Try This at Home

Chapter Four: Creative Control: Using Your Lens

You’re Too Damn Close—or—The Fake Band Shot

Gear: Camera and a wide-angle lens (21mm, 24mm, 28mm or 35mm), tape measure, tape, tripod and notebook

Optional, But Useful, Gear: Laptop and card reader

DoF Calculator: There are a number of free DoF calculators online; some really nice ones are available as smartphone apps, as well. Andy personally likes pCAM, which is an amazing tool to have on your iOS gadget. We’ll be referring to pCam for this assignment (Figure 4.21).

Location: Anywhere. Depending on your fake band, you can shoot in the desert or in front of a brick wall.

Subject: Three friends to make up your fake band.¹ It helps if your subjects are dressed for the part: Try either studded leather jackets, or cardigan sweaters with thick black glasses. Your friends might as well look the part!

Your Mission: This exercise will give you some real DoF experience—with a fake subject. It’ll help you prepare for those times when you‘re working by yourself without a computer and need to move quickly.

Good to Know: Calculating DoF and hyperfocal distance is a loose process. There are many real-world factors—including the resolution of your camera, the quality of your lens and your own personal definition of “acceptably sharp”—that affect how in-focus your images will look.

Calculating Hyperfocal Distance

The point of figuring out hyperfocal distance is to achieve the largest possible in-focus area of your scene that stretches from a fixed near point to infinity. It’s calculated through a formula, but there are many smartphone apps and online calculators that make it easy to determine for a given lens/aperture combination.

Here’s the result of a sample hyperfocal-distance calculation:

If you have a 50mm lens mounted to a full-frame camera body at ƒ/22, the hyperfocal distance is 12ft. 9in. and the DoF stretches from 6ft. 4in. to infinity. By shifting the aperture to ƒ/4, the hyperfocal distance moves to 71ft., 3in., and the DoF stretches from 35ft. 8in. to infinity. (If you go back and look at those numbers again, you might notice that the near point is always one-half the hyperfocal distance.)

Using the DoF Calculator

1. Grab pCAM for your smartphone ² (or use any other DoF calculator). In the settings, choose your camera (or sensor size) and the wide-angle lens you’ve chosen.
2. Start with a value of ƒ/8 and choose 6 feet as your subject distance (aka the middle distance).
3. Use the application to calculate your near and far distance values, and then write them down.³
4. Leaving the distance at 6 feet, write down the distance values for ƒ/2.8 to ƒ/16.

The Examples

(If you have a 28mm lens, you can actually use these calculations.)

1. Example #1: using a 28mm lens on a full-frame camera, pCam gives us these approximate values:
1. ƒ/2.8: Near = 5’, 1”; Subject = 6’; Far = 7’ 3”
2. ƒ/4.0: Near = 4’ 9”; Subject = 6’; Far = 8’ 2”
3. ƒ/5.6: Near = 4’ 4”; Subject = 6’; Far = 9’ 7”
4. ƒ/8.0: Near = 3’ 11”; Subject = 6’; Far = 12’ 9”
5. ƒ/11: Near = 3’ 5”; Subject = 6’; Far = 23’ 11”
6. ƒ/16: Near = 2’ 11”; Subject = 6’; Far = ∞”
2. Example #2: using a 28mm lens on a APS-C ⁴ camera, pCam gives us these approximate values:
1. ƒ/2.8: Near = 5’ 4”; Subject = 6’; Far = 6’ 10”
2. ƒ/4.0: Near = 5’ 1”; Subject = 6’; Far = 7’ 3”
3. ƒ/5.6: Near = 4’ 10”; Subject = 6’; Far = 8’
4. ƒ/8.0: Near = 4’ 4”; Subject = 6’; Far = 8’ 10”
5. ƒ/11: Near = 4’ 0”; Subject = 6’; Far = 11’ 10”
6. ƒ/16: Near = 3’ 6”; Subject = 6’; Far = 19’ 11”

The Setup

1. Frame up your shot with your camera on a tripod and grab your tape measure. Using the back of the camera as your starting point, walk out 6 feet in front of the camera. Put a mark on that spot.
2. Grab your notebook. Look up the near and far distances for ƒ/8, and with your tape measure, mark those out. Put your three band mates at those three points.
3. Focus on the middle subject using your AF system, confirm you have good focus and then switch the lens to Manual focus. You don’t want to accidentally change it; a piece of tape on the lens can be used to lock the focus.
4. Set your camera to Manual mode. Start at ƒ/2.8 and balance your shutter speed and ISO to get a good exposure. Check your exposure and, based on the histogram, make any necessary adjustments. Now take a photo at each aperture value, balancing the shutter speed and ISO each time. By now, your friends will want the free beer and pizza you promised, so pack up and head out.

Analysis

1. Download your images into Lightroom and check out the focus on your near and far subjects, using the 1:1 Pixel View.
2. Compare the sharpness of the near and far subjects with that of your center subject as you move through the aperture values. Note the images where the front and back subjects are as sharp looking as the main (middle) subject; there could be two separate images.
3. Compare the images to your DoF notes. Since you placed your subjects at the distances for ƒ/8, that’s a good place to start. Are they in focus at ƒ/8?
4. Go back through the images and decide which one(s) is the softest focus you could live with, if you had to.

Your Takeaway

This is a pretty rigid set of circumstances—non-moving subjects, camera on a tripod and a prewritten set of parameters to work with. Still, you can use it to practice putting DoF to use creatively. You can also use it to experience the difference between calculated and real-world values—which sometimes overlap, but more often have a gap between them. That’s not to say that the calculations are wrong, but that it’s probably best to use them as a starting point, with the knowledge that other factors can affect the final images.