[bdery]

you need a long plate to balance the lens.

A5mm plate is simply not rigid enough to prevent vibrations

A long plate, absolutely. A thick plate? I don't see why it's mandatory.

[vonBaloney]

The Joby Ultra Plate is about 9mm thick in total, but the top 1-2mm of that is a bit of rubber on the top of the plate -- the metal part is actually rather thin. The rubber is set in a slightly recessed area on the top of the plate -- if you removed it (or sanded it down so it was flush or replaced with some other thinner material) you'd have a 7-8mm thick plate. It has a 30mm center track for a screw (or two) plus two fixed 1/4" holes on the edges. I have one semi-permanently attached to my A*600/5.6 as a spacer. It was the only one I could find with the right hole configuration that would allow me to strongly attach a much longer plate below it using the two fixed holes.

[Lowell Goudge]

A long plate, absolutely. A thick plate? I don't see why it's mandatory.

The stiffness of a plate is directly related to the thickness. Your long heavy lens will flex and lead to serious vibration of the lens on the tripod.

[photoptimist]

The stiffness of a plate is directly related to the thickness. Your long heavy lens will flex and lead to serious vibration of the lens on the tripod.

Exactly! The bending stiffness of the plate increases with the cube of the thickness. A 7 mm plate is actually almost 3 times as stiff as a 5 mm plate.

[pentaxfall]

Long plate helps hand held shooting. The plates that I use goes from wrist to tip of the fingers. That helps balance weight

[torashi]

Stiffness also depends on material. If you need a thinner plate, you would need a tougher and whose tensile strength is greater material. Usually they're made of an aluminium alloy. The right kind of steel would do.

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[MikeyBugs95]

Stiffness also depends on material. If you need a thinner plate, you would need a tougher and whose tensile strength is greater material. Usually they're made of an aluminium alloy. The right kind of steel would do.

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Titanium would probably be better for the purpose, though. But that much titanium is prohibitively expensive for the use.

[bdery]

The stiffness of a plate is directly related to the thickness. Your long heavy lens will flex and lead to serious vibration of the lens on the tripod.

Exactly! The bending stiffness of the plate increases with the cube of the thickness. A 7 mm plate is actually almost 3 times as stiff as a 5 mm plate.

That's all true, in theory. What this discussion fails to mention is what is the minimum thickness required. I could dig out the appropriate material properties but intuitively I think aluminium held in place by two screws doesn't require more than 1 cm.

Stiffness also depends on material. If you need a thinner plate, you would need a tougher and whose tensile strength is greater material. Usually they're made of an aluminium alloy. The right kind of steel would do.

Correct that the material's Young modulus will influence the rigidity.

When coupling, with two 1/4-20 screws, an aluminium plate with a thick (aluminium) foot, the resulting apparatus is probably more than thick enough. I'm pretty sure that having a dovetail on the foot itself would work flawlessly.

[Lowell Goudge]

That's all true, in theory. What this discussion fails to mention is what is the minimum thickness required. I could dig out the appropriate material properties but intuitively I think aluminium held in place by two screws doesn't require more than 1 cm.



Correct that the material's Young modulus will influence the rigidity.

When coupling, with two 1/4-20 screws, an aluminium plate with a thick (aluminium) foot, the resulting apparatus is probably more than thick enough. I'm pretty sure that having a dovetail on the foot itself would work flawlessly.

i can only relate a recient experience i have had.

i use a tamron 200-500/5.6 zoom, that weighs about 3 kilos all by itself.

i tried using a regular tripod head with but changed to a gimball head, a jopbo jr to be precise.

the gimbal has a pivot and an L Shaped arm that hangs down from the pivot, to mount the lens.

this arm is 170 mm long, 8 mm 13 mm thick at the edges (but milled to 8 mm thick in the middle to save weight.

while it seems rigid enough, looking through my 500mm lens, the whole thing bounces, removing this plate, and connecting my same acra swiss adaptor direct to the pivot removed all of this.,

with a 5mm thick plate your lens simply will not be stable. this is real world experience. you can try, but it is likely not worth it.

i am actually looking to replace my 150mm aluminum plate which is 10mm thick with a piece of oak 22 mm thick.

[torashi]

That's all true, in theory. What this discussion fails to mention is what is the minimum thickness required. I could dig out the appropriate material properties but intuitively I think aluminium held in place by two screws doesn't require more than 1 cm.



Correct that the material's Young modulus will influence the rigidity.

When coupling, with two 1/4-20 screws, an aluminium plate with a thick (aluminium) foot, the resulting apparatus is probably more than thick enough. I'm pretty sure that having a dovetail on the foot itself would work flawlessly.

Yes, there are foots with a dovetail already in place. You could always let someone at a shop machine one into your lense's foot.

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[Chris_T]

You could check out the Jobu Surefoot NX4 7" it could be what you are looking for.

Surefoot NX4 - 7.0"

Chris.

[bdery]

You could check out the Jobu Surefoot NX4 7" it could be what you are looking for.

Surefoot NX4 - 7.0"

Chris.

This plate (and their shorter NX3) look nice. They don'T seem to mention the thickness, do you have any info regarding this?

They're quite expensive, but if they fit the bill I'll consider them.

thanks!

[bdery]

You could check out the Jobu Surefoot NX4 7" it could be what you are looking for.

Surefoot NX4 - 7.0"

Chris.

This plate (and their shorter NX3) look nice. They don'T seem to mention the thickness, do you have any info regarding this?

They're quite expensive, but if they fit the bill I'll consider them.

thanks!

[Mikesul]

This has been such a wonderfully nerdy thread!

[photoptimist]

Titanium would probably be better for the purpose, though. But that much titanium is prohibitively expensive for the use.

Although titanium is superior on a pound-for-pound basis it requires a thicker plate. A steel plate would be twice as stiff as a titanium one and 3X stiffer than an aluminum one. A tungsten plate would by twice as stiff as steel one and almost 4X stiffer than titanium.