Flash use with Pentax 645

I bought a Pentax 645 (non-N) and separately bought a Pentax AF240FT flash under the assumption I could use it in TTL mode with the camera (I understand it's a newer flash unit but a post on another forum suggested they are compatible for TTL). I've read both manuals for the camera and flash but I am not sure if something is wrong or not. When I set the camera to Auto P mode, and set the flash to TTL Auto mode, I assume that the camera should automatically switch to 1/60s sync speed. But when I look at the shutter speed in the viewfinder, it seems to be moving all around depending where the camera is pointing suggesting that it doesn't detect the flash. There is also no flash indicator icon on the LCD like there should be according to the manual.

If the flash is compatible, working correctly and your lens is set to A then yes, it should switch to 1/60th of a second speed. But the AF240FT was designed originally for the SFX/SF-1 35mm film camera. While it's shown as compatible in the Pentax 645n manual, it may not be compatible with the "vanilla" Pentax 645.

Mike Butkus has a manual for the 645 http://www.butkus.org/chinon/pentax/pentax_645/pentax_645.htm Print it off, and send Mike a few dollars to keep up his valuable work.

Does the 645 have an X mode? That's what I used on my N and NII for flash photography.

Try and find the AF280T flash. It is quite old by now, so it can be found at a very low price, but it is still a great flash with tilt and swivel, two auto modes and TTL compatible with all 645 film cameras. It can also be used on modern Pentax DSLRs in auto mode (not P-TTL and TTL only on *istD and *istDS).

More info here: http://www.pentaxforums.com/accessoryreviews/pentax-af-280t.html

The AF280T is a nice unit. Now, if you want paint blistering power, look for the Pentax AF400T. This is a professional potato masher, tilt, swivel, etc. Look for the tripod socket bracket and, unless you have shares in a AA cell manufacturer, the auxiliary C cell powered power supply. I have one and used it a lot with my LX. Wonderful combination! There is/was a bracket designed for the 645 and the 645n, but I've never seen one for sale.

With an old flash which hasn't been used for a while the capacitors may need "reforming." "All" you have to do is load in cells - or if you have an AC adaptor that'd be better - turn the flash on and wait...and wait... Generally the flash will finally indicate "charged" and all is well. It might use a lot of cells.....