Eclipse Alert: Total lunar eclipse coming January 20/21, 2019

On Monday, January 21, 2019 from 0236 GMT until 0748 GMT there will be a total lunar eclipse. For those in the U.S., I'll translate. The lunar eclipse will run from Sunday, January 20, 2019 at 9:30pm EST until Monday, January 21, 2019 at 2:45am EST.

In North and South America, the entire eclipse will be visible from the penumbral, to partial, to full eclipse and back again. Other parts of the world will be able to see all or much of the lunar eclipse, though much of Asia and Oceania will miss it entirely.

What the heck is back button focus & why do I need to use it?

When most people make a photo with their camera, they aim, press the camera's shutter release button, wait for the camera to focus, then press the button the rest of the way. Whammo, the image is made.

While that's easy and direct, if you're using a DSLR (Digital Single Lens Reflex) or MILC (Mirrorless Interchangeable Lens Camera) camera, it may not be the best way to focus and shoot. Until 1989, it was the only way to activate autofocus and make a photo with an SLR (Single Lens Reflex) camera, the film based forbearer of today's DSLR and MILC cameras.

It wasn't until 1985 that autofocus was even available. That year, Minolta, having purchased Leica autofocus technology, released the first commercially successful autofocus SLR, the Maxxum 7000. Minolta configured the Maxxum autofocus system to work as most photographers know it today. Autofocus was activated by pressing the shutter release button.

Four years later, in 1989, Canon introduced back button focus. It removes the autofocus function from the shutter release button and assigns it to a button on the back of the camera. Hence the name, back button focus.

Before you switch from DSLR to mirrorless, know how they compare

Compare 7 key areas of DSLRs versus DMIL cameras

With the new Nikon Z series full-frame, digital mirrorless interchangeable lens cameras (DMIL) and Canon's new full-frame EOS R DMIL camera, Sony now has significant prosumer DMIL competition. Now that these manufacturers are fighting it out for supremacy in the quality DMIL market, I think we can expect that improvements in DMIL feature sets and image quality will accelerate significantly in upcoming years.

Major improvements are needed for electronic viewfinders, autofocus on fast-moving targets, battery life and low-light image quality, especially for future pro-level DMIL cameras.

If you're considering a move from DSLR to DMIL cameras, here are seven key areas you need to consider before making the change.