Choosing a neutral density filter

[TCampbell]

There are a few approaches.

I suggest avoiding "variable" ND filters with wide-angle lenses. A variable ND is really two polarizers stacked together. But polarizers don't work well with wide-angle lenses. This is because the amount of light which is allowed to pass vs. blocked depends on the angle of the light hitting the polarizing filter. When using normal to long lenses the angles are all near-enough that the amount of light blocked is fairly even. But when using a wide-angle, the difference in angles of light entering the lens from one side of the frame vs. the opposite side are so far apart that the polarization isn't even and you get a band or stripe through the image where the polarization was strongest and it weakens as it gets farther from that band. ... and it gets worse. Since you have TWO polarizers and you are twisting them, now you get TWO bands instead of one and since you're twisting them you'll get some variation on an X shaped band for a really wonky image.

A non-variable ND doesn't use polarization so the amount of light blocked is consistent across the field.

While you would typically buy a "screw on" type filter, if you have more than one lens diameter size then you could buy for the largest thread-size lens you own and then buy "step up rings" to adapt the filter to your smaller lenses. For example, I have mostly 77mm thread-on filters but I have a 67mm to 77mm step-up ring so I can use them on my smaller lens. But there are another even more versatile approach.

If you buy square "slide in" filters (e.g. Lee filters is probably the top name, then Singh-Ray followed by Cokin) you get the "holder" and then you need a lens adapter ring for each lens size you own... but these adapter rings are cheap so it's no problem buying every size you need (most people only need 2 or maybe 3 sizes.) The 4"x4" (100mm x 100mm) filters tend to work for most wide-angle through telephoto lenses EXCEPT the ultra-side angle lenses (which tend to need the 6x6" (150x150mm) filters.

But the slide in filters are REALLY nice when you start to consider that this is also what you need to start using ND grads (4" x 6" slide-ins which gradually get darker the farther you slide them in). This allows you to darken the sky without darkening the foreground for a more even exposure (the exposure on the sky is usually brighter than the exposure on the ground).

If you only buy 1 ND filter... make it a 3-stop ND. ND filters come in various densities and they may be advertised by number of stops or by optical density. When they use the optical density system (the most common... especially among high-end filters) each "0.3" worth of optical density is 1 stop (0.1 is 1/3rd stop). So an ND 0.9 would be a 3 stop filter. An ND 3.0 would be a 10 stop filter.

You can see through a 3 stop filter to frame and focus a shot... but you can't see through a 10-stop filter. To use one, you frame, focus, and meter with the filter off the camera. Then switch the focus to manual (so the camera doesn't try to adjust), manually dial in an exposure which is 10 stops brighter than your meter indicated... and slide in the 10-stopper to take the shot (use of a tripod is pretty much a requirement when using a 10 stop filter.)

Better ND filters are spectrum neutral... they don't produce a color cast.

 

[Gary A.]

Thank you TCampbell for taking the time for such a detailed explanation.

 

[gossamer]

Thanks so much. That's very helpful. I've seen references to the slide-in filters, but nothing really explaining how it all goes together. I should also mention that I don't ever expect to be doing video, in case that matters.

So where do I go from here? There are a ton of options. It sounds like the slide-in filters are the best investment, but are they so substantially better to warrant the expense for the casual, yet very interested, amateur? I'd also probably have to buy a bigger camera bag

I've just come across this guy's site, and he really appears to know what's going on:

Filters by Thom Hogan

It looks like the article is pretty old, considering he's referring to books he's written on the D100. He's talking about having to modify his Cokin holder to avoid vignetting. Is there a problem with vignetting with the slide-in style filters?

He also talks about having great success with the variable neutral density Singh-Ray filter. Is that not your experience?

I've also found this review of the Singh-Ray variable ND filter:

Fstoppers Reviews The Singh-Ray Variable Neutral Density Filter: A Must For Any Landscape Photographer | Fstoppers

It talks about vignetting as well as a slight color cast. Is that avoided with the slide-in filters?

I do expect to be purchasing a full-frame camera in the near future (6mo or so), so I probably won't have my 67mm lenses any longer and will instead probably be purchasing the 77mm lenses. Using the step-down rings sounds somewhat like a kludge to me, and requires me to carry around additional hardware. Can this all be avoided with the slide-in filters?

I started a search that focuses on the LEE 0.3 4x4 ND filter on B&H and found these:

# LEE 0.9 ND 4x4
LEE Filters 4x4" Neutral Density (ND) 0.9 Glass Filter

# LEE 4x4 Frame Kit
LEE Filters Foundation Kit FK B&H Photo Video

It says it also requires an adapter ring, but I've been unable to find that.

How does this assemble on the lens? Is it a big process to do it in the field?

It says that it accepts three filters at once, correct? So I could purchase three 0.3's or maybe a 0.9 and a 0.3 and stack them in case I needed more stops?

Thanks so much.

 

[TCampbell]

Whenever you use filters... any filters... you want to make sure the filters have anti-reflective coatings on them. Every piece of flat "glass" is effectively a "mirror". They can cause "ghosting" and "flaring" issues and the anti-reflective-coatings help tame these issues.

B+W brand is probably *the* top brand for round thread-on filters... but they're not cheap. A while ago a forum member said they were under the impression that Tiffen was a top filter brand (they are not) so I happened to have a Tiffen brand UV filter and a B+W brand UV filter. I put them both side-by-side on a piece of black craft-board... with a light (out of frame) nearby. In the Tiffen you could see the glassy reflective surface and this made the "black" cardboard below look more like gray. But next to it was the B+W anti-reflective UV filter... which was so non-reflective that it looked like I had removed the glass from the filter and just left the thread-on ring in it's place.

