Cokin Ultra Slim: Something small and thin to protect your lens
The Fuji 27mm pancake lens is commendably compact. It doesn't come with a lens hood and, so far, I have not found one necessary. But that lens does need a bit of protection and my first thought was to screw in one of the many 39mm UV filters I have for Leica lenses. All are thick, especially the otherwise excellent B+W versions. It does seem a pity to add several unnecessary millimeters to such a small lens.
I remembered seeing an advertisement for Cokin's Pure Harmony ultra-slim filters and went to Amazon to order one. It arrived today and I am truly impressed. While I haven't checked the performance, this ultra-slim filter is hardly noticeable when screwed in to the pancake lens. Aesthetically it is absolutely perfect.
So pleased am I that I have ordered two more 39s to fit Leica lenses and, if happy, I will be looking for a couple of 46s. They are a lot cheaper than most filters deemed suitable for covering such rarefied glass but I have no reason to believe they will not perform faultlessly.
LEICA WARNING: These 39mm Cokin filters fit the 28mm Elmarit and 35mm Summicron and look great, far less bulky than standard filters. However, despite the diameter being exactly the same as the rim of the lens, the Leica hood will not fit on either of these two lenses when the Cokin filter is screwed in. On checking, I see that the standard filters (mine are Leica branded but I know that B&W must be the same) are just a fraction of a millimetre smaller than the lens rim and this must make the crucial difference. It's disappointing but, if you like to use these small lenses without the hood on dull days, the Cokin filters do look much neater. I have not had the chance to try the filter on the 50mm Summicron where, I suspect, the slide-out hood would not present a problem. If I get the chance I will try and report back.