Proceed with EXTREME caution whenever you are pointing any camera or telescope at the sun. You can burn the coating of a lens, and you can INSTANTANEOUSLY destroy an eye. Lumicon, Coronado, Thousand Oaks all make a variety of direct viewing filters. Baader film works, but... it is thin and subject to pinholing, handle it gently (Jim Kendrick, at Kendrick Astro in Toronto can make custom Baader filters for you if needed in standard filter rings). Investigate projection imaging as an alternate means, particularly for eclipses. Spectacular images can be made, but there is spectacular danger too if you screw up. There are NO common everyday materials safe for direct solar view for photographic purposes - invest in the proper filters.
Metering is quite difficult with conventional film in the absence of in-camera metering - lots of bracketing required. One of the reasons why the quantum shift to digital for astrophotography. Most digicams that can be coupled to a telescope or used on a long lens can auto expose through an appropriate filter of the broad spectrum type. You might try using a conventional autometering 35mm to get you in the ball park, but to fill a 4x5 screen will take a long lens or projection techniques with a large reduction in intensity at the plane. I have a Minolta meter probe attachment for one of my meters - now you've got me thinking about direct ground glass reading in such a setup - hmmm
If you use a film like Baader over a telephoto lens, or any proper filter, make absolutely sure it can't slip while you are viewing. You can't remove your eye, or blink fast enough to escape damage to your eye when viewing the sun under magnification, if the filter slips.
35mm H-alpha (VERY expensive filters...) will require time exposures due the density of the filters. Programs like Registax along with a string of digital images can make excellent pictures through stacking - something that is technically possible with film, but very hard to do.
"Astrophotography for the Amateur", by Michael Covington (Cambridge University Press, ISBN 0-521-62740-0 2nd ed 1999 - he may have a 3rd in the works) will give you tons of info for film based astro and solar photography. He's a little behind on the digital, but then so is everybody. Digital astrophotography is presently known as "wallet science" (deep space=deep wallet...)
View through Thousand Oaks filter on an 90mm Meade ETX, 26mm obj, Nikon 950 digicam, slightly underexposed, minimal tweaking in photoshop. Very hazy June morning abt 7am. Transit of Venus. I think there a couple of sunspots in the haze shadows on the right limb, but unfortunately it was an extremely hot and humid morning and the sun was low in the sky.
Same setup, zoomed in, auto-exposure by camera, minimal tweaking in photoshop. 3rd contact of Venus, beginning of "tear-drop". Had hoped for a clearer day.
Baader film will give you a "white sun", Thousand Oaks are an orange-yellow as above and H-alpha is a deep reddy-orange, but the imaging can be spectacular. You will need sidereal tracking for H-alpha shots due to long exposure times. You *might* need tracking on 4x5 on the other filters if the exposure times are longish.
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