Re: [Leica] Macro Question

[Jim Brick <jim@brick.org>]

Frank,

The depth of field is the same for all lenses. If you stand and look
through your 100mm and observe the DOF, then replace the 100mm with a 50mm
and physically move up toward your subject until the frame you see through
the 50, is the same as you saw it through the 100, what you see will have
the same DOF.

If the subject is the *same size* in the viewfinder, regardless of which
lens your are using, the DOF is the same. If you don't move the camera, and
change from a 100 to a 50, you will have greater DOF, but half the image
size. There is no way to win. Choose your lens based on how far away from
the subject you want to work AND how much stuff you want in the background.
Long lenses have a narrow angle of view and will include less background
junk for the same subject image size. 

If you want to know the different DOF figures for standing in the same
place with different lenses, consult hyperfocal tables for lenses at the
focal lengths you are interested in.

Of course, Leica lenses have DOF information inscribed right on them.
Looking at the lens scale will tell you the coverage of the DOF.

I use Leica R cameras most of the time. The DOF is easily viewable by
simply using the DOF preview lever. I use it all the time. For macro work,
it is indispensable. I wouldn't own an SLR without it.

Jim

At 07:01 PM 2/4/98 -0800, Frank Filippone wrote:
>Could someone check their DOF tables... 
>
>If you use 2 different lenses, say a 50MM and a 100 MM .....which gives
>more wide depth of field?
>
>The subject area that is in the VF is the same using either lens,  implying
>that the camera will move closer to the subject with the 50 than the
>100....
>The taking aperture is the same.
>The only difference is the distance to the subject ( the 50MM is closer
>).....  Please quote DOF distances in MM or inches....Please do not get
>into the circle of confusion, etc.  Hold all those variables constant...
>
>The purpose in this question is to figure out if a wider angle lens has the
>same or wider DOF: if it does, then the closer proximity to the subject (
>Half the distance) using the wider lens will alow a 2 stop smaller F-stop
>using a flash, therefore increasing DOF even more....a big bonus to tne
>macro types....
>
>Thanks for helping.... I am trying to figure out which R series Macro lens
>I should explore...
>
>
>Thank You
>Remove "ZZ" form auto reply address or 
>please reply to address below:
>
>Frank Filippone
>red735i@worldnet.att.net
>