Graflex.org

[red jenny]

OK I am getting familiar with the hyperfocal concept: basically, to keep everythign in the picture as sharp as possible when doing a landscape shot, instead of focussing on infinity (and causing blurriness in the foreground) you're supposed to focus the camera on a place known as the hyperfocus point, and you can calculate the distance to that point using a table such as the one here:
http://www.nikonians.org/html/resources/guides/dof/hyperfocal1.html

So for example, for a 135mm lens set at f/8, you're supposed to focus the camera on a point 299 feet away.

Is this right? Now, how do you figure out where 299 feet is located?

[Les]

Depth of field and hyperfocal distances have to take in many factors, the film format being one of them. I don't want to overwhelm you with all the stuff you couldn't possibly want to know about DOF charts right now. but I ran the calculator you gave inthe link and using a 4x5 film format at f8 you can focus at 75ft and get everything from 37ft to inf in focus. 75 ft is "just a little off" of 100ft. At f16 it drops to 25ft (and the hyperfocal distance moves to 37.5ft). and if you set the scale to 15ft @ f16 everything from 10ft to 25ft will be sharp.

So when you know that Sammy the Snake Lasagna is going to come out of the court house in ten minutes and your job depends on getting "the shot" , you'll set the focus scale to 15ft, aperture to f16, meter for the courthouse steps and set the shutter speed accordingly. Cock the the shutter and when Sammy comes out of the doors you'll hit the phographer from the Times over the head with your Speed, while elbowing the Post photographer in the ribs, which opens up the your view to Sammy. All you have to do is get within 10ft and it will work. As he comes toward you your put your eye to the peep sight and see the wire frame in front, when Sammy gets in the center, you trip the shutter. Bam! you did it. You got the shot!

It's only after Sammy is in the car pulling away do you realize that you forgot to pull the darkslide.

[ This Message was edited by: Les on 2005-10-11 14:11 ]

[red jenny]

Now that was pretty funny!

[Dan Fromm]

[glennfromwy]

As these lenses do best at around f:16, when I shoot a casual street scene or landscape with no real principal subject to focus on, I just set the focus at around 30 feet, f:16 or f:22 and shutter speed to match the light reading. It works well. To make things even simpler - if you want to bang off pictures rapid fire, the same settings and shutter speed of 1/25 with K-2 filter, ASA 100 or 125, on sunny scenes with average shadows will let you shoot to your hearts content without fuss. F:16 for average land shots, f:22 over water or snow.

[karnopp]

The hyperfocal distance is extremely useful in landscape photography. Let me give you some numbers for 4X5 photography
_____________________________________________
90mm lens .... A = 400 ft.
135mm lens .... A = 600 ft.
210mm lens .... A = 1200 ft.
_____________________________________________

Example (Use a 135mm lens at f22)

Then the hyperfocal distance H is

H = 600ft/22 = 27.3 ft.

If you focus at H = 27.3 ft. the depth of field will be 13.6 ft to Infinity.
That is, focusing at H gives a depth of field of H/2 to infinity.

You can use this in reverse as well. Suppose you want everything from 10ft to infinity to be sharp. Then H = 20 ft and

20ft. = 600ft./f or
f = 600ft./20ft. = f30.
(setting at f32 and focusing at 20 ft would do the trick with some to spare).

1) Wider lenses have more effective hyperfocal distances.
2) Smaller apertures give larger depth of fields when the hyperfocal distance is used.

One of the great things about the super camera is that the distance scale gives distance settings up to 50 ft. (My Horseman VHR gives distance setting only to 30 ft.)

The numbers A given above are based on the 4X5 format as well as a definition of the circle of confusion. Finally, smaller apertures will give smaller values of H, but since the equation above is an equilateral hyperbola, the decreases in H decline as apertures get very small. So figure out what you need to be sharp and double that distance to get your H value. From that determine the f stop.

_________________
Bruce Karnopp
Arthur Thurnau Professor
Mechanical Engineering
University of Michigan
Ann Arbor, Michigan
bkarnopp@sbcglobal.net
karnopp@umich.edu