Focal length of Nikon M Plans

[keks]

Hello,
Does anyone know or know a source for the focal lengths of the Nikon M Plan objectives? I have found hardly any data about that.

Most interesting for me would be the focal length of the 20x and 40x, ELWD and SWLD.

I need the data for calculating depth of field.

Thx in advance!

[ChrisR]

[Chris S.]

I need the data for calculating depth of field.

Actually, all you really need for calculating depth of field is the numerical aperture. See DOF Estimates For Macro/Micro, table 2-C down at the bottom of the page. And be aware than any approach to calculating depth of field just gets you into the neighborhood. My own preference is for steps about half to 2/3 the size of the ones in that chart.

--Chris S.

[keks]

Thank you very much Chris, unfortunately my knowledge about optical stuff is quite limited;)