Yesterday’s Topic: Depth Of Field – Change Your Distance/Zoom
We played around with how to change our depth of field by changing our aperture, focus points and distance/zoom. Now let’s bring them all together to see if we can find a way to get everything in focus; from the closest object to infinity.
Warning: This technique is really hard to master with a point and shoot where you don’t know your focal length. If you have a point and shoot, you might want to skip this and instead enjoy some photos of Petra By Night.
You’re going to need a tool for this one. I suggest a site called DOF Master. It has the ability to print out charts for you and it has apps for your mobile device to run these calculations. I always tell students to use the charts and print them out because the charts will never run out of batteries. It also has a page that let’s us calculate hyperfocal points without downloads or apps. But if you do want to download it for an iPhone, click here. It’s $2. Here’s an Android version and it is by a different company, but the concept is the same.
What are we trying to do in this experiment?
The basic premise we are trying to learn here is how to get everything in your field of view into focus. Hyper focal. Rabid (I like that definition best) focused. It’s close to rabbit focused so we’ll go with it.
Not only are your trying to get everything in focus, you’re likely trying to get very near things and very far things in focus. You’re trying to achieve this:
Everything in the foreground is in focus, everything at ‘infinity’ (the the farthest points we can see, in this case) is in focus.
Here’s the experiment you can run:
1) Before you head out, do the research and then find a location. Or print this page and then download a DOF app.
2) On the DOF Master page, put in your camera model, pick a focal length of 18mm if your lens has it, if not, go for 30mm. Also put in an aperture of f/11 and let’s say we want to have an object at 5.5′ in focus. Put all that in and it will spit out some info on the right side of the screen.
3) On the right, you are trying to get the far limit to be “Infinity”. Keep playing with the numbers until you get there. I suggest leaving your f-stop and focal length the same and adjusting your subject distance. It’s a little trial and error at times.
4) Once you have “Infinity” listed, look at the “Hyperfocal distance” on the right. This is the distance at which you need to focus. If your lens has a distance scale, great! If not, you will need to estimate distance as closely as you can.
5) Take note of “Near limit” on the right as well. That is the closest an object can be to your camera and still be in focus. This is very important.
6) Now head outside. Watch for traffic.
7) First let’s lock your focus and set up your camera. Switch your camera to Aperture Priority. Choose ISO 400 and set your aperture to the number you inputted on the DOF calculator. In the example above, it’s f/11.
8) Now find an object that is the same distance away as your “Hyperfocal distance”. You may need to estimate or maybe you can measure it out. I am usually good at estimating distance and I will stand X feet away from a flat wall and focus. Once you have focused, switch to Manual Focus so it doesn’t change. You can also just manually focus from the start, whichever way. If your lens has a distance scale on it, switch to Manual Focus and use that instead of guessing.
Focus is set. Aperture is set. ISO is set. Your camera will pick a shutter speed and frankly we’re not too concerned about that right now, so good on it for helping. In the future, you can switch to Manual Mode and choose it if you like, but for this lesson, don’t sweat it.
9) Now find a scene where your near object is at the “Near limit” distance you memorized (or have handy on your phone) and you can see to the horizon, or pretty close to it. You may need to crouch down a little to get it all in the frame.
10) DON’T TOUCH YOUR FOCUS! The concept is backward here. You will need to get closer or further from the objects in your foreground until the the closest thing is no closer than that “Near limit”. Maybe it’s just the street. Maybe it is a park bench. Anything will do. Just make sure the object that is at the bottom of your frame (closest point to you) is no closer than your “Near limit”.
11) Keep composing until you have something you like.
12) Take a photo
Done! With shooting.
Take a look at your photo on the back of your camera and zoom in. Pan all around and check focus. Did it work? If not, why not? This test is all just physics, so if it didn’t work, you broke a rule and Physics (capital P) didn’t like that.
If you need to, run the calculations again.
That’s really all there is to it. Plot in the numbers or use one of the charts and then don’t exceed those limits. You’ve already learned how you can get more things into focus by using a different aperture. Now we are setting our depth of field by also being specific about our distance and where we focus. It all comes together!
And what’s even cooler about it is it’s reproducible and there really is no guess work. I’d advise you to learn to use the charts because they will be compatible with your next, new mobile device, I promise. Especially if you leave your phone at home.
Oh! One handy tool to help with this method. Your camera may have a Depth Of Field Preview button. It’s close to the lens, on the front of your camera and probably near the bottom. When you press it, the aperture in your camera closes down and you get a decent preview of what will be in focus. This is handy in other situations, but really helps making sure you’re not too far past your “Near limit”.
The wider your focal length, the closer you can place “Near limit” objects. You can also use this tool to limit your depth of field if you want.
Have a great weekend! I’ll catch you on Monday where we’ll cover Focus Modes.
31+ Days Of Photography Experiments is a series written by professional photographer Peter West Carey on The Carey Adventures.Com. The series is designed to unravel the mysteries of photography so you can take better pictures through practical experiments on the material found in 31+ Days To Better Photography. Subscribe here to receive all the updates and bonus material. Your comments are always welcome.