Exposed! :: Advanced exposure techniques and the Zone System ::
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The man ahead of me at the commercial photo lab lamented the dreary weather that caused his dull winter arctic photos. He had shot some beautifully desolate snow scenes.
Sadly, I could see his 'dull photos caused by dreary weather' were actually all underexposed. Sometimes, accomplished, self taught hobby photographers miss learning the intricacies of exposure.
So, in this edition of Exposed! we delve into finer points of exposure including Ansel Adams' Zone System - it's not just for film users!
The Basics
Mastering light levels
Modern cameras use a reflective light meter to help achieve the correct aperture and shutter speed for a given ISO. Your camera's meter measures the quantity of light reflecting from your subject and then:
- lets you interpret the information to set your shutter speed and aperture manually or
- sets shutter speed and aperture automatically or semi automatically
These light meters compare tone, not colour. Tone is the black and white version of your colour photo scene. For instance, candy apple red will register as slightly darker than mid tone gray - part way between black and white.
The meter encourages you to expose the final photo to be mid tone gray - or 18% gray - on average, even if the scene is much brighter (white snow) or darker (black tuxedo).
This provides excellent results if the scene is, in fact, 18% gray. But sometimes it is not!
Snow scenes, white wedding dresses, black tuxedoes and shaded backgrounds are far from 18% gray and will fool the camera's meter - as they did for the accomplished amateur arctic photographer.
Meter Systems
Most modern cameras have three different meter systems:
- spot
- centre weighted
- a highly technical system that balances the scene's diverse light
Each system will give you different results depending on the scene. The spot meter helps you read light levels on small, specific elements of your subject. There are times the other meters will be useful. Read your owner's manual to find out more.
Shooting modes
Modern SLR cameras have four main metering modes:
- Manual
- Aperture Priority or Aperture Value
- Shutter Priority or Time Value
- Program
With photo fundamentals under your belt, manual mode gives you full control. You set the shutter speed and aperture based on your analysis of the light reading. This mode, with some training and experience, gives you excellent creative control and allows you to get brights bright and dark elements as they should be!
The other modes are automatic or semi-automatic modes (different and separate from auto-focus). The camera makes most of the exposure making decisions and takes creative control away from you.
What are you exposing for?
I encourage all our students to explore in manual mode.
... And I ask them "What are you exposing for?"
Mastering light levels
Shooting in manual mode with a spot meter and being consciously aware of the diverse light and compositional elements in your scene will help you get - not just a good exposure - but an excellent photo.
The pumpkins above were shot in the same location with the exact same light sources. The only difference was what was exposed for. Experience and understanding of exposure allow many creative options!
Iconic landscape photographer Ansel Adams developed the Zone System of Exposure. It is a way to quantify and adjust exposure for light levels in a scene as part of the process of creating an exceptional photo.
Pulling it together
It's easy to get mediocre photos most of the time when you rely on your modern camera's technology. With patience, knowledge, experience, and an allowance for mistakes you can produce consistently good photos that capitalize on diversely lit scenarios.
Chris, graduate of Creative Fundamentals, recently took my portrait, below, in manual mode. I did not move - he made calculated exposure adjustments to create the silhouetted and backlit versions. The photos took seconds to capture.
Easy!
Mastering light levels
Homework
1. Explore the ideas of exposure at a more advanced level:
- how are tone and colour different?
- how does your camera's meter attempt to get a correct exposure?
- explore skills to shoot manually, comfortably... all the time! This will give you more control and better photos in the long run.
2. Explore the ideas of Ansel Adams' Zone System via:
Pro Perspective
In my work I use manual mode and a spot meter 99% of the time. It's quick, easy and gives me complete control.
Shooting the canoeist at the top of the newsletter would have produced different results using an auto exposure mode. Achieving the exposure the way I wanted - and there were not many chances to get it right - required an understanding of exposure and the control of manual mode.
Final Frame
Take a chance - invest the effort in learning to master exposure in manual mode!
Take photos. Have fun.
