> Date: Mon, 1 Jan 2001 12:46:09 -0800
> From: "Kim" <[EMAIL PROTECTED]>
> Subject: Re: EOS 1.4 Tele's and 100-400 IS
>
> From: "Allen, Bob" <[EMAIL PROTECTED]>
>
> > The solution? EOS-1v. Just call B&H (800 - 606 - 6969) with credit card
> in
> > hand and Henry Posner's salespeople will be glad to send you one!
>
> I'm sure they would, but there are a couple problems with that solution:
>
> 1. I got the misleading info from the B & H site--quote:
> "Extender EF 1.4x is for exclusive use with EF: 70-200 f/4L, 70-200m
> f/2.8L,
> 100-400 f/4.5-5.6L IS, 135mm f/2.0L, 180mm f/3.5L Macro, 200mm f/1.8L,
> 200mm
> f/2.8L, 300mm f/2.8L, 300mm f/2.8L IS, 300mm f/4/L, 300mm f/4/L IS, 400mm
> f/2.8L, 400mm f/2.8L IS, 400mm f/5.6L, 500mm f/4.5L, 500mm f/4.0L IS,
> 600mm
> f/4L, and 600mm f/4L IS (Manual Focus only when Extender EF 1.4x is used
> with EF 400mm f/5.6L or 500mm f/4.5L, or when Extender EF 2x is used with
> EF
> 300mm f/4L/IS, 400mm f/5.6L, 500mm f/4.5L/IS and 600mm f/4L/ IS). "
>
> No mention that manual focus is required with the 100-400 IS...why?
>
> 2. I avoid B & H after having been charged without notice for an
> out-of-stock item. When I became aware of the charge and questioned it, B
> &
> H had no idea when the item might be available. (The charge was removed.)
>
> And lastly, unfortunately I don't own the 100-400 :( However, if Henry
> would
> like to send me one as a gesture of goodwill I'd be willing to match the
> value for the 1v :)
>
> Kim
>
Hi Kim.
I am pretty certain that the text you quote from B&H is outdated but was
correct prior to release of the EOS-1v. They probably copied the text from
Canon USA's website which is pitifully out of date and poorly done (and that
is a gross understatement).
Manual focus is required when using 100-400IS and 1.4x tele with my EOS A2
but autofocus works fine with my EOS-1v. Why?
(A) Because the A2 (and many other bodies) can autofocus only when wide-open
aperture is f5.6 or wider (not during exposure, but during pre-exposure
focusing). It works fine with the lens itself, but when adding the 1.4x
tele, the wide-open aperture at 400mm becomes f8, too dim for autofocusing.
(B) The 1v can autofocus when wide-open aperture is f8 or below. Again, the
lens itself works fine from f4.5 to f5.6 (100mm to 400mm). Addting the 1.4x
tele works fine at shorter lengths and at the longest length of 400mm,
becomes f8, at which the 1v can autofocus.
To prove to myself that I got it right, I just performed a highly scientific
test with my EOS-1v, 100-400IS lens, and 1.4x tele. Both with and without
the 1.4x, it autofocused and IS'd just fine while focusing on a bag of
dogfood (brand and size available upon request). Autofocus was noticeably
slower when 1.4x tele was used but this may have been due to low light level
in my kitchen (it's nighttime here) and my dog biting my bare toes during
the experiment.
Gotta run - I think it's time to feed the dog now...
-Bob
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