TTL ETTL ?

[fredlef]

I feel like I am studying hard to try and understand lighting - and making good progress but it's the little things that I'm stumbling over. This one for example. Sometimes my 580EX II comes on as ETTL and sometimes as TTL. I know I get the results I'm looking for when in ETTL but I have to "fiddle" with it to get it to move from TTL to ETTL. What causes the difference between the two and how do you force the change? It's not the CFN 5 setting - I know that.

Thanks

[msowsun]

You are having connection problems with your hotshoe. When you lose contact, it reverts to TTL which is for film only. Because there is no film plane to read the exposure, the flash will always fire at full power and usually overexpose the scene.

There have been numerous reports of the 580EX II having this problem. Probably because of the new metal hotshoe and locking system.

Check out these links for some ideas:

http://shimworld.wordpress.com/2008/02/28/speedlite-580ex-ii-hotshoe-fix/

http://www.conraderb.com/flashrepair/

[fredlef]

Thanks - after reading those two articles it makes sense as before I noticed the TTL/ETTL issue I noticed that I was blowing out my flases. Once back in ETTL everything was normal so looks like it was stuck on full power. Fortunately they were all test shots. So far it wont go back into TTL but I'm keeping these articles handy for when it does.