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Manual Focusing with Contax N

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Joined: 14 Aug 2014
Posts: 3

PostPosted: Wed Aug 20, 2014 3:22 am    Post subject: Manual Focusing with Contax N Reply with quote

I plan to use Conurus adapted Contax N lenses for video / cinematography uses.

I am considering a 24-85 and 70-300 lenses for these purposes.

I've read that these lenses do not have AF/MF switch and must be stopped down to the smallest aperture to enable manual focusing.

Does this mean these lenses can only be manually focused at their smallest aperture? This would not make these lenses very useful for video.

Also, can you please clarify in you FAQ, "Your lens supports full-time manual focus. You may rotate the focusing ring at any time to adjust focus, even in autofocus mode." This seems to contradict what I've read above. Does this mean it is possible to always focus manually/ at any aperture? And stopping down completely simply disables AF?

Also, could you clarify in your FAQ under De-Clicking "Designed for still photography, it has finite resolution which is inadequate for cinematographic work. There will be visible disruption in the resulting footage, even if the aperture ring is declicked. The electromagnetic aperture diaphragm has 1/8 stop resolution, and the electronic aperture ring has even less resolution than that."

What do you mean by "finite resolution" this being inadequate for video work.

Thanks in Advance.
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Joined: 12 Dec 2006
Posts: 21
Location: Vancouver, Canada

PostPosted: Sun Oct 12, 2014 8:55 am    Post subject: Reply with quote

I am not Conurus. But I'll try to answer a few of your questions

1) AF/MF - the aperture ring is not used as an aperture ring (for all intents and purposes) in conventional use on a converted lens. If you want to have it as MF, you set it to the 'smallest aperture setting' but that's just telling the lens 'act like an MF lens and tell the Canon body that you're in MF' mode.
2) you can manually focus the lens at any time, in 'AF' or 'MF' mode. If you want to disable AF focus on half-shutter-press, that's a setting on the camera body to do, not the lens.
3) See (2) re: always able to manually focus.
4) Declicking. The N lenses are electrically operated. The diaphragm that controls the f-stop can only operate in ⅛ stop resolution so no matter how you want to have a smooth analog-like declicked diaphragm, you canNOT have that with these lenses UNLESS you were to hack together a way to manually operate the diaphragm. That is unlikely. So you have a f-stop that can only be controlled in ⅛ stop resolution from wide-open to fully-constricted with a fixed/finite # of stops to set. Mechanical declicked lenses can have gradual-increments between settings that are effectively infinite.
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