blacknet
Contributor
Many of you have heard me refer to the hyperfocal distance many times in the past. This is my chance to explain what it is. The hyperfocal distance is a setting on your camera lens that will yield the greatest depth of field possible.
There are several calculators on the internet to find the hyperfocal distance. I use and recommended f/calc. You tell it what format youre using and the aperture of the lens. It will give a near distance and a far distance. Those 2 marks on the distance scale is the range of in focus for the given f/stop. Another method you can use, good for on the boat/in the water type. Set the desired f/stop then set the distance marker just short of infinity, not the center focus marker but the edge marker. Then read the opposite marker to see what will be in focus.
Say you are using a 35mm system with a 35mm lens and you want to find the hyperfocal distance. If using f/5.6 as the aperture the distance is 28.41 feet. If you focus your camera at 28.41 feet then everything from 14 feet to 7187 feet will be in focus. Now lets use a different number than the hyperfocal distance, say 5 feet then everything from 4 feet to 6 feet will be in focus. If we use a larger number, say 50 feet then everything from 14 feet to infinity is in focus. As you can see the longer or shorter focus distance you use the less your depth of field becomes.
Here are a few numbers for the 35mm world.
Focal length 8
Aperture: f/1.4 = 5.9 feet; f/2 = 4.2 feet; f/2.8 = 2.97 feet; f/4 = 2.1 feet; f/5.6 = 1.48 feet; f/8 = 1.05 feet, f/11 = .74 feet, f/16 = .52 feet; f/22 = 0.025 feet
Focal length 15
Aperture f/1.4 =20 feet; f/2 = 14.76 feet; f/2.8 = 10.44 feet; f/4 = 7.38 feet; f/5.6 = 5.22 feet; f/8 = 3.69 feet; f/11 = 2.61 feet; f/16 = 1.84 feet; f/22 = 1.3 feet
Focal length 20
Aperture f/1.4 = 37 feet; f/2 = 26.24 feet; f/2.8 = 18.55 feet; f/4 = 13.12 feet; f/5.6 = 9.28 feet; f/8 = 6.56 feet; f/11 = 4.64 feet; f/16 = 3.28 feet; f/22 = 2.32 feet
Focal length 28
Aperture f/1.4 = 72.72 feet; f/2 = 51.42 feet; f/2.8 = 36.36 feet; f/4 = 25.71 feet; f/5.6 = 18.18 feet; f/8 = 12.86 feet; f/11 = 9.09 feet; f/16 = 6.43 feet; f/22 = 4.55 feet
Focal length 35
Aperture f/1.4 = 113.63 feet; f/2 = 80.35 feet; f/2.8 = 56.81 feet; f/4 = 40.17 feet; f/5.6 = 28.41 feet; f/8 = 20.09 feet; f/11 = 14.2 feet; f/16 = 10.04 feet; f/22 = 7.1 feet
Focal length 50
Aperture f/1.4 = 231.9 feet; f/2 = 163.98 feet; f/2.8 = 115.95 feet; f/4 = 81.99 feet; f/5.6 = 57.97 feet; f/8 = 40.99 feet; f/11 = 28.99 feet; f/16 = 20.5 feet; f/22 = 14.49 feet
Focal length 80
Aperture f/1.4 = 593.66 feet; f/2 = 419.78 feet; f/2.8 = 296.83 feet; f/4 = 2090.89 feet; f/5.6 = 148.41 feet; f/8 = 104.94 feet; f/11 = 74.21 feet; f/16 = 52.47 feet; f/22 = 37.1 feet
As you can see the larger focal lengths the greater the hyperfocal distance becomes. This also means the harder it becomes to keep objects in focus. Take the 80mm for example. The depth of field is paper thin compared to the 15mm. You would need pristine water conditions to take full use of the 80mm lens whereas the 15mm would work in water with less than ideal conditions.
All lens are rated at an f/stop, this is the limit it will do, i.e. 20/2.8 is a 20mm lens rated at 2.8 so F/2.8 is the limit; 20-35/3.5-4.5 is a 20-35mm zoom lens, when set to 20mm its f/4.5 when set to 35mm its 4.5. The desired goal is to set the f/stop somewhere in the middle of the lens range for optimal performance. This are is where the lens is sharpest and less distortion occurs.
One of the easiest methods to get great shots is to preset the camera, approach the subject and when you reach the desired point just snap the shutter. Theres no tinkering with settings and you are fully in control of the situation. Using the hyperfocal distance is critical on cameras like the nikonos V. I use the water pistol method with my 20mm so it comes in real handy.
For those of you who want to know the math behind the hyperfocal distance its this formula.
( L * L )
---------- = H
( F * D )
Where H = Hyperfocal distance in millimeters, L = Lens focal length; F = aperture and D = Diameter of the circle of confusion. For digital cameras well use D = 0.02, 35mm well use D = 0.03
I intentionally did not cover the circle of confusion as I felt it would more than likely create more confuse than help.
The near hyperfocal point is
( H * D )
----------- = NHF
H + ( D- L )
Where NHF = near hyperfocal in millimeters; H = Hyperfocal distance, in millimeters; D = Lens focus distance, in millimeters; L = focal length of the lens.
