How The “AUTO” Setting Works On Your DSLR

How The “AUTO” Setting Works on Your DSLR

by William Lulow

I had to make some images of my granddaughter’s second birthday party the other day. I decided to set the camera on AUTO just as an experiment to see if if would be any easier than taking a reading each time I wanted to make an exposure. It was a fairly bright day, but the lighting was both in shade and in direct sun all at the same time. As I was shooting with the camera on AUTO, I was aware of the flash popping up from time to time. I was busy making shots so I didn’t really think about it that much. I should have. Because it was telling me that there wasn’t enough light at the settings I had to make a proper exposure. So the flash automatically popped up to provide the necessary light. I should have increased the ISO rating to compensate for the camera not seeing enough light.

What happened was that I did get some nice shots, but too many were just a bit too soft. This is because the camera, on AUTO was trying to compensate for the cases in which the light wasn’t bright enough by either slowing down the exposure or opening up the aperture, or sometimes both. When the shots were all in bright sunlight, it had no problem yielding the correct exposure. Had this been a regular commercial job, the client would have been disappointed.

The lesson is that it always pays to take meter readings of whatever scene you are shooting and decide FOR YOURSELF, what your settings should be. That way, you are assured that you will always be shooting at optimum speeds and apertures for whatever purpose you would need. Here’s one example:

This image was shot on AUTO and it’s not too bad. The setting adjusted for the changing light but had to slow the shutter speed down to compensate. Thus the feet are a bit blurry. The image does not stand up to a decent enlargement, however.  Here’s another example:

This is also fairly sharp, but again a slower shutter made the feet blurry. Her face is fairly sharp. Neither of these shots would be acceptable for use in a brochure, for example. They might be okay if used smaller, on a website.  And yet another example:

This one is a decent snapshot, but again, isn’t sharp enough to stand a good enlargement.

With children running in and out of the sunlight, and knowing that these would probably only be reproduced as 4×6″ snapshots, I decided to give AUTO a try, as I said. If this was a real assignment, I would have  set up some extra lights and used my normal, large reflector as a third light on the camera.

This is what you can expect if you leave your exposures to the discretion of your camera’s computer chip. They are fun shots, but not high quality enough for any commercial use.

The “AUTO” setting is probably something to avoid if you are really concerned about getting good shots. With changing light conditions, you really need to know what your standard exposure for shade and full sunlight and switch between them in MANUAL mode as required. It almost never works to let the camera’s computer make exposure decisions for you.