on 9/16/02 7:09 AM, Roger D. Key at rdk@xxxxxxxxxx wrote:
>
> Same rubber lenshood as 50/1.8 etc.
>
> Regards/Mvh.,
> Roger Key
>
>
>
>
>> Is there a dedicated lens for the 35-70mm f3.5-4.5 lens? Does it fit any
> of the other Zuikos? Does anyone have one for sale of trade? I had the
> lens hood chart, >however have misplaced it during the painting project.
> Bill Barber
>
I've noticed that Olympus sometimes uses a hood for more than one focal
length... This means that at some focal lengths we aren't getting all the
shielding we should. New AF wunderzooms often come with the petal-shaped
'perfect' hoods, which supposedly come as close as possible to the
image-forming light rays without actually blocking them, at least at the
widest focal length. Olympus must know this because the hood for the
35-80/2.8 is such a design.
Rectangular hoods seem like they would be closer to ideal than round hoods,
if you imagine the image-forming light rays as a four-sided pyramid with the
tip inside the lens at the nodal point, then a four-sided hood should be
able to give better stray-light protection without vignetting. But for many
Olympus lenses, the hood is round (which has to be a compromise in the first
place) and then also covers the 35mm and 50mm focal lengths, which means it
must be less effective to the 50mm focal length than it could be... or it
would vignette at the 35mm focal length.
While I know in practice the effect is probably minimal, why didn't Olympus
make dedicated hoods for each focal length, and even better make them
rectangular hoods? With a zoom you're still stuck with shading the widest
focal length best, except that Olympus cleverly worked around that for the
35-70/3.6 hood... seems like they could have done more for the rest of the
lens hood range.
--
Jim Brokaw
OM-1's, -2's, -4's, (no -3's yet) and no OM-oney...
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