Canon flash system behavior question.

Started 3 months ago | Discussions thread
ForumParentFirstPreviousNextNext unread
Flat view
Mr Jam
Regular MemberPosts: 268
Like?
Canon flash system behavior question.
3 months ago

I am new to Canon flash system and was wondering if this is its normal behavior. I have a 6D and 580EX II flash. It seems to me when in ETTL mode, the flash always wants to act as a fill flash. Is this correct?

Here are two scenarios:

In P and Av modes it seems to me the exposure is determined mainly based on available light, even when the scene gets very dark and shutter speed cannot be maintained above certain levels. For example shutter can be down to 1/4 seconds as if the camera doesn’t know there is a flash to light the scene. Why preflash in ETTL does not come into exposure calculations to maintain a higher speed?

If for example I set the camera in M mode, ISO 1600, aperture F4 and shutter to 125in a very dark scene.  With no flash the image is severely underexposed as expected. However when flash is turned on, I am expecting the preflash be included in calculations and flash be fired to maintain a reasonable exposure as the main light. I am finding out in this case flash exposure is underexposed around 2 stops, as if the ETTL tries to provide only a fill light to an absolutely dark scene.

Aside from FEC, is there a way to control the flash either as fill, or main light in ETTL mode?

Canon EOS 6D
If you believe there are incorrect tags, please send us this post using our feedback form.
ForumParentFirstPreviousNextNext unread
Flat view
ForumParentFirstPreviousNextNext unread
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow