I’m going to request your assistance today with an admittedly niche “problem” regarding the Nikon 200mm f/2 that I haven’t been able to solve despite some research and a little trial and error.
What I’m trying to figure out is: What is a suitable lens cap for this lens?
Nikon ships the 200/2 with this:

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It fits over the lens (and the reversed hood) and cinches closed.
The trouble is that it requires two hands to either place over or remove from the lens, and although that doesn’t sound like something to worry about, it is a real practical hindrance out in the field.
A replacement cap that is often recommended is the Don Zeck cap:

The Don Zeck is placed inside the lens barrel. Admittedly, it looks a little goofy with the loop “handle” but some people swear by it. Others say it’s a little rough around the edges (figuratively and literally) and it either scratches the inside of the lens or doesn’t fit well (too loose or tight). Given the current price of this plastic piece of engineering is US$75, I’m not inclined to take my chances and order it.
The second lens cover often recommended is the AquaTech soft cap:

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This cap looks promising in that it is soft/flexible and also fits inside the lens barrel (with the unfortunate attention-seeking logo facing outward); it is removed by pulling on the lip in the top portion.
The cost is a more “reasonable” US$40. The trouble with this one — despite the manufacturer’s claims — is that the cap can sometimes contact the front lens element and leave an oily residue.
The third solution that some people recommend is the Kaiser push-on cap (size 120mm) from B&H:

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The price of this is a relatively low US$18 (though I’m sure it costs $1 to manufacture). What I don’t know is how well it fits on the lens, and — more importantly — whether it is prone to being accidentally knocked off (since it fits over the lens). Lastly, I have no idea whether the 200/2 lens hood can be placed over it and, if yes, whether the Kaiser can then easily be removed. I would be tempted to bite the bullet and buy it anyway but factoring in the $CAN-$US exchange rate, the price for delivery, and customs charges, the price for this simple piece of plastic would more than double.
The last recommendation is the Folgers instant coffee plastic cap that is legendary in internet folklore:

I’m not kidding… the internet says this is the best and most economical solution to place in front of your exotic telephoto lens (by the time you start considering this one you will have been secretly repetitively cursing at Nikon for not shipping a proper lens cap in the first place).
Well, it turns out the internet is wrong. Or its information is out of date. I canvassed two large stores with various sizes of Folgers coffee cans and none of them had the correct-sized lids.
I won’t even tell you about the Tupperware lids I tried 😩
So I’m humbly asking for your input.
I’m wondering if the Kaiser cap is ultimately the one I should get, or whether there is something better out there.
Thanks,
—Peter.