When to take a Incident or a Reflective light reading

[gb hill]

I was reading up on light meters today and many have the capability of being both a reflective or incident. The way I understand it is that with an incident light meter you take the reading toward the light source & with a reflective meter the reading is taking of the light falling off the subject. With the incident LM a white diffuser is placed over the cell & with a reflective LM the cell is uncovered. My question is this. What is the determining factor for when to use a reflective reading and when to use a incident reading when taking a photograph? If I'm incorrect about anything please correct me.

 

[Anupam]

I take incident readings when:

1> I am sure that the contrast range of the scene is within the dynamic range of my film.
2> When I want to record the scene "normally" - that is, when I want to place zone V on the negative exactly on middle gray luminance of the scene. In other words when the scene is an average one.

Reflective (spot, mostly) metering is handier when I want to:
1> check for contrast range.
2> want to place zones differently than the mid gray reading suggests.

-A

 

[payasam]

You're quite right, gb. Incident readings are my preference. I take reflected readings only when incident ones are not possible or are too difficult. With reflected light readings, it's good to know the angle of acceptance of one's meter.

 

[Roger Hicks]

Incident: when you're shooting transparency and don't want to blow the highlights, i.e. exposure is keyed to the highlights. Incident used to be known as 'the artificial highlight method'. The shadows are left to go hang.

Reflected: two options. Broad-area or limited-area. Normally for negative.

Broad-area is generally inferior to incident because neither gives any clue as to the total brightness range but broad-area is deceived by unusually reflective subjects (snow) or unusually dark ones (coal cellars). For subjects with a long subject brightness range you have to give extra exposure to negatives whether you meter incident or broad-area reflected.

Limited-area (spot meter or close up) is ideal for negative as it allows you to key the exposure to the darkest area in which you want detail.

With brightness ranges under about 5-6 stops, it doesn't matter all that much which you use.

For more on subject brightness range, see:

http://www.rogerandfrances.com/photoschool/ps subject brightness range.html

Cheers,

Roger

 

[gb hill]

Incident: when you're shooting transparency and don't want to blow the highlights, i.e. exposure is keyed to the highlights. Incident used to be known as 'the artificial highlight method'. The shadows are left to go hang.

Reflected: two options. Broad-area or limited-area. Normally for negative.

Broad-area is generally inferior to incident because neither gives any clue as to the total brightness range but broad-area is deceived by unusually reflective subjects (snow) or unusually dark ones (coal cellars). For subjects with a long subject brightness range you have to give extra exposure to negatives whether you meter incident or broad-area reflected.

Limited-area (spot meter or close up) is ideal for negative as it allows you to key the exposure to the darkest area in which you want detail.

With brightness ranges under about 5-6 stops, it doesn't matter all that much which you use.

For more on subject brightness range, see:

http://www.rogerandfrances.com/photoschool/ps%20subject%20brightness%20range.html

Cheers,

Roger

Thanks Roger, I love your site and believe I'll become a subscriber. There is a wealth to learn on your site.

 

[Bob Michaels]

the brain and thinking still are the key to exposure control

the brain and thinking still are the key to exposure control

The more I shoot, the more I think and the less I rely on light meters. Now I occasionally will use an incident meter when faced with a difficult lighting situation. Then I think about the subject reflectance and factor in the meter reading to make a final decision. And I'll sometimes look at the camera's built in reflected meter but then I think "yeah, that makes sense".

 

[ruben]

..... The way I understand it is that with an incident light meter you take the reading toward the light source & with a reflective meter the reading is taking of the light falling off the subject. With the incident LM a white diffuser is placed over the cell & with a reflective LM the cell is uncovered. My question is this. What is the determining factor for when to use a reflective reading and when to use a incident reading when taking a photograph? If I'm incorrect about anything please correct me.

Hi GB,

Kindly let me correct first the definitions, for the sake of doing the right thing when metering, and afterwards I will give my opinion about each way.

With the incident metering you don't point the white dome towards the light surce. On the contrary, if there is a strong light source like a brigh sky, sun, spot light, etc you may shadow the white dome with your other hand at abut some 20 cm.

With the incident metering you point the white dome at the place of the subject and towards the camera.


