Spot meters – who needs ‘em? And because they are useful tools, providing you understand exposure really well, and are useful for certain difficult situations, people use the spot metering in their DSLRs.
Here are three boring images, SOOC JPG files. The top one used my Alpha 7R III’s multi-area mode.
The one below took a spot reading from the sky. And the shot at the bottom took the reading from the gutter outside my bedroom window (no expense spared to get imaginative shots of glamorous locations for THIS blog!)
Now, for some specific purposes, you might want to use the spot readings, but for most purposes, they are utter rubbish. The problem is that a spot reading takes the exposure from a very limited area of the frame, usually marked in the viewfinder.
If what is in that spot is bright (lie the sky) the camera will expose to render it as a midtone. That’s a problem if you wanted the bright area to appear bright in the finished image… Similarly, if the spot is over a dark area (like the gutter), this will be a midtone, and highlights will be blown.
It can sometimes (but not very often) be useful to use spot metering and exposure lock (as I did for these shots). But the best way to use it is in Manual model, taking the exposure from the area that you want, and consciously adjusting the exposure to get the tonal values that you want.
With any auto mode and varied tones in your subject, spot metering will change the exposure as you change the composition. That’s really not a great idea.
Program mode and spot metering? Well, if this is something that you think is OK, I suggest you look up ‘moonsault’ on YouTube, and consider whether you’d be happy with your children giving that a go when they’re having a tussle with a friend in the playground. Every TV broadcast of professional wrestling includes the advice ‘Don’t try this at home, at school, or anywhere else’ – and that’s my advice on spot metering!