Thoroughly confused about PTTL & wireless

Sorry... I've read the very nice sticky post about PTTL, but I am still thoroughly confused...

I am doing a still life setup rather than live people or animals, so I thought I'd give the PTTL a go rather than full manual. (I have things working well with manual, but always have to try to learn something new)

It seems that I cannot get any form of expected behavior from the flash.
I thought that PTTL was supposed to try to balance out the lighting with all sorts of pre-flashes, etc... so that the exposure would be "correct".

I have the 540fgz on a light stand set to PTTL, using wireless.
On the K10 I am using Av mode. As I change any setting, the lighting changes drastically as if the flash was on manual and no communication was being done. Is that expected?
i.e.
changing ISO
ISO100 f/1.4 the image sees a bit dark.
ISO200 f/1.4 the image seems a bit less dark.
ISO400 f/1.4 the image seems a about right.
ISO800 f/1.4 the image seems a bit a bit too bright.

or
changing aperture
ISO100 f/1.4 the image sees a bit dark.
ISO100 f/2.8 the image seems a bit more dark.
ISO100 f/5.6 the image is even more dark.
ISO100 f/11 the image is way way too dark

The flash is never exhausting its energy, as it only takes about a second to re-charge. I would expect at some point it would fire full power in order to attempt to get a decent exposure from the camera settings.

Amazingly, if I put the camera in P mode, something changes to allow the image to be more consistently exposed (not perfect, but better). The flash will eventually exhaust its power and take several seconds to recharge if I crank the aperture down real small. So there is some noticeable change in flash behavior when the camera is in P mode.


Am I expecting behavior only found with TTL? If so, what good does wireless mode really give? And why does it seem to behave better when the camera is in P mode. I guess if it is expected behavior I'll deal with it, but it just doesn't make sense and I'm sure I must be doing something wrong or missing some small piece of info.

Any ideas?

Hopefully I just didn't miss something simple in the sticky post, but I am just not making sense of the flash behavior.


Flash: af-540fgz
Camera: K10D with firmware 1.30


THANKS!

Some basic things come to mind to check...

1: Is the popup flash set to controller (option 2 IIRC) in the K10D menu? If it set to master and you are using the 18-55 the lens obscures the flash from the popup.

2: Is the on switch set to wireless on the flash, midddle setting on the switch, it is very easy to push the switch all the way to the right.

3: Is the flash set to the correct channel (1 for wireless)

4: Is the flash set to M (Master)

5: Is the sliding button on the right hand side in the up position.

6: Is the flash set to 35mm mode (top left of screen)

Hope this helps.

Yes, wireless flash is working. The only thing that doesn't seem right is the lack of adjusting the light output to maintain a proper exposure.
Of course, putting the camera in P mode rather than Av seems to make the flash adjust its output.
So I'm sort of lost on how exactly wireless PTTL works... if there is such a thing.

Since I am in a controlled environment I could go to manual, but I'm trying to get a handle on PTTL so that I can feel more comfortable in a less controlled environment. One where I cannot constantly be playing with manual settings on the remote flash.

Anyway,
1. No, using 50mm. Still, one could defelect the pop-up flash completely and still maintain wireless. As long as some light reaches the slaves. (in full manual mode I need to put a dumb slave on the hotshoe. I often have to deflect the light so that it doesnt affect the scene. (dumb flash has no concept of control or master, etc... so it always affects the scene in some way)

2. Yep, set to wireless.

3. Yep Correct channel.

4. No, remote flash is set to Slave. This is the only configuration in which the flash will work. Master is intended, I believe when it is on the hotshoe. I believe this is like the pop-up Fire in wireless Flash modes. (either Master or Control, one will affect the environment, the other will not).
Either way, flash will not fire in Master mode.

5. Side button in in upper position, but this should not affect the flash behavior for anything other the the function of the controlling buttons on the back of the unit.

6. I leave this setting at Digital. The main controlling factor of the light output in wireless should be the flash-to-subject distance not camera-to-subject distance. This setting has no effect.


Thanks

ARRRGGGHHH!!!! Its a bug in the pop-up wireless flash communication!

If I put my af360fgz on the hotshoe of my K10D everything works perfectly!! The exposure is identical for all apertures... well, at least until I get down to f1.4 where the ambient lighting this morning is stronger than the lowest flash power.

I am getting sooooo frustrated with this stuff. Dunno how Pentax compares with other brands in this area but its certainly enough to make me look at other stuff. Unfortunately I have dug myself a deep hole filled with Pentax gear. I guess when I blow the wad on the DA* lens I'll be getting another flash as well. Why even bother with the firmware upgrade? ARRRRGGHH!!! and double-aaarrggh!!!

Oh yeah, FYI, the 360 on the hotshoe is in wireless/control mode. This way the flash does not affect the exposure. If the remote flash is off and the aperture dialed down, the image is almost black. So I know the flash is only being used for wireless communication.


How does one go about making a bug report to Pentax?
Is it even worth it? (Like reporting a bug to Microsoft? )

Another thing just popped into my head

Have you set the flash to W in the function menu on the K10D?

I'd guess it definitely is worth it.

If it's fixable in firmware, I'd be very surprised if they didn't do do, given (a) how frequently they bring out updates and (b) how much, as you've said, it erodes the point of having the features in the first place.

Also, Pentax are probably aware that, unlike Microsoft, they can't afford to rest on their laurels in this sort of area - the K10D and AF540 are their flagship at the moment, and anything that leaves them open to criticism is something I'd expect them to be very interested in. Wireless flash using the pop-up as master isn't some arcane little feature that no one's ever going to use. I think they'll want to get it right.

