Help Needed: Flash Problem : Canon EOS 7D & 580 EX [Archive] - BirdPhotographers.net

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philperry

09-19-2010, 09:46 AM

James Prudente

09-19-2010, 12:39 PM

Go to Custom Function 1 and see how you have the flash set up. Auto, variable or 1/250 sec. That may be your problem.

Jim

philperry

09-19-2010, 03:33 PM

Many thanks for the comment James. I looked at the CF I settings (two bodies) and they were on Auto. I have changed them to a fixed 1/250th.

But that only appears to affect Av mode - and I was always using Tv mode. I will have to run a test to seem if the CF I function also affects Tv mode.

So there may still be a problem.

philperry

09-20-2010, 03:32 AM

James

I have just tried checking my EXIF data and notice that it does not seem to show whether the metering modes are Tv or Av. I had set up a custom setting that did use Av and I guess some of my flash photos were taken on that mode. But I am still sure that most would have been taken on Tv (shutter speed priority) (Memo to self: In future use Aperture priority for flash !).

I did manage to find one set of pictures that were all taken at 1/250th - so that is a relief. But a mostly the photos show a range of shutter speeds.

So still not absolutely sure what the whole problem was caused by.

Dave Blinder

09-21-2010, 01:56 PM

Not sure on how to resolve your metering problem, but I would use both the camera and flash in full manual mode if needed.

philperry

09-22-2010, 02:04 AM

Thanks Dave. If I had discovered the problem earlier in my trip I would have had to go manual. The problem is amending the settings as the subject distance changes - a bit hit and miss. And sometimes you only get one shot !

Chris Ober

09-22-2010, 06:57 AM

moving to the photography gear forum

Christopher C.M. Cooke

09-23-2010, 05:03 PM

I have had the same problem myself so I look forward to an answer. (any explanations should be simple enough for someone with an inability to understand Manuals problem) :)

Geraldo Hofmann

09-25-2010, 01:10 PM

As at night the flash will be the only light source you could use the camera on manual. Maybe you have CFN I-6 enabled (safety shift) ... in this case the camera will override the TV-setting of 1/250 and try to achieve a correct exposure using a much longer exposure time and an open apeture...

Hope you had a good time in Pantanal

Geraldo

Christopher C.M. Cooke

09-25-2010, 05:13 PM

Thanks Geraldo, I will try it.

philperry

09-26-2010, 03:56 AM

Geraldo

Thanks so much. That is the answer. I changed the CFN I-6 enabled (safety shift) setting to enabled after I went through Artie's 7D users guide. Unfortunately I did not realise the impact of this particular setting. For my night-time telephoto flash with spotlight (for focussing) work I need to have a fixed sync speed of 1/250th.

At least I know for the future.

Thanks again.

Geraldo Hofmann

09-26-2010, 04:03 AM

Phil,

Your welcome ... I will be out in a little Forest patch south of Sao Paulo at night all next week. When I return I tell you what I forgot to set back to 0 ... sometimes I hate this modern cameras with all their bells and whistles too many things to change... but then I love them for the same reason :-)

Good luck let me know when you come to Brazil again

Cheers Geraldo

philperry

09-26-2010, 04:28 AM

Thanks Geraldo. Had a great time in the Pantanal. Saw Puma and 5 Jaguars. Including mating pair of Jaguars at close distance in the open on a sandbank. Despite flash problems I just about managed to get some pics of them, though not up to my usual standard. C'est la vie.