1D-MARKII and 550EX

[Photorob]

I am trying to understand the different settings with Mark II and 550ex. When I have the camera set to the P mode and flash set to ETTL mode I get great pictures and acceptable shutter speeds. I have tried to understand the manual with the flash but it suggests that I can set Av setting with camera and set to ETTL mode to select aperature value. When I do this I get very long shutter speeds even with the aperature set wide open. I have to set Iso to 400 and still need tripod due to very long shutter speeds. I do not understand why the exposure would be any different for the two settings. I am sure there is a obvious and simple answer but would appreciate any help.The manual with the flash is somewhat hard to understand.

[robertwgross]

The manual with the flash is somewhat hard to understand.

Join the crowd.

---Bob Gross---

[scottbergerphoto]

I am trying to understand the different settings with Mark II and 550ex. When I have the camera set to the P mode and flash set to ETTL mode I get great pictures and acceptable shutter speeds. I have tried to understand the manual with the flash but it suggests that I can set Av setting with camera and set to ETTL mode to select aperature value. When I do this I get very long shutter speeds even with the aperature set wide open. I have to set Iso to 400 and still need tripod due to very long shutter speeds. I do not understand why the exposure would be any different for the two settings. I am sure there is a obvious and simple answer but would appreciate any help.The manual with the flash is somewhat hard to understand.
Program mode tries to expose for ambient light but has a low shutter speed limit of 1/60. The other modes have no such lower limit. Don't look for this in the flash manual, it's not there. It's a feature common to Canon digital cameras. If you are in a dark room you will get long exposure times in M, Tv, Av. In addition Av and Tv on the Mark II are "fill flash" modes that reduce flash output to match ambient light. M mode has no such automatic fill flash reduction. The most consistent flash results on the Mark II are obtained using M mode on the camera and ETTL on the flash. Flash exposure is not affected by the shutter speed as long as you stay below the max sync speed. You can expose for the ambient light as accurately as you want by adjusting the shutter speed and aperture.
Regards,
Scott

[Photorob]

Thanks once again Scott for helping me when the manual does not spill out the answers. You have helped me numerous times and are a real asset to this forum.

[scottbergerphoto]

My pleasure.
Scott

[CyberDyneSystems]

Would this be of help?

http://www.cps.canon-europe.com/articles/article.jsp?articleId=6202&pageId=1

Haven't read it myself,.. don't have a flash yet :mrgreen: :?

[scottbergerphoto]

Would this be of help?

http://www.cps.canon-europe.com/articles/article.jsp?articleId=6202&pageId=1

Haven't read it myself,.. don't have a flash yet :mrgreen: :?
CDS, that article is a description of ETTL. It doesn't describe ETTL II found on the Mark II. The sections relating to active AF point and flash metering and MF vs. AF in relation to flash metering are not applicable to ETTLII. It also doesn't mention the fact that when a flash is turned on in the hot shoe, the Program mode has a floor of 1/60.
Regards,
Scott