Sinar Auto Shutters f4 versus f5.6

[Jason Greenberg Motamedi]

I am looking to buy a Sinar Auto Shutter for a project I have in mind but am a bit unclear about the differences between the f4 and the f5.6 versions. Is the size of the shutter aperture larger in the f4 version? Or is it simply how they stop down the aperture of the DB mounted lenses.

I will be using it with a few large barrel-mounted lenses so the maximum size of the shutter is of relevance.

[mikec]

Google failed to locate a spec sheet for me so I got the following from a tape measure. Mine has a maximum of f5,6 auto aparture control. It has a rear (maximum) opening of 75 mm. The rear, where the shutter leaves are , is a max of about 20mm deeper than the rear side of the lens board, but that is a limit. My Sinar DB mounted lenses project no more than 17mm into this space, so I suggest that you be equally conservative. I was not aware of a f4,5 version.
The "f" rating only relates to the db mount diaphragms , so you can use barrel lenses at greater aperture provided the rear element is less than 75mm in diameter and extends sufficiently into the shutter space.

[Struan Gray]

Jason, my understanding is that the f4.5 shutters don't have a larger hole, they just allow you to set a wider aperture on the lens. That is, they were introduced to allow f4.5 wide angles to be use with the Sinar shutter system, not f4.5 portrait monsters.

[Jason Greenberg Motamedi]

Thank you Mike and Struan, that is what I needed to know.

[Daniel Unkefer]

If you are using it with large barrel lenses, it sounds like you don't need the aperture interlocks that come with the modern shutter.

I have two of the green Norma mechanical shutters, and they can be reasonably priced, and work great with any of the large barrel lenses.

My longest presently is my 59cm Zeiss Apo-Planar. Now that thing is a real boat anchor, but no doubt, one of my finest. Works great with the Norma shutter.

[Jason Greenberg Motamedi]

Thanks Daniel. I will look for one of the older non-aperture control shutters, but just wanted to make sure that I wouldn't be missing out on a few millimeters.

Anybody got one for sale?