Flash slow synchro

[pehabe]

With my G3 I could use the flash (internal or external - 420EX) as a slow synchro mode, that is the camera will take the surrounding light and fill it a bit with flash.

How could I do it with 20D and 420EX?

Sorry I do search the forum for this topic but no luck. Maybe my search string didnt hit the right one.

Could someone help me?
Thanks

[robertwgross]

You might want to read the EOS Flash Sticky at the top of this forum, and then re-phrase your question.

---Bob Gross---

[PacAce]

With my G3 I could use the flash (internal or external - 420EX) as a slow synchro mode, that is the camera will take the surrounding light and fill it a bit with flash.

How could I do it with 20D and 420EX?

Sorry I do search the forum for this topic but no luck. Maybe my search string didnt hit the right one.

Could someone help me?
Thanks

Have you tried setting the 20D the same way as you would set the G3?

[pehabe]

yeah... sticky. thanks for the help.

In G3 there is a menu Slow Sync and the camera will set the speed and opening itself.
Reading from the sticky (very helpful) it seems there in no automatic or easy way to do it, am I wrong?

I thought I could some special features in 20D for this.

[Andy_T]

If I read that you have a 20D and would like to have slow sync with flash photos (which you don't have at the moment) ... maybe you've set custom function #3 to '1' ... then every flash photo in AV mode is set to 1/250.

I had the reverse problem, my 20D with Tamron 28-75/2.8 would always suggest ridiculously long shutter speeds (1/15 ... 1/50 at full zoom, even at 2.8 and using ISO 400-800) even with the built-in flash activated if I did not set this custom function ...
Obviously my 20D never heard about the 1/focal length rule of thumb ... or it just decided not to apply it, as it clearly does not have a thumb of its own :lol:

Best regards,
Andy

[pehabe]

last night i made some experiment with my 20D and 420X. The result confirms the sticky way (thanks bob ;))

In Tv no matter you set the speed, 20D sent command to 420EX to emit enough light to achieve good result. I noticed it from the power 420EX needed to flash. To my amaze when I compare the histogram they were almost identical (almost...). Then to achieve the same effect like my G3, I learned to use the FEC.

In Av it depends the CFn#3 though... I set it 1/60.

Or in full manual. sigh... Never stop learning.

Andy:
with G3 in slow sync, the camera usualy goes to slow speed to catch the ambient light and send small amount of light from the flash... I think this is the situation you have with your Tamron ;)