The D.O.F.-GUIDE designed by Lutz Konermann ©1990

Let's start with an example of a classical depth-of-field problem (35mm-film):

• How do I focus my lens to equally include into the depth-of-field two objects at a distance of 0.8 and 0.65 metres, respectively?

Since the D.O.F.-Guide's transparent wheel 35A (with black "lens-curves") freely rotates over its grey scale M (with white "distance-lines" and "f/stop-circles"), you will immediately be able to position the focus (triangle) in such a way that the symmetrically corresponding pairs of "d.o.f.-delimiter-dots" along the lens-curves (take e.g. the pair just below the two "25"s, left for far and right for near) are equally close, respectively, to the distances of the farthest and the nearest object in question. (It's harder to put in words than into practice... ;-) As a result the D.O.F.-Guide gives you the following information at your fingertips:

• To equally include the two objects you best focus at a distance of 0.72 metres (no matter which f/stop or focal length you intend to use).

But that's just the beginning! Here are the additional informations which you would hardly get from any other tool at the same speed and ease of use:

• At f/stop 1.4 only the 14mm-lens will give you a sufficient depth-of-field.
• At f/stop 2 you can use the 18mm-lens, too.
• For the 25mm-lens you need f/stop 4, although a half stop between 2.8 and 4 (the border between the full grey circle and the "milky way") comes quite close!
• And so forth, for all focal lengths, without having to change tables, rulers or keystrokes!

Within minutes of practice you will get used to the D.O.F.-Guide's unique interface, which gives you a multitude of choices at a glance. Soon you will learn that - based on the margin which is determined by the corresponding pair of "d.o.f.-delimiter-dots" (related to focal length and f/stop) - you can easily and intuitively distribute any surplus of depth-of-field in either direction by turning the wheel. This way you will be able to quickly solve even the following problems:

• Which is the focus for maximum depth-of-field from infinity to the nearest distance (for any given f/stop and any given lens)?
• Which f/stop do I need for any given depth-of-field, depending on a given lens?
• Which lens do I need for any given depth-of-field, depending on a given f/stop?

Any more wishes?