Help Needed: Flash Problem : Canon EOS 7D & 580 EX

<link rel="File-List" href="file://localhost/Users/user/Library/Caches/TemporaryItems/msoclip/0/clip_filelist.xml"> <!--[if gte mso 9]><xml> <o:DocumentProperties> <o:Template>Normal.dotm</o:Template> <o:Revision>0</o:Revision> <o:TotalTime>0</o:TotalTime> <o:Pages>1</o:Pages> <o:Words>231</o:Words> <o:Characters>1321</o:Characters> <o:Company>Leites Toyota</o:Company> <o:Lines>11</o:Lines> <o:Paragraphs>2</o:Paragraphs> <o:CharactersWithSpaces>1622</o:CharactersWithSpaces> <o:Version>12.0</o:Version> </o:DocumentProperties> <o:OfficeDocumentSettings> <o:AllowPNG/> </o:OfficeDocumentSettings> </xml><![endif]--><!--[if gte mso 9]><xml> <w:WordDocument> <w:Zoom>0</w:Zoom> <w:TrackMoves>false</w:TrackMoves> <w:TrackFormatting/> <w:PunctuationKerning/> <w:DrawingGridHorizontalSpacing>18 pt</w:DrawingGridHorizontalSpacing> <w:DrawingGridVerticalSpacing>18 pt</w:DrawingGridVerticalSpacing> <w:DisplayHorizontalDrawingGridEvery>0</w:DisplayHorizontalDrawingGridEvery> <w:DisplayVerticalDrawingGridEvery>0</w:DisplayVerticalDrawingGridEvery> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:DontGrowAutofit/> <w:DontAutofitConstrainedTables/> <w:DontVertAlignInTxbx/> </w:Compatibility> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="276"> </w:LatentStyles> </xml><![endif]--> <style> <!-- /* Font Definitions */ @font-face {font-family:Cambria; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:auto; mso-font-pitch:variable; mso-font-signature:3 0 0 0 1 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Cambria; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style> <!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} </style> <![endif]--> <!--StartFragment--> Help desperately needed. I have just returned from a once-in-a-lifetime trip to Brazil’s Pantanal. While there I experienced some flash problems. I am sure that I have done something really stupid and will kick myself. But for the moment I cannot work out what the problem is.

I have not deliberately changed anything to the way I normally use my telephoto flash for night-time photography. But somehow things have gone wrong.

I am using a Canon EOS 7D with a 580 EX flashgun and a Better Beamer – for night-time photography using a spotlight to focus. As far as I can tell from the manuals the 7D and 580 EX are supposed to be compatible for ETTL shooting.

For as long as I can remember the flash synchronization speed has always been 1/250^th second. However on this trip I have been getting shutter speeds of anywhere between 1/10^th second and 2 seconds. I have had to use much higher ISO ratings than I have ever used before – up to 6400 – despite modest subject distances. As a result a lot of my pictures have blur due to two images being recorded – one from the flashgun and one from the spotlight.

My settings were :

Canon EOS 7D Settings : e.g. Tv (or C1, C2, C3); 1/250^th ; Flash Control Enabled ; 1^st Curtain sync

580 EX Settings : ETTL ; Manual Zoom at 50mm ; Better Beamer

If I do a test using manual metering – then lo and behold I get 1/250^th shutter speed. But any of the TTL systems give me a weird range of shutter speeds.

I did not even realize you could change the default 1/250^th setting – and no I did not accidentally set 2^nd curtain sync.

Any ideas anyone ?<o></o>
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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

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.

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.

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

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 !

moving to the photography gear forum

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) :)

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

Thanks Geraldo, I will try it.

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.

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

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.