Rodenstock Apo-Ronar 360mm f9.0 lens

Background:

Rodenstock's series of Apo-Ronar lenses have a lineage dating back to the 1920's when the Ronar series was

first introduced.  The Apo-Ronars are a modern series of 4 element multi-coated lenses of a dialyte construction, 

available in shuttered versions, barrel versions and dedicated Sinar system lens panels (illustrated above) orig-

inating from the late 1960s.  The barrel versions can seem large in comparison to the shutter versions however

offer more utility with a dedicated Sinar system, particularly for multi-format capability in either 4x5" or 8x10"

format.   The shutter housing is notably large: one advantage afforded by this kind of housing relates to the

peculiarity of the aperture blades which possess a floral arrangement like the classic Zeiss Sonnar in 35mm format.

Apo-Ronars are process lenses with maximum apertures of f9.0 ranging in focal length from 150mm, 240mm,

300mm, 360mm, 450mm, 600mm and 1000mm.   The Lens Vade Mecum identifies these as excellent introductory

lenses for 4x5" format particularly for macro and process work with excellent performance at infinity focus.  The

relatively long lifespan of the Apo-Ronar has probably entailed minor differences in coatings and/or shutter/barrel

combinations however it's core design has remained the same.  Interchangeability for barrel versions into shutters

are possible for smaller focal lengths however this becomes impractical at whole plate format focal lengths due to

the size of the lens mounts.  There are numerous variations in the barrel lenses, some of which may have

compatibility problems when it comes to remounting barrel lenses into shutters.

Features:

Coverage:                At infinity, coverage at f22 equates to 318mm, sufficient for architectural process work. 

                                 For 1:1 repro' work, coverage is tremendous at 638mm.

Filter size:                58mm screw on type, 0.75x pitch.

Apertures:               From f9.0 to f180 with the famous 'ninja star' blade style of the legendary Contax Sonnar

                                  5cm f1.5 lens.

Shutter:                   If a Compound or large Compur shutter fit is not possible, then a  Betax 3 shutter can be

                                 retro-mounted on the front of the filter thread for accurate control of shutter times.

Regarding the construction of the Apo-Ronar lenses in such large housings, several features entail.  Its dialyte design

possesses a smaller angle of coverage, aperture for aperture, compared to a Tessar type design. Compare

the 360mm Apo-Ronar to the smaller focal length lens, the Nikkor 300mm M f9.0 of Tessar design.  The

Apo-Ronar's covering power of 316mm against the Nikkor's 325mm might seem to prove that dialyte lenses

have huge limitations in coverage.   In practice, the Apo-Ronar's larger aperture housing seems to square up

well.   With the dialyte design, peripheral field imaging is noticeably sharper than that usable from a Tessar

type lens whose circle of illumination may not necessarily translate as a sufficiently sharp image circle for

practical use.  The  larger aperture housing seems to be useful in reducing the constraints which arise when

dialyte lenses are integrated into smaller shutter units with a consequent occlusion of its covering power

secondary to the mechanically smaller aperture openings in these shutter units.

Summary:

Although a process lens, it possess excellent contrasty multi-coated modern optics useful for macro, still-life,

architecture and general purpose photography.  Life-size reproduction at 1:1 is excellent for resolution and

definition across the whole frame.   Advantages of the Sinar mounted Apo-Ronar may be outweighed by lack

of accurate shutter times.  For critical purposes, a dedicated non-process lens offers better performance for

subject perspective and infinity focus however these features are indistinguishable at the level of the contact

print.  The Apo-Ronar series seems to hold advantages over other process lenses in this respect (i.e.

Schneider G-Claron lenses, whose infinity performance is outclassed by the Apo-Ronar series).

Other Rodenstock Lenses: (require image circle of 259mm):

Acknowledgements: www.komamura.co.jp

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Comments, revisions and suggestions welcome.