Yep.... unfortunately the wireless is working. (i.e. all my settings are correct).
It just isn't working correctly.

I am probably going to go back to my other issues and see if they get resolved with the 360 on the hotshoe.
It is sad, as I really need two light sources sometimes and didn't look forward to getting another flash. (I really wanted a DA* lens instead!)
ARRGGGH!!!

What a waste of time. Oh well, at least now I know it isn't my fault and that the equipment is a turd. I may not be happy, but I do have a solution.

Just really hope it is a firmware issue and not hardware. Maybe Pentax will eventually fix that issue. (I'm sure they'll just jump right on that! Argh!)

I havn't had the chance to thoroughly test yet, but have a question....
If the pop-up flash is not powerful enought to get a proper exposure on its own for any given situation; will it cause any slaved flashes to underexpose the scene? Could explain alot of the confusion, and underexposures.....

I usually set the camera so that the pop-up flash is used only as the controller so it has no direct bearing on the final image exposure.


Now what truly confuses me is I have been working more with the 360 on the hotshoe to fire the 540 remotely. Initially (as stated above) it worked great!
Now I am seeing behavior similar to the pop-up flash!!
Even more disturbing is that the 360 (or the 540) when placed in the hotshoe ALWAYS affects exposure. Controller mode is supposed to fire control signal only and not affect exposure. Master mode is supposed to do both. The setting does not seem to make any bit of difference any more. (It did, as stated above since I had aimed the flash away from the subject and the scene was still properly exposed. Now the scene is too bright when the control flash is aimed at the subject and the scene is too dark when aimed away from the subject.)
The remote flash is firing in all instances.

Man, this stuff is so very frustrating!! It makes no sense what-so-ever! Arrrrggggh!!!

I've done a quick run through all the modes here with 2 AF360's. everything appears to work as it should in all modes, popup with one flash or both AF360's with one on the camera, K10D has V1.30 installed.

I would hazzard a guess that you have a firmware issue, don't know if you can re-install V1.30.

Another thought, have you tried it with another lens, might be an issue with your lens contacts/A setting.

Rats!

So you're saying the following works:
1. 360 on camera wireless/control mode, 360 off camera wireless mode - exposes fine (no reflection from on camera flash)

2. 360 on camera wireless/control mode, 360 off camera wireless mode, aperture closed down (lets say three stops) - exposes the same as 1. above?

3. 360 on camera wireless/master mode, 360 off camera wireless mode -- results on flash on camera used in exposure (you my see reflection from on camera flash), otherwise exposure is close to 1. above?

I've tried swapping the 360 and 540 as well, so it isn't a problem that one flash is mildly screwed up either.

ARGH!!!


I will try re-installing the firmware, but I'm hard pressed to see how a partial failure would be possible. (unless the upgrade logic is truly flawed)

Good idea on the lens issue. Just read another thread on something about that yesterday. Anyway, I was using my old SMC Pentax-FA 1:14 50mm lens. switched to the new kit 18-55mm and have the same results.

OK some further observations...

When the 360 on camera is in master mode it fully takes part in the exposure of the subject.

When the 360 on camera is in control mode, it tries not to take part in exposure but if you're close to the subject the flash is still bright enough to have some effect and cause reflections.


I generally have been shooting the remote flash through a brolly. I thought I had mentioned that in my initial post but I see after all the copy/paste and re-writes that I left that out. (stupid!)
Although honestly didn't think the flash needed to "see" the subject for PTTL.

Anyway everything seems to work much better with bare remote flash. (both with pop-up controller and 360 on camera as controller.)
Still some odd behavior with regards to master v.s. controller, but maybe the bigger flash just takes too long to loose power before the main flash fires. That makes total sense and I can accept that one.

Still, it is odd that my initial tests with the 360 on camera seemed to work flawlessly even through the brolly. I think I may have had the remote flash closer to the subject and the ambient lighting may have been more subdued. Perhaps the remote flash's sensor picked up the lighting better on that one test?


Do any of this make sense, or does it sound like my whole system just totally wacked?


I hate the look of bare flash, but I guess that is OK, in variable conditions I'm not likely to have a big umbrella connected to the flash anyway. And for constant environment shooting, I can just go to full manual mode.

At least I now seem to have some methods of getting consistent exposure. It is just a bummer that I have to worry about that.
Of course, I have a nagging feeling that when I come back and try again tomorrow, everything will be different.

Could the brolly be messing with (Smoothing) the encoded flash that the popup sends back to program it after the P-TTL measurement, hence causing the external Flash to think the camera has asked it to set a different power to what it really did?

I dont know how robust the signalling is but I had problems today getting my 360 to fire when the Flash sensor was in direct sunlight.

Could be. But the signal should be in binary. Whether the signal is weak or diffused, on is on, and off is off. Sending analog pulses would of course be too prone to errors caused by distance and all sorts of other factors.
As least logically it makes sense to me that way. So I'm not sure how the brolly would make a difference.

I do not actually know the exact encoding scheme -- but it would be cool to have a way to record whats happening and decipher what is being sent/received.

Of course, as in your case, bright light can mask/overpower the signal altogether and cause the signal to not be seen in one direction or the other, or both.

Where you have something in the way of the light path, you are asking for trouble, so make sure that both flashguns can "see" each other.

Brollies often have bits of silvery metal on them, and it is not impossible that reflections could add to the signal. You know: "Send reinforcements, we're going to advance" becomes "Send three and fourpence, we're going to a dance".

I'm sure your problem is of this nature.

G