Focus… Focus!

I’ve been fiddling around with my camera again lately, and my feature-of-fiddling has been aperture, as it relates to the focus of the camera.

Like a lot of people who get into photography (or so I assume), it’s a little mind-bending at first with all the terms… focal length, depth of field, f-stops, aperture, etc. How they all relate to one another is a bit confusing at first, and a bit of a pill to swallow. So I’ve been taking it one step at a time – or one term at a time, anyway.

Much of my first experiments with the camera were with shutter speed. This was handy for taking pictures in the darker parts of my house (as long as I could hold the camera still), and it is pretty easy to understand – the shutter stays open longer, and lets in more light.

Slightly less easy to understand is the concept of aperture and how f-numbers relate to it. In a way, it’s similar to shutter speed in the fact that aperture is how large an opening is used when the camera takes a picture, but at the same time, it’s different, because focus is also involved. A larger aperture lets in more light (of course) and can be used in low light situations the same way a slower shutter speed can. It’s useful because if you have a big hole to let in lots of light, you might not need to use such a slow shutter speed – and therefore, there’s less chance of a blurry photo (which happens when something moves while your camera is taking the picture). All of this is basic photography stuff, but there’s a real “connection” that happens when you actually SEE the results from what you’re doing in the field (or, y’know, wherever you actually take your photos). Hands-on learning, as it were.

What’s confusing about aperture is the f-numbers. Bigger f-numbers (like f-22) mean… smaller apertures? And smaller numbers mean bigger apertures? Even now I’m never 100% sure I’ve got it around the right way. But maybe that confusion is just me.

The other interesting side of aperture is focus. (Which, coincidentally, is the topic of today’s post!)

Focus can be a powerful tool for turning an otherwise “boring” photo into something interesting. Having just the foreground (or the background) in focus can really draw the eye to your subject and make a photo interesting, as opposed to “just a picture.” And it can make things more “realistic,” too – because after all, the human eye can only focus on one thing at a time (although we do it so effortlessly that we sometimes forget that we re-focus our eyes when we look at something near and then something far away). In real-life, we don’t see everything in focus all at once – but a camera can do that. Or, rather, it can come close.

Here’s where it gets interesting.

The smaller an aperture gets, the closer your camera comes to describing the “ideal” pin-hole camera, which has an infinite focus. If you never made a pin-hole camera, just click on that link to read up on it.

The interesting thing is that just from that tidbit of information, you can figure out that when the f-number gets bigger and bigger (as the hole gets smaller and smaller) the depth of field (the amount of the picture that’s in focus) gets bigger and bigger, until it reaches infinity (or rather, it “approaches” infinity). Just from that information, you can derive the relationship between aperture and focus. (There’s some tasty math in there if you want to try it yourself.)

So, boring pictures – the kind that you see so often in vacation pictures from those disposable cameras people buy, or from so many point-and-shoot cameras that are always left on “automatic” mode selection – are taken with a small aperture. Everything is in focus and the picture looks… flat. Boring. Unrealistic. I’m sure we’ve all taken photos like that at least once (or more probably, hundreds and hundreds of times!).

So on the flip side, if you open your aperture up, or bring your f-number down (if I have it the right way around), you get a smaller depth of field – less of your picture will be in focus. And that can produce really neat effects!

The grand-daddy of this of course leads to “macro” photography and the “macro” (or in my camera’s case, “super macro”) mode – something you’ll see on many cameras, often labeled with a picture of a flower (because it is so often used for taking pictures of flowers, you see). I love macro mode because it makes it easy to take the kinds of pictures I find visually interesting.

Kind of like this:

lettuce closeup

It’s nothing but lettuce, but the macro mode makes it interesting – you can see the drops of water on the lettuce, but the leaf up close to the lens is out of focus, which only helps to lead your eye more to the leaf that is in focus… and that’s a simple, but powerful, effect used by many photographers.

The other side of the focus coin, of course, is movement. (Ok, it’s not really focus, it’s blur, but it’s close enough.) We’ve all taken what we thought was a great photo, only to have it turn out blurry because we moved, or our subject moved.

Well, it turns out (as I’ve now learned through experience), that a little bit of motion blur can add that sense of “motion” to an otherwise boring photo. It suggests action and implies movement… it adds energy to the photo. And you’ll see professionals use it to great effect!

Learning to use it yourself, of course, can be a bit of a trial… and it may involve lots of error. In fact, it almost certainly will. But hey, that’s why digital is so great – photos are free!

The trick is to have a background that isn’t moving and a subject that is – or vice versa. Trust me on this one, getting it just right can be hard, and has a lot to do with lighting. I’ve only just figured it out myself, and I’m still not 100% sure how I did it. But that’s how we learn now, isn’t it!

Anyway, I’ve rambled on enough to throw the whole point of this post – if I may – “out of focus.” And with that bad pun, I leave it to you to go out and experiment with some settings and almost certainly come back with some blurry, out of focus pictures.

I hope they look great!

Author: Keith Survell

A geek, programmer, amateur photographer, anime fan and crazy rabbit person.