Brief Field Report:    Wollensak Velostigmat Series II 8 1/4"  f4.5

The Wollensak Optical Co, Rochester, New York, USA first offered the Velostigmat f4.5 around 1909.  The Series II

Velostigmats were  4 glass design with very good performance and shared many features with the Raptar design,

either as Raptar or Raptar Series II which were the most recent incarnations of the Velostigmat (circa 1951). 

Background:

Summary:   The Wollensak Series II is a Tessar derived lens construction offered in a range of focal lengths. 

The 8 1/2 inch Series II f4.5 lens is of interest to whole plate format users offering full coverage of the whole plate

image area wide-open.  At f22, significant yet modest movements are available.   At just under 210mm focal length,

this lens offers a field of view, slightly wider than normal perspective for the whole plate format.

Lens Construction:        Uncoated Tessar type 4 element

Shutter:                           Betax 3

Filter type:                      Absence of front thread; push on filter type only

Test Camera:                  Charten Whole Plate

Lens Board:                   Custom design for Charten Whole Plate

Use in the Field:            The Series II 8 1/4 inch lens is a remarkably flat lens in its shutter which can be transported

                                        with ease.  At f4.5, it offers a bright ground glass experience with formation of an image,

                                        visible without the darkcloth, thus enabling rapid set-up.  It is a reasonably lightweight lens

                                        whose shutter is best actuated using a tripod release in the field due to the heavy spring loading

                                        action of the Betax 3 shutter.

                                        Shutter manoeuvrability is slightly awkward, requiring a small chromed lever to be positioned

                                        precisely for aperture and shutter control.  The Betax 3 shutter may have reliability issues due to

                                        age and may require a CLA.

Movements:                   The 8 1/4 inch Series II lens has no difficulty covering whole plate format.  A combination of

                                        movements equivalent to approximately 30 mm of vertical shift/rise is possible before expiration

                                        of the image circle at f22.

Image Characteristics: 

Emulsion:             Ilford FP4+

Developer:            Paterson FX39 1:19

Paterson is a modern high acutance developer which can be combined with Ilford FP4+, a traditional silver halide type

emulsion to produce high acutance negatives.  A technique using Paterson FX39 for whole plate film has been described

in Page 4.1.

In comparison to modern lenses, the Wollensak Series II lens shares high image definition across the whole image albeit

with attenuation of macro contrast.  The technique with Paterson FX39 did not avail of a compensating developing method

and a standard 1:19 dilution was used to raise the contrast.  The soft low contrast appearance of the Wollensak lens is not

accompanied by marked flare (due to the limited number of elements in its lens design) nor marked field aberrations.   For

an uncoated lens without a lens hood (flat design), this is an excellent lens for the portable whole plate photographer

offering a distinctly vintage rendition of the image.   Wide aperture performance does no reveal marked  field distortion

circumscribing the zone of focus and therefore out-of-focus areas do not differ substantially from the standard Tessar

appearance.   The low-contrast of the lens can be attributed to the lack of coatings in the lens design, and the lack of flare

can be attributed to its low number of lens-air surfaces.  Photographers wishing for higher contrast will require a customised

lenshood and/or a universal filter adapter for contrast filters and a more intensive development regimen.

Summary:

1.  The Wollensak Series II 8 1/4 inch lens covers whole plate format with approximately 30mm of displacement in the vertical

     axis.  It is possible that the Series II 7 inch lenses may just cover whole plate format.

2.  This a fine resolution lens with good sharpness and definition across the image plane and is relatively flare free

3.  Generally available at competitive cost, this is an excellent lens for starting whole plate format.  

4.  Low contrast characteristics of the lens are not particularly compensated for by higher contrast developing techniques.  

5.  Possesses sufficient coverage for correction of minor field convergence and depth of field control for architectural and landscape work

         +   Advantages                                                                                                 -   Disadvantages

 Low cost excellent performer                                                 No filter ring - push on filters only and/or universal filter adapter required

 Sharp performance from f8 onwards                                     Betax 3 shutter may require servicing for shutter accuracy

 Fast aperture and bright groundglass experience

 Flat Tessar design (portable)                                                

 Covers whole plate format with movements

Acknowledgments:  Table reproduced from www.f32.net

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Comments, revisions and suggestions welcome.