Lens question

[ronlamarsh]

I have a 13" wollensak apo raptar f10 in barrel. does anyone know anything about this lens? it is reputed to be the same formula as an artar? I use it on a 5x7 with a packard shutter but I question its sharpness as it doesn't seem to perform as well as my 240mm G-claron. I admit lately I have used it at rather wide apertures f22-32 due to wind and lighting conditions. But still the contacts don't seem to measure up to my 4x5 contacts when viewed with a loupe. any thoughts?
All negatives are the same film(foma 200) developed the same(d-23 2:1).

 

[Ian Grant]

Lens designs are copied, that doesn't mean exactly the same formulae or even the same types of glass were used. I'm sure reverse engineering, getting ideas from patents etc went on with lens manufacturers but of course some designs were licensed, particularly by Zeiss, Ross, Cooke etc.

Another factor is the quality control at the manufacturer, some manufacturers were just not as fastidious as Goerz or Zeiss.

Older lenses can be excellent and easly as sharp as modern lenses but I think its only to be expected that a Wollensak is not as sharp as a G-Claron.

However are you really comparing like with like, is the G-Claron in a modern shutter and could you be getting just a touch of shake with the Packard shutter.

Ian

 

[ronlamarsh]

I hadn't thought about the shutter. I normally use it as more of a "B" type device rather than the instantaneous mode. I do question camera shake though.
At times I also question my technical ability as my Burke and james 5X7 seems a little less user friendly to setup(as in being assured all movements are at zero at the start) than my linhof Tech III. I have been dismayed before after tripping the shutter to find the rear standard isn't horizontally zero due to the nature of its lock and other such setup problems....so this could be some of it also.
Thanks for the input

 

[darinwc]

If that is your only lens on the 5x7 it may also be the ground-glass registration.
If it is not the same distance from the lens as the film, your focus will be off. Try using your 4x5 lens on your 5x7 camera and view the results.