Thanks for the additional info, guys. This helps a lot. You know, it just dawned on me that I should be able to figure out meter sensitivity for myself. I own an A-1, and several Pentaxes -- a KX, K2, KM, and a few Spotmatics -- I kinda got carried away recently with buying MF Pentax gear. I also own an MV, but it doesn't count, besides, it's for sale. Pentax's equivalent to the Nikon EM and Canon AV-1 -- I think -- maybe the T-50
sans motor.
Anyway, UMC's test, validating the Pentax Super A's metering pattern is what gave me the basic idea. Now, the A-1 was marketed as having a bottom-centerweighted metering pattern (common to all A-series cameras), but unlike UMC's Super A, the metering sensitivity did not fall off toward the corners or edges. So if an extraneous light source made it into the frame, even on the very corner, it could cause the entire photo to be underexposed. It gave me fits because of this. Rather than learn to live with it, I just bought another camera -- an FTb, which uses Canon's 12% partial metering, which to me was just so much better. But I want to confirm my recollections about corner and edge sensitivity.
I've owned a KX for years, and picked up a Spotmatic SP with 50/1.4 Super Tak for next to nothing a few years ago. More recently I've added the aforementioned K2, KM, and a couple more Spotmatics, including an F, to the stable. So I'm gonna see if I can duplicate Cuthbert's claims regarding these cameras. Honestly, I've used both the KX and SP just a few times, and when I used them, there were no unusually lit scenes to fool their meters, so I haven't yet developed a feel for the way they meter.
I don't have an FM right now, but I do have an FE and it uses the same metering pattern. So I can compare the KX to the FE. And you mention that the K2's pattern is tighter, which makes sense since it has an Aperture Priority mode. Nikon did the same thing with the F3, reasoning I guess that if a photographer was going to use the A mode, the metering pattern had better be tighter. So Nikon went with an 80/20 pattern on the F3 compared to the 60/40 pattern it used in just about every other camera at the time.When I bought my first F3, I was a bit leery about using it on the A setting, but I decided to try it out -- shooting slide film, no less. And every photo came out perfectly exposed. I finally got to where I'd put it on "A" and not worry anymore about the outcome. I still have an F3, so I'll compare the way it meters a scene to the way the K2 does. This will be helpful. And if the KM and Spotties are just straight averaging, I can compare them with my Bronica ETRSi or Pentax 6x7. I have metering heads for both cameras and as far as I've been able to determine they have just a straight averaging pattern.
Well, this ought to be very interesting. I think I'll report back my findings in a separate thread.
Last edited by cooltouch; 04-23-2015 at 06:41 PM.