Shutter blades jam - Hasselblad 50/4 C with Fotodiox Pro Hasselblad to Nikon adapter

I recently got this adapter to mount my Hasselblad 50/4 Distagon C version lens on my Nikon D750 - FotodioX Pro Lens Mount Adapter for Hasselblad V HBV-NIKF-PRO

 

The first hour or so seemed good - shooting wide open or using the DOF preview lever to stop down and shoot (then opening up aperture blades by switching the lens to wide open at f4).

 

However it randomly jams (the lens shutter blades suddenly close and can't be released again with aperture ring or DOF lever). There doesn't seem to be a pattern to when or how. When it happens, I have to wind the lock on the lens to re open the aperture blades as per this video -

It's happened a few times already in the course of one day.

 

Do you think the problem is the adapter? Or the lens? Or something about my technique?

For the price of that adapter, or just slightly more, you could have bought a used 50mm Nikkor lens with full functionality and a wider aperture. I haven't seen any 50mm Nikkor lens that won't give near-perfect image quality when stopped down to f/4 or below.

 

What advantage does using the oversized Distagon give you on a D750? The larger image circle is actually a disadvantage, because it'll cause excessive body flare in the camera. It's not as if the adapter gives you tilt/shift functionality, which IMO would be the only good reason to use an MF wideangle on a 35mm size body.

 

It sounds as if the 'blad lens shutter is getting accidentally tripped somehow, and then naturally you can't do anything until it's re-cocked for viewing.

Edited August 29, 2018 by rodeo_joe|1

The lens is being accidentally tripped. The latch is a little lever inside a half-tube on the rear of the lens. It is engaged by a pin in the Hasselblad body, releasing the shutter which is held, controlled and recocked by the coupling which looks like a screw head.

 

There's nothing in the Fofotiox adapter to do this. My guess is that the latch or spring is worn from long use, and can be dislodged in normal handling. It's a very simple repair. It is also a liability, because if the lens trips while mounting or dismounting it on a Hasselblad body, it will cause a very serious (expensive) jam you can't fix at home.

The Fotodiox (and all similar made-in China Hasselblad>smaller format adapters) can be fun to use, but they tend to have exactly this problem rather often. I have two different near-identical generic Hasselblad>Nikon adapters, bought years apart, and they both trigger the leaf shutter with annoying frequency. Half the time its when removing the Hasselblad lens from the adapter, and half the time its after playing with the stop-down button one too many times. Its been more of a problem with my older C lenses than later CF, possibly because of the EV link between aperture and shutter in the C lenses.

 

What Ed_Ingold explained about the release pin is true, but may or may not apply in your case. A lens with pin trouble usually starts acting up when used on the Hasselblad bodies it was intended for, typically firing the shutter while removing the lens (causing some degree of jamming). If your lens is not doing that and never has, most likely the problem is limited to adapter use. As Ed_Ingold mentioned, Hasselblad bodies have a mechanism that interacts with the lens pin, normally preventing the shutter from closing except when desired.

 

Adapters don't have this "pin retaining mechanism", which makes the lens shutter prone to fire if the pin vibrates against part of the adapter when mounting/unmounting. And repeated use of the DOF stop-down button with the lens on an adapter eventually wiggles the pin enough to accidentally fire the shutter. This happens because stopping down the lens uses some of the cycle required to fire the shutter: each time you release that spring to stop down (then re-cock it by rotating the aperture ring back to wide open) you disturb the entire mechanism that hyper-sensitive pin is connected to. Like poking a snake with a stick, eventually you get bit.

 

The workaround is to plan your shots more carefully, so you don't need to constantly re-cock the diaphragm. Use the DOF button to stop the lens down the first time, after that don't re-open it all the way to f/4.0 again (where you can feel the springs re-cock). If you must use f/4.0, for a series of shots, do all of those first before pressing the DOF button to access smaller stops. Then, don't open wider than f/5.6 for the rest of your session. That should cut way down on spurious shutter firings.

 

rodeo_joe, logic doesn't always figure when experimenting with lenses. You're absolutely right: no one in their right mind would mount the gigantic 50mm Distagon to a Nikon body as a daily driver instead of a proper 50mm Nikkor. But the old 50mm Distagon-C is unexpectedly sympatico with small format digital sensors: it makes killer images on Nikon FX especially (and zero issues with the image circle). Ed_Ingold hates when I use the term "rendering", but theres no other word for it. Zeiss is Zeiss: the colors and contrast, even with the 50 year old Distagon, are distinctly different and sometimes preferable to what you can pull from a Nikkor. Some subjects that record as "meh" with a Nikkor 50mm make your eyes pop out when shot with the Distagon. Sure, you can kill a few hours trying to replicate the look in post, but where's the giggles in that? A Hasselblad>Nikon adapter is a $40 ticket to fun town if you already own some Hasselblad lenses, and occasionally want to shake things up.

 

Not that I'd recommend anyone go out and buy an old Distagon C just to play games on a Nikon: thats pointless. If one doesn't already own a Hasselblad, but wants to experiment with Zeiss glass on Nikon-Sony-Canon bodies, there are newer-smaller-faster Zeiss lenses made specifically for those bodies/formats.

Edited August 30, 2018 by orsetto

You're trying to use the lens in a way the maker didn't design it to be used, so can't really fault the lens if there's a problem. Have you contacted Fotodiox about the issue? As the maker of the adapter, surely it's incumbent on them to sell items that are of merchantable quality.