ND Filter Advice wanted

[HDNitehawk]

On my upcoming trip to Yellowstone I want to try a few waterfall pictures. I have already searched the forums and read most of the past threads about this.


I have been looking at the B+W filters and B+W will be the filters I buy so the advice I need relates to those filters.


I always buy the MRC coated lenses. The price is about double. For this particular application, the filter really will not be used occasionally. Not like a filter that stays on the lens.


The questions:

1. Do the MRC filters have better IQ? Other than cleaning and protection of the lens do I really need the MRC coating since at most the lens will only be used occasionally?
2. There are somefilters with the "Wide" designation, on the 24mm or if I go to a 21mm do I really need this? Is vignetting a problem?
3. With ND .3, .6 or .9 would this cover the typical situations. Going darker for a novice such as myself is probably not necessary?

I am also thinking getting either the TS-E24mm L or the Zeiss 21mm F2.8 Distagon but that's another thread completely.

[neuroanatomist]

Do the MRC filters have better IQ? Other than cleaning and protection of the lens do I really need the MRC coating since at most the lens will only be used occasionally?

B+W filters now come in 5 'flavors' with regard to coatings:

• uncoated
• single coated
• multi-coated (MC)
• multiresistant coated (MRC)
• nano coated

A single coating is primarily to reduce reflections and ghosting. MC does the same, but additionally allows higher light transmission. MRC is like MC, but with a dust- and water-repellant layer (similar to the fluorine coating on the front and rear the newest Canon lenses). Nano is their newest coating, and is like MRC but with slightly higher light transmission.


In the case of ND filters, the goal is to block light, so the increased light transmission that MRC offers is no benefot - the only reason to go with MRC for an ND filter is for easier cleaning (not a big deal for an occasionally-used filter, IMO). Also worth noting is that MRC is only available in 1- to 2-stop filters; the 1- to 3- stop filters are available with a single layer coating, and 6-stop and darker only come uncoated.

There are somefilters with the "Wide" designation, on the 24mm or if I go to a 21mm do I really need this? Is vignetting a problem?

Probably not necessary. The 'wide' designation means a larger filter than the threads (e.g. it's like a one-piece combination of a filter and a step up ring). The 24L already suffers from pretty bad vignetting wide open, but it doesn't get any worse with a UV filter (see Bryan's vignetting tests). Plus, you're unlikely to be shooting a landscape shot wide open, and vignetting improves when you stop down. So, a normal F-Pro mount should be fine.


Also, stay tuned...I recently did a whole set of test shots (>500 shots) to look at the effects of stacking multiple filters on vignetting. I don't have a 24L, but I used a 16-35mm, 24-105mm, 35L, 85L, and 17-55mm, each with various combinations of filters, to simulate stacking a standard ND onto an XS-Pro UV, a standard CPL onto a standard or XS-Pro UV filter, etc. The tests shots are done, I'm just in the process of doing the quantitative analysis - I'll post results next week.

With ND .3, .6 or .9 would this cover the typical situations. Going darker for a novice such as myself is probably not necessary?

Honestly, I'd skip the 0.3 and 0.6 (1- and 2-stop) filters all together. Get a 3-stop and probably a 6-stop (#106). In cases where you need one or two stops worth of slower shutter speed, you can use the 3 stop and bump the ISO from 100 to 200 or 400, with no real penalty on the bodies you're using.


Hope that helps...


--John

[Sean Setters]

I can

[neuroanatomist]

look very closely at the variable ND filters out there.

One big issue I have with the variable ND filters is that for wide angle use, they suffer from a 'maltese cross' effect. VariND's are basically a stacked pair of polarizers (one linear, one circular). In a situation where a CPL would give uneven polarization (e.g. 24mm on a FF body), a variable ND filter will result in a cross-shaped darkening through the image (see an example here).

[Sean Setters]

<p sizset="40" sizcache="7"]One big issue I have with the variable ND filters is that for wide angle use, they suffer from a 'maltese cross' effect. VariND's are basically a stacked pair of polarizers (one linear, one circular). In a situation where a CPL would give uneven polarization (e.g. 24mm on a FF body), a variable ND filter will result in a cross-shaped darkening through the image (see an example here).

That is true, indeed. However, I thought that issue was primarily caused when the ND was used very close to its maximum opacity. I could be wrong, though...

[neuroanatomist]

Sean, as I understand it, the effect is there even at lower density settings at wide/ultrawide angles. The wider the angle and/or the darker the setting, the worse the effect. If you turn the variND beyond 'max' you can see the effect even at non-wide angles. On your 7D, you'd need something wider than 17mm (27mm FF-equivalent) to see the effect due to wide angle.

[andnowimbroke]

I wish they had a stop set for minimum and maximum points on the genus. I get lost a lot unless I start the filter the same way so the reference dots point up. All in all I

[neuroanatomist]

Forgot to add, but if you

[Sean Setters]

Forgot to add, but if you're interested in a variable ND, Rick, given your preference for B+W - they now offer one. It's not as convenient as the Genus or similar options, which are standard screw-in types. B+W's is actually a round CPL with a separate 4" square linear polarizer in a rotating holder mounted in front (a bit unwieldy, IMO, unless you're used to using rectangular filters, and it also precludes using a hood).

John, could you provide a link to this? I looked but couldn't find any info on it...

[neuroanatomist]

Apologies for the confusion, Sean. Technically it's not B+W, but rather their parent company, Schneider Optics. They market this set under a different line. Here's the link to the 77mm True Match Vari-ND kit. There's also a 95mm version.


FWIW, Schneider also produces the only Schott glass ND and graduated ND rectangular filters that I know of (vs. Lee, Singh-Ray, Cokin, which are all resin). They're targeted to the cine crowd, thus sold as the MPTV line (motion picture television), but they'll work fine for stills. B&amp;H carries many of them in 4x5.65".