Quick lens hood advice anyone?

On Mon, 27 Aug 2007 12:20:03 +0900, David J. Littleboy wrote:

>>> A single lens hood may work with both lenses,
>>> but only well at a subset of the focal length ranges.
>
> The idea that a single lenshood is adequate for the standard zoom in
> question is itself fairly nuts. It's a 28-135mm equivalent. Better than
> nothing, but not much.
>
> This probably isn't quite as much of a problem on the 70-300. Maybe.

A fair solution would be to design the lens and matching hood so
that when the lens is zoomed, the lens hood is also moved to the
position that would block as much light as possible short of causing
vignetting. It can't be very hard to design, especially since great
accuracy isn't needed, and even speedlights have zoomed to match the
lens's viewing angle for decades. The front lens element could also
be moved, but that might complicate the lens design too much. I
don't see the world clamoring for such a feature, but if this
feature is added to one of their $4000+ pro lenses, it might gain
fame as Canon's "what the L?" lens.

If any lenses already do this it wouldn't surprise me too much,
but I haven't heard of any that do . . .

ASAAR <caught.DeleteThis@22.com> wrote:
> On Sun, 26 Aug 2007 05:14:30 GMT, Matt Ion wrote:

>>>> Is there a single lens hood that I can buy that will work well with both?
>>>> In either case, what would you recommend I buy?
>>>
>>> Look at the ends of the lenses. Are they the same size?
>>> No. That means one lens hood would not fit both.
>>
>> Depends on the lenses. My older EF 75-300 fits the same 58mm filters
>> and lens hood as my 300D's 18-55 kit lens.

> That they fit does not indicate that they'll work well. If you
> put a lens hood designed for the EF 75-300 on the 18-55mm lens and a
> hood designed for the 18-55mm lens on the EF 75-300, I'd imagine
> that one would provide no benefit and the other would cause severe
> vignetting, if not outright blockage. If the lens hood's thread is
> too large, a step-up adapter will allow it to be used. But whether
> it fits or not, the lens hood still has to accommodate the viewing
> angle of the lens, and that's unlikely to be the case with such
> dissimilar lenses. A single lens hood may work with both lenses,
> but only well at a subset of the focal length ranges.

Unless of course it's a collapsible or telescopic lens hood, such as
the three stage rubber lens hoods you can get which range from medium
wide to medium telephoto. They're also quite good at buffering knocks
to the end of the lens

--
Chris Malcolm cam.DeleteThis@infirmatics.ed.ac.uk DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
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