Re: [Rollei] Zeiss S-Planar 120 f5.6 info

[bigler@ens2m.fr]

> Anybody out there could please explain me what the "S-Planar" means
> in the name of Zeiss S-Planar 120 f5.6 and what are the qualities of
> this lens for SL66 ? Thanks Roberto Aita Italy

Hi Roberto

In short : a great lens for macro work and portrait.

Now in detail ;-)

The S-planar 120mm f/5.6 was a Macro Zeiss lens supplied also in
Hasselblad mount. The current version has been improved to f/4 and is
named "Makro-Planar 120 f/4". "S" probably means "Spezial" in a sense
that this lens family is intended for a specific application, namely
high quality close-up, as opposed to a general purpose lens like the
standard planar 80. According to the current Zeiss data sheet for the
120 Makro planar, Zeiss now reserves the "S-planar" name to "really
special" photo-reduction lenses used by the semiconductor industry. I
am happy to be able to use for photomask fabrication here at the
University such Zeiss lenses, a 10X pattern generator lens and a true
marvel, a 10X photo-repeater lens with a 4"x4" object field, final
resolution 0.8 micron (~600 lp/mm) on a 1x1cm field... this is 25
year-old optical technology, unfortunately if you may find one as a
second hand item, they are useless for regular photographic work since
they are optimized for a single .4 micron wavelength *and* a 10:1
ratio, only.

Using a 80 with the maximum extension of the SL66 built-in bellows (or
with an additional bellows) does not necessarily mean that the 80 will
deliver poor images in close-up work ; it simply means that the 80
planar being optimised for infinity-focus, if you want the top of
Zeiss image quality in close-up you have to switch to another lens
optimised differently or close down the 80 to a small aperture.
Consider Zeiss MTF charts on www.zeiss.de for the 120 Makro planar,
you'll understand why it is better at 5:1 than infinity-focus. I think
I may have at home a paper copy of previous MTF charts for the
S-planar 120-5.6, I have to check.

Quoting the current Zeiss documentation about the 120 Makro planar,
this kind of lens is at their top image quality at ratios 1:1 (object
= 6x6cm) -> 5:1 (object : 30x30cm) and not infinity-focus ; they
should be excellent to reproduce artwork, paintings, etc... from an
smaller than an A4 page to 1 square meter. Beware however that like in
all close-up photography the depth of field is small. So do not blame
the S-planar for not being able to render sharp a complete volume of
30x30x30cm ;-). However combined with the unique (at least, built-in a
MF SLR camera) tilt capability of your SL66, you can rely on Herr
Scheimpflug to to increase the depth of field for a slanted object.

A last note : you can of course use this lens at infinity and for
portrait work. I am sure that many people using the f/5.6 f/4 maacro
planar use it as a "normal" lens. Now if you want the results at
infinity to be of the best quality you'll have to stop down the lens.

I hope this response is not too long...
- -- 
Emmanuel BIGLER         
<bigler  

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