Focusing depth

Depth of focusing differs on the image angle of the lens promptly as shown in the photo. The wider the image angle the lens is designed, the deeper the focusing depth becomes at the same iris closing condition. For example, the depth on Super Elmar 15/3,5 when the iris position is set at 8, focusing depth would be established between infinity and 0,5m. So, focusing procedure is not always required in ordinal photography if the iris and focusing ring were set as an usual manner. On the other hand, on Macro Nikkor 105/4, the depth would be done between infinity and tens of meters in the same condition. Then, how about standard Leica Summilux 50/1,4? The depth would be infinity and 5m. This is why Leica Super Elmar 15/3,5 could be utilized even on Leica M9 without focus coupling connection in view finder, just imagination of view angle and comprehensive composition. Of course the purpose of imaging might requires much more accurate focusing in proximity.

Pictures of Morning glory were all done by Macro Nikkor 105/4 at f-8 iris position.