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Focal Reducer problem

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As a newcomer to imaging, I get confused easily. I have been taking images using a Canon 350DSLR at prime focus on my LX90 for a few weeks. I am both frustrated and pleased at the results. Getting sharp focus is SO HARD ! I recently got a flip mirror and all seemed simple. Then, getting ambitious, I splashed out on an f6.3 focal reducer - the idea being lower magnification and wider field. Seemed a reasonable idea to me. But, problem - I can't seem to reach focus with the focal reducer in place.

I seem to remember reading about this being a "back focus" issue. Can anyone enlighten me? Would the problem be solved with an extension tube? Sorry for the stupid questions - but but I need some guidance here. :insects1:

Confused of Glasgow

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Hi Confused!!

It's a killer isn't it! I have the same issue and mine's only a .5 reducer!

The back focus is the problem - which means that the focuser can't travel far enough DOWN for the light to come to focus. This is a problem with the newtonian design.

I have been playing with different optical configurations, but have not yet managed to find one that works... :lol:

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Yes, I have the flip mirror in situ. Order is as follows: Telescope back - f6.3 focal reducer screwed into rear cell of 'scope - flip mirror. No diagonal.

Can't get enough back focus to focue EP on flip mirror. As EP is parfocal with camera focal plane - can't get focus on camera.

Very frustrating. Read the Meade instructions carefully, and down at the bottom of these is a statement that some 'scopes may not be able to achieve focus with both a flip mirror and reducer in place - grrrrrrr.

Can't think of a way around this.


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