I'm having an issue with the R5 II, EL-5 and ST-E10 where the flash zoom head is not following the lens.
All are on the current FW. The flash is communicating with the ST-E10 and triggered correctly for exposure. If I set the zoom to the fixed value of 24mm and then to A either it stays where it is or goes to whatever the lens is just at that time. When the flash is on the camera it zooms correctly, i.e., the flash head goes from 24-105 with a 24-105/4 and goes from 80-200 with a 100-500 as they should. I used two EL-5s and it's the same issue with both. If I use the OC-E4A cable then the head zooms as if on the camera, but that only gets me one flash and the cord is short. Can anyone test and see if I am the only one? Thanks.
To my knowledge, the flash heads on Canon speedlights do not zoom automatically when used as wireless remotes. You would have to set the zoom manually, I believe.
I could be wrong (I have older flash gear), but it has always worked this way in the past, so I think it is plausible that this is the behavior for the current gear too.
It works with the off camera shoe cord simply because the flash still thinks it is mounted in the hot shoe. This makes sense because the cords are typically used with flash brackets, so the flash is still "on camera" more or less.
I think in a a wireless remote scenario, no assumption can be made about the placement or location of the flash, so having the zoom head track the lens automatically would not make sense in many situations.
Of course, it might be nice to have this option as a custom function just for the cases where it might.
garyvot wrote:
To my knowledge, the flash heads on Canon speedlights do not zoom automatically when used as wireless remotes
This is correct, and always has been. The challenge is that the focal length determines the flash angle of the light cone, and that works only if the flash is on the camera (the camera knows exactly where it is). If the flash is off camera, it could be in front of or behind the camera; it could be pointing up or down, or be otherwise off axis. The camera has no way of knowing (or rather, the flash has no way of knowing its position relative to the lens).
Thanks. That really sucks. I'm not sure if there is a good technical reason or just not getting it right in the URS. Somebody made an fallacious assumption that nobody wants the zoom to work on wireless. It's doubtful that the costs would be much higher and auto-zooming could be controlled by the A or M setting. At the very least the A should be disabled on the flash so that it does not appear to be a defect. For now on wireless I will set each to 200mm and try to align as best as possible with the brackets. If I can get by with one flash I'll be more inclined to use the cable, bulky and stupid as that is. I wish a third party would make a cable with just the flash contacts not all that other video junk.
EB-1 wrote:
I'm not sure if there is a good technical reason or just not getting it right in the URS.
EBH
Not sure what an URS is, but it's unclear how it could be done without the flash having some capability to communicate its relative, extremely precise location to the camera, in real time, as the photographer / camera moves through space. For example, 85mm isn't the same for a camera & flash that's 3m away from the subject, vs. a camera that's 3.5m away (with the flash in the same place), or worse - 2.5m away. Similarly, tilting the camera just a few degrees would truncate the flash coverage and you'd end up with dark bands in the image. Not keeping the camera perfectly level or placing the subject off center would have same results.
This is a very problem to solve, especially with multiple flashes, which is what's usually used with a radio transmitter, and to the best of my knowledge the hardware doesn't exist in the current flashes (a means to precisely measure relative distance and geometry between the items in play.)
But that is the problem. The system should not impose any unnecessary limitations because someone ("photographer x") does not consider how it will be used. It should not work differently because it may be used differently, when in fact I want to use it the same way as on camera. I doubt that I'm the only person in the world that doesn't want to lose the functionality.
URS is user requirements specification. It's basically a lost of everything the system (typically software and also applied to hardware) must do. The FRS (functional requirements specification) is developed from the URS and consists of how the system will achieve what is expected in the URS. (Sometimes you spend months going back and forth with compromises.)
A simple line item would be "when the flash EL-xx is connected to the camera Rx with the wireless transmitter ST-xx the flash head will have the ability to continuously and automatically zoom to match the focal length in use of the lens on the camera."
It seems that you would have much more difficult item that the "camera and flash would be able to determine the relative positions and compensate flash zoom and exposures..." or something like that which is not so practical at this time.
I think the reason they don't implement such a simple solution (without my specification, as you say), is that then 99% of the users (probably more 9s) who are less sophisticated than you would be reporting "bugs" in the function, causing under-lit sections of the image because the zoom head wasn't correctly zoomed out, and the cost of the support calls is too high. Similarly, the few customers who have your degree of sophistication have been able to deal with manual strobe zoom (and "real" lights with barn doors etc.) since the days of black and white, as my kids call it.
I agree with the cost / benefit analysis that Canon made.
I'm using it outdoors, not in the studio. The practical issue is the reach and I'm sick of those bulky and/or fragile light modifiers that pick up the winds and get whacked on everything. The 200mm setting of one (or better two) flashes is a good option with the lenger lenses. The other reason to use the Canon flashes is that the LP-EL has quite a lot of power and can be recharged with an LC-E6 or a small USB charger like the Nitecore. Everything has to go with me since it is all international air travel.
FWIW, I was building flash units and portable power supplies well over 40 years ago mostly for macro work. I had two heads with 6 tubes each and one head with 4 tubes. It was like blasting the subject with ~16 V283s, though I could dial them back by switching various capacitors in/out. We needed a lot light at effective f22-32 (at 1:1 magnification two stops are lost) and Kodachrome ASA 25. There was no flash exposure control at all from the camera so everything was difficult! Those push-pull self oscillators in the power supplies were so overdriven I'd be blowing up something every few weeks.
That’s a really odd one, and your testing is solid. The fact that both EL-5s behave the same way and everything works perfectly on-camera or over the OC-E4A pretty much rules out the flash units, body, and lenses themselves. It really sounds like the ST-E10 just isn’t passing focal length updates to the flash for auto zoom, even though E-TTL triggering and exposure are fine.
I can’t test it myself right now but I wouldn’t be surprised if this is a firmware limitation or bug with the ST-E10 rather than something you’re doing wrong. I’ve seen similar quirks where zoom data only gets sent at initial wake-up and then doesn’t track changes. If a few others can confirm it, this feels like something Canon will need to address in a future FW update.
RoadRnrA wrote:
It really sounds like the ST-E10 just isn’t passing focal length updates to the flash for auto zoom, even though E-TTL triggering and exposure are fine.
Yes, exactly.
As Stan has pointed out, this is by design, not a bug or a firmware issue.
There was no flash exposure control at all from the camera so everything was difficult! Those push-pull self oscillators in the power supplies were so overdriven I'd be blowing up something every few weeks. 
