AF540FGZ in TTL mode

Nick SD · 11-05-2009, 06:52 PM

Hello all,

I reciently got the AF540 flash for my K200D. Im new to flash and bought a Gary Fong lightsphere Cloud diffuser. It suggests you put your flash into TTL mode for a proper flash exposure however when trying to follow the AF540 manual, its near impossible to figure it out. It asks you to change from PTTL to TTL by pushing the mode button however when I do so it doesn't change. Im getting a bit frustrated over it. I dont know who wrote that manual but they need to get a new job.

Can anyone give me some direction?

Thanks

*SOldBear* · 11-05-2009, 07:07 PM

K200D (and all Pentax DSLRs after the ist* series) does not support TTL mode. The flash detects that and thus does not change to TTL.

Leave the flash in p-TTL mode.

I agree that the 540 manual leaves much for to desire. But in this case, Gary Fong, not Pentax, needs to change the instructions.

*Ash* · 11-05-2009, 07:09 PM

Just keep in P-TTL mode. This is effectively the TTL metering for flashes on Pentax's new dSLRs.

Nick SD · 11-05-2009, 07:58 PM

I noticed that when I attach my 50mm f1.7 M series manual lens, it automatically changes to TTL on the flash. I had assumed that it supported TTL when it changes to TTL for manual lenses.

Thanks for the reply's guys

*Ash* · 11-05-2009, 08:08 PM

AFAIK, P-TTL won't work for M lenses, given the camera cannot communicate with the lens to calculate flash light intensity. So it will always fire at full power.

*Canada_Rockies* · 11-05-2009, 10:45 PM

Originally Posted by Ash

AFAIK, P-TTL won't work for M lenses, given the camera cannot communicate with the lens to calculate flash light intensity. So it will always fire at full power.

True. p-ttl will only work with a lens with the aperture set to the A position. It needs matrix metering.

mazdamazda · 11-09-2009, 09:15 PM

For M lens, use the A-mode of the 540FGZ (where you input the aperture, iso, etc.)... works pretty well.