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Back of hand metering by Mark Cornwell

Submitted by on October 10, 2010 – 11:10 amOne Comment
How well do you know the back of your hand?
If you are a photographer you should get to know it better!
Here is a corner of my garden. The table and the chair on the left are in the sun. The actual exposure values on this one are irrelevant but I’m happy with the exposure.
Here is the histogram for that shot:
Apart from the very first shot in this article all shots are straight off camera and sized for the web (the first one was cropped slightly).
Here is the back of my hand. I take this picture regularly. The background is the shrub by the shed. I have spot-metered off the back of my hand and it gave me a reading of ISO 200 1/125th at f/8.0
The exposure looks fine to me. But when I say I spot-metered off the back of my hand what I did was meter the back of my hand and turn the dials until the needle was exactly one stop above the “middle” reading. I know that the skin of my hand (unless I’ve got a serious suntan) is a stop above the mid-point on my Canon 5D (mk I or mk II). It might be different on a Nikon – or even on another Canon. But for the Canon that I use that is where it lies.
Where does your hand lie on your camera meter?
Why on earth do I even want to know?
Here is a black pop-up, spot metering on it gave me 1/30 at f/8.0 – that’s two stops less than my chosen setting to get the needle in the middle. It doesn’t look *horribly* bright does it? Well maybe when you look at it and think that it is a black object not a gray one. The camera has seen the object and tried to expose it as a mid-tone.
Here’s my hand again. 1/125th f/8.0 The exposure looks good on the hand and the background and that flag are as dark as they ought to be.
Now compare that first shot of the chair in the shade with the pop-up. Looks about right to me. If I had relied on the exposure scale in the camera I would have worried that it was flashing “under exposure” by more than two stops.
So that was a black object. (Like maybe a groom’s suit.)
What about a white one (Like a bride’s dress.)
Spot metering off the white reflector (the other side of the pop-up to the black) I zeroed the needle in the middle of the exposure scale at 1/640 at f8.0 (note I’m keeping everything but shutter speed constant here so you don’t have to work out the equivalent exposures!)
Of course the reflector is gray as anything. The camera has assumed it is a gray object with lots of light on it and has tried to under-expose it to get the exposure right. Well it has managed to under expose it. It looks awful.
Back to my trusty hand. 1/125th at f/8.0. If anything I’d say I the reflector is a touch gray still. But my hand is OK and there’s enough latitude in RAW if I wanted to fine-tune that.
Here we are with the 1/125th at f/8.0 all looking good still… as above I might want to fine tune that exposure just a touch to brighten it.
Remember that silver/gray table at the top of the article. I checked exposure with the spot meter on it too and the camera told me 1/250th at f/8.0 which is a stop less than I have been using so far. At 1/250th it looks a bit dark to me – about a stop dark. The shininess of the surface may have fooled the meter.
Here is my hand again, and a bit of the table, at our regular 1/125th at f/8.0. It looks fine now.
And finally the table at 1/125th at f/8.0 looking just perfect.
Have you noticed something yet?
At the start I metered my hand at f/8.0 and 1/125th of a second. The light levels have not changed at all through this sequence and I could have ignored the meter completely and worked at 1/125th f/8.0 in this spot and been close enough for all of my shots without metering anything.
If you know the “sunny 16″ rule (http://en.wikipedia.org/wiki/Sunny_16_rule) I was shooting at ISO 200 so 1/200th and f/8.0 for overcast but this was a little more like heavy overcast (f/5.6) so opening up to 1/125th is nearly the same thing.
I have then got two things telling me that my exposure should be around 1/125th at f8.0:
  1. Sunny 16
  2. The back of my hand.
Try this experiment for yourself in some constant lighting conditions to see what the back of your hand meters to with your camera’s spot meter. Then, the next time you wonder about exposure try using the back of your hand to check what you are going to do.

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  • http://www.morethanaphotograph.com Mark Cornwell

    The problem with typing stuff and putting it in a blog is sometimes you miss mistakes until it is too late!

    “I was shooting at ISO 200 so 1/200th and f/8.0 for overcast but this was a little more like heavy overcast (f/5.6) so opening up to 1/125th is the same thing.” should have read “nearly the same thing”

    In other words opening up one stop f/8.0 to f5.6 but that would have been 1/200th going to 1/100th so my choice of 1/125th is 2/3 of a stop difference not a full stop. I did of course cross check with shooting a 1/100th but it was too bright for my liking so I went for 1/125th which matched what my “hand reading” was telling me anyway.

    As I spotted it on re-reading I thought I’d better clarify before someone queries it! :)