Pentax 645 ev comp upgrade

[revdocjim]

I found a very dodgy looking Pentax 645 in the junk bin for less than $50 and the only reason I picked it up was that it has the aftermarket upgrade to allow exposure compensation in less than full stops. The rear dial that normally is used to set continuous or single frame drive has been reassigned to control ev comp. I'm just looking for some confirmation on how to use it.

Here is what the dial says on it as I turn it clockwise:

0 (in green)
+0.5 (in orange)
+1 (in orange)
0 (in green)
-1 (in white)
-0.5 (in white)
0 (in green) this is back to where I started

So I presume you just spin the dial to where ever you want... I just wanted to confirm that you don't have to back up and can just keep going the same direction and it will still be set at normal exposure whenever either "0" is selected.

I have yet to get a lens for this body since I wasn't even sure if it was working when I bought it, but it seems okay so I'll probably pick up a standard lens just to play with it, but as I recall, this lens is hard to test out without actually putting film in it... or that special rear cover which I don't have now.

I previously owned this camera but sold it to finance the purchase of my RB... but I've often thought it would be nice to have one again so when I saw this one, especially with the upgrade I jumped!

 

[Bob-D659]

Easy to test without film, look at the pressure plate, there are two silver contacts sticking thru it, use a couple of pieces of masking tape and cover the contacts, the camera will think is has film.

 

[revdocjim]

Bob,
I tried that... but after one shutter release the camera tries to advance the film and it just keeps winding and winding for ever...

Jim

 

[Bob-D659]

Interesting, thought it might work, so I just tried it and same here with the regular 645. The lower roller is a measuring roller, if it doesn'r rotate, the camera advances the film until it "sees" the leader pass. Oh well.

OK, did some playing around, on the grip side, right on the upper edge, there are two pins the back of the film insert presses in. If I hold the upper one in I can fire the shutter no problem. If I hold the lower one in the advance motor just runs. So try holding down the top pin only and see what happens.

Edit, How you are going to make the open back light tight to test the metering................ dunno.

 

[revdocjim]

That is what the special back cover is for I think. But I don't have one right now. I found a lens for it today... the 120/4 macro so I think I'll take a chance and load some film tomorrow and see if it works.

 

[Bob-D659]

Yes, that is what it does, I do have one, it came with the camera. It also lets you know there is no film in the camera if you use it and keeps the dust out.
The caps are only $6 used from KEH.COM, but the postage to Japan would be a little much.