As we sometimes do, I'm going to base this week's assignment on questions that were asked during a previous assignment. Towards the end of the Zone VII assignment, several people asked questions about how to use the manual exposure mode for their cameras. Based on those questions, I thought it might be helpful to take the time to cover manual exposure in more depth. So, I needed to pick a topic that would have you use manual exposure again. This week's topic is "Zone VI." For ease of reference, I'll provide the Zone System diagram and description of the zones again.
(http://spiritofphotography.com/coppermine/albums/userpics/10001/image001.jpg)
Zone I Black without any texture
Zone II Black with slight suggestion of tonality
Zone III Darkest areas that still retains visible detail
Zone IV Average shadows in landscapes/portraits
Zone V Middle Gray - 18% gray card
Zone VI Average Caucasian skin
Zone VII Lightest areas that retain visible detail
Zone VIII White areas with slightly visible textures
Zone IX Glaring white surfaces - Highlights
Zone X A light source (maximum white)
As you can see, Zone VI is defined (in our modified zone system) as one stop above "mid-tone," or +1 EV on your camera's manual exposure scale. Simply spot meter on a subject that you want to render in Zone VI, and set your shutter speed and aperture so that your exposure scale displays the reading as +1 EV on the scale. Having trouble finding something in Zone VI? How about "average caucasian skin?" One benefit of this exercise is to get you to consciously think about the tonality (brightness) of skin tones reproduced in your images.
This is also a fun opportunity to experiment with "guessing" the tonality of colors and seeing how close you get. I challenge you to find colors that you perceive as belonging in Zone VI, and then photograph those colors at +1EV to see if you were right. (Yellow, or any of the pastel colors might be good colors to try.) Again, this experiment should be able to help you "nail" the exposure of challenging colors in the future. Not everything in life is "average tone" or Zone V, and as a good photographer you should be able to modify your camera's exposure settings when needed to capture the scene properly.
Since most of the questions about using manual exposure came from individuals that use Canon dSLRs, I'll base the rest of my discussion on setting manual exposure in the Canon system. The first step is to put your camera's mode dial in the "M" or manual position. Once you have placed the camera in this mode, setting the exposure is up to you. For this assignment you will need to choose a shutter speed and aperture combination that results in an exposure reading of +1 EV on the exposure scale. For "rebel" type Canon dSLRs, you adjust the shutter speed with the "main dial" (the wheel by your index finger when it is resting on the shutter release button), and you adjust the aperture by holding down the Av+/- button on the back of your camera by your right thumb and rolling the main dial. As you change the shutter speed and aperture, watch the exposure scale in your viewfinder so that you can set it properly at +1 EV. Your exposure will be indicated by an "exposure level mark" underneath the scale that will move as you adjust your shutter speed and aperture. Adjust your shutter speed/aperture combination so that the exposure level mark is underneath the "1" on the plus side of the scale. (Note that for Nikon cameras, the scale is reversed, and "+" is actually on the left side of the scale. This is because with Nikon cameras, we have historically moved the controls to the left to increase exposure, and so Nikon reversed their scale to keep the directions consistent.)
Semi-Pro and Pro level Canon cameras have an added "Quick Control Dial" on the back of the camera that is used to adjust the aperture. To enable the Quick Control Dial you must set the camera's on/off switch to the "Quick Control Dial" setting above the "on" position.
I talked earlier about using "spot metering" to take a meter reading of your subject. This might have been confusing for readers that have Canon dSLRs from the Rebel (or 3-digit model number) series, since these cameras don't have a "spot" metering mode, but a "partial area" mode instead. The difference between "partial area" and spot is that the partial area covers a much larger area of the viewfinder/scene than spot metering. The "partial area" metered in this mode corresponds to approximately 10% of the viewfinder at the center of the frame. (Roughly equivalent to a circular area contained within the vertical AF sensor locations in your viewfinder.) Using "partial area" often requires you to zoom into an area of your frame to take your meter measurements, and the zoom back out to compose the scene. Use the (http://spiritofphotography.com/coppermine/albums/userpics/10001/canon_metering_symbol%7E0.jpg) button on the top panel of your camera to select the partial area metering mode. Readers that have semi-pro "d" (or 2-digit model number) series Canon dSLRs (such as the 50d), or pro "D" (or single digit model number) series Canon dSLRs should have a spot metering mode available as one of their options. This metering mode covers approximately 3.8% of the viewfinder at center, and is indicated by the center circle in your viewfinder.
A notable difference with Nikon's implementation of spot metering is that the Nikon spot metering area is always tied to your selected focus point. As you move your selected AF point, you are also moving the area that will be metered when in spot metering mode. Spot metering for Nikon cameras covers about 2.5% of the viewfinder centered on the selected focus point.
If you have any questions about how to use the manual exposure mode on your camera, please ask questions and give me the opportunity to clarify this assignment.
The assignment for the week of 8 - 14 March 2010 is to use manual metering mode and spot/partial area metering to properly expose a subject with a "Zone VI" exposure. Please upload your images to the "Zone VI" album in the weekly assignments category of the Gallery no-later-than midnight Mountain Time (GMT -07:00) on Sunday, 14 March 2010.
I'll look forward to seeing your images! (Especially the "fun" images where you attempt to properly capture a Zone VI color.)
Keith