Using a digital camera as a light meter to shoot film

[wiltw]

Well hand meters work the same way. You get a different reading depending on where you point it or the angle it's reading. Metering is actually easy. Once you know where to point it.

And if you point ALL of them at the same blank uniformly illuminated featureless wall, ALL of them should result in the same reading...regardless of 1-degree vs. 45-degree angle of acceptance, vs averaging or centerweighted or Matrix or Evaluative!

 

[cowanw]

I'm sorry. But I don't understand. Could you clarify?

Sure. The ISO requirements for meeting the exposure requirements for film are predicated on the outcome of a film negative looking a certain way using a standard set of chemicals.
But A) the digital outcome is a positive not a negative so any concepts of toe and shoulder are inversed. More exposure means more black in a negative; a second exposure is needed to get to a print where the two exposures together result in an increasing of the camera's exposure making things brighter but more brightness on a digital receiver is the first generation response to increasing exposure.
and B) Since a digital file cannot be seen, as a film negative can be, the outcome of the ISO process is a monitor image, which is a positive and so mimics the second exposure and chemical transformation of a print that film requires to be seen as a positive.
and C) A digital is not reliant on a common set of chemicals but on the companies self created algorithms. So Sony's "developing" is different from Fuji's. To interpret Sony's exposure meters (and meet ISO standards) one should use Sony's interpretation of development to meet an ISO standard, not Fuji's- much less Ilford's.
Obviously mixing and matching works alot, its just not the same.

 

[benjiboy]

Yeah. I know. Switch to a handheld meter. That's not what I want to do though even though I've used one for years. I started this journey based on another photographer's suggestion whose work I like. The camera also gives me the ability to see the views in BW and figure out which lens I need using the zoom. I can also record settings, and other notes and capture an image of the scene for reference.

I'm the first to admit Allan that I know nothing about digital cameras, my remarks were based on as I wrote on an extensive test report in U.K Professional Photographer Magazine several years ago that I remember because it was so interesting, that I wish I could remember it better

 

[Alan Edward Klein]

Sure. The ISO requirements for meeting the exposure requirements for film are predicated on the outcome of a film negative looking a certain way using a standard set of chemicals.
But A) the digital outcome is a positive not a negative so any concepts of toe and shoulder are inversed. More exposure means more black in a negative; a second exposure is needed to get to a print where the two exposures together result in an increasing of the camera's exposure making things brighter but more brightness on a digital receiver is the first generation response to increasing exposure.
and B) Since a digital file cannot be seen, as a film negative can be, the outcome of the ISO process is a monitor image, which is a positive and so mimics the second exposure and chemical transformation of a print that film requires to be seen as a positive.
and C) A digital is not reliant on a common set of chemicals but on the companies self created algorithms. So Sony's "developing" is different from Fuji's. To interpret Sony's exposure meters (and meet ISO standards) one should use Sony's interpretation of development to meet an ISO standard, not Fuji's- much less Ilford's.
Obviously mixing and matching works alot, its just not the same.

It's still a little opaque but thanks for the explanation.

 

[Alan Edward Klein]

I'm the first to admit Allan that I know nothing about digital cameras, my remarks were based on as I wrote on an extensive test report in U.K Professional Photographer Magazine several years ago that I remember because it was so interesting, that I wish I could remember it better

That's OK. Thanks for contributing.

 

[markbau]

I think it’s a great method and have been using it for a while now. When I started I used it as a guide to where to start bracketing but I almost always find that the neg I go with came from the original exposure the camera gave me.
I believe there is a way to get the exposure data off an iPhone which would be great as I wouldn’t have to get it off my digital SLR which would mean I could leave it at home. I find my Pentax digital spot is usually useless for the type of time exposure/low light photos I make.

 

[markbau]

Take the digital camera’s reading for the box speed ISO and add 1/2 f stop. OR as a friend I recommend that you just a good light meter.

