Help me with RRS clamp and plates

Hi everyone,

I have a Manfrotto 490RC4 head, and I would like to change the clamp with an RRS.

First question: Can anyone tell me whether I should go with a 1/4-20 or M6 screw?
RRS clamp selector table does not have 490RC4 on it, and my e-mail to them was replied with suggestion for me to disassemble the head and to find out the type of screw by myself. The problem is I can have both 1/4-20 and M6 screws side-by-side, and I still won't be able to tell which one is which.

Second question: I know that camera plate is camera specific. But what about lens plates? Currently I have two different tripod collars, a Canon and a Sigma. Do I have to buy two different lens plates?

Thanks in advance!

If you disassemble the 490RC4 and try using the screw from the lens plate in place of the one you removed (or try threading the screw you removed into your camera's tripod socket) (don't force it in either case) you can easily tell. You could also pick up a 1/4-20 nut or M6 nut at your local hardware store and see which one threads onto the screw you removed. Again, don't force it - it should go smoothly and easily on.

On the plates for your tripod collars the answer is "Probably". When you go to order from them, you can select your lens and they'll show the correct plate options for it.

Jon pretty much nailed those answers, I just wanted to add one thing about the lens plates: sometimes you can find a size lens plate that will fit both your lenses, but switching them back and forth is a pain IMO. Its best to get the RRS specific plate for each lens, but if you have to, most of the time you can work with just one.

They do offer "universal" lens plates and I use an RRS B86 E plate on both my 100-400 and 70-200L's.

Try searching for thread information on both 1/4" and 3/8" UNC. I found the internet has masses of info on thread dimensions and make identifying which you are looking at easy. None of my kit uses M6 but times change.

Thanks Jon, Ben, and Richard, for your answers.

Lowner wrote in post #8120855
They do offer "universal" lens plates and I use an RRS B86 E plate on both my 100-400 and 70-200L's.

Very true, I actually did exactly the same as the recommended plate for the 70-200 2.8s and the 100-400 is the same and it will work on a number of other lenses as well.

I would add that the customer service at RRS is very good. Call them up and discuss the issues with them if you are still not sure.