Using the TMA-B with the EF 100mm f2.8 Macro USM

The (optional) tripod mount adaptor B as used with the other TMA-B compatible macro lenses but requires an adaptor part YG2-0500-000 not used with the other macro lenses.

This is much cheaper than obtaining the retail TMA-B that comes with the ring, assuming you have the TMA from another lens. The TMA is useful for using the lens on a tripod or a monopod particularly if teleconvertor and/or extension tubes are used with the lens and the assembly gets long and poorly balanced. Note that the TMA-B comes in a black and white version TMA-B(B) black and TMA-B(W) white that are exactly the same physically, the TMA-B(W) comes with the EF 300mm f4L IS for example.

I obtained this part in the UK from Lehmanns Direct for under £12 +VAT within a week or two. The part comes with no instructions so the below may be helpful.

It is a small plastic ring with a felt lining and three plastic ridges on the inner surface that engage quite securely on the lens in three matching indentations in the knurled area of the lens. The outer surface of the ring includes the four studs that are integral to the MP-E 65mm f2.8 and other compatible lenses.

The ring has a indent on the outer surface that needs to be aligned with the lens red dot mount alignment and is then slipped on with the studs first to fit firmly against the step in lens diameter as shown below. Ensure the three plastic ridges to click into the matching slots in the lens.

The TMA-B is then aligned with the red dot in the normal way and slipped on and put in the normal parking position.

In use the assembly works well but is not as smooth as it is with other lenses. The TMA locking knob needs to be loosened about two turns as opposed to one for free movement.