[LargeFormat] Wolley Ex W 6.25" f12.5 series III 8x10

[Les Newcomer]

On Sunday, August 25, 2002, at 02:34 AM, Clive Warren wrote:

> At 3:00 pm -0700 14/8/02, Richard Knoppow wrote:
>> At 01:19 PM 08/14/2002 -0700, you wrote:
>>> I finally got around to fixing this lens I got in a box lot of other
>>> neat stuff.
>>>
>>> I've noticed that the iris is limited to f12.5 but the glass is much
>>> larger than that.
>>>
>>> I was wondering what part of life as I or the lens knows it would come
>>> to an end if I removed the stop and allowed the iris to open up to 
>>> it's
>>> full potiential?
>>>
>>> While I understand anything less that 12.5 will not give desireable
>>> sharpness,
>>>
>>> but it might be a whole lot easier to focus........unless there's a
>>> focus shift when you stop down on this lens.
>>>
>>> Any body have any experience with this one?
>>>
>>>
>>> Les
>>>
>>   I am not sure what design this lens is but believe its a Series IV 
>> Protar.
>>   The oversize elements are to prevent mechanical vignetting. The lens
>> opens to f/12.5 for focusing and composition. It should be stopped 
>> down to
>> f/36 for use. The maximum coverage is at f/45.
>>   The Wide Angle Protars are part of the family of lenses designed by 
>> Paul
>> Rudolph, of Zeiss, and considered to be the first anastigmats. They are
>> four elements in two cemented groups. The front is made of "old" 
>> glass, the
>> rear of "new" or Jena glass. Wollensak may well have modified the 
>> design.
>>   You can tell something about the construction of the lens by 
>> shining a
>> flashlight into it and counting reflections. Glass-air refelctions are
>> bright, cemented surfaces are very dim. Even in single coated lenses 
>> the
>> coated surfaces will have much brighter reflections than the cemented 
>> ones.
>> I have a couple of multicoated lenses and its still possible to
>> differentiate the surfaces. If I am right each cell will have two 
>> bright
>> and one dim reflection.
>>   I think Wollensak may also have made an f/12.5 version of a lens 
>> which is
>> more commonly f/9.5. Essentially a four element double-gauss type but 
>> with
>> all four elements compounded. The reflections from this type will show 
>> four
>> bright and two dim reflections per cell.
>>   The same thing about stop applies to this type, wide open is for
>> composing, the lens is meant to work at around f/22 - f/36 mimimum.
>> ----
>> Richard Knoppow
>
> Hello Les and Richard,
>
> Would normally snip posts but all of the above is relevant!
>
> I have the Wolly Velo Extreme WA Series III 6.25" f9.5 which is 
> uncoated and in a Betax #3 shutter. Have only recently dug it out of a 
> draw and CLA'd the shutter.
>
> This lens is also iris restricted with larger glass. As Richard 
> suggests this is probably to avoid mechanical vignetting. You could 
> open it up to make focusing easier by removing the iris plate - the 
> world would probably keep spinning ;-)
>
> Les, the f9.5 is probably easier to focus than the f12.5 but both are 
> searingly bright compared to the Protars that you like using....
>
> As for numbers of elements, the f9.5 has four in each cell according to 
> my count by reflected light. The f9.5 was in production later than the 
> f12.5 although both probably continued in production with one maybe 
> less expensive than the other? Later versions were coated. Seems as 
> though the lenses are possibly of different construction - how many 
> elements in your f12.5?



<snip>  My mini mag comes to the rescue and I find two reflections in 
the front cell and two in the rear.  Smells like a Protar IV to me.

Les
>
>
>
>
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