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A Nikon body cap, but will it fit your camera?
I buy mine here.
The manual to my new Nikon F6 says only to use the BF-1A body cap. The BF-1 was expressly forbidden. Pardon my acronyms, but WTF, what's the BFD with body caps?
I've been using my Nikons almost daily for most of the past three decades and have never noticed any body cap not fitting. Every Nikon lens made in the past 30 years mounts on every Nikon camera ever made since 1959 (even if all the features might not work), so how in the world could Nikon have incompatible body caps? They all have to be the same, right?
OK, my TC-20E has rubber-bumpered optics which poke out of its lens mount, so it takes a special BF-3 cap, but otherwise, every body cap I own has fit every body or converter.
Rifling through my body caps, I finally found one marked BF-1. I tried it, and Holy cow, it doesn't fit my F6. It doesn't go on all the way. It doesn't fit my digital cameras either. What weird juju is this that suddenly I have incompatible body caps?
Now I got really curious. What mystery of compatibility has been hiding right in my own camera bags these past 30 years?
Since the outer lip of the body cap didn't want to float over the outside rim of the lens mount, I got out my caliper and investigated.
Lo and behold, Nikon quietly increased the diameter of the lens mount flange on its AF SLRs. Ever since then they've used the BF-1A cap. The inside to which lenses attach is the same, but the outside diameter was increased slightly to leave more metal after the hole for the AF screw was drilled. Thus Nikon slightly increased the clearance of the new BF-1A cap.
I found a clearly marked BF-1 cap. Many of my newer caps, including the one marked "Nikon F6" that came on my Nikon F6, have no model number markings.
The Nikon BF-1 Cap, 56.33mm clearance for lens mount mating flange.
Manual focus camera (F2AS) lens mount mating flange diameter: 55.89mm.
Modern AF camera (D80) lens mount mating flange diameter: 56.96mm.
The junk brands have this all figured out. The cheap third-party caps don't seal over the edge of the lens mount. The cheap caps simply cover the front without wrapping around. This lets them fit everything, but doesn't do as good a job of sealing the camera against crud. They don't feel as good coming on or off, either.
Nikon cap on left, crappy copy on right.
The Nikon cap on the left has a lip to seal your body from dust; the crappy copy on the right doesn't.
Just use the BF-1A for everything. It fits fine.
Don't worry if there's no marking and it fits fine. It probably is the new cap, since Nikon's been using the new one since about 1984.
Oddly, I have seen a somewhat sloppily made cap that does say BF-1A and doesn't fit well. I suspect it's a counterfeit.
If you have a Nikon body cap which won't fit a modern camera, chuck it and replace it with the BF-1A.
COUNTERFEIT WARNING: I pay $8 each for my Nikon body caps. $8 sounds like a rip-off, and it is. Therefore counterfeiters make fakes and sell them in bulk on eBay, also at rip-off prices, but for less than the real thing.
A reader sent me one, and it looks like the real thing. If I look more closely, especially at reflections off the back, it seems less flat and precise. Lo and behold, it doesn't fit well!
When I say counterfeit, I mean a counterfeit that says NIKON BF-1A, Made in Japan, and looks from a foot away exactly like the real thing, even though I presume it's made in China by God knows who.
They don't fit well. Just search "nikon bf-1a" on eBay, and most of the listings for multiple caps seem to be for fakes. The key is that the counterfeiters don't even bother to fake the packaging and prefer to sell them in bulk, saving them the expense of duping the packaging.
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