In Sharp Focus

Sharp focus is one of the five basic requirements of a quality image.   It's so fundamental, I think it's the most important.  If you have bad exposure or bad color, you can sometimes correct in post production.  But focus? It's very difficult to correct.  So, best to be sharp right off the bat.

To focus, you need to zoom all the way in, set the focus, then zoom out to your preferred framing.  

Many people rely exclusively on auto focus.  But, depending upon your camera, this can be dangerous.  You have to understand the idiocyncracies of your auto focus.  Our auto focus wants to focus on the brightest spot.  So, if we're watching  a couple on the dance floor, but the walls are washed in lights, you guessed it.  The focus will be on the back wall!  Or, if you are focused on the aisle that a bride will be walking down and the back door opens to a brilliant sunny day, your auto focus will be pulled to the back of the church and will stay there until the doors are closed. 

The auto focus also loves vertical lines. So, if you are trying to focus on someone walking on the sidewalk, the focus will be pulled to the vertical slats of a wooden fence. These are at least two reasons that it's important to master manual focus so that you can stay focused where you want to. 

It's much easier to focus in daylight.  But what happens indoors after sundown?  It is MUCH more difficult to focus.  Why?  Because the contrast is low.  The subject you are trying to film must be lit to some degree in order for the camera to focus.  So, if you'd like to become proficient, try practicing focusing in low light conditions.

When to Use Manual Focus

I can think of at least four situations where manual focus is a must.

1.  In low light conditions.

2.  Shooting through glass, wire fences, or veils.  The camera gets confused where to auto focus, so manual focus will avoid this.

3.  Fast moving objects (or people).  It can be very difficult to keep a fast moving object in focus.  One way to overcome this is to set the camera to manual focus, prefocus on one fixed point and watch the subject move through it.

4.  When filming people, make sure their eyes are in focus, especially when shooting them close up.

When is it OK to use auto focus?  When the dance floor is lit and the surrounding area is dark.

Three Tips on Manual Focus

TIP 1:  Try to get your focus when the camera is off so the raw footage doesn't have constant zooming.

TIP 2:  If your subject is a constant distance from you, note the distance.  Then, you can always return to that focus.

TIP 3:  When in doubt, zoom out.  The wider the angle of view, the more of the scene appears to be in focus.