Any suggestions on where to read about the proper technique for prefocusing using the depth of field scale on my leica lens. I think I know what I am doing, but a review of how to interpret the DOF scale would be appreciated.

-- Jesse Kramer (Jesskramer@aol.com), February 13, 2002

Answers

Read it out of the manual:

http://members.fortunecity.com/canoneos/manuals/leicam4p161 7.jpg

-- John Collier (jbcollier@powersurfr.com), February 13, 2002.

Jesse: the DOF scale has paired markings (4-4, 8-8, 11-11, etc.) that correspond to aperture settings. In theory, any marked distance on the FOCUS scale that falls between the pairs of marks for the aperture you are actually using will appear to be sharp.

You can pick an aperture, and the scale will show you what range of distances around your actual focusing point will appear sharp using that aperture.

Or you can pick a range of distances you want sharp, and the scale will tell you what aperture you must use to cover that range. In this case you don't 'focus' on anything in particular, but twiddle the focus ring until the full range of distances you want sharp is "enclosed" by some pair of marks.

i.e. to get max. DOF with my 35, and include infinity, I set infinity at the f/16 mark. The nearest sharp point will be (per the scale) about 4 feet. The actual focused point (the 'hyperfocal point' for that aperture and range - also per the scale) is somewhere between 6 ft. and 10 ft. - but doesn't matter, since my concern is with the overall range.

Bear in mind that DOF scales are based on (per Erwin Puts) things appearing sharp in 4x6 prints (!) If you are planning larger blowups the DOF will be less than marked.

-- Andy Piper (apidens@denver.infi.net), February 14, 2002.

Andy has contributed pretty well.

Now, I'll give some of my secrets: I use the DOF often in a case where I have not time to properly adjust.

You will tell me that with a R7, it's rather easy, well, it depends.

As an example, you want to take pictures during the Chinese New Year Dragon Show in the streets of Paris on Feb 16th.

You want to have portraits very sharp and blurry behind to enhance the photo. Of course, you are on the first ranks (1 to 3 meters) and you will pick your favorite 35mm (mine is 24 mm). To create the picture, you will choose an aperture that gives the desired results (with a 35mm, 4 or 5.6 may be, look at the scale). At close range (1.5 m)the DOF should be enough to cover the depth of a body/face. Farther, the main suject should show sharp in the environment.

It's a matter of experimentation. I leave you with all those dimensions to explore and find your own compromise, it will not work at once, keep trying.

And... Have Fun.

-- Xavier d'Alfort (hot_billexf@hotmail.com), February 14, 2002.