Hello, Allan,
I am calculating for my Canon S110 on my MM3 60ED.which has the SDLV2 eyepiece fitted. I am using the listed Nikon PS100 as a surrogate for the Canon as it has the same sensor size, similar zoom and mega pixels. I think that will be good enough for me.
I use aperture priority set at f5.9 because wider apertures tend to close down to that anyway, or it did on the MM50 ED.
The camera zoom range is 24mm - 120mm on 35 mm equivalent format. I have to set the rig to maximum zoom to save the camera lens from hitting the buffers (the eyepiece lens).
The camera has a stepped zoom ring and I can set it from 120 mm down to 100mm and 85mm without significant vignetting, but no further.
With the Scope eyepiece at 15x magnification and the zoom at 85mm the calculated focal length is 1,274mm and for 45x and at 120mm the calculated focal length is 5,400mm, so that is the range.
IMHO digiscoping is not a good choice, for me anyway, up to about 1,200mm focal length. I am using two bridge cameras, the Panasonic Lumix FZ150 with a maximum zoom length of 600mm; with two teleconverters it can reach 1,020 mm and 1,320 mm respectively. Image quality is very odd on both, but not towards the periphery in the latter case which I find not to be problem for birding. This camera has good performance shooting in RAW. Unfortunately the RAW performance in the Canon SX50HS is nowhere near as good, but it does have a maximum zoom of 1,200mm.
If I get a windfall, I may try to buy a used Opticron 32x eyepiece (40858) but opinions on fixed lenses over the SDLv2 do not give me confidence that the money would be well spent.
Thanks for your help