Super Tiny Grey Soil Bugs

There is a particular patch of my garden where the soil seems infested with extremely tiny grey bugs.  They're very hard to see, given their size and color.  In fact, I noticed them sort of by accident when I disturbed some soil with my hand and saw movement.  I had to get down at ground level to really see them.

I took some video, but honestly, unless you maximize to full screen, you can't really even see them.  If you could see them, what's useful about this video is that a roly poly bug ambles through and you can compare the size - the roly poly bug looks like a volkwagen compared to the grey soil bugs.

Some other characteristics of these bugs:
- They are fast and if disturbed will hop like fleas
- I have never seen them on any plants, only in the soil
- They do not appear on the surface of the soil.  It's only when I dig down a little that I see them.
- Their bodies appear pear-shaped.
- I can't tell how many legs they have

I haven't seen them before and haven't observed them elsewhere in my garden this year.  I have a theory that they might be springtails, but I am not sure. 

I wonder if they could have been part of the problem with my radishes, because where I'm seeing them is my former radish patch (which was also overrun by ants). 

Thoughts?