My overdue visit to Galway last weekend was nice and relaxing, as a visit to Galway should be, and included a Sunday stroll in Knockbrack, where we were once again enjoying the hospitality of friends. The walk was a chance to get out and enjoy some fresh air and sunshine and so was a walk to nowhere in particular, but the ultimate destination ended up being a patch of woodland which lies off a road that itself leads off the road from Athenry to Monivea. And in there, I found this photograph. Actually I found a slightly different photograph which I took first. You can see that image below, but first a useful tip about photographing green.
The tip about green is something I picked up from Bryan Peterson’s excellent introductory book “Understanding Exposure”, which is a must-read for any photographer, particularly beginners (but is also a book experienced photographers will find good to dip into every now and then to reinforce the basics). He calls the tip “Mr. Green Jeans”, which is a reference that is a bit lost on me… perhaps I’m not from the right era or country to get it?
The tip is simple. If you meter off something green, the correct exposure is the one that is 2/3rds of a stop below what your camera is telling you. It is useful if, for instance, you’re photographing a bride with fair skin, blonde hair, and a white dress, holding a bouquet of flowers. If she and the flowers are in the same light, and you zoom in and spot meter off some green in the bouquet, adjusting your exposure by -2/3rds of a stop down from what the camera gives you as the “proper” exposure will mean that everything else in the photograph will be correctly exposed. And that tip, in my experience, works pretty well.
For a scene like above, if you’re photographing something which is predominantly green the tip reminds you to adjust the exposure for the overall scene by -2/3rds of a stop. I applied this adjustment using exposure compensation in aperture priority mode, but you could also of course override the camera using manual exposure controls.
The reason I was in aperture priority mode was that my first instinct with this scene was to maintain some depth of field and use a small aperture. I tried f/16 but the shutter speed was too low, and rather than increase the ISO (no real reason why I didn’t, other than ease of control) I opened up the aperture until the shutter speed was something I reckoned I could hand hold. f/11 gave me 1/20s, which I can just about manage more often than not (shooting weddings will improve your slow shutter speed capabilities pretty quickly!).
That gave me this:
Reviewing it on the LCD screen – also known as chimping, because the story goes that when a photographer sees he’s got a good one on the screen he goes “oooh… oooh… oooh….” like a chimpanzee might do – I was bothered by dominance of the highlight on the left edge of the tree at the left of the frame. I decided to see how it might look if I opened up my aperture (adjusting my shutter speed accordingly) to get a shallow depth of field, and throw that highlight out of focus.
I chose the stump in the foreground as the focal point (as I had for the first image) and the result is the photo you see up top. The exposure here – f/2.8 @ 1/320s – is equivalent to f/11 @ 1/20s. Of course, if the camera had had its way I would have overexposed both of these frames by 2/3rds of a stop.
That wouldn’t have been catostrophic for the second frame, given that I could have probably recovered over-exposed areas in post processing from the RAW file, but it would have changed the first frame by pushing me to f/9 instead of f/11 to maintain that self-imposed limit of a 1/20s shutter speed. Perhaps not a big deal for this particular scene, but you can see circumstances where an unintentional over- (or indeed under-) exposure like this could end up dictating artistic elements to your exposure (such as depth of field) unnecessarily.
So even though you can recover over- and under-exposed areas in post production, it still pays to know these little quirks of exposure, and to try to get it right in camera.
I never knew about the -2/3 thing. I just took some pictures at a park and wondered why exposure settings were off. It’s worth mentioning there’s a 3rd edition of that book available for preorder. Comes out August 10, 2010. Have this on my wishlist and may be the first photo book I’ve bought as exposure is one of those things that can still get the best of me. The link to 3rd edition is: http://www.amazon.com/dp/0817439390/
Not to turn this into a book club, but in a later post maybe mention some of the books you enjoy even though you know your stuff. Seems like a lot of the books I find are geared towards beginners. I understand things like the exposure triangle, difference between spot and evaluative metering, aperture values and what they mean (man, that took YEARS to finally “click”), even have a basic understanding of off-camera lighting. I guess after looking at that list I need to evaluate what it is I’m trying to improve before I go book hunting. Like for example why I meter something and it still doesn’t come out exposed “properly” (the camera thinks it’s proper, but I don’t). Guess that’s why I’m excited about this book since it’s finally something I can see I need to improve on. But I’m stubborn and see a new edition is coming out so I HAVE to wait till that one comes out.