Sorry, perhaps I was lacking in how I described what I meant. (I tend to either ramble on or cut things too short -- gotta find a happy medium somehow. )

As far as I was concerned, when the A mode of the flash is used, I still consider it manual, as the camera settings are static and need to match what the flash is going to do. (or vice-verse, the flash has to match how the camera is set).
The flash will adjust for the flash settings, but there is no communication between flash and camera to balance each other out without some other human intervention.

I believe the concept is the same. But thanks for the clarification.

As stated, you do not need PTTL, but the K10D does not support TTL.
So you would have to work totally on manual settings.

Great job. Certainly no shortage of choices this week.
Congrats Tony.

BTW, the arm in my photo is part of a multi-piece metal sculpture here in Washington DC called "The Awakening".
Basically a giant waking up from a nap underground. His arms, legs and head are breaking through the ground.
The arm is probably near 15' tall.

eh, eh, stupid idea with the flash meter. I should have thought about it earlier. Duh... PTTL will send a pre-flash which will trigger the flash meter.
Perhaps some have bore logic, but mine is old and cheap. (works great in the studio, but of course has its limitations).
Anyway, every flash read about F2.0 regardless of what showed up in the resulting image.

Anyway, Just playing around in A mode. Using the AF540FGZ
I did not change the camera settings in any way. Left that in manual mode and just let the flash adjust for its settings. (In A Mode, the camera should have little effect anyway).
Obviously consistent scene, on a tripod, blah, blah, blah...

Sorry for the odd notation below... The meter has numerical F stop readings, then a digital dial like area for partial stops in between. I've rounded to the nearest 1/4 stop.

I did each flash a few times to make sure the meter reading was consistent. In that regard, for each particular setting the metering was consistent for the flash. So once you figure out what setting to use, the flash will give acceptably consistent results.

Flash setting: Meter Reading:
ISO 100:F2.8 --> F2.8 1/2
ISO 100:F4.0 --> F4.0 1/2
ISO 100:F8.0 --> F5.6 1/2
ISO 100:F16.0--> F11.0 1/2
ISO 100:F22.0--> F16.0 1/2

ISO 200:F2.8 --> F2.0 3/4
ISO 200:F4.0 --> F2.8 1/2
ISO 200:F8.0 --> F5.6 1/4
ISO 200:F16.0--> F8.0 1/2
ISO 200:F22.0--> F11.0 1/2

ISO 400:F4.0 --> F2.0 1/2
ISO 400:F8.0 --> F4.0 1/2
ISO 400:F16.0--> F5.6 1/2
ISO 400:F22.0--> F8.0 1/2

ISO 800:F8.0 --> F2.8 1/2
ISO 800:F16.0--> F5.6 1/4 compare to F22 below...
ISO 800:F22.0--> F5.6 1/2 (yep, fired these six times each to be sure.) WTF?!?!

ISO 1600:F8.0 --> 2.0 3/4
ISO 1600:F16.0--> 4.0 1/2
ISO 1600:F22.0--> 5.6 1/4

If the flash does internal calculations for PTTL anything like it does in A mode, I have little wonder about its behavior.

I did not have any reflections, but may give that a try. I'm just out of time to play tonight and thought I'd post my findings to see if anyone else finds them interesting and/or to see if they get consistent behavior.

Not much to add, but...
From what I've got from Pentax when asking about PTTL behavior, the pre-flash metering is in matrix mode.

Some of my initial confusion was that I wanted spot metering but there was no effect on flash output. As a bright object broke a certain percentage of the frame, all went to hell. Which certainly makes more sense when you know the intended behavior.

What might be interesting to add to the data is a light/flash meter reading of how much flash power was being pumped out on each frame.
I think it is quite apparent that the flash is not working as expected in all cases, but it adds another data point on what is going on.

Now that I have a light meter I may try to re-run the PTTL tests I ran last year... probably won't get time until this weekend or so.
It is just nice to see others are getting similar findings.

Sounds very interesting.
I have yet to get good results from PTTL but haven't the time, and quite honestly I probably don't have enough knowledge to go through what appears as a pretty intense set of tests that you've done to figure out exactly why the results are so "inconsistent".

The historgrams on the web page loaded quickly, but none of the images loaded. I guess I'll download the ZIP and look at it later.

Well, Cactus V2s are safe for DSLR.

As I understand, there is confusion on other triggers by Gadget Infinity whether they work with Pentax flashes, although I could not figure out why they may not work. The paragraph above is one of the more intelligible ones I've seen -- I've been looking to compare brands for some time and went with Cactus V2s because it is the only one I found that comes up repeatably as successfully/safely working with Pentax DSLR and flashes.


Anyway, the Cactus V2s is a safe way to go. But read up on the issues and see if the low cost is worth the potential troubles.

Relatively low working distance.
Potentially inconsistent/unreliable triggering of flash.
Potentially low flash sync speed.

So far for $35, I am happy. Will see today as I'll do some real life testing.
The mods are quick and easy so I may try that to increase range and sync speed.
For my use I only need one receiver. The rest of the flashes will work off flash sync. Obviously for obscured locations, and outdoors you may need multiple receivers.

The Cactus will connect to the camera via hot shoe or via PC cable.
The receiver will connect to flash via either hot shoe or cable (not a PC connector on the transmitter). It includes a short cable to connect from the receiver to the mono block or other flash. (You could probably even connect a flash to each - hot shoe and PC cable - and control two flashes this way with each receiver. Don't know if that might overload th circuitry but I've seen other brands advertised with that capability. )


In short - go with Gadget Infinity (a.k.a. Harvest One Limited) remote named "Cactus V2s".

I would have to agree, the camera probably uses a less sophisticated algorithm, but those things are getting pretty quick so I can't say for sure.

The benefit of processing on your computer is that YOU get to choose how your image looks before it is converted to lossy JPEG.
If you need to adjust the white balance for instance, you will get much better results using a RAW converter on your computer than trying to adjust the 8 bit JPEG generated by the camera.

Now, plenty of people just like the results of JPEG out of the camera or their skills are high and they do not need to make many adjustments. So shooting JPEG is fine.

I'm not going to add to any debate on RAW v.s. JPEG, there are simple facts about each, but as to which is "better"... to each his own.