Does one sometimes also use exposure compensation on incident metering?

[peterB1966]

I have noticed that they always talk about 50% grey for reflective metering, but it seems unclear if this is what incident metering works towards as well, so it is unclear if I should make the same EC decisions here?

 

[wiltw]

incident meters should result in about the same exposure as pointing a reflected light meter at midtone target (18% grey)

Unlike reflected light meters, incident meters are not fooled by a black background or a white background, so there is no fundamental need for 'exposure compensation'. But if a scene contains a wider-then-typical dynamic range of brightnesses that do not fit within when the film can capture (or what the sensor can deal with) you may need to alter exposure and bias the exposure so it captures that portion of the range which would otherwise be lost details (and sacrifice at the other end of the scale)

 

[peterB1966]

incident meters should result in about the same exposure as pointing a reflected light meter at midtone target (18% grey)

Unlike reflected light meters, incident meters are not fooled by a black background or a white background, so there is no fundamental need for 'exposure compensation'.

So let's say I am shooting the cliched "buddhist monks in a really dark monastery" shot ... if the incident reading also tries to average it to 18% grey, does that not mean this dark scene will be too light?

 

[wiltw]

So let's say I am shooting the cliched "buddhist monks in a really dark monastery" shot ... if the incident reading also tries to average it to 18% grey, does that not mean this dark scene will be too light?

No. If the scene has light falling upon it which says to expose for EV5 and assuming the range the film can capture is EV3 to EV10, the incident meter will say EV5 = 'proper exposure' although the middle of the brightness range (EV3-EV10) is at EV6.5

The incident meter does not detect that an extra wide dynamic range scene has elements at EV1 and EV14, although measurement with 1 degree spotmeter might show the presence of stuff at both EV1 and EV14.
The middle of the brightness range is EV7.5, but the incident meter reads the light intensity falling on the scene at EV5

You might decide that the range of EV1 to EV14 far exceeds the range the film can capture, and you might decide that there is too-important detail at EV13, so you decide EV14 down to EV7 is what can be captured in the film, so the middle of that range requires an exposure of EV10.5, even though the light falling on the scene is at EV5...so YOU are compensating based upon what you thought was important, and ignore the incident meter.
Lest that kind of situation be dismissed as unreaslitic, imagine light just around sunset and you are shooting the glowing molten laval of a volcano and the orb of the setting sun partially below the horizon is in view.

 

[peterB1966]

...

Much appreciated ... OK, so pretty much like if I use EC with my digital camera's matrix metering then, i.e. I still make an evaluation on the overall scene and add compensation?

 

[Bill Burk]

No, not like a histogram. You don’t usually compensate for dark or light dominant subject unless you mean a slight compensation (which is sometimes recommended). The incident meter reads light falling in the scene ignoring what bounces back. So your normal readings are already “integrated” for the shot.

There is some technique though. Whether you use the flat sensor (retracted dome) or the dome. Whether you are physically able to be at the subject location or not. If you can’t be at the subject (e.g., landscapes) is the lighting the same as where you are (cloud cover).

Beyond The Zone System (BTZS) gives a whole school of thought about the technique of “simulating shade” and evaluating Subject Luminance Range. I recommend it as a tutorial for Incident Metering.

But generally if you aim the incident meter at the camera from the subject you use the reading as-is.

 

[Sirius Glass]

The short answer is "No, never."

 

[Bill Burk]

The short answer is "No, never."

Agreed.

 

[pentaxuser]

Peter, this may not be strictly relevant to you but I offer it for what it is worth. The attached video describes a case where an exposure based on a spot reading appears to have the edge over an exposure using an incident one. The presenter explains what was needed in the spot exposure v the incident one

The difference is shown at about 17 mins 40 secs if you want to go straight to that moment. I need to add that both are pics of scanned negatives as prints. I think he is a hybrid worker so not darkroom prints but i found his comments interesting



pentaxuser

 

[gone]

You're going to have to base your metering decisions based on what's happening at that given moment. If you're shooting landscapes, it's obviously impossible (or highly unlikely) that you'd travel to the mountain in your viewfinder to meter in w/ an incident meter. I use a technique" that many photographers use. Just hunt around for something near you that's the same value, or a middle value, like the grass under your feet, or the palm of your hand probably. If I'm shooting a portrait, I'll just walk over and meter off the subject's face w/ a reflective meter. The values should be exactly the same as w/ an incident meter.

 

[Chan Tran]

I have noticed that they always talk about 50% grey for reflective metering, but it seems unclear if this is what incident metering works towards as well, so it is unclear if I should make the same EC decisions here?

OK I need to point out a number of things here.
1. I don't think they talk about 50% gray but rather 18% or there about.
2. Some said the 18% gray isn't true but what's true is that the 18% gray is what connect the incident and reflected light meter.

 

[Paul Howell]

The only time I rigorously used incident metering was for commercial color product shots, studio under hot lights, in the field natural light. Otherwise I find reflective meter to work better for me, I carry a small 18% gray card or use my the palm of my hand if I'm in trickily and bracket. If you shoot sheet film you use Phil Davis Beyond The Zone System, he advocated using a incident meter to determine scene brightness range, and then the magic or was it the wonder wheel or software to calculate shutter and F stop for a given film.

