What is the small +- wheel next to my view port for?

Question

I had a scare last night when everything in my view port looked blurry on my brand new Canon 60D, even the digital display a red focus boxes.

The images photos came out clear, the live view was clear, the auto focus was working but everything in the view finder was fuzzy.

I realized spinning/adjusting the small wheel next to the view port fixed this issue.

So my question is, why is this needed at all, what is it for? Is there a way to turn it off? I don't want to accidentally spin it again and make everything fuzzy.

Asked by John Isaacks

Answer

That control adjusts the diopter, an optical adjustment to the viewfinder that allows folks with varying vision abilities to see things clearly. Think of it a bit like reading glasses - it allows for minor vision correction. The idea is that folks who have decent vision but might need minor correction can make an adjustment on the diopter so that as they look through the viewfinder, objects are clear.

As you note, for someone with perfect vision, throwing and adjustment in there can actually make things look worse and cause problems with manual focus.

As it is a manual/mechanical adjustment, I'm not aware of a way to disable the ability to adjust the diopter, although a bit of gaffer's tape over the dial might help avoid inadvertent adjustments.

Answered by ahockley

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