Fellows, I have an odd piece of optics labeled "Bushnell Booster 2.5x32". It appears to be an objective bell housing designed to screw into the objective bell housing of a scope. (Sure would look odd!)

Questions:
1. Should the original objective be removed before this is installed?
2. From the label, I assume this is intended to increase the scope magnification by 2.5x. Is this correct?
3. From the lack of current production, I assume these weren't really very useful, or had drawbacks like reducing brightness. Is this correct?
4. Does anyone have any actual experience with one of these?

Thanks for any info.
kbmolly

Years ago (60's & 70's) you could buy these for single lens reflex cameras that was installed between the lens and camera body. As you surmised the 2.5x meant a two and half times boost on lens magnification thus turning a 100mm lens into 250mm. The down side was you also increased the largest f stop or in effect cut light transmission by a considerable amount dependant on maker, design etc. Since yours is 32 mm would seem likely it was used on something other than a camera since most of these were course thread screw ins or of a bayonet mount type. You wouldn't want to unscrew your objective as that would break the seal and loose you gas filling. I have one for a Nikon camera and used it some years ago. Believe I have some old Bushnell literature that had there product line listed from the early 70's but would have to dig for it.

...The down side was you also ... cut light transmission by a considerable amount ... You wouldn't want to unscrew your objective as that would break the seal and loose your gas filling. I have one for a Nikon camera and used it some years ago. Believe I have some old Bushnell literature that had there product line listed from the early 70's but would have to dig for it.

Thanks, Hailstone, that's pretty much what I figured: Reduced light / brightness. Wasn't too sure about the objective removal, as I think a lot of older scopes didn't even have dry gas filling back then. But of course I knew what would happen with today's scopes.

Any input on what effect it might have on focus and parallax? I've got an old(er) scope I've been thinking about putting on a .22 ...

Molly

i HAVE ONE AND YOU SCREW IT on the scope as is.at the time there were not many high power scopes also the price was right.you have to have a scope that has the right dia.a 4 power would then be 10 X .