Canon 100-400mm L EF mount alignment question

[CANONisOK]

Good afternoon, I have a question for the group regarding the EF mount on the 100-400mm L. I just received the lens on Saturday and tested it out this weekend. I am very impressed with the optical performance of the copy I received. Will enjoy having the extra reach on my 5D3.

However, one issue that I noticed immediately is the difficulty in getting the proper alignment when mounting this lens to the camera. For a pretty simple system (align the red dots, insert lens to mount, rotate clockwise) this lens required 5 or 6 attempts to get aligned and mounted each time I put it on the camera. The lens hardware seemed to want to go in the mount in a non-normal orientation. I've never experienced this with any other lens on this or previous cameras I've owned.

Looking at the bayonet mount, I could not detect anything different than my other lenses which would cause these alignment issues - but I'll look closer again today after work.

My question to the brain trust is this: Has anyone else had issues with the EF mount on this specific lens (or specifically with a 5D Mark iii)? I hate to send back a lens which is optically good if this is a universal attribute of this specific lens. However, I don't want to keep it if this is not a common issue and risk damaging the mount on my 5D3.

Thanks in advance for any experience you all can share.

 

[Loswr]

Mine mounts easily, like every other lens I own (and has done so on three different bodies).

 

[vbi]

Never had a problem with mine either. Perhaps it is just the size of the lens that is a little awkward at first.

 

[RGF]

Never seen or heard about this problem. Safe routine is to return the lens

 

[CANONisOK]

Thanks for the quick replies. Having searched the forum and google, I didn't see any other reports of this being a known issue. But it's nice to have actual confirmation from other users that this is not a consistent issue.

I already ordered a replacement from B&H... I'd gotten the first from Amazon when it was the lowest price, but they were out of stock now. Now B&H is in stock at the same price as I paid through Amazon PLUS they have the 2% credit going. Fair tradeoff, I suppose.

Now let's hope the second one is just as good as the first copy from a performance standpoint!

 

[viggen61]

Mine can be a little finicky, but it always mounts up properly in the end. Part of it is simply the weight of this lens. At 3 lbs plus, it's a heavyweight, and if your hands aren't used to it, it may take you a couple tries.

 

[CANONisOK]

.

Perhaps it is just the size of the lens that is a little awkward at first.

At 3 lbs plus, it's a heavyweight, and if your hands aren't used to it, it may take you a couple tries.

I'd considered that at first - but my 70-200 f2.8 ii is heavier and longer when mounting. And I've never had any issues mounting it on several different bodies. I think this 100-400mm mount was a little bit off-spec when manufactured.

Thanks again for the feedback!