Hyperfocal Distance The problem Suppose that your image includes something at infinity, such as a mountain; it also includes something in the foreground, such as a flower; and, you want everything from the foreground to infinity from the flower to the mountain to appear sharp. The problem is that if you focus on the mountain, the flower will be out of focus; if you focus on the flower, the mountain will be out of focus. The (possible) solution It may be possible to focus the lens at some distance between the flower and the mountain so that both the flower and the mountain will be close enough to being in focus that they will both appear to be sharp. The hyperfocal distance is the closest distance at which you can focus the lens and still have objects at infinity appear to be sharp. If you focus any closer, the mountain will look fuzzy. It turns out that if you focus at the hyperfocal distance, then things in the foreground will also appear sharp starting at half the hyperfocal distance. That is, if the hyperfocal distance is 10 feet and you focus at 10 feet, then everything from 5 feet to infinity will appear sharp. Why it s only a possible solution Hyperfocal distance depends on the focal length and aperture of the lens you re using:
Hyperfocal distance in feet APS C sensor focal length, mm 20 40 60 80 100 120 140 160 180 200 220 240 260 280 1 60 239 537 954 1491 2147 2923 3818 4832 5965 7218 8590 10081 11692 1.4 43 170 383 682 1065 1534 2088 2727 3451 4261 5156 6136 7201 8351 2 30 119 268 477 746 1074 1461 1909 2416 2983 3609 4295 5041 5846 aperture, stops 2.8 21 85 192 341 533 767 1044 1363 1726 2130 2578 3068 3600 4176 4 15 60 134 239 373 537 731 954 1208 1491 1804 2147 2520 2923 5.6 11 43 96 170 266 383 522 682 863 1065 1289 1534 1800 2088 8 7 30 67 119 186 268 365 477 604 746 902 1074 1260 1461 11 5 22 49 87 136 195 266 347 439 542 656 781 916 1063 16 4 15 34 60 93 134 183 239 302 373 451 537 630 731 22 3 11 24 43 68 98 133 174 220 271 328 390 458 531 32 2 7 17 30 47 67 91 119 151 186 226 268 315 365 The aperture required to achieve sharpness depends on the focus distance and the focal length of the lens. The following chart (for 35 mm cameras) shows the required aperture values:
Hyperfocal distances, 35 mm/full frame digital camera close focus Focal length, mm point at 24 28 32 36 40 45 50 60 80 100 150 200 300 350 400 450 500 2 4 19 27 3 6 13 19 22 32 4 8 9.5 13 19 22 27 5 10 8 11 13 19 22 27 6 12 6.7 9.5 11 16 19 22 32 7 14 5.6 8 11 13 16 19 27 8 16 4.5 6.7 9.5 11 13 19 22 32 9 18 4.5 6.7 8 9.5 13 16 19 27 10 20 4 5.6 6.7 9.5 11 13 19 27 11 22 4 4.5 6.7 8 9.5 13 16 22 12 24 3.5 4.5 5.6 8 9.5 11 16 22 13 26 3.5 4.5 5.6 6.7 9.5 11 13 19 14 28 2.8 4 5.6 6.7 8 9.5 13 19 32 15 30 2.8 4 4.5 6.7 8 9.5 11 16 32 20 40 2 2.8 4 4.5 5.6 6.7 9.5 13 22 25 50 1.8 2.5 2.8 4 4.5 5.6 6.7 9.5 19 27 30 60 1.4 2 2.5 2.8 4 4.5 5.6 8 16 22 40 80 1.4 2 2.5 2.8 3.5 4.5 6.7 11 19 50 100 1.2 1.4 2 2.5 2.8 3.5 4.5 9.5 13 32 75 150 1.2 1.4 2 2.5 3.5 5.6 9.5 22 100 200 1.2 1.4 1.8 2.8 4.5 6.7 16 27 150 300 1.2 1.8 2.8 4.5 11 19 200 400 1.4 2.5 3.5 8 13 32 300 600 1.4 2.5 5.6 9.5 22 27 350 700 1.4 2 4.5 8 19 27 32 400 800 1.2 1.8 4 6.7 16 22 27 smaller will work 450 900 1.8 3.5 6.7 13 19 27 32 500 1000 1.4 3.5 5.6 13 19 22 27 This table shows, for example, that if the closest thing you want sharp in the image is 8 feet away from the camera and you re using a 36 mm lens, then you should focus the lens at 16 feet and set the aperture to f/11. It also shows that in some cases, such as a close point of 100 feet with a 24 mm lens, you can use any aperture you like. In other cases, such as a close point of 4 feet with a 60 mm lens, you can t stop the lens down far enough to achieve sharpness you ll just have to try another composition. So in some cases it s possible to solve the problem and in others it s not. How I use the chart To set up a shot, I Anything f/1 or Impossible. f/32 is too large. 