Landscape Photography Exposure Considerations
Posted: Saturday, January 24, 2009
by Phil McDermott
Phil McDermott Photography
Exposure control in landscape photography is one of the most important aspects of photography and fundamental to the principle of our photographic knowledge. To really learn how to master exposure we must use the creative controls on our camera and say goodbye to the auto settings.
Exposure is controlled by 3 things - the ISO rating, the aperture and the shutter speed. It is this relationship that controls the exposure. Although it is simply a relationship it is a very involved area of photography and a continual learning process so time spent understanding exposure will be invaluable.
Achieving the correct exposure is really a misnomer, what we are aiming for is an exposure that accurately records to the digital file what we want to record. If it is darker or lighter than we intended then we have failed to master exposure.
Landscape work is more often than not done on a tripod, this holds the camera still, enables considered composition and allows a small aperture to maximise depth of field. As we are using a tripod we can use a slow ISO setting, say ISO 100, a slow speed will produce an almost noiseless image. I would select this as a maximum speed for 90% of my landscape work, occasionally going down to 50 ISO if necessary.
Having set the ISO speed we can now consider the relationship between the aperture and shutter speed. If you change either one the other will have to be changed to maintain
this relationship.
Depending on the subject matter we have choices to make. If we want to cover a grand vista that is pin sharp from foreground to infinity we will need a small aperture, a large f stop number. If the converse applies and we want to isolate a flower or tree in the foreground and render the remainder of the image diffused and out of focus then we need a large aperture, a small f stop number.
These examples are extremes at either end of the f stop choices, reality states that we should use the most suitable f stop to portray the image as we wish it to be recorded.
By selecting Aperture Priority on the camera controls we are allowing the camera to select the shutter speed to match our preferred f stop to determine the exposure. We can of course over-ride this by adding or subtracting compensation to make the image lighter or darker. This is entirely under our control, the camera is our tool.
Our cameras digital sensor can record up to 6
stops of dynamic range so we need to ensure that our scene can be
contained within this range, failure to do this can leave the image with blown highlights or clogged up shadow. Depending on the subject matter we have choices to make. If we want to cover a grand vista that is pin sharp from foreground to infinity we will need a small aperture, a large f stop number. If the converse applies and we want to isolate a flower or tree in the foreground and render the remainder of the image diffused and out of focus then we need a large aperture, a small f stop number.
These examples are extremes at either end of the f stop choices, reality states that we should use the most suitable f stop to portray the image as we wish it to be recorded.
By selecting Aperture Priority on the camera controls we are allowing the camera to select the shutter speed to match our preferred f stop to determine the exposure. We can of course over-ride this by adding or subtracting compensation to make the image lighter or darker. This is entirely under our control, the camera is our tool.
There are time when the contrast range will exceed 6 stops, if so we can either use a neutral density graduated filter to lower the contrast of the sky or alternatively we can blend two differently exposed images in Photoshop.
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