Raynox and (real ?) infinity

rjlittlefield · Post by **rjlittlefield** » Wed May 29, 2019 2:17 pm

aidanmoore wrote:Thanks Rik...not a silly question in fact I have had the lens in a tube for so long that I forgot the model...yes it is a DCR-250!

Should I move this thread somewhere else?

No need to move the thread. It's fine where it is, and some of the discussion may be useful in the long term for other people anyway.

--Rik

aidanmoore · Post by **aidanmoore** » Thu May 30, 2019 4:12 pm

Thanks Rik,

Yes the lesson here is to double check your equipment model number before posting

rjlittlefield · Post by **rjlittlefield** » Thu May 30, 2019 6:55 pm

aidanmoore wrote:And I guess the 10X objective acting like a 6.5X (approximately) is due to the shorter (110mm) tube?

When the rear lens is focused at infinity, the magnification scales directly in proportion to the focal length of the rear lens.

So, if you're using an objective that gives 10X when used with a 200 mm tube lens, then it will give 6.25X when used with a 125 mm tube lens.

--Rik