Incident metering of shadows? Sandy King says so

RPC · Oct 28, 2014

John Koehrer said:
An incident reading will give you an average reading and you get an average exposure not influenced by the shirt color.

Not sure what you mean by "average reading" and "average exposure".

An incident meter, making use of an integrating dome, is calibrated to give you an exposure based on the assumption the light in front of the scene is integrated, or combined, not averaged. Done correctly, it should always put an 18% gray at it's proper place on the curve.

A reflected meter, on the other hand is calibrated to give an exposure based on the assumption the light reflected from the scene is averaged, not integrated. Done normally, it will put an 18% gray at it's proper place on the curve only if the scene metered averages to 18% gray.

markbarendt · Oct 28, 2014

Steve Smith said:
They will. On another forum, we had a long debate about incident metering with many believing that you point the meter dome at the light rather than the camera!

Steve.

Pointing the dome at the camera is just one way to get a reference point for deciding how to set the camera. For most people and most photos this is probably plenty.

As with spot metering though, incident metering can be used creatively/artistically.

Using the main light as a reference point is as well proven a method, as the "the normal" point at the camera method. The movie industry uses it a lot and it is well documented in books like "Exposure Manual" by Dunn & Wakefield.

Sandy King's and BTZS's use of shaded areas in determining camera settings is simply a way to peg to the "background/ambient" light and ignore the "key/main" light. It is a refinement/special case use.

bdial · Oct 28, 2014

Steve Smith said:
They will. On another forum, we had a long debate about incident metering with many believing that you point the meter dome at the light rather than the camera!

Steve.

If you are balancing studio lighting then you do point it at the light, but for determining exposure, you would point to the camera most of the time.

The exception might be in situations where you have strong highlighting where most of the subject is in shadow and you want to preserve the highlight details by exposing only for the highlight.

Bill Burk · Oct 28, 2014

chiller said:
For those that bag incident metering one man's spot metered zone 3 is another man's zone 3 1/2 or zone 2 1/2 so in reality is there such a thing as a real zone 3 consistently in a scene. [I do know there is by the way on a step wedge] Interpretation of what you personally decide is your zone 3 will impact all aspects of your work flow. Use of a spot meter doesn't guarantee correct exposure, it doesn't even guarantee consistency because of flare with the 1 degree spot meter in varying light conditions. Neither does an incident meter unless your system has been fully tested based on how you intend to meter. I personally use Incident metering with BTZS and the ExpoDev but I also have a Pentax 1 degree spot that works equally as well with BTZS.

BTZS testing is much more efficient than Zone system testing because in just five sheet you have all the information you need for full BTZS or the traditional ZS. Even if you don't go as far as running paper tests. Set the ES at 1.05 -1.10 and you will be fine.

When it is all said and done no one should be able to tell how you metered a photograph, either spot or incident, what system you used or even the camera because all are tools for correct exposure.

chiller,

That's true, if you do Zone System reflected spot metering of a subject in shadow might be the bark of a tree or a gray rock, and these two things might put the needle in different places, and when you place the reading on Zone III even one person looking at the same scene might get different readings for the same photograph... I think it probably amounts to a difference that "does not matter" because in both cases your readings would lead you to give sufficient exposure.

BTZS testing with 5 sheets is really standard sensitometry. (I do the same kind of tests with my sensitometer and densitometer and paper charts derived from the Density/Log Exposure charts invented by Hurter and Driffield)...

markbarendt · Oct 28, 2014

bdial said:
If you are balancing studio lighting then you do point it at the light, but for determining exposure, you would point to the camera most of the time.

The exception might be in situations where you have strong highlighting where most of the subject is in shadow and you want to preserve the highlight details by exposing only for the highlight.

The highlight reading is also used when duplexing to protect both shadow and highlight.

Highlight "pegs" are regularly used for silhouettes, partial or full. And anywhere the scene needs to look normal in relation to, for example, a street light; in that situation faces may be allowed to look darker than in typical portraits.

Old-N-Feeble · Oct 28, 2014

Steve Smith said:
They will. On another forum, we had a long debate about incident metering with many believing that you point the meter dome at the light rather than the camera!

Steve.

Wow...

Old-N-Feeble · Oct 28, 2014

I'm not going to walk several hundred yards so I can hunker down in the small shadow area of a scene and take an incident meter reading. I'm also not going to leave footprints in the snow (if present) to take a meter reading. I'll stick with my spotmeter, thank you very kindly.

John Koehrer · Oct 28, 2014

RPC said:
Not sure what you mean by "average reading" and "average exposure".

An incident meter, making use of an integrating dome, is calibrated to give you an exposure based on the assumption the light in front of the scene is integrated, or combined, not averaged. Done correctly, it should always put an 18% gray at it's proper place on the curve.

A reflected meter, on the other hand is calibrated to give an exposure based on the assumption the light reflected from the scene is averaged, not integrated. Done normally, it will put an 18% gray at it's proper place on the curve only if the scene metered averages to 18% gray.

Ayup. So you're saying in a bunch of words that it's averaging. You're combining(averaging) the light. BTW it's not the "light in front of the scene", it's the light falling onto the scene.

The reflected reading is average as long as "the scene metered averages to 18% gray". Quite a few people don't understand that doing things normally IE:directing the camera or meter towards their average scene will give less than an optimum exposure. That's like aunt Ethel standing with her back to the sun when you take her portrait without correcting the exposure. Even with today's WunderKamera it's easy to screw it up.
While shooting landscapes, how many photos have you seen where the sky is burned out and foreground is black?