 

[peterB1966]

OK I need to point out a number of things here.
1. I don't think they talk about 50% gray but rather 18% or there about.
2. Some said the 18% gray isn't true but what's true is that the 18% gray is what connect the incident and reflected light meter.

As I understand it this is a 50% average, but the 18% refers to the printing process used to arrive at it.

 

[peterB1966]

The short answer is "No, never."

Agreed.

Love the short answers. Too often technical types start answering questions you didn't even ask, and you get even more confused
Bill, you have been so useful since I have joined this forum, I may as well just come straight to you!

Peter, this may not be strictly relevant to you but I offer it for what it is worth...
pentaxuser

Much appreciated - will give it a look.

 

[MattKing]

The short answer is "No, never."

Unless you want the result to be either darker, or lighter than what "correct" exposure would be.
And you only do that very rarely - usually you do that at the printing stage instead.

 

[wiltw]

The only time I rigorously used incident metering was for commercial color product shots, studio under hot lights, in the field natural light. Otherwise I find reflective meter to work better for me, I carry a small 18% gray card or use my the palm of my hand if I'm in trickily and bracket. If you shoot sheet film you use Phil Davis Beyond The Zone System, he advocated using a incident meter to determine scene brightness range, and then the magic or was it the wonder wheel or software to calculate shutter and F stop for a given film.

It must be mentioned that the palm of most hands is +1EV brighter than an 18% grey card..regardless of the race of the owner of the hand!
My Asian hand just now measured precisely +1.2EV, compared to measurement of a genuine Kodak 18% grey card, for example, and will not change by much even if I was well tanned at end of summer by a pool.

 

[Chan Tran]

As I understand it this is a 50% average, but the 18% refers to the printing process used to arrive at it.

Actually not! The printing process is 50% the reflectance is 18%

 

[wiltw]

Actually not! The printing process is 50% the reflectance is 18%

And, if you took a photo of an '18% grey' card with a digital camera, and then interrogated it with the postprocessing eyedropper tool which reports R-G-B values, the values reported would come out very close to 50% density in all three channels. Using my Canon 7DII, I get values of about 48.5%, the last time I did that test, which was very recently.

 

[Chan Tran]

And, if you took a photo of an '18% grey' card with a digital camera, and then interrogated it with the postprocessing eyedropper tool which reports R-G-B values, the values reported would come out very close to 50% density in all three channels. Using my Canon 7DII, I get values of about 48.5%, the last time I did that test, which was very recently.

Actually the digital value is about 117 which is slightly less than half but very close to half. Reflection density measurement would be 0.75 density. It's considered the mid point of the exposure scale in most cases. So OK you can call it 50% but I haven't heard anybody said so before.
Now many people said that meters are not calibrated to 18% gray and I don't argue right or wrong but the 18% is really the connection between reflective and incident light meter.
For a reflective light meter calibrated to K14 and an incident light meter with a flat receptor calibrated to C250 then the reflective meter will give the same reading from the 18% gray card as the incident meter under the same light.

 

[wiltw]

Actually the digital value is about 117 which is slightly less than half but very close to half. Reflection density measurement would be 0.75 density. It's considered the mid point of the exposure scale in most cases. So OK you can call it 50% but I haven't heard anybody said so before.
Now many people said that meters are not calibrated to 18% gray and I don't argue right or wrong but the 18% is really the connection between reflective and incident light meter.
For a reflective light meter calibrated to K14 and an incident light meter with a flat receptor calibrated to C250 then the reflective meter will give the same reading from the 18% gray card as the incident meter under the same light.

Charlie, every postprocessing program is a bit different. I use Lightroom and it reports values from 0% to 100%, another programe might report R-G-B values as 0 - 255 for the identical sample area.
In Lightroom, 50% is dead center of its histogram; the historgram peak of a grey card filling the frame falls at 50%..mid tone between black (0%) and white (100%)

 

[BobD]

The short answer is "No, never."

You don't compensate an incident reading when using lens filters?

 

[BrianShaw]

You don't compensate an incident reading when using lens filters?

LOL... I’ll bet he does!

 

[Chan Tran]

Once again what is EC? If it means the Exposure Compensation on the camera then NO. At times you do increase or decrease exposure from an incident meter reading but not using the EC on camera.

 

[Paul Howell]

It must be mentioned that the palm of most hands is +1EV brighter than an 18% grey card..regardless of the race of the owner of the hand!
My Asian hand just now measured precisely +1.2EV, compared to measurement of a genuine Kodak 18% grey card, for example, and will not change by much even if I was well tanned at end of summer by a pool.

That true, my palm is about 3/4 of a stop lighter than a gray card, zone VI rather than zone V, still in a pinch, better to overexpose than underexpose and lose shadow detail. In day to day shooting I generally rely on my Minolta and Sony matrix metering, shooting 4X5 I either use a spot meter or a digital camera body's matrix metering, MF tend to use a digital body or my Gossen in which case I use a gray card.

 

[Sirius Glass]

You don't compensate an incident reading when using lens filters?

Yes, but that was not the question. The question was getting the exposure before adjusting for filters.