Both of these are good solutions. Pentax, however, came up with their own solution for the SV (and S1, S2, S3 etc) - a clip-on CdS (Cadmium Sulphide sensor) light meter.
Now of course, for the light meter to work it does require a battery - the now defunct 1.3v Mercury battery used by many a camera of that era. Fortunately, a guy on TradeMe just happens to sell a modern equivalent which will work (coupled with a little rubber 'O' ring to make it the right size), so I had to pay about the same price for a couple of batteries. Still, for around $25.00NZ I've now got a pretty cool clip-on meter for the Pentax SV.
|Page from the Pentax SV Manual on the CdS Clip-on meter|
It has four settings around the main ring; Off (self explanatory), B (battery check), H (High) and L (Low). If you are shooting in bright conditions, set the meter to 'H' and read the fstop from the black lines in the window. If you are shooting indoors or in low light, set the meter to 'L' and read off of the red lines. Easy.
As soon as you point the camera at your subject, and the meter is turned on to the appropriate setting, the needle should jump into life in the top window and line up with an aperture (fstop) reading. This will change depending on what shutter speed you have set on the camera. Move the shutter speed, and the apertures slide to the left or right to indicate the new exposure combination.
It makes a beautiful addition to an already gorgeous looking old camera. It also adds a steampunk element to the overall design of the camera, which I kinda like. You can leave it on, or take it off, as you see fit, and it adds almost no weight to the camera itself (which is just as well, since the SV is a hefty little beast to begin with).
Overall, the Pentax Clip-on CdS meter is a beautiful piece of engineering and a great addition to my Pentax SV kit. I've got the bug now, and a case of G.A.S. (Gear Acquisition Syndrome). I want to get a few more lenses, and actually brought an old Vivitar 28mm on TradeMe for $9.00. The guy selling said it had some fungus and needed cleaning, but unfortunately that was an understatement :-( So now I'm actually going to get a pristine 28mm f3.5 Super Takumar Pentax lens from a local guy I know. I like a 28mm for landscapes and wider shots - it's one of my favourite focal lengths. And his copy looks mint, so very excited about including this in my kit.