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PL mount for 8 hole Zeiss ex Slomo Digital


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I just got some PL mounts for 8 hole Zeiss off eBay from Frank, who works at Slomo Digital in Burbank. Supposed to be identical to the factory Zeiss, but I can't assume that yet. Just wondering if anyone else has tried them, and if there is any feedback.

They come without the black painted light shield/ dust cover at the back. I'm wondering if anyone has tried 3D printing that part. Maybe Dom or someone knows if it is dimensioned differently for different lenses.

https://www.ebay.com/itm/Zeiss-PL-Mount-8-Hole-for-Zeiss-lenses/223756070082?hash=item3418e6acc2:g:8DAAAOSw0j5dnRu1

May be a while before I get mine fitted, but I will post on how it goes.

Cheers,

Gregg.

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2 hours ago, Gregg MacPherson said:

Maybe Dom or someone knows if it is dimensioned differently for different lenses.

If you mean the screw-in rear baffle, I think the thread is always the same but the opening is variable depending on the size of the individual lens rear element.

I'm not familiar with those PL mounts, but they look pretty good.

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It's hard to tell from those photos what the quality of the machining may be like.  I'll have to see them and take some measurements. I don't know if there is a thread for the rear baffle yet.

What do you think about having no rear baffle? Or a machined plastic baffle that clips into place rather than threaded on? Or a baffle fixed with hot glue, a small groove in the baffle and the mount so that it's a mechanical connection, not just glue in shear?

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I've seen a lot of lenses without a rear baffle, or just with a matte black ring around the lip. It depends on the lens and how much space there is between the rear of the lens and the inside edge of the mount, but you could easily just velvet line the inside or even paint it with matte black paint. Or your suggestions. Light from the lens itself usually won't hit that surface (unlike say the inside of the lens barrel or edge of an element), it's just reflected light bouncing back off a sensor or film, which would then need to bounce back again to affect the image. So it's fairly low risk.

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  • 2 weeks later...

Prefix this with my admission of not being a machinist. I got a sample of one of those mounts. I showed it to a machinist friend and he thought that the finish and de-burring was good. Looks like made on a multi function CNC so at least all are identical. My concern is with a couple of the dimensions. Refer attached pdf drawing.  Sorry it's not sharp, my cheap old phone was better.

- Diameter A on the Slomo PL mount  is oversize at about 54mm. It's supposed to be 25-75microns under. I only have one PL camera port to try it in here. The factory Zeiss mount I have fits sweet, but the Slomo mount is unusably tight. But I think this is an easy fix,. Some skilled manual work on a lathe could do it.

- The undercut in the corner above diameter A is almost nonexistent. Which is fine unless you are mounting to a port that has no chamfer on the external corner. But this could be fixed easily if machining diameter A. 

- Diameter B is undersized at 61.85mm. The Zeiss one is 61.95 - 62mm. So the Slomo one wiggles around a bit within the constraints of that little lip on the Zeiss lenses. This may not matter with good screws in place. Also, if needed maybe some improvised shims on the side could be used to keep the mount concentric.

So, faults may be easily fixable and must be related to the price.....

Gregg.

PS. The dimension C looked a bit under 5.5, but hard to measure with the tools I had. Maybe 50microns under? The Zeiss on looked the same.

 

 

 

Pic of PL mount DWG for forum.jpg

Edited by Gregg MacPherson
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  • 1 month later...

Don't know if Slomo have sold all their stock, but here are some extra details. The diameter that fits into the lens port (diam A in the pic) was varying. I decided to manually grind that with precision file, emery paper (on a lathe) to a diameter that should work.  My machinist friend was a bit horrified, but the result is actually quite good. I'm sure that Slomo will specify a more undersized part if they go again.

Meanwhile, I spotted some really cheap PL rear caps on eBay, from Poland (Funky Photo Group) . They look like this,

https://www.ebay.com/itm/Fifty-50-Lens-caps-for-PL-Mount-Rear-Cover-Size-54mm-2-13-H/372437606556?hash=item56b702e09c:g:sL4AAOSwW4ZbnVab

but my google is down so I can't easily identify them.  There are many good engineers in Poland, so I rolled the dice. The result looks quite good. Fits well and snugs to a pinch, closed. About USD9.  The only serious comparison for them that I have is by Cooke, and I don't know how old.  Are they all just ABS plastic?, will they all wear on the surface that snugs to the wing...?

So cheap though, and many are selling rear caps at oddly high prices. Price vs quality in the current world is not a rational equation that's easy to understand. You get the value that you can be bothered to notice or interpret.

Edited by Gregg MacPherson
Extra content....
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  • 9 months later...

P+S Technik has them: https://www.pstechnik.de/pl-adapter-arri-vorm/a-1012/ . I heard from someone that bought them that the screws they sent were not a direct match and they had to source their own.

Visual Products also sells them: http://www.visualproducts.com/storeProductDetail02.asp?productID=1111&Cat=3&Cat2=43

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The person that used the P+S Technik one used it on a standard speed that was Arri bayonet.

I don't know for sure about the VP one, but I'm almost positive it's for vintage lenses.

You could always email the companies and ask them.

Edited by Joshua Cadmium
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  • 2 years later...

I just had the rear light baffles made that I needed for the Slomo PL mounts. Turned on a manual lathe. Coated really inexpensively with Ferrophos. Total cost was about USD60 each, but I don't know if the machinist enjoyed it.  Unfortunately we did not go to CNC, otherwise there might be a cheap source of these parts.  If someone wants to prep for CNC we might share the 2D Autocad drawing.

https://www.dropbox.com/scl/fi/1grcrzzdv131ga53d1toh/light-baffles.jpg?rlkey=p0zajtc2qxjm296tqcqa4eepa&dl=0

The one on the right is an original Zeiss/Arri part fitted to a Slomo PL mount. I don't assume that all baffles have the same inside dimension fitting over the lenses, but the Zeiss one from the 16mm format f=50mm lens looked like it would fit the other 16mm format lenses. When I know for sure I will report.

Gregg.

Edited by Gregg MacPherson
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