I have an M6TTL and the SF20 flash. I would like to understand when it makes sense to use exposure compensation with a TTL camera.

-- David Enzel (dhenzel@vei.net), April 21, 2001

Answers

Two scenarios: First, like any non-evaluative-type AE system (Leicanuts who won't hear of an AE Leica seem not to mind the M6TTL but TTL flash is AE)it is calibrated to 18% reflectance (average subject tonality) and needs compensation if the subject tonality is different...(+) for brighter subjects and (-) for darker subjects. That seems at odds but that's how it works. The TTL sensor tries to make every subject medium-tone, so it underexposes bright ones (therefore you need to add + flash)and overeposes dark ones (need - flash). Second case is where you want the flash to play a more or less prominent role vs the background (ambient) light. One example is so-called daylight fill flash ("synchro-sunlight" we used to call it)where you want just the shadows eliminated but without the obvious look that flash has been used. So, you tell the flash to back off, by setting (-) compensation; typically -1/7EV, more or less to taste.

-- Jay (infinitydt@aol.com), April 21, 2001.

You have to test all your different films as the flash exposure reading is taken off the film base. Different films have different colours of film base and this affects how the TTL flash operates. I commonly use the old standby of having both ambeint and flash at -1.0 stop. Experiment as Jay suggests until you get the look you like.

Cheers,

-- John Collier (jbcollier@home.com), April 21, 2001.

Is it that easy to do outdoor fill-flash with the SF20?

Jack

-- Jack Belen (jbelen@aol.com), April 22, 2001.