1. compose the picture; 2. estimate how far it is to the closest thing that has to be sharp; 3. focus at twice the distance to the closest thing that has to be sharp; 4. read from the lens the focal length I used for the composition; 5. set the aperture to the value given in the table. Suggestions When I can, I'll reduce the aperture a stop just to be on the safe side (I don't always estimate the distance correctly.) That is, if the table calls for f/8, I'll make it f/11 if I can.
You can't always do that maybe there's a flower moving with the wind and you need the fastest shutter speed possible. But if it's all rocks from here to infinity, I say crank it down a stop, unless doing so gets you to f/27 or some other very small aperture diffraction can degrade the image at very small apertures. I m not too great at estimating distance, so I use some distances I m familiar with. For example, it s 12 feet from my chair to the TV. So if it looks like it s a little farther to the near point than from my chair to the TV, I ll estimate 15 feet. Then I just look around to find something twice as far away as the near point, and focus on that. Even if I'm in a hurry and I m just going to set a small aperture and hope for the best without consulting the table, I still focus at twice the distance to the closest thing that has to be sharp. This maximizes my chances of having everything sharp. This is an alternative to the rule of thumb that says to focus 1/3 of the way into the scene I ve had better luck focusing at twice the distance to the closest thing that has to be sharp. In fact, my current camera has focus peaking blinkies that show what s in focus and what s not. To use that, I focus at twice the distance to the nearest thing that has to be sharp, then dial down the aperture until that thing has blinkies. I consult the chart most often when I want to maximize shutter speed if the flower is blowing around, for example. In that case I want to use the largest aperture possible, and the table will tell me what it is. Digital images are free bracket the aperture whenever you can.
A more convenient chart for 35 mm/full frame digital To make the chart smaller and easier to carry, use this: Close focus Focal length, mm point at 24 28 32 36 40 45 50 60 80 100 150 200 300 350 400 450 2 4 19 27 3 6 13 19 22 32 4 8 9.5 13 19 22 27 5 10 8 11 13 19 22 27 Impossible. f/32 6 12 6.7 9.5 11 16 19 22 32 7 14 5.6 8 11 13 16 19 27 is too large. 8 16 4.5 6.7 9.5 11 13 19 22 32 9 18 4.5 6.7 8 9.5 13 16 19 27 10 20 4 5.6 6.7 9.5 11 13 19 27 11 22 4 4.5 6.7 8 9.5 13 16 22 12 24 3.5 4.5 5.6 8 9.5 11 16 22 13 26 3.5 4.5 5.6 6.7 9.5 11 13 19 14 28 2.8 4 5.6 6.7 8 9.5 13 19 32 15 30 2.8 4 4.5 6.7 8 9.5 11 16 32 Close focus Focal length, mm point at 24 28 32 36 40 45 50 60 80 100 150 200 300 350 400 450 20 40 2 2.8 4 4.5 5.6 6.7 9.5 13 22 25 50 1.8 2.5 2.8 4 4.5 5.6 6.7 9.5 19 27 30 60 1.4 2 2.5 2.8 4 4.5 5.6 8 16 22 40 80 1.4 2 2.5 2.8 3.5 4.5 6.7 11 19 50 100 1.2 1.4 2 2.5 2.8 3.5 4.5 9.5 13 32 75 150 1.2 1.4 2 2.5 3.5 5.6 9.5 22 100 200 1.2 1.4 1.8 2.8 4.5 6.7 16 27 150 300 1.2 1.8 2.8 4.5 11 19 200 400 1.4 2.5 3.5 8 13 32 300 600 1.4 2.5 5.6 9.5 22 27 350 700 Anything f/1 or 1.4 2 4.5 8 19 27 32 400 800 1.2 1.8 4 6.7 16 22 27 smaller will work 450 900 1.8 3.5 6.7 13 19 27 32 500 1000 1.4 3.5 5.6 13 19 22 27 Print it, cut it out, cut along the line between the top and bottom sections, use double sided tape to tape the sections back to back, laminate. It fits in your pocket or you can attach it to your tripod or vest.