Please recommend a good light meter that can be used in situations where the correct exposure will be in the vicinity of EI 100, f8, 40 seconds. In situations like that my Pentax spotmeter says “come back when the sun rises”

 

[Sirius Glass]

Please recommend a good light meter that can be used in situations where the correct exposure will be in the vicinity of EI 100, f8, 40 seconds. In situations like that my Pentax spotmeter says “come back when the sun rises”

Or you could change the film in the camera.

My Pentax Digital Spot Meter tells me that I do not take it out and use it often enough.

 

[markjwyatt]

Please recommend a good light meter that can be used in situations where the correct exposure will be in the vicinity of EI 100, f8, 40 seconds. In situations like that my Pentax spotmeter says “come back when the sun rises”

Trial and error. Maybe a Gossen Luna Pro SBC could be helpful if you can walk the scene.

 

[Light Capture]

But you aren't trying to do that Alan.
You are trying to use the in-camera readout (not the meter reading itself) from your digital camera in an entirely unconnected piece of equipment.
That in camera readout isn't there for that purpose - it is there to inform you, but not to assist you in setting anything on another camera.
As I said, if you check it, over a wide range of circumstances, and it matches the results of a piece of equipment that is designed to be used with other cameras, then go ahead and use it for that purpose.

I would agree with this.

In my experience trying this with several different digital cameras it worked but not as consistent as I would like.
Different digital Nikon DSLR's didn't really have film in mind when metering. It is close but digital cameras don't really have film in mind when metering.

On the other hand color matrix metering from Nikon F80 and F6 were spot on and simply produced great negatives in almost all situations.
Other meter that matched them in precision was Hasselblad PME prisms, PME 45 and 90 are especially precise with reflective, spot and incident metering built in.

Handheld meters works well but with film Nikons there is much less chance to miss something.

I used some other film Nikons, Minolta AF and few others but not enough to comment on metering. On small sample they all seemed competent.
Cheap film Nikon SLR with newer color matrix metering might be better choice and all of their user manuals should have correction factors for B&W contrast filters if that information is needed.
I remember reading somewhere that different manufacturers used gray value slightly different than 18% for calibration.

 

[BrianShaw]

Please recommend a good light meter that can be used in situations where the correct exposure will be in the vicinity of EI 100, f8, 40 seconds. In situations like that my Pentax spotmeter says “come back when the sun rises”

Black Cat, or the like. Not a meter, per se but…

 

[Alan Edward Klein]

@Alan Edward Klein this article on digital vs film ISO is pretty good. The gist of it is captured on this diagram, which basically says that for most practical purposes they are equivalent. I actually find film box speeds to be far less consistent across manufacturers (or even truthful, looking at you Fomapan) than sensor ISO ratings. An ISO 100 shot looks the same on my Canon, Sony and Fuji digital cameras.

Thanks. It could that film is more variable because the chemical development process is not exact from one day to the next. With digital, the program remains exactly the same from shot to shot.

 

[wiltw]

Please recommend a good light meter that can be used in situations where the correct exposure will be in the vicinity of EI 100, f8, 40 seconds. In situations like that my Pentax spotmeter says “come back when the sun rises”

You merely need to find a meter whose working range goes as low as 0EV...not uncommon.

 

[benjiboy]

Thank you. This is a good summary of the differences between film exposure measurements and digital measurement/computation. The "photographers" on Dpreview spent months gnashing their teeth about why certain digital camera manufacturers were "cheating on the ISO.". I doubt any of them knew what it was, but they sure argued.

That was the conclusions of the Professional Photographer Magazine test that I couldn't remember, in short, the digital image is a positive, like slide film,and the more exposure you give it the lighter it gets, and the I.S.O on the sensor used by the camera manufacturer is calibrated to that particular make and model.

 

[markbau]

You merely need to find a meter whose working range goes as low as 0EV...not uncommon.

