[gosman]

Just received my 540 GZII flash from the special last week from BH Photo. It seems to be working OK but I'm getting a lot of underexposures inside the house. Of course I can up the flash intensity to fix, but I always though that P-TTL would produce perfect pictures!? Can you all share with me your settings such as X,P, Av program? What is your exposure meter set at: should I use the wide setting or spot setting? I'm using mostly ISO 100. Maybe I should up it to 200? Let me know if you have any suggestions.

[bdery]

I always though that P-TTL would produce perfect pictures!?

Perfect is a strong word...


AF540 with K-3 is a fantastic match in my experience. Much less underexposure than with the K20D.


However, PTTL is not magic. It will underexpose if there are strongly reflective surfaces in your field of view, if you try to bounce on a poor surface or a surface too far away. There are ways to fool the meter. Experiment a bit and try to mind where you're sending your light.

[Tanzer]

Can't speak to the K-3, but on the K-5, Program mode doesn't work so great with P-TTL, because the camera has no idea how big your room is or high your ceilings are, yet still has to pick ISO and aperture a priori. I find myself using mostly manual mode, which is not as hard as it sounds - you can just leave the flash in P-TTL mode, and let it take care of balancing the overall exposure.

[devorama]

Can you post some pictures with EXIF info so we can see the effect?

[gosman]

I notice the manual says in wireless mode to use M or B mode! I wasn't using this when I was using this flash as a slave. Maybe I should just keep it on manual all the time. I did notice that in manual mode and high speed setting I got excellent results outside. Nice balance with existing light.

[Tanzer]

Something's not adding up. Wireless optical P-TTL works fine without requiring M or B mode. It sounds like your slave mode is set to mode #2, which is the "dumb" slave mode. For P-TTL you should set that to #1, which is the "smart" (P-TTL) slave mode.

There is an EV compensation dial on the flash, is it set to +/- 0 compensation?

Also, when you say "high speed setting", I think this is by coincidence, as outdoors it is already bright, so the flash is just a fill, so you will have plenty of latitude in the flash exposure. (I'm assuming you were not referring to High-Speed Sync (HSS) mode, since that requires the flash to be in P-TTL mode.)

[gosman]

No I'm in #1slave. And yes I mean HSS. This way I can expose for the background at a faster shutter speed and low aperture setting. In order to get that beautiful Bokeh that everyone wants!

[Tanzer]

OK, then your P-TTL communication is working fine. And your outdoor shots are coming out as expected.

For indoors, when you say "Of course I can up the flash intensity," what exactly are you referring to? Are you currently limiting the flash output, like 1/4 power or something? As devorama said, maybe post a sample pic.

[bmw]

I always though that P-TTL would produce perfect pictures!?

Ah, you've been drinking the Koolaid. :-)

I only use P-TTL when doing indoor event shooting, flash on camera. I still have to chimp a lot and frequently adjust exposure comp.

For all other flash use I go fully manual and incident meter the light where possible. P-TTL is no smarter than the camera's meter and both are fooled by non-average scenes.

[awaldram]

Ah, you've been drinking the Koolaid. :-)

I only use P-TTL when doing indoor event shooting, flash on camera. I still have to chimp a lot and frequently adjust exposure comp.

For all other flash use I go fully manual and incident meter the light where possible. P-TTL is no smarter than the camera's meter and both are fooled by non-average scenes.

I find with 86,0000 reference points P-ttl is often better than my two eyes.

Give the camera half a chance by adjusting correctly and P-ttl will nail the shot
I'd say 99% of the time but truth be known out a 1500+ shots its 1:1.

But then I use the same logic I'd apply to Manual flash and use compensation where I think it will be needed, Using P-ttl to give me latitude that Manual would not allow.

---------- Post added 14-03-14 at 10:37 AM ----------

I notice the manual says in wireless mode to use M or B mode! I wasn't using this when I was using this flash as a slave. Maybe I should just keep it on manual all the time. I did notice that in manual mode and high speed setting I got excellent results outside. Nice balance with existing light.

Something is not right, I can't understand what your doing or what your trying to achieve.

Maybe post an image and explain how you set up the flash/s (channel configuration etc)

Are using wireless with popup as controller and 540 as main light source or 540 on camera etc etc.

[gosman]

As I use the flash more, I will post some pictures. But it seems like my expectations are too high for P-TTL. I can easily chimp shoot and adjust as I go. Seems like that is all you guys do anyway?

[Tanzer]

Well I think the question is a little broad. Going over the responses above, everyone has their own way of working with flash automation in general, which may not be a P-TTL limitation per se.

Flash automation has limitations regardless of which manufacturer's system you are using. I think it is worth learning and understanding those limitations on your system (in this case Pentax), because one does not always have time to shoot in a fully manual mode.

There are times to shoot full manual, but for all its limitations, personally I do not think it makes sense to give up on flash automation entirely.

Good luck!

[Pheo]

The biggest problem I have with PTTL is not knowing when the flash has fired full power and yet thats still not been enough light.

I'm also still experiencing that I get better photos with my K-01 + Metz 58AF1 than my K-3 - puncher images, better contrast, better exposure - no idea what is up with that. K-3 is much better than the K-30 which was unusable virtually.

This is for indoor event shooting, ballrooms, white ceiling, approx 10-15ft away.

[clackers]

but I always though that P-TTL would produce perfect pictures!?

Go manual for better predictability, Gosman.

[AquaDome]

P-TTL eliminates the need to chimp every shot after manually adjusting the flash. Instead, you will chimp every shot trying to get the meter to read the scene correctly.
Both scenarios should be experienced by every photographer. Its part of the learning process.