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Macro-Hexanon 105/4 and Auto Helicoid AR
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PostPosted: Tue Mar 20, 2018 3:14 pm    Post subject: Macro-Hexanon 105/4 and Auto Helicoid AR Reply with quote

I am trying out my Macro-Hexanon 105/4 and Auto Helicoid AR combination on my Sony A7Rii with a Fotga adapter.

I don't know why but I'm not able to use the lens as a macro lens. I can use the lens as a normal 105mm, sharp from infinity to about 70cm from the film plane. What am I doing wrong?


PostPosted: Tue Mar 20, 2018 4:02 pm    Post subject: Reply with quote

I think there is nothing wrong. The extension is not enough for focusing to life-size.


PostPosted: Tue Mar 20, 2018 4:26 pm    Post subject: Reply with quote

Yes, I sort of figured this out myself. When I put the lens on bellows I get closer but still not closer than using a normal macro lens. What is the point then. Or is this simply old technology rendered obsolete?


PostPosted: Tue Mar 20, 2018 4:41 pm    Post subject: Reply with quote

They made a bellow too, or you can add tubes..


PostPosted: Tue Mar 20, 2018 6:27 pm    Post subject: Reply with quote

http://www.buhla.de/Foto/Konica/Zubehoer/eAutoHelicoidAR.html
Quote:
The Macro-Hexanon AR 105mm / F4 is a so-called bellows head. It is intended for macro use on bellows or on extension rings and has no helicoid for focusing. The focusing is normally done by the bellows extension. The lens does not have the standard flange-film distance of the other Konica SLR lenses (40.5 mm) – would you mount this macro lens directly on a camera body, it would be far too close to the film plane to be able to make a sharp image.

With the Auto Helicoid AR, the Macro-Hexanon AR 105 mm / F4 can be used on a camera body without bellows, and it can be focused the normal way by turning the helicoid's ring. At the minimum length of the Auto Helicoid AR, you get infinity focus with this macro lens. If you set the Auto Helicoid AR to it's maximum length, you can get macro images with a scale of 0.23x (1:4.35) with the Macro-Hexanon AR 105 mm / F4.

The intent was to give the 105 a normal focus range, if you want a macro range, you'll need a bellows or you'll need extension rings to go with the Auto Helicoid.


PostPosted: Tue Mar 20, 2018 6:40 pm    Post subject: Reply with quote

Pontus wrote:
Yes, I sort of figured this out myself. When I put the lens on bellows I get closer but still not closer than using a normal macro lens. What is the point then. Or is this simply old technology rendered obsolete?


Nothing wrong with your lens, I think. I suppose that when you talk about normal macro lens, you mean a 50-60mm lens. When it comes to macrophotography, one usually thinks in terms of magnification, which is given by the ratio of the extension to the focal length:

m = e / f

Thus, for a given extension, the magnification is inversely proportional to the focal length. For example, using a fully extended bellows, the magnification for a 100 mm lens will be half that of a 50 mm lens. And for a given magnification, the extension required for a 100 mm lens is double than for a 50 mm lens.


PostPosted: Tue Mar 20, 2018 8:28 pm    Post subject: Reply with quote

Another difference, with a longer focal length, you don't have to get as close to the subject. E.g. for insects this can be an advantage, as a lens too close can make them move away.