Focusing Distances

So you're one of those kooky people that like your images in focus? In that case we'll need to introduce you to the happy family and their pet mountain on the edge of your lens.

The Loner

This fella is your first focusing point. He'll focus approximately 3ft (0.91m) in font of your camera. For me, that's the length of my arms plus 1ft.

The Menage a Trois

These cheeky chaps will focus approximately 4-6ft (1.83m). That's about the size of your average 6ft person.

The Party

These septuplets focus approximately 8-10ft (2.74m) away. That's roughly the distance from floor to ceiling in the places I visit.

The Mountain

This one is mysterious. It's labeled as infinity, so if your object is very far away, spin your lens round to this. In reality this could be anything from 18ft upwards.

Note: One rule of thumb that many forget is that depth of field is one third in front of the focus point and two thirds behind. So when guesstimating the focus, always error in front of the subject (thanks TPO'Dell!)

Want proof?

I recently conducted a super-scientific test comprising of light meters, tape measures and marker pens. You can find my results on Flickr.

Estimating Distances

Estimating distances can be quite hard at first, but with experience it becomes second nature. If you need a little extra help estimatiting, there is an excellent reference card you can use, called the Human Rangefinder. You start by putting in a few details; such as your arm length, the distance between your eyes, and the focus distances (3, 5, and 9 feet). It will then generate a card for you to print out. To use the card you simply follow these steps:

Hold the card in your hand at arm's length. With your left eye, line up the '0' marking with a vertical element of the object you wish to measure the distance to. Now look through your right eye. The distance measurement that lines up while looking through your right eye is the one you want.

I'll be recording a video explaining the process soon, but in the meantime, check out the video on Figital Revolution.