Topic: Light Meter on SLR Cameras

[sapata]

I guess the lightmeter on my Rolleiflex SLR it's not working properly... at least when comparing to my hand held meter the difference it's huge. I'm not sure how long the batteries are supposed to last but I have it on the camera for a couple of years I believe.

This whole thing led me to another thought which is how the light meter on this type of cameras works? Is it selenium as well ? I wonder if I change the batteries and still have the problem, is there anything I can do to solve the problem myself ? This is one of my favourite cameras but I didn't want to spend a huge money to fix that. I guess I could take my hand held meter with me but this is the camera I use when I want some quick "shots"...

Maybe I should learn how not to use the meter at all

Thanks... !

[Phil Bebbington]

I'm not sure how big the difference is, but, could it be the camera taking reflective readings and the hand held meter taking incident light readings? Just a thought

[Francois]

I know I've compared a lot of meters before and most of them give way different results. Cells don't have the same sensitivity to colors of light so the results can vary quite a bit.

For instance cameras that use a CDS cell have an issue with red sensitivity (not good when shooting under incandescent light). These have a battery.

Others use a selenium cell, which doesn't require a battery but is also less sensitive.

Then, there's the Silicon Blue Cell (SBC) used in handheld meters which requires a battery and reacts pretty evenly to light.

Even battery type can affect a meter. I have a Konica T3 which requires mercury cells. When I put the Weincell replacements in it, I need to divide the ISO by 4 to get results... not convenient.

The best thing is to test everything outside using the Sunny f/16 rule. It's the only reliable way to calibrate the meters and know for sure if your Rollei is going on the fritz.

[Urban Hafner]

Maybe I should learn how not to use the meter at all

You certainly should. You'd be surprised how forgiving color negative and black and white films are. Just try using the Sunny 16 rule or make yourself an Exposure-Mat. It's totally worth it if you don't have to carry around a hand held light meter everywhere.

Urban

[Francois]

The expomat is really a great little gizmo. I use it often when I have a camera that lacks a meter. Light, expandable, cheap and reliable... you can't get better than that.

[Urban Hafner]

The expomat is really a great little gizmo. I use it often when I have a camera that lacks a meter. Light, expandable, cheap and reliable... you can't get better than that.

Yup. The credit card sized one is always in my wallet.

Urban

[Pete_R]

I guess the lightmeter on my Rolleiflex SLR it's not working properly... at least when comparing to my hand held meter the difference it's huge. I'm not sure how long the batteries are supposed to last but I have it on the camera for a couple of years I believe.

But do you get correctly exposed pictures? If you do, you don't have a problem with the camera but maybe just in the way you are comparing the two.

This whole thing led me to another thought which is how the light meter on this type of cameras works? Is it selenium as well ? I wonder if I change the batteries and still have the problem,

Which camera is it? SL35 maybe? If it is, it uses CDS cells and the meter circuit is a bridge arrangement which makes it very tolerant of battery variations.

is there anything I can do to solve the problem myself ?

Often, meter problems are caused by poor electrical contacts, especially on the ISO dial because they don't get a lot of use. Try moving the ISO dial back and forth a few times to clean the contacts. You could try the same thing with the shutter speed dial. Sometimes just exercising them will often clear the problem.

[Francois]

Also, if the batteries were left in for a long time (especially mercury), you can get wires to corrode with no apparent reason. Happened on one of my small Sekonic meters.

[sapata]

Phil... I checked using the lightmeter on reflective mode  

Urban... I'd seen that before but nevoer thought about using it since I've got a lightmeter but it's great to have one in the wallet.

Peter... Yes, it's the SL35 and I did have some weird shots on the roll and that was the reason that made me check the camera against the hand held meter. I'll definitely do what you suggested me and run a test film when I have time

Francois... how do you use the Sunny f/16 rule ?

Thanks guys...

[Francois]

Francois... how do you use the Sunny f/16 rule ?

It's really the simplest of all exposure tricks...

Set your lens to f/16.
Load the film in the camera. If it's a 100 ISO, set the shutter speed around 1/100 (1/125 is close enough). If it's a roll of 400 ISO, set it around 1/400 (1/500 is close enough)... and so on.
On a sunny day, it should give you perfect exposure.
The only time I heard it doesn't work is for people who live on a mountain at high altitude.

[LT]

you have to use a sunny 11 rule here in the uk unless it's full sun in June or July.  the light just isn't strong enough generally.

Mind you, I guess it depends on how much shadow detail you prefer.

[Francois]

I know the rule was probably designed for June 21st at noon in front of the White House in Washington... or at least that's the standard used by Vitalite fluorescent tubes.

I think I could bend the rule by saying that if I turn red from the sun and heat, use f/16. If I turn white from the cold, use f/11