I'd echo that. Baader do a ND5 solar viewing film that's designed to be safe for direct viewing. They also do a weaker ND3.8 version for imaging. I have previously used the ND5 version with the 100-400L, with Sigma 2x teleconverter to help fill the frame some more. Ball park exposure was ISO800 1/1000s f/11. I think I could have got away with a shorter exposure and thus lower ISO too. It will show sunpots but otherwise you get a rather featureless image.
Baader Solar Film (ND5), 600D, 100-400L + Sigma 2x for 800mm, f/11 1/1000s ISO800.
For something a bit more interesting, if higher budget, look at H-alpha imaging. Simple filters are not good enough here, and the budget option is getting the Coronado Personal Solar Scope. However I had a bit of trouble initially getting a DSLR mounted to that, and in the end had to use eyepiece projection as opposed to prime focus. The Baader Hyperion eyepieces have an optional ring which lets you connect it to via a T-mount adapter to a DSLR. Note the H-alpha emissions are in a region of a standard DSLR where it isn't very sensitive. You can get more sensitivity with something like a 60Da or otherwise a regular one modified to alter the IR block response or remove it totally. Also note only the red sensors are significantly sensitive so don't expect high resolution without some serious processing tricks I haven't tried yet.
Canon 450D full spectrum modified. ISO100 1/50s. Coronado Personal Solar Scope (400mm f/10). Baader Hyperion 17mm eyepiece with T-adapter + 7.5mm extension to T-mount.
I know I need to work on my processing!
A further option is to look at Calcium K-line emissions. Again Baader do a filter kit, consisting of an eyepiece filter and a pack of their ND3.8 film. You need to add that to a regular scope though, and I think a cheap one would be ok. Maybe there's a way to bodge it to a lens. I'm currently debating going this route myself. This is way over the opposite end of the spectrum to above, where it is bordering between blue and near UV.
