Focal reducers in H-alpha MOD photography

[solarmax2016]

Recently I tried again to use a 0.5X focal reducer in front of my DMK41AUQ camera for H-alpha photography. Because Modded optics (with PST or
LUNT Mods) capture such a small angle of detail it would be nice if you could enlarge the field by at least a factor of 2X with a 0.5 focal reducer. I had
no luck at all at first, as the DMK camera would not come to focus with the 0.5 reducer on it, but subsequently I cut the nose of the DMK shorter to
about 1/2" long and the camera would focus nicely but had a sweet spot in the centre of the field with nothing but a white-out all around it. The contrast
was very high, and the video unusable with such a blazing hot-spot. It seems that the snout on the camera may have to be an EXACT length in order to
yield a proper full field at 0.5X. Has anyone had any experience with focal reducers in front of DMK cameras? - especially in H-alpha where the hot spot
becomes a critical issue?

John

[MapleRidge]

Hi John...

I have used compressors, but usually have to crop off the saturated edges like you found, or other artifacts that appear.

It gives a wider FOV, but not nearly as wide as you would like.

Brian

[Montana]

I've tried a reducer too and also get the white out round the edge, I didn't like it so cropped it out

Alexandra

[robert]

The MODs to PST and Lunt are usually to increase the focal length and decrease the FOV in order to get close up views and higher resolution, so why would you put a reducer in front after modifying? Why not just go back to the un-modded instrument for a wider view?
Roebrt