Talking about Canon flash, it is the poorest flash system I have ever used,
even the old Olympus T-flashes are better (I once tested my T32 in TTL mode
was around +/- 0.3 stops from 3 to 15 feet). The most reliable flash I have
ever used was the FL50 in auto mode, in TTL mode it suffered from under
exposure with strong reflection objects (mirror.. etc.) inside the frame. My
Canon 430EX is consistently 2/3 to 1 1/3 stop under in TTL mode, may be I
have used non original Canon lenses but they are both latest design from
Tamron (17-50 and 70-300 LD Macro 1:2) and there is no excuse for such big
error. The 430EX also has no auto mode and only provide 1/2, 1/4... half
stop manual mode, compared with FL36 it is highly overpriced.
C.H.Ling
----- Original Message -----
From: "Chuck Norcutt" <chucknorcutt@xxxxxxxxxxxxxxxx>
>
> Canon and Nikon also use distance data. Nikon has apparently used it
> for a long time and Canon more recently with its E-TTL II which also
> requires specific lenses with distance encoders. As to why distance
> alone is not the sole exposure determinant I point you to this excellent
> article on Canon flash and the logic (or illogic) behind it. See the
> sections on E-TTL and E-TTL II near the middle of the page.
> <http://photonotes.org/articles/eos-flash/index.html>
>
> I guess I would be very surprised if E lenses do not also provide
> distance data to the camera for flash power computation.
>
> Dr. Flash
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