If anyone has comments, concerns or the like then please make a post or contact me about it. Remember there are no stupid questions! I dont expect everyone to fully understand what I wrote so please ask.
Ed
There are several calculators on the internet to find the hyperfocal distance. I use and recommended f/calc. You tell it what format youre using and the aperture of the lens. It will give a near distance and a far distance. Those 2 marks on the distance scale is the range of in focus for the given f/stop. Another method you can use, good for on the boat/in the water type. Set the desired f/stop then set the distance marker just short of infinity, not the center focus marker but the edge marker. Then read the opposite marker to see what will be in focus.
Say you are using a 35mm system with a 35mm lens and you want to find the hyperfocal distance. If using f/5.6 as the aperture the distance is 28.41 feet. If you focus your camera at 28.41 feet then everything from 14 feet to 7187 feet will be in focus. Now lets use a different number than the hyperfocal distance, say 5 feet then everything from 4 feet to 6 feet will be in focus. If we use a larger number, say 50 feet then everything from 14 feet to infinity is in focus. As you can see the longer or shorter focus distance you use the less your depth of field becomes.
Here are a few numbers for the 35mm world.
Focal length 8
Aperture: f/1.4 = 5.9 feet; f/2 = 4.2 feet; f/2.8 = 2.97 feet; f/4 = 2.1 feet; f/5.6 = 1.48 feet; f/8 = 1.05 feet, f/11 = .74 feet, f/16 = .52 feet; f/22 = 0.025 feet
Focal length 15
Aperture f/1.4 =20 feet; f/2 = 14.76 feet; f/2.8 = 10.44 feet; f/4 = 7.38 feet; f/5.6 = 5.22 feet; f/8 = 3.69 feet; f/11 = 2.61 feet; f/16 = 1.84 feet; f/22 = 1.3 feet
Focal length 20
Aperture f/1.4 = 37 feet; f/2 = 26.24 feet; f/2.8 = 18.55 feet; f/4 = 13.12 feet; f/5.6 = 9.28 feet; f/8 = 6.56 feet; f/11 = 4.64 feet; f/16 = 3.28 feet; f/22 = 2.32 feet
Focal length 28
Aperture f/1.4 = 72.72 feet; f/2 = 51.42 feet; f/2.8 = 36.36 feet; f/4 = 25.71 feet; f/5.6 = 18.18 feet; f/8 = 12.86 feet; f/11 = 9.09 feet; f/16 = 6.43 feet; f/22 = 4.55 feet
Focal length 35
Aperture f/1.4 = 113.63 feet; f/2 = 80.35 feet; f/2.8 = 56.81 feet; f/4 = 40.17 feet; f/5.6 = 28.41 feet; f/8 = 20.09 feet; f/11 = 14.2 feet; f/16 = 10.04 feet; f/22 = 7.1 feet
Focal length 50
Aperture f/1.4 = 231.9 feet; f/2 = 163.98 feet; f/2.8 = 115.95 feet; f/4 = 81.99 feet; f/5.6 = 57.97 feet; f/8 = 40.99 feet; f/11 = 28.99 feet; f/16 = 20.5 feet; f/22 = 14.49 feet
Focal length 80
Aperture f/1.4 = 593.66 feet; f/2 = 419.78 feet; f/2.8 = 296.83 feet; f/4 = 2090.89 feet; f/5.6 = 148.41 feet; f/8 = 104.94 feet; f/11 = 74.21 feet; f/16 = 52.47 feet; f/22 = 37.1 feet
As you can see the larger focal lengths the greater the hyperfocal distance becomes. This also means the harder it becomes to keep objects in focus. Take the 80mm for example. The depth of field is paper thin compared to the 15mm. You would need pristine water conditions to take full use of the 80mm lens whereas the 15mm would work in water with less than ideal conditions.
All lens are rated at an f/stop, this is the limit it will do, i.e. 20/2.8 is a 20mm lens rated at 2.8 so F/2.8 is the limit; 20-35/3.5-4.5 is a 20-35mm zoom lens, when set to 20mm its f/4.5 when set to 35mm its 4.5. The desired goal is to set the f/stop somewhere in the middle of the lens range for optimal performance. This are is where the lens is sharpest and less distortion occurs.
One of the easiest methods to get great shots is to preset the camera, approach the subject and when you reach the desired point just snap the shutter. Theres no tinkering with settings and you are fully in control of the situation. Using the hyperfocal distance is critical on cameras like the nikonos V. I use the water pistol method with my 20mm so it comes in real handy.
For those of you who want to know the math behind the hyperfocal distance its this formula.
( L * L )
---------- = H
( F * D )
Where H = Hyperfocal distance in millimeters, L = Lens focal length; F = aperture and D = Diameter of the circle of confusion. For digital cameras well use D = 0.02, 35mm well use D = 0.03
I intentionally did not cover the circle of confusion as I felt it would more than likely create more confuse than help.
The near hyperfocal point is
( H * D )
----------- = NHF
H + ( D- L )
Where NHF = near hyperfocal in millimeters; H = Hyperfocal distance, in millimeters; D = Lens focus distance, in millimeters; L = focal length of the lens.
If anyone has comments, concerns or the like then please make a post or contact me about it. Remember there are no stupid questions! I dont expect everyone to fully understand what I wrote so please ask.
Ed
