Sinar-mounted lens: Shouldn't it open all the way ?

[Ken Lee]

I just got this lens via eBay, and wonder if there's a problem.

It's a Sinar-branded Macro-Sironar-N, in DB shutter.

It works fine with my Sinar Shutter. Depending on the selected f/stop, it will close appropriately when the shutter is released, but...

...as you can see, it doesn't open all the way. Is that normal ? (The shutter looks asymmetrical, but that's only because of the viewing angle).

I am allowed a 14-day return policy. Should I return the lens ?

Thanks !!

[Ken Lee]

Here's a photo of the rear of the lens.

There is a screw on the left, which appears to control how far open the lens will go when moved by the sliding pin on the right - but I am reluctant to mess with it. As you can see, the pin is at the extreme right, and should be opening the shutter all the way.

[Orfitinho]

Yes, the screw controls the max lens opening.

If your shutter opens wide enough you can detach it. But, if your lens opens wider then your shutter, the shutter will not be able to close the lens. The screw closes the lens wide enough for the shutter to reach the lever (right wording?).
In my case the shutter supports only f5.6 but the lens opens to 4.5.

Just try it. You can see the difference clearly at slow shutter speed.


Hope that helps


Gerd

[Ken Lee]

My Sinar Shutter opens to f/5.6, and the lens itself is described as f/5.6.

I am reluctant to try the screw, until the eBay seller gives me his approval.

[Ken Lee]

Here is another photo, showing that there are actually 2 pins to adjust.

The seller has given me approval. All done !