Minolta Autocord aperture accuracy question...

[audidudi]

I have three Autocords of varying vintages. Last week, I shot several

rolls of Provia 100F with one of them (an Autocord III) and discovered

that all of them were 1/2 to 2/3 of a stop underexposed. Since I

just had this camera CLA'd and the shutter was adjusted to fix a minor

speed error across the range, I assumed the problem had to be with the

aperture settings instead.

 

This morning, out of curiosity, I decided to determine the accuracy of

the aperture settings on this particular camera using the Horseman 6x9

meter I occasionally use with my view camera. Here's what I found:

 

Using f/22 as a baseline, opening up to f/16 indicated one-stop, as it

should have. However, opening up from f/16 to f/11 indicated only 2/3

of a stop on the meter and this was also true for the change from f/11

to f/8 as well as from f/8 to f/5.6. Opening up the aperture all the

way, from f/5.6 to f/3.5, indicated just a one-stop change when it

should have been 1-1/3

stops.

 

Obviously, this explains the reason for my underexposures since what's

supposed to be a three-stop range (f16 to f/5.6) is only two stops and

this is where I do most of my shooting. Now I'm curious as to whether

this is typical of Autocords (my other two are aren't available at the

moment, as they are in the shop being CLA'd) or a problem to be fixed.

 

Has anybody else experienced this with any of their Autocords? I love

these cameras and recently noticed that despite all of the other great

photo gear I have around, the vast majority of my favorite photos were

taken with an Autocord. I think there's a lesson here for me...

[jeff_drew4]

Jeff,

My Autocord is a non-meter version, late 50's I think, and still near mint. Your last sentence is important! I imagine that it's possible a diaphragm dial is not marked accurately, but are you sure you are looking at the f/stops carefully when selecting them? My eyes now work better with glasses, and my TLRs are getting more use because they are easier for me + eyewear! Do you have a handheld, accurate meter? I use them religiously, now, foresaking some of the in-camera choices. My Luna Pro SBC and little Pilot are perfect for my TLRs. You can run tests and then compensate. BTW: I've been using more print film in my 'cords, Rollei & Minolta, and find more foregiveness in exposures on print film, whereas 'chromes need more exactitude.

Jeff

[audidudi]

There doesn't appear to be any (well, at least not very much) play in the system so I don't think it's a question of wear or misadjustment. It's certainly possible that the dial is marked incorrectly but since this is a mass-produced part, I'd expect this problem to show up with other Autocords hence the reason why I posted a query to this forum.

 

The meter I used for my testing has a 6x9 measuring area so I blocked off the portion that wasn't needed. I then locked the shutter open on the "B" setting with a cable release and watched the meter readout as I changed the aperture settings. I'm reasonably confident my results are accurate; it's the _reason_ for the discrepancy that concerns me, as I only shoot Astia and Provia these days and need to make sure the exposures are as spot-on as possible. Given that the error varies for nearly every f-stop, it'd be highly impractical to compensate for this as I'd potentially have to memorize the correction factor for _each_ aperture setting on all three of my Autocords.

 

This particular Autocord doesn't have a meter and although the one on my L is fairly accurate, I generally use a hand-held meter unless I'm slumming with the "sunny f/16 rule" and fill-flash. It takes great photos regardless, though, and I intend to start shooting with it -- along with my other two -- more often than I have in the past.

[nolan woodbury]

Jeffery, I have 5 (going on 6) Autocords of various vintage as well, and have not encountered this situation. To my way of thinking, this would be intolerable trying to remember to over-expose with one certain camera, and not having to deal with the problem with the rest of them. Have you visually inspected/compared the f-stop openings on the Autocord with the problem (with another Autocord that you know is correct) to be certain it isn't a shutter speed issue? At any rate, the camera needs to be adjusted again...may I suggest Paul Ebel in Wisconsin?

[murray_twelves2]

Hi Jeffrey -

 

I also have 3 Autocords, a CdS-III and two Autocord I's, and I haven't observed this problem. The meter on the CdS-III is so good, that I rarely use a handheld meter with that camera.

 

I have found that it is hard to tell by looking in the aperture/shutter speed display over the viewing lens when I have pegged the aperture accurately. What I have done to compensate for this is check the pointer on the aperture control lever against the EV numbers around the left side of the taking lens. The intervals here are a little easier to gauge. Sometimes I even set my handheld meters to give me EV numbers to facilitate this process.

 

Hope this helps in your case (if you haven't devised similar measures already).

[jeff_drew4]

Murray, I generally use the method of setting the EV on camera and meter, also. It's a handy idea, indeed!

[audidudi]

I got one of my other Autocords back today -- an LMX that was serviced by Ross Yerkes in Los Angeles, California -- and it behaves just about identically to the Autocord III described above. I double-checked the Horseman meter's accuracy by performing the same test procedure on several of my view cameras lenses (all with Copal shutters) and their f-stop markings proved to be virtually spot-on.

 

Bottom line, I guess this means the Autocord is not as precisely made as I'd thought it was and while I've gotten superb results with slide films in the past, it's probably better suited to negative films that are more forgiving of exposure variations. Even so, I still think they're great cameras...

[photojim]

The aperture scale in the little window can slip. This seems to happen with my camera. That might explain your problem.

 

I'm going to try to get mine repaired.