W.T.B ND filter [Archive] - Canon Digital Photography Forums

12345Michael54321

26th of May 2007 (Sat), 05:22

I often use a B+W 72mm neutral density filter. It's a 1.8, which means it's got a filter factor of 64x, or 6 stops; I especially like using it on photographs of flowing water, as it permits long exposures which might not otherwise be practical with the more common 1, 2, or 3 stop ND filters. (Well, one could combine multiple filters of lesser density, to obtain a net effect of 6 stops, but I prefer keeping the number of filters on my lens to a minimum.) It's the standard F-Pro mount, not the Slim mount, but I've used it on moderate wide angle lenses without any vignetting problems; if I were shooting ultra-wide, I'd likely get a filter in Slim mount.

The filter never seems to freeze up on me (you know - sort of get stuck to the lens onto which it's screwed), which may or may not be due to B+W using brass instead of aluminum in the construction of the filter. Optically, the filter doesn't significantly shift focus or reduce resolution in all or part of the image. I have no complaints with it as regards flare, or glare, or that sort of thing. While it can sometimes add a very slight warm tone to images, it's a fairly subtle effect, and not necessarily an unpleasant one. Might be worth keeping in mind if you shoot mostly film; if shooting digital, it's just not a significant factor at all.

As an aside, I'd note that a 6-stop ND filter can reduce the light sufficiently that thru-the-lens metering may not be accurate. I typically meter (and compose) without the filter on the lens, mentally subtract 6 stops from what the meter says, then screw on the filter and set exposure manually.

I believe B&H has this filter in stock. It probably sells for a little over $100 or so. I bought mine a few years ago, and honestly don't recall exactly what I paid.

My only other 72mm ND filter is a Hoya 0.9 (3-stop) HMC Pro 1 filter, which quite honestly I rarely use. But I've got no complaints with it; it's just that I've little use for a 3-stop ND filter. (If I want to reduce the amount of light, I usually want to reduce the heck out of it. So 6 stops suits me better than does 3 stops. But hey, exceptions exist.) Frankly, I only bought it because it was being sold by a pretty reputable seller on eBay, and my ridiculously low bid turned out to be the best offer he got.

I've sometimes made use of a 72mm circular polarizer as a sort of makeshift ND filter of around 1 1/2 stops or so. Not often, but I've done it. It's not always an ideal solution, but if it's all you got...

Finally - and I don't mean this in a nasty way, okay? - if you don't know what degree of opacity you want, might I suggest that perhaps you're not yet ready to buy a neutral density filter. Since the degree of light being blocked is sort of the fundamental characteristic of a neutral density filter. Kind of how if you decide you want to buy a lens, you should have some idea what focal length you'd like. Well, just a thought.
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Michael