something else to remember is that about a third of the area within the hyperfocal distance is in front of perfect focus and about two thirds are behind it (excepting focus at infinity).
If you were confused before, I think we both are now!
Whooee, I love photo making stuff!
Last edited by Charles Webb; 04-30-2006 at 03:08 AM. Click to view previous post history.
An after thought, is any one else confused when attempting to apply the 1/3, 2/3 rule with some soft focus lenses? :-) If you are unsure of what I am talking about, ask Jim Galli. :-)
I didn't notice anyone referring to dofmaster.com. There one will find a very instructional software package that is Windows friendly, and which has tunable parameters for focal lengths, formats, circles of confusion, etc. The program puts a DOF calculator on the screen, sort of a circular slide rule. It can be changed, operated, and even printed out to make a field serviceable DOF calculator. This may be of interest to people who have cameras without DOF indications, or to students who want to understand DOF better.
There is also a Palm Pilot variant on the same website. It is all available via FREE downloads.
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I made a set of discs for my LF lenses a couple of years ago using this software but forgot where I go it from - thanks for reminding me!
Originally Posted by T42
Works very well.
In landscape photography, hyperfocal distance can be effectively doubled using a simple trick...
If you require everything in focus from infinity to as close as possible, set the aperture as small as possible (f16 for expample). Rotate the focus so that the infinity mark is opposite the f16 hyperfocal distance mark on the lens (if you've got these markings on the lens). 'In theory' the hyperfocal distance will then be from the one f16 hyperfocal distance mark to the other one. The image may look blurred in the viewfinder.
You can double check whether the setting will work if you've got a depth of field preview button on the camera.
As others have already said, the hyperfocal markings on the lens are a bit optamistic, so allow a bit of a 'fudge factor' if you intend to blow the image up to any reasonable size. The lens manufacturers definition of 'acceptable focus' is similar to the legal term 'reasonable length of time'.
My Voigtlander 25mm lens has click stops on the focussing ring. If I click the lens to the 3m setting and shut the lens down to f11, there's virtually no need to focus the lens as everything will be in focus from infinity to about 2m.
This 'trick' is often employed in point & shoot and single use cameras. The lens is permanently focussed at a distance less than infinity and a small aperture is used to get as much into focus as possible.
Voigtlander Bessa R2A, CV lenses: 25/4, 35/1.7, 50/2.5, 1936 Leica 9cm f4 Elmar
Leica R7, 50/2 Summicron, 90/2.8 Elmarit, 180/3.4 Apo-Telyt-R
I'm not going digital... It's not photography, its computing!