very confused with FEC using Mini TT1/Flex TT5

I have been using my TT1/TT5 combo for about a month now and am still baffled on how to properly use FEC.

Below are four very quick and crude sample shots I took with various FEC adjustments. I was shooting using my 5DM2 in Manual mode (1/100, f/5.6, ISO 640) with my 50 f/1.4 lens and a 430EX behind me bounced off an umbrella on a light stand.

Pic 1: No FEC at all
Pic 2: FEC +2 via the 5D body
Pic 3: FEC +2 via the 5D body AND FEC +1 on the 430EX
Pic 4: FEC +2 via the 5D body AND FEC +2 on the 430EX

What is going on here? I assumed that if I dialed in FEC+2 with the body only that I would get the max flash output, but that's clearly not the case. I am able to override it with the controls on the flash head and get even more power.

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What camera settings, FEc can't do nothin if flash already putting max power. The FEC is so much easier with that AC3.

I was under the impression that the flashgun and body FEC settings were separate and cumulative. So, you can set +2 on either and get the same effect (+2 stops) but set +2 on both and you get +4 stops. Which fits your examples well as you have 0, +2, +3 and +4 getting brighter accordingly.

+2 doesn't give maximum output, it just gives two extra stops worth of light, that may or may not reach the maximum it can put out.

what kind of metering are you using, and are you always metering off the same point?

When I try to do things like this, I try to use spot metering and I try to meter off the same point to see if my results are consistent. It appears there's slight movement so you don't appear to be on a tripod..

sandpiper wrote in post #14545585
I was under the impression that the flashgun and body FEC settings were separate and cumulative. So, you can set +2 on either and get the same effect (+2 stops) but set +2 on both and you get +4 stops. Which fits your examples well as you have 0, +2, +3 and +4 getting brighter accordingly.

+2 doesn't give maximum output, it just gives two extra stops worth of light, that may or may not reach the maximum it can put out.

While your answer is logical (and was my understanding of it as well based on my photos), I didn't know that you could have achieve such a cumulative effect. I was under the impression that it if you adjust FEC via the flashgun, it overrides any FEC setting on the body.

Mistabernie wrote in post #14545657
what kind of metering are you using, and are you always metering off the same point?

When I try to do things like this, I try to use spot metering and I try to meter off the same point to see if my results are consistent. It appears there's slight movement so you don't appear to be on a tripod..

Evaluative metering, center focusing point always on the teddybear. Did not use a tripod but I was seated for each shot.

Phototeacher wrote in post #14546229
Metering should not matter, since he had the camera in manual mode, and did not change the exposure settings.

what kind of metering are you using, and are you always metering off the same point?

When I try to do things like this, I try to use spot metering and I try to meter off the same point to see if my results are consistent. It appears there's slight movement so you don't appear to be on a tripod..

Even for flash?

Metering should not matter, since he had the camera in manual mode, and the exposure setting remained the same for each shot.

Mistabernie wrote in post #14545657
what kind of metering are you using, and are you always metering off the same point?

When I try to do things like this, I try to use spot metering and I try to meter off the same point to see if my results are consistent. It appears there's slight movement so you don't appear to be on a tripod..

coeng wrote in post #14546134
While your answer is logical (and was my understanding of it as well based on my photos), I didn't know that you could have achieve such a cumulative effect. I was under the impression that it if you adjust FEC via the flashgun, it overrides any FEC setting on the body.

Yes, it says in the manual that it overrides the camera, but I was once having issues using fill flash at -3 FEC trying to put catchlights into the eyes of some big cats. That side of things was working fine, but big cats often have a number of white hairs in their fur and even at -3 they were just picking up the flash and standing out too much. I mentioned this to another Canon user I was with and he said that adding some -ve FEC in camera as well helped, as they seemed to be cumulative in practice. I tried it and it definitely helped stop the white hairs standing out.

I've never tried it with +ve FEC as I have never wanted more than +3, so can't say anything from experience there. However, I have used it when I have wanted just a slight touch of fill in and it does seem to reduce power more by adding -ve on the camera as well as on the flash unit.

Maybe the manual means it overrides it if they are opposite (-ve on one and +ve on he other) I don't know. I agree that it apparently shouldn't work cumulatively, but it seems to in practice. Your own test would seem to back the theory up too, as otherwise your shot with 5D FEC +2, 430 EX 0 should have two stops of compensation, but your 5D FEC +2, 430 EX +1 should only have one stop of compensation (as setting +1 on the 430 EX would override the +2 on the camera) which should make it darker, not brighter as it clearly is.

If you use the MiniTT1+FlexTT5 with a Speedlite, FEC on body adjusts the FEC on the flash. That's it. It's not cumulative.

http://wiki.pocketwiza​rd.com/index.php?title​=PowerTracking

ocabj wrote in post #14546347
If you use the MiniTT1+FlexTT5 with a Speedlite, FEC on body adjusts the FEC on the flash. That's it. It's not cumulative.

http://wiki.pocketwiza​rd.com/index.php?title​=PowerTracking

Then all three images above, with the 5D set at FEC +2, should be identically exposed, but they aren't.

sandpiper wrote in post #14546417
Then all three images above, with the 5D set at FEC +2, should be identically exposed, but they aren't.

That's what I said. There must be more to this.

interesting, i had a similar question with pocket wizard since i noticed a change in other settings since the implementation of firmware version 6.0 with the TT5.

In version 5.5 turning everything one, the flash and camera synced the FEC starting point to whatever was on the flash. It doesn't seem to do this now. Though, if you just read the LCD on both they read to be in sync. But in fact, the camera could be set to - 1/4 while the flash is actually set to -1/32. I came across this almost be chance.

to fix the problem, i discovered, I now need to set both my flash and camera FEC to "0" before turning on the TT5...then using either the camera of flash they seem to be in sync. ( then using either flash or camera +3 would be +3 with no spare room by using one or the other.)

give it a shot by setting both to 0 before turning on the TT5 and try again...

sandpiper wrote in post #14546417
Then all three images above, with the 5D set at FEC +2, should be identically exposed, but they aren't.

Interesting problem, & I hope you get it figured out. But that's one reason why I prefer manual settings. It really isn't all that hard when you get used to it.
More on that here: Fill light at sunset

mikewinburn wrote in post #14548009
give it a shot by setting both to 0 before turning on the TT5 and try again...

I will certainly give that a shot.

Another sort-of-related issue. I'm beginning to feel that my 5DM2 and my 430EX don't like each other too much. I was shooting manual mode indoors over the weekend with 430EX mounted on body bounced off ceiling. Realizing that I need more flash power I added FEC on the flash gun from the previous setting (when I was using outdoor fill flash) from -1 FEC all the way to +1/3 FEC. I did this in +1/3 increments.

As I went from -(1), to -(2/3), to -(1/3) to (0) I saw what I expected....EVENLY increasing levels of flash output. As soon as I went from 0 to +1/3 it seemed like it jumped by +(1 and 1/3) instead of just by +(1/3). I tried going back and forth again, and the same thing happened.

What the heck is going on here? I will try to post test shots tonight similar to what I did for the OCF shots in my OP.