RPC · Oct 28, 2014

John Koehrer said:
Ayup. So you're saying in a bunch of words that it's averaging. You're combining(averaging) the light. BTW it's not the "light in front of the scene", it's the light falling onto the scene.

The reflected reading is average as long as "the scene metered averages to 18% gray". Quite a few people don't understand that doing things normally IE:directing the camera or meter towards their average scene will give less than an optimum exposure. That's like aunt Ethel standing with her back to the sun when you take her portrait without correcting the exposure. Even with today's WunderKamera it's easy to screw it up.
While shooting landscapes, how many photos have you seen where the sky is burned out and foreground is black?

The light in front of the scene is the light falling on the scene, that is what I meant. In an incident reading the dome may "average" all this light but the meter is not assuming the light averages 18% as in a reflected reading to give a correct exposure.

Yes, most scenes probably don't even come close to exactly 18%. That's why metering an 18% gray card is better for reflected readings.

Old-N-Feeble · Oct 28, 2014

Here's my take on BTZS...

Less complicated does not necessarily mean better. And how much less complicated is it really... especially if one is forced to walk 200 meters to hunker under a shaded area and "guess" at what things in that shaded area need more or less exposure vs. what one's incident meter reads? For me, it's far easier, faster and more accurate to take spot meter readings from the camera position.

We can all argue until we're blue in the face but all you BTZS folks, in your deepest of hearts, know we spotmeter folks are right.

markbarendt · Oct 29, 2014

Old-N-Feeble said:
Here's my take on BTZS...

Less complicated does not necessarily mean better. And how much less complicated is it really... especially if one is forced to walk 200 meters to hunker under a shaded area and "guess" at what things in that shaded area need more or less exposure vs. what one's incident meter reads? For me, it's far easier, faster and more accurate to take spot meter readings from the camera position.

We can all argue until we're blue in the face but all you BTZS folks, in your deepest of hearts, know we spotmeter folks are right.

Well, here's an update for you ONF, actually BTZS works fine with either spot or incident metering, the choice of meter type is left to the photographer.

The reason that measuring incident light is "simpler" than measuring reflected light, is that reflected light readings require "human judgement" or a "known target" to be usable, incident readings do not.

As to having to walk 200 meters to get a reading, not.

The reason many people regularly take incident readings at the subject is because the meter is being used to deal with artificial light. For example a portrait under a street light or in a studio; places where subject to light source distance matters. For sunlit or sky-lit scenes there is no need to be under the subjects nose with the meter.

If I'm 200 meters from a sunlit subject (and I'm not standing in a cave looking out at the subject) then standing where I'm at: if I point the incident meter directly at the sun then I get the highlight peg; if I point the incident meter directly away from the sun then I get the shaded peg (equivalent to the reading Sandy King suggests in the shaded area); if I point the incident meter at the camera then I typically get something in between.

Edit: to mimic Sandy Kings idea more closely it may require shading the meter say with an open hand and spread fingers so that you mimic what the meter might see under a tree. This is simply a refinement that one might make based on experience and in my experience very reliable. Sandy's direct measurement is easier if you are close to the subject and less prone to error.

baachitraka · Oct 29, 2014

Old-N-Feeble said:
Here's my take on BTZS...

Less complicated does not necessarily mean better. And how much less complicated is it really... especially if one is forced to walk 200 meters to hunker under a shaded area and "guess" at what things in that shaded area need more or less exposure vs. what one's incident meter reads? For me, it's far easier, faster and more accurate to take spot meter readings from the camera position.

We can all argue until we're blue in the face but all you BTZS folks, in your deepest of hearts, know we spotmeter folks are right.

Reflected metering with known target(gray card) may require to run that long too...

The overall confusion with incident meter i.e., where to place the meter is still prevalent.

MartinCrabtree · Oct 29, 2014

I'm going to give that a shot.......or twenty. I'm relatively new to using meters other than in camera and open to options. I've found incident metering to be foolproof. And when it comes to exposure I can be a fool.

John Koehrer · Oct 30, 2014

"Can't we all just get along?"
"Agree to disagree?"

It all sounds just like politics or religion only worser.

Vaughn · Oct 30, 2014

MartinCrabtree said:
I'm going to give that a shot.......or twenty. I'm relatively new to using meters other than in camera and open to options. I've found incident metering to be foolproof. And when it comes to exposure I can be a fool.

Basic law of evolution -- Make something foolproof, then Nature makes a better fool.

markbarendt · Oct 31, 2014

Vaughn said:
Basic law of evolution -- Make something foolproof, then Nature makes a better fool.

Giggle.

markbarendt · Oct 31, 2014

John Koehrer said:
"Can't we all just get along?"
"Agree to disagree?"

It all sounds just like politics or religion only worser.

Much of the discussion is a matter of faith and a defense of that faith.

The reality is that either type of metering system can be used well with experience.

Regular Rod · Oct 31, 2014

Vaughn said:
Basic law of evolution -- Make something foolproof, then Nature makes a better fool.

Brilliant!

RR

MartinCrabtree · Oct 31, 2014

Vaughn said:
Basic law of evolution -- Make something foolproof, then Nature makes a better fool.

How kind of you.

John Koehrer · Oct 31, 2014

Constant evolution isn't it?
Something about a theory proposed by a fellow named Darwin I believe.

Sirius Glass · Oct 31, 2014

Sirius Glass said:
Sandy King's method will work. An other method which I use us to decide on the zone level for the shadow, set my Gosen Luna Pro SCB light meter for that zone and use the spot meter attachment set on the shadow.

I shall continue to reflect on the method that I use.

Incident metering of shadows? Sandy King says so

Privacy & Transparency

Privacy & Transparency