on 10/25/03 12:33 PM, Daniel Sepke at fred42@xxxxxxxxx wrote:
> Hi there All,
>
> Just got one of the wacky lenses. I was wondering if anyone in the group has
> used one and might have tips for exposure compensation. It is the screw on
> the front of your lens type with a variable aperture (has a system for
> working with 30-200mm focal lengths). It came up recently when any of the
> group fanged one.
>
> I undersatnd that you set the focal length and then this allows you to get a
> recommended aperture range. If that is the wrong way a correction would be
> appreciated.
>
> Aparently this type of lens was used to build HAL's eye.
>
> Dan.
Many of the 'screw-on-the-front' lens adapters don't require any exposure
compensation... in theory. For instance, the B-300 supposedly doesn't change
the exposure when used on the IS-3 (although it seems to change the exposure
slightly when used on an OM with, say, a 135/2.8 lens.)
However, if the Kenko fisheye adapter is used with a lens where the 'curved
image' leaves black corners or even creates a fully circular image in the
viewfinder, then that -will- affect exposure, as the camera meter is trying
to set the exposure based on a fully-imaged and fully-illuminated frame.
I suppose if you use the spot meter function (OM-2s, OM-3x, OM-4x for
instance) that would adjust for this factor, maybe...
I have one of these fisheye adapters, I'll have to check into it
sometime... it will yield a full-circle image when used with a 28mm lens.
If I could -ever- get my fungus-damaged 8/2.8 Zuiko fixed that would be
interesting to know...
--
Jim Brokaw
OM-'s of all sorts, and no OM-oney...
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