ND Filter

[JohnR48]

I have given up on a variable neutral density filter due to the bad reports on the net.
Looking at B+H but don't know which one to buy. Have been considering the .9 or 3 stop. I want it for waterfalls, to give me the fluid look.
Your opinions or advice please.

[Colin Southern]

Hi John,

I use a Singh-Ray Vari-ND - it's one of the highest-quality pieces of equipment that I own (in fact I have 2 of them).

Can't speak for other manufacturers products, but I use mine on just about every landscape shoot involving water, and have no problems what so ever. I have however heard of colour shifts and artifacts with "budget" copies where folks are trying to get away with just using a couple of polarisers (which IS the general principle, but there's more to it than is obvious on the surface).

In terms of functionality, a variable ND eats a static ND filter alive; for moving water shots we typically want control over both our aperture (for depth-of-field considerations), and shutter speed (for motion control); with a variable filter we can just use manual exposure mode - dial in the aperture and shutterspeed that we want, and then dial in the attenuation that give the correct exposure.

[Bobobird]

Colin for us newbies - perhaps an example?

Thanks.

[Colin Southern]

Colin for us newbies - perhaps an example?

Thanks.

I'd be delighted to, but example of what? Image?

[Bobobird]

An example of how to calculate the "attenuation" ?

Am I making sense? Ignore if it does not. Trying to understand something that is way over my head at this point in time.

[Colin Southern]

An example of how to calculate the "attenuation" ?

Am I making sense? Ignore if it does not. Trying to understand something that is way over my head at this point in time.

Ah - I get what you mean now. That's easy. Even though a camera may be in manual mode, the metering still works - it just falls back to an "advisory" mode though. So all you need to do for a good starting point is vary the attenuation until the meter is in the middle, and go from there (assuming an exposure of 30 seconds or less). As with any metering sometimes it's not 100% accurate, but that's a seperate issue.

The pure joy of a variable filter is that you can easily compensate as light levels drop (eg sunset shot); I've even been known to adjust them DURING a long exposure if I have a gut feeling that light levels are dropping too quickly.

[Colin Southern]

PS: I've written a few blog articles for Singh-Ray over the past few years - many feature images make with the Vari-ND, so it may (or may not!) be of interest!

http://singhray.blogspot.com/search/...lin%20Southern

[Mark von Kanel]

I use a Lightcraft workshop which works very well, as im sure youve noticed these are stupidly expensive bits of kit so i bought one big enough to fit my largest filter size and use step down rings for my other lenses.

[JohnR48]

Thank you Colin. I'll take your advice, save a few more pennies and go with the Singh-Ray variable.

[Colin Southern]

Thank you Colin. I'll take your advice, save a few more pennies and go with the Singh-Ray variable.

No worries John,

If you look after it there's no reason it shouldn't last many lifetimes.