EXIF data and SIGMA 70-200mm lens

[WyzMan]

Hello,
I have a 10D and a new SIGMA EX f2.8 APO 70-200mm lens.
When I check out the EXIF data, after shooting at the full 200mm zoom, using either Photoshop or the CANON Fileviewer utility - I get a focal length of 456.0mm shown.
Is this common?
The lens data is reported correctly as 70.0 - 200.0mm, all other EXIF data looks OK as far as I can tell. (Aperture, speed, ISO ...)
When shooting at the shortest focal length, the EXIF data reads correctly - 70.0mm.
Can anyone confirm that their lens does the same or is it just me? (Or I am making some obvious mistakes here?).
Alan

[WyzMan]

Sorry - one last point...
When I look at the EXIF data in the CANON utility, some pictures show the full story, a few miss out things like focal length and other stuff - this happens with lenses other than my SIGMA EX.

[mattchase]

I also have this lens, and haven't noticed that it reports incorrect focal lengths in the EXIF info. I have noticed that it doesn't show all the values that some Canon lenses do, but that is normal. Different lenses send different specs to the camera, some sending more than others.

[JABACo]

I haven't noticed anything of this sort with my Sigma. The only problem I have with the Sigma is when I use the 2x extender. At 200mm (400mm), it has problems with focusing correctly.

Happy New Year

Bradley

[WyzMan]

Ha ha! I'm not the only one. Did some googling around and found that other folk are experiencing the same sort of problem.

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=006uXJ

Thing is - can this be fixed or is there some firmware inside the lens which would need changing?

If have found that at around 140mm focal length, all reports as it should. Above 140mm or so, I get silly data, below 140mm, all is fine and dandy.

[hickory]

I just checked some of my shots with my Sigma 70-200 and my exif is correct. I'll be interested to see what you learn about this anomaly.......

[CyberDyneSystems]

That is odd,. my exif all seems correct as well..
I run into exif problems with t-cons installed,. sometimes that will throw off the exif. (especially of you 'tape pins" )