Rigidly mounting an odd combination: T2i + 85L f/1.2

Folks,

I've got a project where I need to rigidly mount my camera (a T2i) and an 85L f/1.2 prime to an optical table. The lens will be set to its minimum focus and the the target will be put in-focus by moving a micrometer stage until it's centered and sharp in live view X10 viewed on an HDTV. My hope is that someone in the group has a suggestion on how to mount the lens (more so than the camera) rigidly. Obviously I can mount the camera with the 1/4-20 hole on the bottom. I could mount a quick-release plate, etc. However, I'd prefer to find a mount that holds the lens first. Then I can support the body using adjustable hardware I already have around my lab.

Does anyone have a suggestion of a tripod ring or some other mount that can hold this lens without translating or spinning?

Thanks!

Interesting problem...

Quote:

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Originally Posted by ChadS

Folks,

I've got a project where I need to rigidly mount my camera (a T2i) and an 85L f/1.2 prime to an optical table. The lens will be set to its minimum focus and the the target will be put in-focus by moving a micrometer stage until it's centered and sharp in live view X10 viewed on an HDTV. My hope is that someone in the group has a suggestion on how to mount the lens (more so than the camera) rigidly. Obviously I can mount the camera with the 1/4-20 hole on the bottom. I could mount a quick-release plate, etc. However, I'd prefer to find a mount that holds the lens first. Then I can support the body using adjustable hardware I already have around my lab.

Does anyone have a suggestion of a tripod ring or some other mount that can hold this lens without translating or spinning?

Thanks!

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Chad, Will you be mounting the camera to shoot straight down on the table or will you mount it horizontaly to shoot across the table?

@Bob I'll be shooting horizontally.

I forgot to ask, How far off of the table does the camera and lens need to be and will this be hardmounted or something temporary?

@Bob at the moment I've got the centerline of the camera about 6 inches off the table. However, it could be more than that. This will be something semi-permanent for the next several months but I'd rather not damage or mar the lens if I can avoid it. Something that I could take in- and out easily would be great so long as it will return to the exact spot. I'm thinking about machining something to mate to the filter threads if no other idea presents itself (with cushioning supports for the rest of the lens and body).

This might be what your looking for.

http://reallyrightstuff.com/ProductD...-Quick-Release

I think this could be adjusted to fit your needs

This is a lab setting? Walking through the chemistry labs in my building, there are large clamps to hold reaction vessels (glass or stainless steel), of sufficient diameter to hold the 85L at the wide part of the barrel (where the distance window is located). The clamps can be mounted to a ring stand (in the labs, there are mounting lattices across the back of the fume hoods). They rigidly support vessels up to several liters.

If that sounds like something that might work, I can find vendor/model information.

--John

@Bob, that looks like a nice steady rest but doesn't appear to rigidly grab the lens. @John, I know exactly the type of hardware you're discussing. However, most of the clamps I can think of have rubber-coated arms that are likely to over-constrain the lens so that depending on how I bump it, etc. it'll move and stay put.

I think I'm going to build my own steady-rest similar to what Bob linked but with some sort of mechanical fixture above. This might be a spring-loaded arm or even a Velcro strap.

I've run into this problem on many occasions but rarely get to use off-the-shelf hardware. I was hopeful this lens might have a tripod mount that's perfect for it. It's really hard to constrain something that's not designed to be rigidly mounted! If you touch something in more than 4 spots and don't allow the proper DoFs (like the wheels in the mount Bob linked) things will NOT stay put!

Similar to Bob's suggestion, I was thinking along the lines of:
http://www.manfrotto.com/telephoto-lens-support
You can then bolt the camera-lens combo straight through the table, in two or more spots.

Or how about a home-made version, look at your local hardware shop for something like this: http://www.slateandcopper.com/Portal...ut_bracket.jpg or http://www.drainageonline.co.uk/imag...pe_Bracket.jpg
you can get them with thin-rubber-lining so you don't damage the lens, and it'll hold it very steady.

Or I don't see why not just bolt the camera to the table, the 85/1.2 doesn't stick out below the bottom of the camera does it? if you bolt and/or superglue or otherwise fix an A-S clamp (like a kirk or wimberly 3-4inch eg http://www.bhphotovideo.com/c/produc...ase_Clamp.html) to the table, and put a plate/L-bracket on the camera body, you can get it back to within <0.5mm if you take it out and put it back in (once it's in position the first time, grab a sharp knife and carve some lines on the plate and clamp that line up, so you know where it goes back in place). Or is that too much tolerance too?