Metering for window light portraits

[ndwgolf]

I'm going to be doing some nude window light portraits and have a question about the metering;
Do you meter on the models face back to the camera or out to the window light?
I plan on using a profoto B1 light as a fill light
Thanks in advance

 

[mike weeks]

personally I would say you meter to each lighting source, start with the window and then adjust the B1 to whatever level you want

Mike

 

[Garry Edwards]

The technically correct answer is that you meter to the lens, and the reason for this is that you need to measure the light that will reach the lens - if you meter towards the source of the light you will get a false reading, because no means all of the light that your meter sees will be travelling towards the lens - very basic physics.

BUT although metering towards the lens will, in the vast majority of cases give you a technically correct exposure, as with everything else in photography you need to interpret the information, because you may want to create a different effect.

 

[ndwgolf]

The technically correct answer is that you meter to the lens, and the reason for this is that you need to measure the light that will reach the lens - if you meter towards the source of the light you will get a false reading, because no means all of the light that your meter sees will be travelling towards the lens - very basic physics.

BUT although metering towards the lens will, in the vast majority of cases give you a technically correct exposure, as with everything else in photography you need to interpret the information, because you may want to create a different effect.

Thanks Garry that's what I thought, I just wanted to check

 

[sk66]

BUT although metering towards the lens will, in the vast majority of cases give you a technically correct exposure, as with everything else in photography you need to interpret the information, because you may want to create a different effect.

This is actually a situation where a reflectance (spot) reading is better suited, if your meter has that capability.

In this scenario, metering towards the camera may well result in blown out window lighting... of the window itself and where it falls on the subject. You could hold the meter flat at the subject position to meter both the light coming in from the window and what will be reflected by the subject. This will result in better exposure of the backlight/window, but make the subject darker (to be filled with the strobe).

Your best bet may be to meter directly towards the backlight, and then towards the camera. You can then use the difference in exposures to determine how far you want to offset, and how much fill you want to add. I'm assuming this will be a film shoot... if it were me, I would use a digital camera to set the exposure/ratios before I committed a bunch of film; a digital polaroid as such.

 

[Garry Edwards]

This is actually a situation where a reflectance (spot) reading is better suited, if your meter has that capability.

In this scenario, metering towards the camera may well result in blown out window lighting... of the window itself and where it falls on the subject. You could hold the meter flat at the subject position to meter both the light coming in from the window and what will be reflected by the subject. This will result in better exposure of the backlight/window, but make the subject darker (to be filled with the strobe).

Your best bet may be to meter directly towards the backlight, and then towards the camera. You can then use the difference in exposures to determine how far you want to offset, and how much fill you want to add. I'm assuming this will be a film shoot... if it were me, I would use a digital camera to set the exposure/ratios before I committed a bunch of film; a digital polaroid.

If you meter towards the lens then the meter will give a technically correct reading of the light that's falling on the subject. It will take into account both the window light, the fill light and any other light that is incident upon the subject, other than a backlight.
Obviously, if you include the window in the shot then yes, it will be over-exposed, but that is inevitable if the camera is set to expose the subject correctly.
The OP hasn't said, but I'm assuming that the window is being used only as a light source - but it's a nude shot, so it's possible that what he has in mind is a silhouette or a silhouette with fill, which is a different situation entirely - I do have some art nude examples of this type of lighting, but I don't think I should post them here

 

[ndwgolf]

This is actually a situation where a reflectance (spot) reading is better suited, if your meter has that capability.

In this scenario, metering towards the camera may well result in blown out window lighting... of the window itself and where it falls on the subject. You could hold the meter flat at the subject position to meter both the light coming in from the window and what will be reflected by the subject. This will result in better exposure of the backlight/window, but make the subject darker (to be filled with the strobe).

Your best bet may be to meter directly towards the backlight, and then towards the camera. You can then use the difference in exposures to determine how far you want to offset, and how much fill you want to add. I'm assuming this will be a film shoot... if it were me, I would use a digital camera to set the exposure/ratios before I committed a bunch of film; a digital polaroid as such.

Stephen
I will be shooting the whole shoot in digital. I do have a L758 DR (I think thats what it is and that has the spot meter feature.

 

[ndwgolf]

If you meter towards the lens then the meter will give a technically correct reading of the light that's falling on the subject. It will take into account both the window light, the fill light and any other light that is incident upon the subject, other than a backlight.
Obviously, if you include the window in the shot then yes, it will be over-exposed, but that is inevitable if the camera is set to expose the subject correctly.
The OP hasn't said, but I'm assuming that the window is being used only as a light source - but it's a nude shot, so it's possible that what he has in mind is a silhouette or a silhouette with fill, which is a different situation entirely - I do have some art nude examples of this type of lighting, but I don't think I should post them here

Garry
I am planning on using the window in the picture.
Below is a couple of film shots of the location where we plan to do the shoot.

 

[sk66]

If you meter towards the lens then the meter will give a technically correct reading of the light that's falling on the subject. It will take into account both the window light, the fill light and any other light that is incident upon the subject, other than a backlight.

I know you know this Garry...
An incident meter doesn't know ratios or directions as such, it just averages what it sees. If the window light is also rim light, or even side light it will be "overexposed" if it is much less than 50% of the reading (i.e. highlights/shadows don't average out to mid grey). Basically, if you take an incident reading pointed toward the camera the recorded image will look as the scene does to you (i.e. blown whites/hard blacks/etc). And if you take a spot reading from a mid tone area you'll get the same result. I guess you could call that the technically correct exposure... but it's quite possibly not the desired exposure.

Stephen
I will be shooting the whole shoot in digital. I do have a L758 DR (I think thats what it is and that has the spot meter feature.

I would probably not bother with the incident meter in that case. Heck, I would probably just use the B1 in TTL and lock it in once set... why not?

 

[HoppyUK]

It's a tricky metering situation and I'd probably favour Steven's method in post #5.

But heck, you're shooting digital - what's wrong with chimping? And let blinkies be your guide

 

[Phil V]

It's a tricky metering situation and I'd probably favour Steven's method in post #5.

But heck, you're shooting digital - what's wrong with chimping? And let blinkies be your guide

I have to agree with this.

We shoot window lit portraits all the time and we don't have time for 3 different meter readings and working out ratios.

Straightforward, pose subject in windowlight, shoot, check blinkies, adjust if necessary, check shadows, adjust pose as necessary, add reflector if necessary (often a pillow case).

Now if it was the basis for a portrait shoot I might take a bit more care, but all the above sounds more like navel gazing than shooting a pretty girl.