Help Needed: CDS Light Cell

Thomas Keidan · Nov 18, 2017

Hi everyone, my new Olympus 35 RC recently arrived with a slightly too small lens cap. When I was trying to put it on I noticed It may have rubbed against the CDS light cell which is on the side of the camera lens. Do I have to be super fragile around the CDS cell or does it not matter if it get's scratched or anything like that? I'm a complete novice so I apologise if this is a stupid question.

AgX · Nov 18, 2017

The CDS cells I know of are either coated on top or completely cast around.

Thomas Keidan · Nov 18, 2017

AgX said:
The CDS cells I know of are either coated on top or completely cast around.

If I do anything to the coating by accident is this a problem? For example if there is a small scratch on the coating at all?

BrianVS · Nov 18, 2017

The CDS cell is behind a lens, which is designed to collect the light for the cell. The cell itself is "one pixel".

Don't worry about it- a few scratches will make no difference. You are having no affect on the actual CDS cell.

Svenedin · Nov 18, 2017

Maybe try to find the correct lens cap to avoid this problem in future.

Thomas Keidan · Nov 18, 2017

Svenedin said:
Maybe try to find the correct lens cap to avoid this problem in future.

Hi Brian, yes I know it was my fault or rather the seller's who provided me with a 43mm cap instead of a 43.5mm cap. Do I have anything to worry about? Will I have damaged anything or should I be ok? Response would be much appreciated!

Thomas Keidan · Nov 18, 2017

BrianVS said:
The CDS cell is behind a lens, which is designed to collect the light for the cell. The cell itself is "one pixel".

Don't worry about it- a few scratches will make no difference. You are having no affect on the actual CDS cell.

That's exactly what I was hoping to hear, thank you so so much Brian!

Svenedin · Nov 18, 2017

Thomas Keidan said:
Hi Brian, yes I know it was my fault or rather the seller's who provided me with a 43mm cap instead of a 43.5mm cap. Do I have anything to worry about? Will I have damaged anything or should I be ok? Response would be much appreciated!

Brian? I'm sure it will be fine. Don't worry about it.

Stephen

Thomas Keidan · Nov 18, 2017

Svenedin said:
Brian? I'm sure it will be fine. Don't worry about it.

Stephen

sorry stephen, I was looking at the wrong message when I replied! Thanks for all your help as always!

Svenedin · Nov 18, 2017

You're welcome. RE your other thread; I'm taking a camera to a beer festival tonight for some available light stuff. Like you, the camera I'm going to use (MInox 35 ML) cannot be set as high as 3200 for Delta 3200 but I can get 1600 so we'll see what happens (I also have a small flash if necessary).

Thomas Keidan · Nov 18, 2017

Svenedin said:
You're welcome. RE your other thread; I'm taking a camera to a beer festival tonight for some available light stuff. Like you, the camera I'm going to use (MInox 35 ML) cannot be set as high as 3200 for Delta 3200 but I can get 1600 so we'll see what happens (I also have a small flash if necessary).

That sounds great! I'd really appreciate if you could send me some results! I've been looking at the Fuji Natura 1600 for my 800 iso Olympus so it will be interesting to see how you get on!

AgX · Nov 18, 2017

Thomas, look up images of Cds cells, most of them are just coated, some old style are inside a kind of transistor housing with glass window.
But none has a kind of lens. In photography visible cells are either behind a seperate window as in your case or located deeply recessed.

Thomas Keidan · Nov 18, 2017

AgX said:
Thomas, look up images of Cds cells, most of them are just coated, some old style are inside a kind of transistor housing with glass window.
But none has a kind of lens. In photography visible cells are either behind a seperate window as in your case or located deeply recessed.

Hi, I think mine is coated. I was just wondering if any damage to the coating would be a problem but from other people's response I don't think it is!

AgX · Nov 18, 2017

No , yours is behind a convex window, unless that has gone, but then still the cell woul be too recessed to hurt it.

Thomas Keidan · Nov 18, 2017

AgX said:
No , yours is behind a convex window, unless that has gone, but then still the cell woul be too recessed to hurt it.

Ah yes my mistake you are correct, OK that is good news. This is my first film camera so I was completely unaware as to how fragile the outer coating/window was!

BrianVS · Nov 18, 2017

The lens in front of the CDS cell is designed to "smear" the image, some are center-weighted, others simply average the image. This is the "Meter Pattern" that you will see referred to on a test of a camera. Even when taking apart an SLR with through-the-lens metering, you will find a lens in front of the CDS cell.

NikonF_CliponMeter by fiftyonepointsix, on Flickr

The lens is more obvious on a Selenium Cell, the CDS cell is much smaller.

Thomas Keidan · Nov 18, 2017

BrianVS said:
The lens in front of the CDS cell is designed to "smear" the image, some are center-weighted, others simply average the image. This is the "Meter Pattern" that you will see referred to on a test of a camera. Even when taking apart an SLR with through-the-lens metering, you will find a lens in front of the CDS cell.

NikonF_CliponMeter by fiftyonepointsix, on Flickr

The "lens" is more obvious on a Selenium Cell meter, the CDS cell is much smaller- smaller lens.

Thanks for this info brian, i'm very relieved I haven't done any damage!

AgX · Nov 18, 2017

Which means that it better should not be taken off or matted by solvents. But that's about it.

Thomas Keidan · Nov 18, 2017

AgX said:
Which means that it better should not be taken off or matted by solvents. But that's about it.

Thanks, and obviously scratches don't class as matting at all?

BrianVS · Nov 18, 2017

Some solvents- such as acetone- will partially dissolve plastics, including plastic lenses. Best to clean the meter window using an air-blower, breathe on it- then clean with lens paper. Clean it the same way you would a lens, filter, or eyepiece.

The meter window would have to be very dirty to affect the exposure. Very deep scratches might change the metering pattern, but will not likely affect exposure. A few marks in the coating will do nothing.

Help Needed: CDS Light Cell

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