Fotodiox Tripod Collar users, please help

I just purchased a Fotodiox tripod collar for my 70 200 f4L - got it yesterday and it fits perfectly, very well-made piece of kit for the price.

However, the female thread on the base does not fit the male threads on my tripod plate - they appear to be the same diameter, but the thread count is different - my tripod plates (average Slik and Manfrotto) will not thread onto the base of the collar.

I've never used one of these, so I just want to check that this is indeed a defect or am I supposed to buy a different plate screw for this thing?

Thanks a bunch for any help.

Cheers.

As far as I know, the standard is 1/4-20 National Coarse Thread for small format camera gear. No Fine Thread or Metric Version in use in any market I've heard of. The next size up is 3/8-16 for Medium Format Camera gear. My Fotodiox Tripod Mount (for 70-300L) seems fine. Haven't put it to use yet, but did thread it on.

Can you post a good picture of the thread and a male thread beside it for comparison. A Fine Thread 1/4"diameter would be 28 threads per inch. I have read of somebody having a tight fit on a tripod mount (not necessarily a Fotodiox unit though).

Thanks Fan: I'll try to get a picture. I may have to return it anyway.

Re; the tight fit, that's not the problem: the thread simply won't 'thread' into the female part at all, although on first glance it looks like it will.

Otherwise the darn thing fits beautfully on the lens.

Cheers.

Do the threads look clean? It could be paint, powder coating, or even metal shavings obstructing it.

Hi Kir.b -
The threads look as they should, clean well-turned metal, definitely not anything wrong with them. A nicely manufactured piece of kit, except for the thread issue.I got the RMI today so will be sending it back, hopefully for a replacement.

Cheers.

greyswan wrote in post #15748121
Hi Kir.b -
The threads look as they should, clean well-turned metal, definitely not anything wrong with them. A nicely manufactured piece of kit, except for the thread issue.I got the RMI today so will be sending it back, hopefully for a replacement.

Cheers.

That's weird. You verified that there's nothing wrong with the screw/bolt as well. You should be able to just screw it into the bottom of your camera for a quick test.

I have a Fotodiox Tripod Collar for my 70-300L. When I was using my Manfrotto QR plate, it screwed in fine. Now I've switched to Arca plates, but they all seem to use the same screw.

My issue with the tripod collar is that the tightening nut refuses to stay tight. It's a damn shame Canon won't get off their butts and make more of their outrageously priced tripod collars. At least they would stay put.