Caltar Rodenstock 135mm aperture scale

[korby]

Hello, newbie here.

Just got into 4x5 and I got a good deal on eBay for a Caltar II-N Rodenstock 135mm f/5.6.
Nice glass, clean, the shutter looks new and aperture knob is not faded.


So far so good, until I noticed the knob moves past 5.6 and past 64. Upon inspection, the blades are slightly closed at the 5.6 mark, and closed even further past f/64.

What are your thoughts on this? I'm guessing since the markings on the aperture scale don't match what the blades do, I'm unable to set the aperture properly. The scale is unusable. Is there an easy fix to this other than returning the lens and getting a new one?

Thanks for the wise advice!

[JimL]

For many shutters on large format lenses there are no limits on the aperture lever's movement. It's normal for the shutter blades to be just visible at the large opening, and for the knob to move past either end of the f-stop scale. The aperture is set properly when the pointer is pointing at the desired mark on the aperture scale!

[rdeloe]

My Caltar 90mm f/6.8 does the same thing. I haven't noticed this design on Fujinon or Nikkor lenses. My Caltar works fine though, so enjoy.

[Vaughn]

The f-stop number is determined by the focal length of the lens divided by the diameter of the aperture.

So you can double-check it by measuring and a little math, if you like.

[Larry Gebhardt]

The one I have behaves the same way. Mine has 0011.067 on the aperture scale. What does yours say?

[Bob Salomon]

Your lens is in a Copal 0 shutter. Rodenstock has lenses from the 28mm Apo Sironar Digital to the 150mm Apo Sironar N and S that all use this shutter. These lenses are 4.5, 5.6 or 6.8 maximum aperture. Depending on the maximum speed aperture decides which aperture scale is mounted on the shutter. The maximum and minimum openings have the 0 shutter are the same for all of these lenses. So, if your scale is the correct one for the 90mm 6.8 the effect you see is correct.

[Dan Fromm]

The f-stop number is determined by the focal length of the lens divided by the diameter of the aperture.

Not aperture, entrance pupil.

[korby]

0011.067 as well! Interesting. I had also gotten another Caltar Rodenstock in 150mm, but the 5.6 was spot on; the 64 end had a little extra. It was fitted on a Copal 0 shutter with a Nikon w 150mm label.

Since I'm liking the 135mm focal length a little better, I switched the shutters. It kinda bothers me that the 5.6 end is a little closed

[Vaughn]

Not aperture, entrance pupil.

Close enough...look thru the front of the lens to measure the aperature.

[Bernice Loui]

Not wise and not respecting those who designed and produced this lens as they know what they are doing and why they did what was done.

To believe the f5.6 end is a "little" closed is wrong is much projection of what one wants to believe, not what has been designed into where f5.6 is to be.

It is possible this mind-set came from using cameras and lenses designed and produced by a single brand as a fixed and mostly closed system offering. In these camera-lens systems the aperture scale and settings have positive stops at full to smallest f-stops with no easy way to altering this. In the view camera world most of that is gone as shutters have standard sizes and lens cells are often designed to standard size shutters with customization done by attaching the aperture scale as needed. This allows shutter manufactures to be independent from optical companies that make lenses, but use their shutters as production items. This applies to lens barrels where the barrel
often has an aperture mechanism and some times a closable opening to allow for insertion of fixed aperture cards or disc with the specific aperture opening size and shape. Lens barrels can be sized to the precise length for a given lens cell set to optimize optical performance. This is also done with lenses in shutter by shims which are often specific to that lens cell set.


Bernice

Since I'm liking the 135mm focal length a little better, I switched the shutters. It kinda bothers me that the 5.6 end is a little closed