RF and EF extenders on the EF 600/4L IS II

[JKT]

Looks like he used the control ring version of the adapter, did you use that one or the vanilla one? I used the vanilla one and like you, I had to trim it back sufficiently to expose the PCB (see this post from earlier in the thread). I did cover the opening with electrical tape.

That is quite correct. I've done both and the plain adapter exposes electronics and the control ring one doesn't. My plain adapter also missed springs behind the pins and thus relied on pressure from circuit board to make contact. That was not reliable at all. That may have been assembly error or they changed it after that as someone wrote later that his plain adapter had springs.

 

[neuroanatomist]

That is quite correct. I've done both and the plain adapter exposes electronics and the control ring one doesn't.

Thanks! My modified adapter functions perfectly, and with the rarity that I use it, it isn’t worth the effort of getting the other version for a ‘cleaner’ result.

 

[JKT]

Your'e welcome! I wouldn't have either except for the pin spring issue.

 

[justashooter]

I realize this an older thread but thought I would add this informtion.
I recently used a ProMaster 5154 model EF-RF adapter to make this modification. It has a wide opening and minimal filing was needed to allow the RF Extenders to fit. The pins also have springs behind them, they feel just like the Canon adapter in that regard. I use it with a RF 1.4x and 300/2.8. I Just receive a RF 2x to test out.