I don't believe there is any such light meter that would be helpful the situation I outlined. Using a digital camera's settings is very helpful as a starting point from which to bracket.

 

[benjiboy]

I don't believe there is any such light meter that would be helpful the situation I outlined. Using a digital camera's settings is very helpful as a starting point from which to bracket.

The price of film and processing today, who can afford to bracelet ?.

 

[Chan Tran]

And if you point ALL of them at the same blank uniformly illuminated featureless wall, ALL of them should result in the same reading...regardless of 1-degree vs. 45-degree angle of acceptance, vs averaging or centerweighted or Matrix or Evaluative!

Except for the Matrix (could be Evaluative too but I don't have a camera with that mode) if the light intensity if very high and if the blank wall is of certain color. Nikon Matrix metering bias against certain color like yellow and also with light level above 16LV.

 

[cowanw]

Thank you. This is a good summary of the differences between film exposure measurements and digital measurement/computation. The "photographers" on Dpreview spent months gnashing their teeth about why certain digital camera manufacturers were "cheating on the ISO.". I doubt any of them knew what it was, but they sure argued.

Glad it was of help. Thamks.

 

[Alan Edward Klein]

That was the conclusions of the Professional Photographer Magazine test that I couldn't remember, in short, the digital image is a positive, like slide film,and the more exposure you give it the lighter it gets, and the I.S.O on the sensor used by the camera manufacturer is calibrated to that particular make and model.

But the camera has to be adjusted to ISO standards. Otherwise, a photographer couldn't use an external meter to set their exposure. The ISOs have to match.

 

[cowanw]

But the camera has to be adjusted to ISO standards. Otherwise, a photographer couldn't use an external meter to set their exposure. The ISOs have to match.

You are stuck on the idea that the meters have to read the same settings and are interchangeable. They don't and aren't.
Regarding ISO, it is the pictorial outcome that has to be the same, regardless of the path, not the meter readout.
To be sure for myself, I just set up my grey card evenly lit by the modeling lights of my flashes. My Gossen Starlight reads 1/30 sec on ambient light, 1/45 on 1 degree spot meter. My Sony FF digital camera, on spot meter, reads 1/90. My wife's micro 2/3 Sony reads 1/180. The digital camera and it's meter have to be seen as a package. film and film meters are two separate packages.
One can use any meter, internal or external, but they are not necessarily interchangeable. You have to interpret each readout based on experience or testing.

 

[Alan Edward Klein]

Gregg, Can you explain why digital cameras are the best meters for film, by far?

 

[Sirius Glass]

The price of film and processing today, who can afford to bracelet ?.

If you just do it right, you do not have to bracket.

 

[Sirius Glass]

You are stuck on the idea that the meters have to read the same settings and are interchangeable. They don't and aren't.
Regarding ISO, it is the pictorial outcome that has to be the same, regardless of the path, not the meter readout.
To be sure for myself, I just set up my grey card evenly lit by the modeling lights of my flashes. My Gossen Starlight reads 1/30 sec on ambient light, 1/45 on 1 degree spot meter. My Sony FF digital camera, on spot meter, reads 1/90. My wife's micro 2/3 Sony reads 1/180. The digital camera and it's meter have to be seen as a package. film and film meters are two separate packages.
One can use any meter, internal or external, but they are not necessarily interchangeable. You have to interpret each readout based on experience or testing.

If you get your light meters in and out of cameras calibrated the will all agree. If they are not calibrated how do you know which one is correct and which one is not?

 

[cowanw]

How I tell is that the 'film" meters ( I have 30 counting all my film camera and hand held meters) agree cause they read the same. I can tell the digital cameras are right cause they make pictures that are correctly exposed for that camera.

 

[Sirius Glass]

How I tell is that the 'film" meters ( I have 30 counting all my film camera and hand held meters) agree cause they read the same. I can tell the digital cameras are right cause they make pictures that are correctly exposed for that camera.

Get them calibrated.