A chart for APS-C digital cameras The ideas are the same but the aperture values are different for digital cameras. For cameras with APS-size sensors (magnification factors of 1.5), use this table: Close point Focal Length 12 14 16 18 20 24 28 32 36 40 45 50 60 80 100 150 200 300 350 400 450 focus at 2 4 5.6 8 9.5 13 16 22 32 3 6 4 5.6 6.7 9.5 11 16 22 27 4 8 2.8 4 5.6 6.7 8 11 16 22 27 32 5 10 2.5 3.5 4 5.6 6.7 9.5 13 16 22 27 32 6 12 2 2.8 3.5 4.5 5.6 8 11 13 19 22 27 32 7 14 1.8 2.5 2.8 4 4.5 6.7 9.5 11 16 19 22 27 8 16 1.4 2 2.8 3.5 4 5.6 8 9.5 13 16 19 27 9 18 1.4 1.8 2.5 2.8 3.5 5.6 6.7 9.5 11 13 19 22 32 10 20 1.2 1.8 2 2.8 3.5 4.5 6.7 8 11 13 16 19 27 11 22 1.2 1.4 2 2.5 2.8 4 5.6 8 9.5 11 16 19 27 12 24 1.4 1.8 2.5 2.8 4 5.6 6.7 9.5 11 13 16 22 13 26 1.2 1.8 2 2.5 3.5 4.5 6.7 8 9.5 13 16 22 14 28 1.2 1.4 2 2.5 3.5 4.5 5.6 8 9.5 11 13 22 15 30 1.2 1.4 1.8 2.5 3.5 4 5.6 6.7 9.5 11 13 19 32 Impossible. f/32 is too large. Close point Focal Length 12 14 16 18 20 24 28 32 36 40 45 50 60 80 100 150 200 300 350 400 450 focus at 20 40 1.2 1.4 1.8 2.5 3.5 4 5.6 6.7 8 9.5 13 27 25 50 1.2 1.4 2 2.5 3.5 4 5.6 6.7 8 11 22 32 30 60 1.2 1.4 2 2.8 3.5 4.5 5.6 6.7 9.5 16 27 40 80 1.2 1.8 2 2.8 3.5 4 4.5 6.7 13 19 50 100 1.4 1.8 2 2.8 3.5 4 5.6 9.5 16 75 150 1.2 1.4 1.8 2.5 2.8 4 6.7 11 22 100 200 1.2 1.4 1.8 2 2.8 5.6 8 19 32 150 300 1.2 1.4 2 3.5 5.6 11 22 Anything f/1 or 200 400 1.4 2.8 4 9.5 16 smaller will work 300 600 1.8 2.8 5.6 11 22 32 350 700 1.4 2.5 5.6 9.5 22 27 400 800 1.4 2 4.5 8 19 27 32 450 900 1.2 2 4 6.7 16 22 27 500 1000 1.2 1.8 4 6.7 13 19 27 32 I think this should work OK for cameras with 1.6 magnification factors, too. Ken Craven 3/26/14