Can camera metering suddenly go off by 2 stops?

[Paul Verizzo]

The camera: a Ricoh XR-P that I've not used a lot since bought last year.

And yes, the batteries are fine.

I started processing my own C-41 last week and I got the strangest results. Of course, I blamed my processing, but after being extremely careful and with a fresh developer batch, same thing. A plus/minus two stop bracketing tests showed extreme underexposure.

So then I just played with metering and using the Sunny Sixteen for at least an approximation, boy, was this off! I tried to find a working light meter, but all had issues of one kind or another. So I ultimately did the palm of the hand metering thing (I trust it more than gray cards, the latter often have some shininess), and came to the conclusion that my metering is off about 1 2/3 stops to two stops.

I went back and looked at shots from a few months ago, perfect.

I shot a roll at +1 2/3 stops, processed, and they were just what I would expect.

?????????

 

[Les Sarile]

Older cameras that do not use the silicon cels can certainly degrade. I suppose it is possible that can happen quickly but usually it is over a course of time. Depending on the circuitry, I suspect there maybe other components that can deteriorate and cause this failure too.

Of course a number of things come into question but you should be able to verify if the meter itself is accurate but you would need to compare it to a known reference - another camera or light meter, using a gray card. This will eliminate any variances in metering modes. So if the meter is good then the next suspects are shutter speeds and processing and for that you can test using a slides or b&w since most C41 - and even more so b&w, can easily overexpose by more than 2 stops and still get perfectly good results.

 

[DWThomas]

Don't know this camera, but is there any chance you changed from a mercury battery to silver/alkaline between these outings? I expect that could account for about a two stop change in some meters.

 

[Rol_Lei Nut]

Many things can cause that problem:

Once on a Nikon F Photomic, neither a private rapairperson nor Nikon's offical importer could solve a similar problem (CdS cell and resistance rings were both changed).
I eventually found the problem myself: a dirty contact on the meter's on/off switch... :-()

Anyway, a dead or dying cell or a bad contact somewhere are likely culprits.

 

[Paul Verizzo]

Don't know this camera, but is there any chance you changed from a mercury battery to silver/alkaline between these outings? I expect that could account for about a two stop change in some meters.

Designed for 1.5 volt alkaline or lithium! Good try!

 

[Paul Verizzo]

Older cameras that do not use the silicon cels can certainly degrade. I suppose it is possible that can happen quickly but usually it is over a course of time. Depending on the circuitry, I suspect there maybe other components that can deteriorate and cause this failure too.

Of course a number of things come into question but you should be able to verify if the meter itself is accurate but you would need to compare it to a known reference - another camera or light meter, using a gray card. This will eliminate any variances in metering modes. So if the meter is good then the next suspects are shutter speeds and processing and for that you can test using a slides or b&w since most C41 - and even more so b&w, can easily overexpose by more than 2 stops and still get perfectly good results.

Not sure what you mean about a silicon cell. The only two types I know about - not that something isn't new under the sun - are the old passive selenium cells and the battery powered CdS, Cadmium Disulfide. Sulfite? Anyway, the seleniums absolutely do go bad with time, and I have an early ca. 1965 CdS hand held meter which is way off now.

I have a couple of other XR-P's and the predecessor XR-7, never a problem.

Oh well, I did some tests using the other known good camera bodies and I'll just set the speed dial +1 2/3 stops.

thanks, all.

 

[Excalibur2]

From memory, someone mentioned on a forum that:- on the A series Canons the photocell measuring light can get dust, haze, chemical corrosion (or whatever was mentioned) on it and give the wrong reading....maybe you have a similar problem.

 

[lxdude]

Not sure what you mean about a silicon cell. The only two types I know about - not that something isn't new under the sun - are the old passive selenium cells and the battery powered CdS, Cadmium Disulfide. Sulfite? Anyway, the seleniums absolutely do go bad with time, and I have an early ca. 1965 CdS hand held meter which is way off now.

I have a couple of other XR-P's and the predecessor XR-7, never a problem.

Oh well, I did some tests using the other known good camera bodies and I'll just set the speed dial +1 2/3 stops.

thanks, all.

Silicon cells have been used since the early 70's, and some cameras have gallium arsenide cells, which work the same way. The cells generate a current which goes through an amplifier circuit. More sensitive and quicker to respond, and not susceptible to being "blinded".

 

[Paul Verizzo]

Thanks. Live and learn.

 

[Excalibur2]

From memory, someone mentioned on a forum that:- on the A series Canons the photocell measuring light can get dust, haze, chemical corrosion (or whatever was mentioned) on it and give the wrong reading....maybe you have a similar problem.

Would you believe it, I got my Canon AV1 out after a long spell not used and now my meter in the view finder is off....this is a bit weird in that the meter is reading about 2 stops lower from the correct exposure, but if I point it into the sun that seems to get it working correctly for a while for different bright exposure readings, well until I point it into the shadows then it reverts back to 2 stops under again...any ideas for solving (the battery is OK)?
...also does anybody know if what the needle says in the viewfinder is the exposure you get on the film OR is the viewfinder info just for reference/guide, so if the needle say snapped off the camera would still work with correct exposure based on the ASA setting and aperture of lens?

 

[2F/2F]

I'd test again using a grey card. You cannot trust reflected light meters to provide the proper exposure unless you meter off of a grey card and then open up half a stop from what the meter sez. The recommendations camera meters give are based off of the brightness of the subject, not the brightness of the light; for best exposures, you usually want to use the brightness of the light as a guide. Camera meters will more times than not give an exposure that is generally acceptable for the average user shooting a shot of average contrast and brightness, and one that is usually within the latitude of the film to make an OK print. However, if you want the best exposures and best prints all the time, you are better off either using a grey card, or pulling your batteries and using your best judgment and/or a separate light meter.

There may very well be a problem with your meter. However, before jumping to that conclusion, do the same test metered off of a grey card.

 

[Excalibur2]

***There may very well be a problem with your meter. However, before jumping to that conclusion, do the same test metered off of a grey card.***

Thanks but it is the meter as I have other cameras to compare with reading bushes or grey paving , but the camera being aperture priority semi auto it looks like I'll have to run a film through to see if the stepless shutter speed works independently and accurate, from what the needle shows in the viewfinder (which is inaccurate).

 

[2F/2F]

Ah, it is an AE camera.

How can you compare it to other cameras' readings? Does it display the nearest shutter speed that it selects for you?

You can use the EI dial to tweak exposure on those. I do it with my Yashica all the time to try and get faster or slower shutter speeds than what I think the camera is going to give me..

 

[Excalibur2]

****Does it display the nearest shutter speed that it selects for you?****

Indeed

***You can use the EI dial to tweak exposure on those. I do it with my Yashica all the time to try and get faster or slower shutter speeds than what I think the camera is going to give me..****

Well yes as long as I don't point the camera at the sun as this "recharges" the needle to show the correct shutter speed for a while so adjusting the ASA dial wouldn't work at this time, but as mentioned before if I point the camera at shadows or don't use the camera it then reverts to show incorrect shutter speeds.
Got it temporary working properly pointing it at a electrical light bulb, but left the camera for half hour and it was back to 2 stops out.