Alexa Classic/Plus Submount Flange Distance

[Policar]

I want to swap the Alexa Classic's PL mount for something else (this has been done a lot before: C7 Adapters, Leitax, etc.) but do not know the flange distance of the sub mount on the Alexa Classic when the PL mount is removed so I am not sure how long to make the adapter.

Where can I get this information? Thanks.

[Jan Heugel]

Dear Policar,

before driving into schematics: PL Mount is 52mm. Subtract the mount from that and you have the distance that's left for your calculations.

Cheers,
Jan


EDIT: correction on the number

[Policar]

Thanks, Jan. I thought PL was 52mm? Or do you mean the PL mount part on the Alexa protrudes 2mm extra?

[Jan Heugel]

Sorrry, yes. I corrected it. My mind was going 52...44 (LPL).... 54mm is the diameter of the PL.

[Policar]

No worries, and thanks.

I'm finding it a bit hard to get an exact measurement because the black locking ring in the PL mount extends past the area where the back of the lens contacts the mount – so I can't get a precise measurement with calipers.

I've heard it's 20mm to 21mm but want to know what it is precisely so I can have a part machined.

[Jan Heugel]

Dear Matt,

if you're intestested in the drawings, please get in touch with [url=mailto:service@arri.de]ARRI Service[/url].

Cheers,
Jan

[Policar]

Thanks, Jan. I sent an email a bit earlier actually and I have the flange distance from Arri but, while talking with a few machinists, have realized it's a bit more complicated than one number. But I think we have what we need to move forward.

[Jan Heugel]

Great! Feel free to share the result if you fancy.

Cheers,
Jan

[Policar]

Thanks, Jan.

For anyone else interested, the submount flange distance (as illustrated in the attached graphic) is 20.983 mm.

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