[ivanvernon]

P-TTL standard settings on the AF-360FGZ works great on my K-3, but very poorly on the K-20, with huge under exposures, almost a black screen. Settings on the flash unit are exactly the same, and settings on the two cameras are the same--green mode.

Wondering if anyone has experienced this, or has any ideas I can explore. BTW, the lens being used is the Sigma 30 f 1.4.

[imtheguy]

P-TTL standard settings on the AF-360FGZ works great on my K-3, but very poorly on the K-20, with huge under exposures, almost a black screen. Settings on the flash unit are exactly the same, and settings on the two cameras are the same--green mode.

Wondering if anyone has experienced this, or has any ideas I can explore. BTW, the lens being used is the Sigma 30 f 1.4.

fwiw, I use the 360 occasionally on both those bodies and never noticed an exposure difference. However my usage could very well be quite different from yours as it typically for macro or a fill when shooting outside. Good luck tracking it down.


EDIT - reread you post and noticed the green mode. I have never used the flash in green mode.

[maxfield_photo]

Green mode is the problem. Essentially green mode is like Program mode but dumbed down a shade. In Program mode, the camera follows a certain set of behaviors for a given amount of light. Those behaviors may be different for each camera. Also the "weight" each camera gives to the flash exposure in the decision making process may be different. When you think about it, there are essentially four exposure variables you are dealing with: Aperture, ISO, Flash power, and to some degree shutter speed. In green mode, you are putting the camera in charge of all four variables and saying "ok, read my mind and decide which variables will give me the look I want to achieve". That just isn't going to work very often, cameras are some of the dumbest machines on the planet. They really can't think like a human, or make creative decisions. The camera is really best at solving just one of those variables. When you start allowing it to handle two or three (or four), mileage may vary, as they say.

I use manual mode on the camera, and manual flash, that way if something is over or under exposed, I can just make a change on either the flash or the camera to correct it, but my way may not work for the type of shot you are trying to capture. At least try switching to Program mode, but ideally, if you can't use manual for the particular shots that you want, try to take control of two of the variables using either TAv mode, or Av mode with a locked ISO.