From reading the notes on this exercise we are to find out about the cameras light metering capabilities in auto mode compared to Manual Mode
I found these cards in the back of The best Abode Photoshop CS5 book for Digital photographers by Scott Kelby. So I set the camera in auto mode and proceeded to take images of the black, grey and white card. The focus didn’t matter as long as the tone filled the viewfinder. Trying to take an image of the white card wasn’t going to plan. I tried it with flash to see what the histogram looked like for comparison then I went outside and took a picture of a white wall which showed a less messy histogram for the purpose of this exercise.
The histogram horizontally charts the tonal values of a scene that is photographed. the pure black is at the far left and the pure white is at the far right on a scale of 0 – 255. The vertical axis shows the number of pixels in each particular tone.
Here are the images of the histograms with the camera in auto mode.
From the images in Auto mode you can see the peaks for white and dark are quite close to the middle grey tones area, they are bunched up effectively.
Here are the images of the histograms with the Camera in Manual. These are more effective because the white and black tones are definitely situated further away from the middle grey tone.
The thing I have learnt when looking at histograms is that the goal is to prevent your histogram bunching up too much at the far ends, which indicates that the details are lost in pure whites or pure blacks. Ideally the histogram should start at the bottom left corner and rise into a mountain peaking in the middle of the chart ( mid-tones) and gracefully taper off back down to the bottom right hand corner, similar to a bell curve.
In Manual setting achieving the perfect exposure is easier and more creative because you can use the cameras light meter as a guide. The thought process is I pick my Aperture depending on what I what my image to exhibit with respect to composition then I adjust the shutter speed accordingly so that the marker on the exposure indicator returns to ‘0’. If I change my aperture to be wider I will need to reduce the shutter speed to be faster. Switching the camera into manual mode gives you complete control over Aperture, shutter speed, ISO and focus.
I’ve found that I am increasingly shooting in manual because I get frustrated with Aperture/Shutter priority settings. Getting the image I want and what I have to set the camera at to achieve it is getting easier the more practice I have. As the coursework suggest the intuitiveness comes over time.