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Oconnor O-Box and Canon lens

Adam Michael Carr

Adam Michael Carr

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With reduction rings, is it possible to attach lenses that are 72mm or 77mm diameter to the o-box? Most canon lenses aren't much bigger than 77mm, so I'm hoping it is possible. It says it's able to do 150mm-80mm diameter, but how much light leakage will there be with a 77mm on there?
 
I would suggest using LW 15mm rods when using the O-Box with Cannon lenses. The O-Box still has some heft to it and I'm not sure many Canon lenses would take well to the weight or the clamping force, which can distend lens barrels. And even the Titanium Canon mount could get strained it seems to me. I finally got my modular assault plate and it allows easy use of the O-Box with Canon lenses in a lightweight configuration. There are other options from Viewfactor and Wooden camera that will not add much weight to your rig, but may give better results than clamping on.
 
Im going with a LW 15 setup. My question is how to use the o-box with a lens that has a diameter of 77mm. The o-box supports 150-80mm. I'm assuming someone makes a reduction ring that is flush with the lens barrel so that no light will leak in from the sides
 
Gt the flexi ring. That's what I have for my Obox and it rocks. And it's easy to swap out lenses and not have to change rings.
 
Randall Brown said:
Gt the flexi ring. That's what I have for my Obox and it rocks. And it's easy to swap out lenses and not have to change rings.
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Agreed. Another nice thing about the flex ring is it allows for lenses that rack when focused. The hard mount travels with the lens fore and aft and if you have it screwed into the lens AND the matte box, you're not going to be able to focus. Depends on the lenses you have, but a simple solution is to not clamp down the matte box to the step down ring and if the lens doesn't rack beyond the joint. This only works if you have the matte box on rails however. The downside to the flex ring is they will wear out over time and usage, so you'll have to buy more. Also, it could potentially not have as tight of a seal as the metal step down ring allowing light to enter, but probably not. Some folks are ham-handed with equipment and will ruin stuff prematurely, ymmv.

I have both and actually prefer the metal version, but carry the flex one also. I don't think the Nikon or Canon mounts or the lenses are strong enough for supporting the Obox loaded with filters. Have no empirical evidence, just my opinion.
 
hi Adam, i have to obox with the 15mm lws and it fits all my canon lenses beautiful. I use their 80mm screw in ring, and have a protective filter in front of my canon glass and this fits tightly in. I actually have the felling their 80mm is more close to 77mm as their is no light leak and it fits exact :)
 
Actually it is 80mm…the screw in filter has the threads at 77mm BUT the outer diameter of that round filter is right about 80mm (Mitch Gross taught me this trick years ago.) I personally have a 17-40 L Zoom from Canon and with the Tiffen 77mm UV Filter screwed on the front of the lens my O-Box clamps perfectly; no rods required.
 
thanks Eric, that explains why it's a nice fit :)
 
No Problem...I have a demo with this same set up this Tuesday so I'll post some pics then.
 
Hi Paul,

There may be some sort of 4 1/2 to 138mm step up ring out there but we recommend using a 138mm round glass filter only in the bellows retainer.
 
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What would be the best way to donut from the 138mm bellows down to a small lens? It'd be on rods so no need to mount, just need something to block the light.
 
Adam Michael Carr said:
Thanks guys, Im getting this for the time being http://www.bhphotovideo.com/c/produ...2_AC_450_22_Flex_Ring_Flexible_Step_Down.html
http://www.bhphotovideo.com/c/product/743398-REG/OConnor_C1243_1117_C1243_1117_Bellows_Ring.html
http://www.bhphotovideo.com/c/product/743439-REG/OConnor_C1243_2171_Reduction_Ring_114_110_mm.html

Will probably go with solid rings in the future, but this seems like a good compromise for now.
Click to expand...

I just bought this exact setup to go with my Obox, Side brackets and side flags. It works perfectly with my canon lenses - if only my scarlet would arrive.
 
Hi Shawn,

Happy New Year to you!

The back of the O-Box has a 150mm opening which matches the outer diameter of the bellows ring. This bellows ring then can act as a third, rotatable filter stage via its 138mm round screw in filter retainer. The threaded aluminum ring facing the lens is 114mm. This is standard pitch threading for ARRI, Chrosziel and OConnor so rings are interconnectable. The 114mm to 110mm (threaded) step down ring can be used with the Chrosziel Flexi rings; they have a small and large one.

Great setup for still lenses; it's what I use on my own rig.
 
Paul Russell said:
Hi Eric, I've been looking but can't find one. I was hoping I might be able to adapt a 114mm clamp ring. Failing that I'll take my angle grinder out and cut them to fit into the 4x5.65 sliders
Click to expand...

It sounds like you Sir, just invented a product! Now you just have to get it made...
 
Here's Eric's pic showing his setup
 

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