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Anonymous File :-(, x)
>>135187 Yes, it does help you judge depth of field.
Note the markings below the distance window. The first one of importance is the bold vertical line in the center. This indicates the distance at which the lens is focused. Next notice the two lines on either side that both say 11. These indicate the depth of field at f/11. That means that whatever distances are between those two lines will be in focus at f/11. For example, if you wanted to focus at the hyperfocal distance for f/11, you would rotate the focus ring until the infinity symbol lines up with the 11 on the left side. The number that lines up with with 11 on the other side is the closest part of the scene that will be in focus.
The same applies to the 16, it's just for f/16. Notice that the range between the two 16s is larger than between the two 11s. This is because there is greater depth of field at f/16 than at f/11. The nicer the DOF scale, the more specific f-stop values it will provide on the scale. Older lenses often listed the full range of which the lens was capable.
And while discussing markings, we might as well cover the little dot to the left of the big vertical line. That's an infrared focusing mark. Infrared light focuses at a slightly different point behind the lens, so some compensation is necessary. You just focus like normal, then before you take the picture you rotate the focusing ring until the current distance lines up with that little dot.
The lens in my pic, a Leitz 50mm f/2 Summicron, shows a very nice DOF scale but lacks an infrared focusing mark.
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