Paul C. Buff, Inc. Technical Forum

This question has been raised a few times, and there may be a few who have wondered this or never thought of, so here is an answer you may or may not know to have asked!

You can meter ambient light with the Cyber Commander. In fact, when the meter button is activated, it has to meter ambient light along with any light from a flash. If you want to meter ambient only set the Cyber Commander to a channel that is not used by a CSR+ or CSRB+ receiver and meter as normal. This will give you a reading at the top of the screen.

Tip: Doing the above will give you a reading, however, it will not place a yellow marker on the graph like it does with the flashes. You can go into the SPEC LIGHTS menu, define your ambient light channel as OTHER> UNDEFINED (you can actually SPEC this as anything you want from any of the choices, but the UNDEFINED option is the best in my opnion for several reasons that I will not bore you with). Now that the Commander thinks there is a flash it need to keep track of at that location, it will meter and mark the reading for a quick reference. Since it is defined as an undefined light, it will not track the meter reading as you bracket the flash settings up or down, since the Commander cannot control the sun (or other ambient light).....yet.

"the Commander cannot control the sun (or other ambient light).....yet"

Can you roll this into the next patch 8-)

Related:

Can the CC be used to take an incident reading of a flash that is fired manually? In other words, while waiting for my CSR+ receivers to arrive, could I use the meter to read my monolights individually fired?

I've attempted this, but so far have not been able to get usable results.

No, there is not an "arming" function where you can set the commander to wait for a flash.

Thanks!

...come on, UPS...

Thanks for the tip, that helps a lot! A couple of questions/possible requests though. . .

It seems to me that (and definitely correct me if I'm wrong!) the behavior of metering a flash, for the sake of argument, let's say an E640 is to take the flash/ambient reading in a single step. In other words, it doesn't meter the ambient at the given ISO/shutter and then the flash, but instead just meters the whole shooting match together. I am guessing this based on my observation when turning the power down on the E640 in a situation where the ambient was a significant contributor to the overall exposure.

So let's say I'm metering a single E640 at f/5.6, ISO 100, 1/250th. Let's also say that my ambient is running f/2.8 at the given shutter and ISO. Now I want to dial down my power on the E640 by a stop to f/4. If I do that blindly by just decreasing the power on the E640 to where it says f/4 does it really bring it down such that the ambient and the flash mix meter f/4 now? I'm not sure, but I don't believe so. Now let's say I want to bring it down to below ambient, maybe to f/2.0. Obviously this isn't possible, but there is no kind of warning to let you know you've just done something incredibly stupid.

If all of that is more or less accurate (it *seemed* to me when I ran into this in the field that was exactly what was happening), then it seems like there could be *significant* benefit to making "Ambient" a first-class light source. Internally the CC could at minimum change the color or make blink the graph for a light that you're trying to bring down below ambient as a warning. Even better, couldn't it calculate the actual exposure of the combined flash and ambient and then when you bring the bars down you really wouldn't need to remeter even with a significant ambient exposure.

It seems like a bit of nit picking I realize, but I'm thinking of the principle of least surprise here and also that one of the major things that makes the CC so awesome is not having to always remeter. I absolutely love it for shooting in the field now as well because I don't have to constantly run around to all the lights, where in the studio I don't mind that quite as much (and don't need to change setups as rapidly), in the field it can be a major pain to even get to lights sometimes, let alone get to a subject to do the metering.

-Daniel

Every flashmeter made must, by simple physics, measure both ambient and flash combined, during the time interval selected when measuring flash. The only way around this would be to first measure ambient alone, then ambient + flash, then calculate the difference between the readings, using log math, to determine the separate contribution from the flash. You can do this mentally (or with a calculator) by the same means.

It would never do that. First, to get a smaller aperture, you would have to increase the power of the flash unit. To get a larger aperture, you would decrease the power of the flash, but if the ambient exposure is f/2.8, the "warning" would be that the meter would never suggest an aperture larger than f/2.8.

I think you misunderstood what I was saying (it perhaps wasn't so clear). What I was trying to say is that if I'm metering a *total* exposure at f/5.6 with an ambient contribution of f/2.8. *Then* if I decrease my exposure from f/5.6 to f/4.0, does the CC know how much was contributed by ambient? Paul answered that question above, with a "no" (albeit not directly, but none-the-less, I believe that conclusion is valid). It is metering both together and doesn't take a separate reading to be able to subtract the ambient out, which is basically the feature I was asking for since I shoot 90% outdoors where ambient is a major factor. It's not a *huge* deal, but I do loose the simple ability to be able to dial down the power accurately without remetering (or as Paul said, doing my own math, but I stink at doing math in my head). So I just revert to my old ways and remeter (or pop test shots and compare histograms) when making all but very minor adjustments. Still saves me walking and with the Einsteins it saves the constant lowering of lights to be able to see the back and adjust and then raising them back up. Pretty major win in that alone:-)

EDIT: Paul, what you said about metering ambient alone, then ambient plus flash is *exactly* the feature I'd like to see. It could also use a separate channel to track the ambient part as a built-in as well since, as you said, it's part of every exposure regardless. Being able to meter just ambient is nice, but it's way more nice to have the math automatically done for me with regard to total EV for each channel when I want to start changing power settings.

I believe some of the Sekonic meters can break down the total exposure such that it gives you the percentage being contributed by strobes.