe it needs replacing? I'm not sure.

It sounds like we will need to take a look at it. If you reference this conversation in the note you return with the unit, we will make sure the same problem does not persist. Again, this is not a common problem, in fact, this is the first time I have seen this "locking" on to a particular meter reading.

ok, i'll give pcb a call to send in the cybercommander. I'll go ahead and do another test when the cybercommander comes back to me.

thanks TS

i have an L358 and i immediately tested it vs the newly arrived CC a couple times cuz i wanted to know if i could eliminate using (redundant) L358. (i still do test CC vs L358 once in while just to see if there is any drift going on. still good to go).
my findings were very very close never more than a tenth out and bang on more than not.

*as a note-if/when i take i reading i always take more than one for each location/light as i sometimes get a slight (no more than 1 or 2 tenths of a stop) variance between reads no matter what meter i happen to use.
i fully trust my CC's light meter.