Nikon 72mm 77mm

Circular Polarizing Filter

. . . what size of lens cap to fit? (scroll to the bottom if you can't wait to know the answer...)

May 2006

One of the best and most expensive Circular Polarizing filter...



There are two versions of Nikon Circular Polarizing filter. The current available new in the market is the II (second) version, having front element same diameter as the filter ring. Eg. a Nikon 72mm Circular Polar II is having 72mm filter thread in front, hence you can use the same 72mm lens cap for it.


However, the old Nikon circular polarizing filter is different. All of them are having larger front filter thread. In other words, the glass/elements Nikon used for the first generation circular polar filter is larger than the lens filter thread that it is intended for.


Eg. A Nikon 72mm Circular Polar is having a 85mm front filter thread. When mounted onto your lens, you can't use a 72mm filter cap for it, but need a larger cap. This is the main reason why Nikon Circular Polar is so much more expensive than others.


Both Nikon 72mm and 77mm Circular Polar is using the same size of glass elements. Both of them are using 85mm front filter thread or front glass. Nikon did not include any filter cap with the Circular Polar, so what size of lens cap should we use for it?




I have a hard time finding the exact info for the question above, and I have a Nikon 72mm Circular Polar myself. I use a ruler to measure the size of the front diameter, and it is around 85mm. I searched on the net for a 85mm lens cap, yup...not avail. Even Nikon themselves did not produce such a weird size lens cap. The nearest I can find from Nikon offering is just 82mm, which is definitely TOO SMALL for the Circular Polar filter.


So I take a look at third party lens cap. Tamron is the first company that I know of that produce the snap-on type of lens cap. Which in my opinion is a genius design! It takes a long time for Nikon to come out with a similar design in Year 2001~2002 (if I am not mistaken). Canon is still using the old design of lens cap. Tamron has a 86mm lens cap in their listing, which I took a bet and order a piece. Though it isn't really that expensive (roughly US$10), but if it doesn't fit, then it will be an useless item for me (I don't have any lens that uses 86mm lens cap!).


So, how's the finding? That's the main reason why I am writing this article.


As you can see in the picture on the left, it fits PERFECTLY! The lens cap is not any slight bigger or smaller than the 72mm front element!


Nikon 72mm and 77mm Circular Polar filter is having a 85mm front filter size.

A 86mm Tamron Snap On Lens Cap will fit the 72mm and 77mm Nikon Circular Polar filters PERFECTLY!


I hope this info will be useful to some of the readers. Happy shooting!