Problem with TTL prism

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Hi, I have P67 and the TTL prism is not working as it should. If I set the film speed to 100ASA it is over exposing by about 1-2 stops. If I use a large gray card (covering all the frame) and the meter in my canon EOS 50 or a hand held light meter I can get the exposure correct at f8 by changing the film speed, but at f22 the expousure is out by 2-3 stops. This is lens independant, I've tried 55mm, 75mm and 135mm lenses. I have put a new battery it the camera.

I do get great shots if I ignore the TTL prism and use a hand held meter but I shouldn't need to.

The prism is at least 10-15 years old Basicly the meter isn't linear or correct The battery is new The camera itself works well with slide film

Any ideas Thanks Leif Pigott

-- Leif Pigott (Leif.Pigott@ew.govt.nz), April 05, 2000

Answers

I've got the same problem. Maybe I have wrong type of battery, or, maybe, there is some kind of temperature compensating element in the circuitry which is not working properly. I use a handheld meter, too.

Sakari

-- Sakari Makela (sakari.makela@koulut.vantaa.fi), April 06, 2000.


I had a similar problem with the prism I bought on a second-hand set, but fortunately I noticed it in the guarantee period. I brought it to Pentax Benelux, and the repairman told me that there are several pot- meters (is this an English word?), and that every meter is responsable for a certain metering range. In my prism they where "off key" for some unknown reason. It was fairly simple to calibrate. Now it works fine. In the same reparation I had the "ringing" sound in my 55mm fixed (it still is there a little) I hope this is of any help. Peter

-- peter gooijer (rockrose@freeler.nl), April 13, 2000.

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