I use digiscoping mostly for ring reading. For almost 9 years I use a Canon A590 attached to Zeiss Diascope 85. For long distance shootings, what is very often the case, I apply the 60x magnification of the Zeiss eye-piece and both the full optical and digital zoom of the A590. Picture quality then is not outstanding, but with some patience (100-1000 shots) I could safely crack some ring codes which without digiscoping would have been left unrevealed.
To improve image quality I'm looking for a better digicam, meaning a bigger sensor, equivalent focal length of ca. 140mm and a faster lens, some little vignetting doesn't matter.
I hesitate to go for the Canon S120 due to its maximum aperture of 5.7 at 120mm. Concerning the Canon G16 comes in play the often discussed problem of the retracting lens when zooming. Someone here has an idea how severe vignetting with the G16 (or G15 or G12) really is when using the 5x optical zoom on the Zeiss 85 (20-60x) ? Is there a better choice for long disctance digiscoping ?
Thank you for any advice.