Canon AE1 Program light metering

[Agulliver]

I was recently given a complete Canon AE1 kit....body, three lenses, flash, light meter etc. Sadly a friend's brother died, and the friend knew I'd appreciate the camera.

I've run two rolls of film through it and it's a nice camera, could definitely find a place in my arsenal. But it appears to be under exposing. The display shows the suggested aperture for the selected shutter speed changing with the light conditions but the first thing I noticed was that it does appear to be selecting too small an aperture.

So I ran a bit of an unscientific test....took both the Canon and a Voigtlander to my favourite jazz club loaded with the same type of film. The Voigtlander was set at 1/30s, f2.8. The Canon, I set the meter to 800ISO believing it to be a bit optimistic, and set the shutter to 1/30s. The suggested apertures were coming up at f4, f5.6. This is with a 3.5 35-70 zoom lens.

Developed both films in the Jobo tank at the same time, pushing the film to 1600 (the somewhat mysterious Exeter Pan 400 which acts very much like HP5 with less effective antihalation). Lo and behold, the negs from the Voigtlander are beautifully exposed, one or two perhaps a touch over exposed in the highlights....and the Canon's film....well...the negs are scannable but they are very thin. Like it was metering for 400 perhaps?

Is this something anyone has encountered before? Any ideas?

 

[koraks]

my favourite jazz club

The typical lighting in such a place (also going by photos you've posted earlier) is characterized by very high contrasts and point sources that can easily fool any meter. How an integral or center-weighted meter will respond, depends strongly on its sensitivity pattern. You'll find some info for the AE1 here: https://www.mir.com.my/rb/photography/companies/canon/fdresources/SLRs/ae1/basic5.htm

Furthermore, due to the nature of the lighting, which tends to be colorful and narrow-bandwidth, spectral sensitivity differences between two meters can easily throw off the measurement by a stop or even more.

To verify if the meter is somewhat accurate, benchmark it against a known-good meter, using an evenly lit surface without bright highlights or deep shadows; something like a plain wall works fine. Take into account the reflectance of the wall if you're using an incident meter as your benchmark. Personally I generally use my digital EOS 7D as a benchmark because its metering system is plenty reliable and it's easy to compare with other cameras.

 

[Chan Tran]

I wouldn't be surprised that your AE-1P underexposed.

 

[pentaxuser]

I wouldn't be surprised that your AE-1P underexposed.

Can you say why? It might help the OP

pentaxuser

 

[BrianShaw]

Does the AE-1 meter correctly under less stringent and more normal conditions?

 

[ronaldj23]

You say that you set the iso to 800. Is that the film iso? If the film is slower 400 for example, that would explain the underexposures...that's assuming I am interpreting your opening comments correctly. RJ

 

[Laurent]

My AE1-P had an issue like this some time ago, it appears the ISO setting dial had some oxydation that made the contacts flimsy.

A stop gap solution was to quickly "play" with the setting: set from the minimum to maximum, then back, a few times and as fast as you can/dare.

The REAL solution was a proper CLA which fixed the "squeak" at the same time.

 

[Chan Tran]

Can you say why? It might help the OP

pentaxuser

Back in the 80's I managed a 1 hr. photo finishing store and a good number of my customers had the same model as well as the AE-1. Their negatives tend to be underexposed. My own AE-1 and AE-1P also underexpose by about 1 stop. However, I found it's fairly consistent so using a lower ISO would fix the problem.

 

[pentaxuser]

Thanks for the reply Chan Tran.

pentaxuser

 

[MattKing]

The AE-1 cameras were, in some ways, oriented toward slide film users - particularly Kodachrome 64.
So some of the issue may relate to that - exposing using a bottom weighted centre weighted metering pattern, at least partially optimized to protect highlights.

 

[Agulliver]

Thanks everyone, all your replies are useful. @koraks you are correct the specific lighting for the two rolls I've shot with it so far might well be part of the issue, as might the weighting on the meter as described by @MattKing

I've successfully used other auto and semi auto (aperture priority) cameras at the same club but usually just use manual....f2.8 and 1/30 second with 1/15th or 1/8th if there's little light on the performer and they're not moving too fast.


I think I need to take a few test photos in more "normal" lighting conditions to begin with.

 

[koraks]

Yeah, see how that works out. It's always possible there's a systematic deviation to either side as suggested by @Chan Tran . So far I've never ran into something like that with my own cameras, but I've spent relatively little time benchmarking them against each other, mostly for a lack of perceived need. In your case, there's reason to do it, so let's see what comes out.

 

[wiltw]

I echo the need to neutralize all variables when comparing meters...in particular, differences in sensitivity areas.
So meter with two meters pointed at the same UNIFORMLY ILLUMINATED nearly featureless area (e.g. white wall, with not much shadowing across its surface) That way, any difference in metering patterns is neutralized and you can directly compare the suggested exposures from each meter...both theoretially suggest an exposure which renders the target area to record as a midtone gray.