As for the reflective metering, here you are reading the light reflected by the subject towards your camera, this is the basic way in which all cameras meter light. The problem here is that a white dressed woman will reflect much more light than a black clothed priest.

Hence, two basic conclusions.
The reflective metering asks for compensation (the white dress of the lady will byass the reading, making her face rather black). I, e, with the reflective metering the photographer needs to think what is the metering reading and what he has to do in order to compensate what the meter is reading..

The incident reading, on the other hand, is more like an averaging way to get away quickly.

In very general lines, which always have their exceptions, a beginer will be better of with the incident white dome, safer way.

But once you get an advanced stage, most of the times you may be using and compensating reflective readings.

Because the averaging white dome reading is a compromise in which the shadowed parts of the image will suffer to some degree.

Cheers,
Ruben

 

[gb hill]

With the incident metering you point the white dome at the place of the subject and towards the camera.

Ruben

Hi Ruben,
I agree with what you are saying but if you are pointing the meter back toward the camera from the subject, aren't you in a since reading the light. When at the camera taking the photo the light will be at the photographers back or side? I was assuming this was what the writer was talking about.
cheers

 

[Bob Michaels]

Do you managed to get it right under artificial lighting?

No, that's one of the times I'll take a meter reading and interpret from there. You still need to analyze and think about it instead of just following the meter. Night shots are a classic example. Follow the meter and they will end up looking like daylight shots with really flat lighting.

The times that I become clueless are using a flash meter. Then I just have to follow it blindly.

 

[charjohncarter]

Thanks, Roger. Your insight is welcome. (by me)

 

[Doug]

There are two ways to use the incident meter: First the highlight protection method outlined by Roger, and secondly the --what should it be called-- maybe "average incident" method described by Ruben.

Ruben's method is the one I was taught as the way to use an incident meter. The dome is pointed from the subject location directly toward the camera, not the light source. That positions it to receive exactly the illumination of the subject as seen from the position of the lens. The dome then "sees" both light and shadow, same as the subject, for a balanced exposure.

Shading the dome from direct light, as mentioned by Ruben, is something I hadn't heard before, but I can see how this could be a "shadow protection" technique for negative film.

Roger describes pointing the dome toward the light source, which would tend to give less exposure, a good approach for slide film vulnerable to highlight blow-out. Probably equally reasonable for digital cameras.

The only instance the two methods would return exactly the same result would be when the light comes from directly behind the camera position, flat frontal light for the subject.

 

[Roger Hicks]

Sorry, I seem to have given the wrong impression with the incident light thing. I didn't say you point it at the light source. There are three schools of thought:

1 Straight at the source from the subject position (or equivalent). .

2 Straight at the camera from the subject position (or equivalent)

3 Split the difference: still from the subject position (or equivalent) point it at an angle that bisects the light/subject axis and the subject/camera axis.

A simple thought-experiment about backlighting shows that #1 is far from universally applicable.

Side-lighting would often work best with #3.

As a general rule, #2 is the most useful.

Another good trick is to take a broad-area reflected reading and an incident reading, and average the two.

A thought experiment again:

A blonde in a white dress against a white wall.

A broad-area reflected-light reading will recommend quite serious under-exposure because the subject is not of 'average' reflectance.

But you need to under-expose slightly, as compared with an incident-light reading, in order to get detail in the whites.

Average the two, and bingo!

Cheers,

R.

 

[Sparrow]

It’s a pity there isn’t something that reflects the same amount of light as the reflective meters are expecting to read.

 

[ruben]

Hi Ruben,
I agree with what you are saying but if you are pointing the meter back toward the camera from the subject, aren't you in a since reading the light. .............

I don't follow you here GB

Hi Ruben,
....When at the camera taking the photo the light will be at the photographers back or side? I was assuming this was what the writer was talking about.
cheers

Here you are assuming that beforehand the sun, or light SOURCE, is behind the photographer's back, making a kind of straight line sun-photog-subject.
And then you are right, you will point the white dome towards the same point where the photog is going to stand.

But what if, while the sun and sujbect remain constant in the above example, the photog decides to move 90 degrees to the left of the subject ? Then you will move 90 degrees the white dome, again pointing it towards the photog.

And always, again with strong light sources, you will shadow somewhat the white dome in order not to inflate too much the reading.

