[Kmier]

I have the shutter dial components and the six small perimeter screws removed. The cover begins to lift up at the shutter dial arm, and at the back, near the eyepiece, but I cannot lift it up at the front, near the “PENTAX” nameplate. This is a newer (s/n 639256) 67 prism, so I didn’t think there were additional screws up front that I missed. There’s a nice YouTube disassembly video by ‘Lens Heaven’, but he completely jumps over that step. Are there more screws that Ive missed? I don’t want to break the cover.

Why am I doing this? My TTL over-exposes by 1.5 stops (compared by multiple means) and I’m curious if I can do the adjustment on my own. [Not opposed to buying a handheld meter - I’m just trying to baseline the ‘new’ 67 first.]

There was a forum post by ‘MysteryOnion’ some years ago on adjusting one of the three meter adjustment screws, but he was inconclusive (ie: he forgot) exactly which screw to turn. I don’t mind the trial and error process, as I’m pretty careful to back-track methodically, and I love a challenge.

Anyone done this recently?

Thanks in advance.

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Last edited by Kmier; 07-27-2019 at 08:39 AM.

[tuco]

I've never took mine apart so I can't say. But how do you know your middle gray is being placed 1.5 stops to high?

[Kmier]

tuco - I’ve not used an 18% gray card formally yet, so I know I’m not extremely precise. I’ve downloaded the ‘my light meter pro’ app, and found various low contrast areas on the outside my house early this morning to compare to. This app seems to be one of the more highly-rated for $3.99. I see almost identical results to my 645 readings; certainly within 1/2 a stop.

Clearly, I’m still learning, so please bear with me. 😉

[tuco]

Okay. I have an aging Pentax TTL prism too. I never thought about checking it for accuracy. But maybe I should.

I didn't catch if you are going to be shooting BW, C-41 or E-6 film primarily. But in the case of BW and color negatives, don't over think it. Just go out and shoot. Use the feedback you get to learn when to tweak setting from your light meter readings. Those pictures I posted using the lightmeter app show that for two types of film and lighting conditions it placed shadows and highlights in the recordable range of the film. That's a good start. What more could you want?

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Last edited by tuco; 07-27-2019 at 11:39 AM. Reason: Spelling

[johnha]

I have the same phone meter app, I had to calibrate it with a known meter (still not sure it's a linear correction). As above from tuco (he knows his stuff!) shoot some film, note the readings and check what you get back, adjust and repeat.

All meters need the user to compensate for their own preferences, metering technique, EI, stock, development, printing etc.

[Kmier]

tuco - sorry, I tend to overthink about everything...that’s a fault of mine 😁

I plan to stick to color negatives; possibly B&W once again. If I can’t find a service manual online, I may throw in the towel and ship it to Eric for a full CLA plus meter adjustment.

Thanks for the reply.

---------- Post added 07-27-19 at 12:06 PM ----------

I have the same phone meter app, I had to calibrate it with a known meter (still not sure it's a linear correction). As above from tuco (he knows his stuff!) shoot some film, note the readings and check what you get back, adjust and repeat.

All meters need the user to compensate for their own preferences, metering technique, EI, stock, development, printing etc.

John - thanks; I just dropped my first roll in the mail to The Darkroom - I instructed them to ‘pull -1.0 stop’, sort of as a compromise adjustment.

[desertscape]

If I shot print film, I would not try to adjust the TTL, especially when it is not too far off and overexposing by 1.5 stops. Slide film is another matter completely.

[Silent Street]

Oh dear...