Hasselblad to M42 adapter (generic) connected to M42 to Aaton mount adapter (made by Les Bosher)

[Stephen Perera]

Hi all, so I'd like to use a Hasselblad lens connected to my Aaton XTR XC camera via 2 adapters.

I have a Hasselblad to M42 adapter and  an M42 to Aaton mount adapter which Les Bosher made for me some years ago. I've shot with a Pentax Takumar 110mm?? lens on the Aaton with beautiful results. I'm wondering whether I need to add a stop to exposure or not given the x 2 adapters. I cant test it as I dont have a lab in country and Im hoping you guys can give me an answer or indication.

.....the answer to the question why the hell would I want to do that is....why not. @Dom Jaeger any thoughts my friend?

 

Edited March 12 by Stephen Perera

[Mark Dunn]

You can't just connect adapters together, the FFD will be incorrect. The lens will be too far from the film.

You will probably have a great macro lens, though😉

Edited March 12 by Mark Dunn

[Stephen Perera]

40 minutes ago, Mark Dunn said:

You can't just connect adapters together, the FFD will be incorrect. The lens will be too far from the film.

You will probably have a great macro lens, though😉

macro....yes exactly...thats what I want to investigate......thanks Mark for the reply

[Dom Jaeger]

Well if both adapters are accurate, and allow clearance of the lens, then together they should seat the lens at the correct depth. You’re just making a Hasselblad to Aaton adapter in two steps. No need to compensate aperture unless there are optical reducers in there but it sounds like these are just mechanical adapters right? 

The lenses might be a little soft for 16mm, but worth a try.

How does it look in the viewfinder? 

[Stephen Perera]

8 minutes ago, Dom Jaeger said:

Well if both adapters are accurate, and allow clearance of the lens, then together they should seat the lens at the correct depth. You’re just making a Hasselblad to Aaton adapter in two steps. No need to compensate aperture unless there are optical reducers in there but it sounds like these are just mechanical adapters right? 

The lenses might be a little soft for 16mm, but worth a try.

How does it look in the viewfinder? 

Thanks for the information Dom appreciate it....I will report back on what it looks like

[Steve Switaj]

Stephen, I think we need some more information here to figure out what you're after.

There are (basically) three kinds of lens adapters.

The first one is purely mechanical, a short tube with a flange on either end, meant to mount a lens with a deep flange (backfocus) depth to a camera with a shallow flange depth. It simply holds the lens in place at the correct distance from the film plane and fills up the space in between. 

These adapters do not have any optics in them, and, if made accurately, allow the lens to focus to infinity. They are commonly found adapting a still lens to a small-format cine camera. They don't affect the size of the image at the focal plane or the image brightness, though you may see a "crop factor" because you're on a smaller sensor, and what was once a normal lens on your 35mm still camera now crops down to a mid-telephoto in super 16. 

The second type is mechanically like the first, but with active optics in the tube. This type can shift the focal plane around or shrink/grow the image. For example, I have a PL-to-EF adapter that goes on a cine zoom and expands the academy-sized image to cover a full-frame sensor, at the expense of creating an image one stop dimmer (because it's spreading the same light over a larger area). There are "speed increasers" that go the other way, shrinking a full-frame image down to an APS-C or 4/3 frame size. Since they take the image and concentrate the same light over a smaller area, the image gets brighter, but there is no crop factor (because the image is smaller).  

The third type is exclusively a play for macro focus. These are usually purely mechanical, like type 1, but they purposely have way more than the "correct" amount of back-focus, usually by 10-50mm or so.  By spacing the lens out farther than normal they basically extend the focusing threads allow additional close focus, but at the expense of no longer being able to reach infinity (because the lens can't get back far enough any more). Think of them like old-school extension tubes on a still camera. 

Sometimes these macro tubes can employ a second helicoid to make them adjustable and thus more versatile.

This type of tube definitely will affect your image brightness. Effectively, you're moving the focal plane farther from the lens, and the inverse-square law will start to come into play. The effective focal length will also seem to grow as you focus closer. These are both results of the basic laws of optics, but since they are exponential you usually only notice them in macro work (many true macro lenses have barrel markings to indicate this shift, btw).  Look up "bellows factor" from still photography for a better explanation.  

In your case you probably have two normal "type 1" adapters. The first goes from the 66mm backfocus of a Hasselblad lens down to the 46mm backfocus of an M42 camera body, and the second goes from the 46mm backfocus of an M42 standard lens down to the 40mm backfocus of the Aaton mount. 

Assuming there's no glass in there, and you can focus to infinity, your exposures should not shift (though your Hassleblad still lens will be marked in F-stops instead of T-stops, so you might want to dial in an extra half stop or so)

[Stephen Perera]

Very informative and very kind to take the time to write all this. Yes I have dumb adapters as I think they call them! I use Hasselblad extension tubes in my stills photography and wanted to experiment with my Aaton as I'm going to be filming soon loads of close up stuff with 500T in a guitar luthier workshop