BTW, GB, light metering is rather a deep and complex science, with experience needed. And the Ecumenical Concilium raising in this thread is just a proof of it.

Therefore, my advice is to approach it from a practical angle suiting your current needs. If I am not wrong you own a metered Bessa. Are you having bad auto exposures ? In that case what you will be needing to learn is how to compensate and when to compensate your camera's Auto readings.

Cheers,
Ruben

 

[Roger Hicks]

It’s a pity there isn’t something that reflects the same amount of light as the reflective meters are expecting to read.

Like a 13% grey card for example?

But it still wouldn't tell you what the brightness range was, so although it would be an adequate (if pointless) substitute for an artificial highlight incident light reading, it would be next to useless for negative film when photographing subjects with a brightness range greater than about 5 stops. You'd never know how much darker the deepest shadows were: the only way to do that is to meter them directly with a limited-area meter.

(Note to lurkers: yes, I do mean 13%, which the original Kodak research found to be the average reflectivity of outdoor scenes around Rochester, New York. The adoption of the 18% grey is one of life's little mysteries.)

Cheers,

R.

 

[gb hill]

I don't follow you here GB




Here you are assuming that beforehand the sun, or light SOURCE, is behind the photographer's back, making a kind of straight line sun-photog-subject.
And then you are right, you will point the white dome towards the same point where the photog is going to stand.

But what if, while the sun and sujbect remain constant in the above example, the photog decides to move 90 degrees to the left of the subject ? Then you will move 90 degrees the white dome, again pointing it towards the photog.

And always, again with strong light sources, you will shadow somewhat the white dome in order not to inflate too much the reading.

BTW, GB, light metering is rather a deep and complex science, with experience needed. And the Ecumenical Concilium raising in this thread is just a proof of it.

Therefore, my advice is to approach it from a practical angle suiting your current needs. If I am not wrong you own a metered Bessa. Are you having bad auto exposures ? In that case what you will be needing to learn is how to compensate and when to compensate your camera's Auto readings.

Cheers,
Ruben

I do have a metered Bessa, but I also have a hand held meter that I am trying to understand a bit better.

 

[Florian1234]

I also have a question regarding metering:

Do I have to get very close to the object for a reflective light reading with a hand-held meter? Or does it strongly depend on the situation. Let's say I want to do street photography - do I then meter my hand and then open up one stop?

Hope someone can point me in the right direction.

It was discussed in the photo course I took this week, but we went real close as for doing portrait. What about street for example?

Thanks in advance.

 

[Sparrow]

I also have a question regarding metering:

Do I have to get very close to the object for a reflective light reading with a hand-held meter? Or does it strongly depend on the situation. Let's say I want to do street photography - do I then meter my hand and then open up one stop?

Hope someone can point me in the right direction.

It was discussed in the photo course I took this week, but we went real close as for doing portrait. What about street for example?

Thanks in advance.

If you are photographing people the back of your hand +1 will give you the perfect exposure, ......if they are the same colour as you are that is, and you're in the same light, obviously

 

[Florian1234]

If you are photographing people the back of your hand +1 will give you the perfect exposure, ......if they are the same colour as you are that is, and you're in the same light, obviously

Good, thank you for the input. That clears it up.

 

[ruben]

I do have a metered Bessa, but I also have a hand held meter that I am trying to understand a bit better.

Ok, I will go to the most basic issue, and apologize beforehand if this is arleady known to you.

I would put the question in these terms: When the (reflective) meter in your Bessa is likely going to fool you, and you will do better by using your hand held meter with the white dome ?:

Whenever your subject appears small at the viewfinder and the background is of opposite tonality. This phrase needs a break down.

Suppose a situation in which you are photographing from afar a man with dark clothes against a big clear background. The man will appear rather small to the camera light reading. Then most of the chances are that the overall metering will by byassed by the big clear background, But the man was your subject, not the background.

In such a situation by having a white dome hand held meter, you simulate the position of the man against sun, position the white dome accordingly (see my other posts) and the hand held meter will give you a more balanced reading for your subject, than what the camera sees.

Of course that the opposite is also true, a white clothed lady against a dark colored background. And of course that your hand held meter shoud be reasonably accurate.

This is just for a start.

Cheers,
Ruben.