Originally posted by SteveB The Sigma EF610 DG Super does the opposite on the K-30, it underexposes 1/2 stop in the straight ahead position and overexposes 1 stop in bounce mode, even tilted marginally as it happens as soon as the bounce icon appears on the Sigma LCD. There is less error though if I use a bounce card or diffuser. Exposures are very consistent though.
What that proves I'm not sure other than the K-30 needs a bit of firmware fixing for bounce flash, any make.
If there were a separate bounce flash EV compensation in the camera (if that's possible), we could all please ourselves with any flash.
SteveB, I don't think a bounce flash EV compensation in the camera would solve the problem. From the emails I have exchanged with Metz it seems that the camera tries to control the flash power based on the distance to subject. It does this whether in bounce mode or straight ahead. Normally this feature should turn off when you tilt the flash head into a bounce mode even for a small angle. The reason is that the distance between your lens and your subject will then have nothing to do with the distance between your bounce surface and your flash (it will be completely random based on how high/reflecting your ceiling is or how far/reflecting your wall is). Older cameras like the K-x don't suffer from this because the camera doesn't communicate any distance to the flash in any mode, bounce or not. The newer K-30 should normally turn off this distance communication feature as soon as it senses the bounce mode, but it does not, which results in random exposures, at least that's how I understood it. I agree with you that the K-30 needs a bit of firmware fixing, I just don't know what's the best way to bring that problem to Pentax's attention, especially that you and I are using non-Pentax flash brands. If I could get a confirmation from another member that he/she experiences this same problem with Pentax's own AF360 or AF540, then it would be a very strong case. Metz wrote back to me that this is not the kind of problem that they could address with an update to the flash firmware (which leaves the camera firmware update as the only potentially viable solution). Metz's more advanced flash (the 58 AF-2) can allegedly get around this problem as it has its own sensor and can work without P-TTL but I'm not ready to pay $400 for that yet.