Session 5: EXPOSUREHow a light meter worksHistogramsExposure Compensation
The light meter in your camera is reflective, meaning it sees light as itbounces off of objects. The tonal value of those objects are assumedto average out to middle gray. Light meters are not yet intelligentenough to know what they are looking at. Most times, this works out just fine and dandy.
1. Multi / Matrix / EvaluativeIf you go into yourcamera’s shooting (name differs with differentmenu, you will see it camera manufacturers)is a bit more Takes into account manycomplicated than that. different points and their relationship to each other. ItYou can set your also may place importancemeter to read light on areas in focus.from multiple pointswithin the image, or a 2. Center Weightedsingle point in the Assumes your subject is incenter. Having control the center of the image andover this can be places importance there,helpful in different excluding the sky or other light sources that mayshooting situations. confuse the reading. 3. Spot / PartialIn this class, we are You can meter at one pointgoing to use the of your choosing (the ideamatrix / evaluative being, that you are sure thismode. It is pretty darn point is middle gray).smart and good mostof the time.
So what happens when thesubject is not middle gray atall?A bright or all white subjectwill come out looking gray, orunder-exposed. A dark or allblack image will come outlooking gray, or over-exposed.Luckily, we are going to learnto fix this problem using theexposure compensation (+/-)button on your camera.
Another common situation where exposure compensationcomes in handy…
And another…If you want silhouettes and rich sunset tones, you’ll have totell your camera to underexpose.
In some high contrast situations, you get to choose which part of theimage you expose for. In this case, the outside (window) or inside(plants). The lighting is so different between outside and inside, you simply can’t have them both exposed properly.
OR CAN YOU?!!! New HDR (High Dynamic Range) technology is nowbeing incorporated into some DSLR cameras. The camera takes twoexposures and stitches them together to get more detail and overallbetter exposure.We won’t be working with HDR in this class, but feel free to check yourcamera manual to find out if yours can do this, and how.
Meet your new best friend, the HISTOGRAM!!!!Histograms show us a map of where all the tonal values occurin the image. The higher the graph, the more pixels the imagehas in that tonal range. This histogram must be for an image with lots of mid-tones, and not too many highlights. This tool is very helpful while shooting and later when editing our pictures in Photoshop.
To the right, seehow the histogramshifts to the left orright as theexposure changesfor the same image.Here we see thathistograms are likebeautifulsnowflakes, and notwo are the same.For a brighterscene, the graphshould lean towarsthe right
What you don’tever want, is thegraph to spike offeither side. Thatmeans you arelosing detail,which is VERYBAD. You can’tever get it back.
Refer to your cameramanual to find out how todisplay histograms whileshooting. Differentcameras have differentfunctions. Some will evenblink over the image if youare losing highlight detailin an area.
Assignment #4:BE SMARTER THANYOUR METERThis week, we are going topractice with exposurecompensation by photographingscenes that would confuse themeter.WHITE ON WHITE- filling theframe with all bright valuesBLACK ON BLACK- filling theframe with all dark valuesBut, I’m sure you guys will comeup with more creative picturesthan this.
One way to approach this would be looking around to find a scenethat is naturally “black on black” or all dark values.
… or “white on white” in the world around you.
Or, if you have an idea you want to try you can create a “white onwhite” or “black on black” situation for yourself. Set up a still life…
…or ask a friend to model…(but PLEASE DO NOT ENDANGER ANY BABIES. THANK YOU)