I have the Nikon z 5 ii camera and shoot in auto iso. I’ve done this with previous Nikon cameras. So I wanted to try something different. I took auto iso off and set it manually. My photos seemed to turn out very nice. The setting I was using was manual. Do a lot of shooters just shoot with auto iso. Does the camera always get the correct exposure or is it touch and go. I will probably go back to auto iso since that’s what I normally use.
Auto ISO is a tool. It handles changing light quite well. It's not perfect - and sometimes is the wrong tool. Sometimes Auto ISO is simply more trouble than it's worth.
Auto ISO uses your camera's metering choice. There are several choices. Matrix metering consider the entire frame, incorporates scene recognition, and weights the subject more heavily so it can get closer to the correct exposure. But it can miss - and you have to use Exposure Compensation to adjust your exposure as needed. The most common reason for it missing exposure are changes in the luminance of the background (much lighter or darker), changes in the brightness of your subject (especially white or black clothing), and the size of the subject in the frame. Other metering modes weight the center of the frame or the subject more heavily - or meter based on a specific part of the frame. Every metering mode is subject to errors.
No - the camera does not get exposure right every time if lighting and scene are changing - it's up to the photographer to understand what the camera tells them, how it determines exposure, and whether adjustment is required. Experienced photographers can read a scene and know that it needs an adjustment of + or - 1.5-2.0 for exposure compensation and have a minor exposure adjustment when editing. But if the scene does not change and you set up your exposure correctly, the camera is completely consistent and will produce the same exposure for every frame.
Sunny 16 is always the same. If your subject is in full sun, the exposure never changes and is based on the Sunny 16 rule. That exposure works for anything that is in the sun.
Constant light on your subject - even if it is not full sun - still means a constant exposure. The exposure only changes when the lighting changes. This applies to light clouds, overcast conditions, shade, or even astrophotography.
Depending on your scene and metering choice, changes in the scene, subject size, subject clothing, etc., automated metering requires exposure compensation to adjust the exposure so the exposure is correct. Manual exposure simply locks in those settings. Manual with Auto ISO is just another automated exposure choice. You still need exposure compensation for the correct exposure.
When you have situations with constant lighting, you don't need Auto ISO. A fixed ISO is more predictable and does not require constant adjustments to Exposure Comp as backgrounds, subject distance, and subject luminance change.
Arthur Morris photographs primarily birds - wading birds, shorebirds, and similar subject. One of his first steps it to determine the sun angle so he chooses an angle of light where the subject is well lit. Creatively he can make choices and use other settings for other lighting situations. Ideally he'll spend an hour or two working subjects with the same lighting - so the exposure does not change and every subject is perfectly lit. Using this method I've photographed birds in full sun for more than an hour without needing to make any changes in exposure even though I was photographing white and dark birds with water, sky and sand as backgrounds.
For birding photography - photographing subjects where the primary goal is bird observation and identification - you spend a very short time on each subject, the bird is small in the frame, and subjects can be at any angle with any lighting. Auto ISO is a lot more useful in this scenario because light on your subject is constantly changing.
Here is an example of where Fixed ISO pays off. The same subject group made a single pass in formation and the background was all that changed. With Manual and fixed ISO every image was perfectly exposed. If you used Auto ISO you would need to adjust Exposure Comp every frame or two and might be forced to make corrections using your editing tool - if those adjustments were even possible.
The great option you have with Auto ISO is it is easy to activate. You can set your camera for a fixed ISO, but if light changes and you need an automated exposure, just hold the ISO button and rotate the front control wheel to switch to Auto ISO. Repeat the process to switch back to a fixed ISO.
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Eric Bowles
Eric Bowles is an Atlanta based commercial photographer specializing in the Southeastern United States. His specialty areas include nature, equestrian, events, sports, and bird photography. His work has been published in magazines, newspapers, and commercial publications. He is a regular speaker...
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