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ETTL II flash and N mount conversion

 
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erichard



Joined: 11 Feb 2009
Posts: 12

PostPosted: Sat May 23, 2009 5:41 am    Post subject: ETTL II flash and N mount conversion Reply with quote

Bo-Ming, I used my 17-35 with great success over the previous month or two, but I did have one occasion where I couldn't figure out what was going on. I was using it with the 5DII at night with the 580EXII flash in aperture preferred mode and ETTL on the flash. I kept getting underexposed images until I bumped up the FEC on the flash by 1.5-2 stops. After that it was OK.

Now I know there have been some issues like this on the 5DII and the EX flashes, but I was reading tonight where most chipped adapters for the alt lenses have trouble with ETTL functioning properly. It was mentioned in a Tago programmable chip ad on eBay ( http://tinyurl.com/qwduul ), and the quote was:
"All about E-TTL flash Enabled

As many manual lens users are awared, E-TTL does not function properly with ordinary adapter. With this proprietary Europe made chip module on the adapter, your E-TTL flash gives you the correct exposure everytime, regardless of aperture setting of your lens, be it f1.8 or f32.
"

I didn't have the problem with other Canon lenses later, but at the time I didn't think hard about it being lens related (ie. the 17-35 in particular). Anyhow, I can't test it now because I sent it in to you (should be there by now, but not in the queue report). It's probably not an issue, but if it is, hopefully it would be rectified in the new firmware, as ETTL is very important. Probably nothing, but thought I'd mention it.

Regards, Richard
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conurus
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Joined: 15 Aug 2006
Posts: 795
Location: Vancouver, Canada

PostPosted: Sat May 23, 2009 6:40 am    Post subject: Reply with quote

Hi Richard,

Thank you for your problem report. As you mention it, I found myself also dialing in a FEC of +1 most of the time, and sometimes all the way up to +2, although our reference flash is a Metz 54 MZ-3. (Someone watching me shooting chuckled at me using German-branded stuff for everything except the camera body, although I am sometimes seen with a Sunpak high voltage pack, too.)

I didn't pay too much attention to the "underexposure", and thought I may have a scene with very high reflectance which would fool the meter (both flash and ambient alike). It is hard to know for sure without some grey-card type testing, but I will try to think of a test which proves one way or another.

Bo-Ming

_________________
I am a bird and I uncovered the E, EF and N-mount communication protocols!
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erichard



Joined: 11 Feb 2009
Posts: 12

PostPosted: Sun May 31, 2009 4:51 pm    Post subject: ETTL II flash and N mount conversion, testing Reply with quote

Bo-Ming,

For your test, of course try to avoid items with high reflectance, but most importantly, try to use a comparable Canons lens as a control. If the wide angle Canon has relatively good exposure and the 17-35 looks dark with no other variables different, then something needs to be addressed in the firmware, etc. My hunch is that you will see a significant difference between the Canon and Contax when set to ETTL, aperture preferred (perhaps other modes as well), where the flash is the dominant light source (ie. subject/background is fairly dark to start with). I realize aperture preferred mode tends to work in the "fill flash" mode, but if a Canon lens is used as a control, it should not matter (just use a similar focal length.) Using the manual mode on the camera would be useful information, as well, as many/most pro's use the manual mode when not desiring simply fill flash (but still try ETTL on the flash mode in the test.)

I wish I had thought of this and tested it before I sent the lens in. Anyhow, good luck in reviewing this issue.

Regards, Richard
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huhging



Joined: 24 Jan 2008
Posts: 43
Location: New York

PostPosted: Sat Jul 02, 2011 10:21 am    Post subject: Reply with quote

I'm just wondering if this issue has been updated....???
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conurus
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Joined: 15 Aug 2006
Posts: 795
Location: Vancouver, Canada

PostPosted: Sun Jul 03, 2011 12:04 am    Post subject: Reply with quote

Did you experience some issue with flash exposure? If so, please describe the problem you are experiencing.
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