Here is a shot I took today of the sun through a Meade ETX-70AT with a Seymour Solar Filter mounted for protection. The Meade telescope has a focal length of a 350mm f/4.0 lens. I used a GH-2 and cropped the picture. The sun with a number of sunspots visible {} Same picture as above except converted to B&W {} A shot of the solar filter {}
I have a similar filter and have used my solid catadioptric lens on a Meade GoTo mount, but what I'd really love is a Hydrogen Alpha filter, then you could get some amazing shots of the sun. Unfortunately, those filters are hideously expensive. E-5 on GoTo mount and Autostar controller: {} Sunspots: {} Mock Hydrogen Alpha filter (playing around with software): {}
This was shot at ISO 160 and underexposed by two stops. I also took another shot where the exposure was correct but in Lightroom I had to turn down the exposure by about 2.5 stops in order to get it to the point of being able to see the sunspots.
Mine varied between ISO100-1000, 1/3-1/25 sec. The shot shown here was taken at ISO640, 1/50 sec and f5.6, so I must have used the 90-250mm with 2x extender (it comes up as a 500mm lens).
Another one from yesterday but I used eyepiece projection this time instead. This used the burst mode in the GH-2 to get about 30 frames and combined them using RegiStax. {}