Metering For Snow With Incident Meter Question

[IanBarber]

I usually meter from the camera position, with the dome above my head pointed toward my back. - Leigh

For a snow scene would you just expose at the meter reading

[Leigh]

For a snow scene would you just expose at the meter reading

It depends on the subject.

Snow in direct sun normally has no detail (other than at the microscopic level).
I just let it go dead white.

If there is detail, it's usually the result of something else in the scene.
That may be other items like sticks, rocks, etc, or shadows from whatever.

If those details are significant and small, I may decrease the exposure by a stop to bring the highlights down a bit.
If they're significant and large, they should show up in a normal exposure unless you have lens flare.

The main way of controlling highlight density is with reduced development, not reduced exposure.

- Leigh

[chassis]

Another endorsement for incident reading. Sekonic's website specifically addresses incident metering with snow here: https://www.sekonic.com/united-state...-mistakes.aspx

[jp]

Just use an incident meter simply as it's intended, without adjustment.

[Doremus Scudder]

If it's a white cat on snow, you might want to decrease the exposure so that the negative is not completely black -- no detail.

If it's a black cat on coal, you might want to increase the exposure so that the negative is not completely clear -- no detail.

I know it is counter-intuitive in some ways, but with negatives, everything is bassakwards.

Maybe we need some clarification here to avoid confusion:

When you meter the white cat on the snow using a reflective meter, say a spot meter, the meter wants to make the snow middle grey, so will underexpose. In order to compensate, you must increase exposure.

This is the same as "placing" the snow in a higher Zone than Zone V if you're using the Zone System.

If you're metering the black cat on coal with a reflective meter, the meter will want to overexpose, so you must decrease exposure.

This is the same as "placing" the coal in a lower Zone than Zone V if you're using the Zone System.

If you are using an incident meter, you are not measuring anything being reflected from the subject, rather the light illuminating the subject. In most cases, all you need to do is take a reading and shoot.

In cases of extreme contrast, a bit of overexposure is advisable, since the average reading you get from the incident meter may not be enough to retain shadow detail. In this case, some development adjustment would be ideal, but not needed if you have enough leeway in your process to use less-contrasty paper grades.

Note that with incident metering you are not "placing" anything, but simply measuring the amount of light falling on the subject and finding the correct exposure to render all "Zones" correctly for a normal scene.

There are more sophisticated incident methods that take into account lighting ratios (i.e., incident readings of both main and secondary light sources such as sun and blue sky) that, like the Zone System, tailor exposure and development to the lighting ratio. The BTZS system is a good example of this latter.

Hope this helps,

Doremus

[Pere Casals]

Snow (fresh snow) reflects from 80% to 90% of sunlight, so this is some x5 more light than a grey card or what an incident meter says.

So, if you use incident metering reading then snow will appear some 2.3 stops overexposed and people faces will be ok, depending a bit on how snow itself is illuminating those faces, acting as a reflector. Snow overexposed 2.3 may be ok for color negative film but it may be too much for slides.

Note that a big mistake with incident metering happens when you are metering incident in the shadow while your subject is bathed by sun rays, then you are not metering the incident light arriving on the subject... it had happened to me while learning incident metering !!!



For metering with snow I use two ways, one is spot metering in manual monde, so I know what under/overexposure will result in each zone of interest. There is another way I use: the matricial mode of Nikon F5, it has a 1,005 segment RGB color matrix, so the F5 knows if a channel (R, B or G) will be out of range alone, this is important for color film, sometimes (with saturated subjects) exposure will burn a color layer of the film while a BW photometer may read lower.




The F5 uses the 1005 RGB segments meter, the latitude specification of film taken from DX bars in the 135 cassette, and a neural network that was trained with all important situations. When I meter manually, later I check what the F5 matricial meter says. The F5 is always right if you don't want using exposure as a creative tool, there is little chance that the F5 makes a mistake, even with snow challenging scenes.

Other SLRs are more prone to make mistakes in matricial mode because lacking the RGB metering. As F5 meter can see colors it detects sky, sea, forest, faces... if sun is in the framming it substracts the sun area from the calculations...

F5 is the best photometer ever (apart from Pro DSLRs, that have similar system, but not considering latitude, DX encoded) for a view camera and for color film... but one has to place a 135 cassette of the same emulsion to tell the photometer with what latitude we are to play.

[Luis-F-S]

When using roll film where you cannot change the development time for each frame, would it be better to meter a snow scene with an incident reading and if so, would you still open up the exposure by 2 stops above what the meter reading is telling you

This is what you'd do with a spot meter. I always use a spot meter since an incident meter tells you nothing about what you are trying to photograph. It's pretty much the same as measuring your hand with a spot meter and opening up one stop. You probably ought to find a Pentax digital with a zone dial and get a copy of Fred Picker's Zone VI Workshop book. About $5 used at auction. Or you could use Pere's methodology above, but the snow could melt by the time you figure out how to take the photo.

[Pere Casals]

an incident meter tells you nothing about what you are trying to photograph.

well... incident is not that bad... in some cases it is the best way to meter, delivering very consistent results.

Incident metering (with N development) will place in the toe those zones reflecting less than 10% of incident light to the camera (equivalent to 3.3 stops, from ISO speed definition), while highest reflecting zones (like snow, reflecting 85%) will be some 2.3 stops overexposed.

Problem of incident metering happens when part of the scene is not illuminated with metered incident light, for example the shadows of perhaps subjects emiting light, so we have to go there to take more incident light readings.

Or you could use Pere's methodology above, but the snow could melt by the time you figure out how to take the photo.

It is not always like this, yesterday night the snow did not melt, but I got nearly frozen while guessing the good HP5 exposure !!! Also I forgot the dark cloth at home so I was using my coat for it !!!

[IanBarber]

Thanks for all the replies. 99% of the time I have been using the spot meter for everything and incident for landscapes is fairly new to me so I need to bring myself up to speed with this method.

[BrianShaw]

Try it; you’ll like it.