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02 December 2010

How to place exposures?

Following my article on "Feel the light - on the edge of darkness", there have been requests on how to take such photos. I have taken some time off to write my experience and thoughts on this subject. Of course I do not expect everyone to agree with what I have written. These are thoughts and methologies based on my personal experiences accumulated over the years.

Introduction

The human eye some says is able to capture about 15 stops of exposure latitude that is without the iris changing its size. However, the best photographic medium can only record 9 stops.

Trying to emulate what the eye sees has been a dream for most photographic product researchers.

Given the limitation of the medium, Photographers have to find creative ways to work with it.. One of the methods is the creative placing of exposures.

What are the light measuring methods?

Newbies to photography are often bewildered about the use of the exposure meter and how to meter a situation. Most built-in camera exposure meters (be it- average, spot or matrix metering) are programmed to meter 90% of the various lighting situation. There will be 10% of the situation that would fool the camera meter to read wrongly. It is this 10% situation that makes the photo stands out. Some may disagree with this statement, so be it. I am not here to convince anyone but relate my personal experience with metering an exposure.

A brief explanation on the difference between 2 methods of measuring light

Firstly, a brief explanation about the difference between reflective and incident metering. Reflective metering is measuring the light that is reflected from an object. A black object and a white object under the same lighting conditions will have different meter readings. All built-in camera meters fall into this category.

Incident light metering on the other hand is the measuring of light falling on an object. So both a black object and a white object will have the same light measurement. Most handheld meters read incident light (ambient light)


Learning how to see light

Learning how to read light is not that difficult. When I first started photography (not so long ago), we were taught to look at the scene first, look at where the light is coming from, then frame it with the camera’s viewfinder. We even made rectangular cardboard frames and bring it out for shoots so that we can have a very good feel of how the “picture is painted”

Today off course, most photographers instantly take the camera up to their eyes and try to find the best angle and if the angle is not that good they just zoom the lens without moving the feet. After clicking they just look at the LCD and if it sucks just press the delete button. It is not that bad actually it gives instant gratification but most photographers have lost the art of “smelling the flowers.” Some says photography is a journey. I can’t say the same for the professional photographers who have to meet deadlines and clients’ needs.

Pre-visualizing

Before the shutter is pressed, a photographer should pre-visualise on how the final image should look like. Deciding on what exposure value to use for a photo is the right of the photographer. (I don’t think one should surrender this right to the camera’s electronics)

Understanding the zone scale

All light meters (reflective or incident) are calibrated to read an 18% grey (some may read 12% but then it is another story). So wherever you point the camera’s meter, it will read 18% grey.

If you increase the exposure by one stop, the resulting image will look lighter, while the opposite is true for decreasing by a stop. Here is the zone scale for an easier understanding.





Understanding exposure latitude (DR) of the film / sensor.

All sensors, film or digital have exposure latitude (DR). One should take some time to find that out. I am very used to Tri-X and I have tested it to have an exposure latitude of 7 to 7.5 stops.



Metering for film or digital sensors

Metering for negative film, slides and digital sensors are different. For negative film one would meter for the darkest shadows and underexposed by 2 to 3 stops to retain shadow details.. For slides and digital sensors, one would meter for the brightest part of the photo and overexposed by 2 stops to prevent the clipping of the highlights.

Of course the digital guys will say, but we have a histogram to help us…..yes by that time the scene might disappear….and you will need to press the delete button.


How do you place an exposure? (A practical example)

1. Pre-visualisation
I wanted to capture the multi-purpose living space in this house. However, I respect the privacy of the occupants. In order to create a relation of this living space with the background I decided to show some details of the countryside.

2. Deciding on what exposure to use
I use eye metering most of the time and this photo is no exception. For eye metering I am comfortable to work with EV nos. Some may use a different system. An example on how the lighting conditions in that living space are shown here.

I wanted to show very little detail of the occupants and yet show the feeling of a crowded space.

By placing the exposure at EV 9, I visualized that the details of the occupants will be in the shadows while the brightest part of the image will show some details.




Cheers! Hope you all enjoyed reading my rantings.
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credit: Maxby -PM

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