The Hoya "Pro1" line is also very good. I say "Pro1" because Hoya is part of a company that sells lots of lines as well as filters under different names. Their "good stuff" is sold under the "Pro1" name. Not just any Hoya filter is good.

In other words... "you get what you pay for".

If you don't have the budget to buy B+W filter... don't kill yourself trying to afford it. Just now that they're not just ripping people off by asking for twice as much for the "same thing". It's not the same thing. There is a noticeable difference in performance and it shows in your photos. If you stack filters then it really becomes more noticeable.

As for the square slide-in filters. Not everyone "needs" this type of filter. But if you look at stunning landscapes and say "someday I want to take images that look like this"... then you might as well buy the slide-in contraption. Even if you buy the slide-in holder and adapter ring and then buy the Cokin filters (Cokin filters are the low-end slide-in brand) at least you have the hardware so that when the day comes that you realize you want ND Grads (hard or soft)... you'll have the ability to use them.

One more thing... budget ND filters can create a color cast (but you can fix that with white balance). Budget polarizers can cause wonky colors. Turns out if you mount the polarizer backwards it does wonky things to the colors (on purpose.) You can buy artsy polarizers that are deliberately installed "backwards" to create gold/violet polarization effects.

 

[Gary A.]

If you are thinking of getting into Lee type filters I strongly suggest you look into "The Filter Dude" filter holders and adapters.

FilterDude - Affordable Photography Accessories

He makes the holders not the filters. His holders and adapters are similar to Lee and will work with Lee type filters at a significantly lower price than a Lee Foundation Kit.

I use The Filter Dude filter holder and adapters with Lee Filters.

Gary

 

[D-B-J]

Thanks so much. That's very helpful. I've seen references to the slide-in filters, but nothing really explaining how it all goes together. I should also mention that I don't ever expect to be doing video, in case that matters.

So where do I go from here? There are a ton of options. It sounds like the slide-in filters are the best investment, but are they so substantially better to warrant the expense for the casual, yet very interested, amateur? I'd also probably have to buy a bigger camera bag

I've just come across this guy's site, and he really appears to know what's going on:

Filters by Thom Hogan

It looks like the article is pretty old, considering he's referring to books he's written on the D100. He's talking about having to modify his Cokin holder to avoid vignetting. Is there a problem with vignetting with the slide-in style filters?

He also talks about having great success with the variable neutral density Singh-Ray filter. Is that not your experience?

I've also found this review of the Singh-Ray variable ND filter:

Fstoppers Reviews The Singh-Ray Variable Neutral Density Filter: A Must For Any Landscape Photographer | Fstoppers

It talks about vignetting as well as a slight color cast. Is that avoided with the slide-in filters?

I do expect to be purchasing a full-frame camera in the near future (6mo or so), so I probably won't have my 67mm lenses any longer and will instead probably be purchasing the 77mm lenses. Using the step-down rings sounds somewhat like a kludge to me, and requires me to carry around additional hardware. Can this all be avoided with the slide-in filters?

I started a search that focuses on the LEE 0.3 4x4 ND filter on B&H and found these:

# LEE 0.9 ND 4x4
LEE Filters 4x4" Neutral Density (ND) 0.9 Glass Filter

# LEE 4x4 Frame Kit
LEE Filters Foundation Kit FK B&H Photo Video

It says it also requires an adapter ring, but I've been unable to find that.

How does this assemble on the lens? Is it a big process to do it in the field?

It says that it accepts three filters at once, correct? So I could purchase three 0.3's or maybe a 0.9 and a 0.3 and stack them in case I needed more stops?

Thanks so much.

I use the 77mm Wide-Angle adapter for my Lee filter holder, and never had vignetting at 11mm on DX and 16mm on FX. Even with it setup to hold 3 filters. I would suggest you get a W/A adapter, the basic holder, and the set of three (0.3, 0.6, and 0.9) graduated neutral density in SOFT edged. The filters will run you $260, the holder maybe $80 and the adapter ring $70. So for $410 you can be up and running with some filters. And you could add (budget depending) a Lee Little Stopper (6 stop neutral density) for $140.

Jake

 

[gossamer]

I sat in on a presentation for the D750 last night, and it looks like the camera I'll be purchasing after the new year, so anything I purchase now will be intended to support the 77mm lenses then.

Can you explain the wide-angle adapters? I suppose you need those with wide-angle lenses, but how do they work? It's in addition to the holder and the lens itself?

Can you point me to specific items either on the LEE site or B&H, perhaps? Of course I could search (and I have), but I figured a direct pointer would be the easiest way to explain...

And are you an amateur? Or do you use these as a pro? I could probably afford the $400 as an amateur, but I'm not sure I'm actually going to be using this one filter all that often - still have to buy a UV and polarizer after this....

 

[astroNikon]

as an amateur, the Lee System adds up quickly. Filterdude.com makes the Ring (attaches to the lens), HOlder (attached to the Ring, and Filter Holder (holds the filters) less expensive. But the Lee filters are still expensive.
Cokin filters are a bit cheaper

That being said. I use screw-on B+W filters for CPOL, and ND 2x, 4x,6x, 10x etc

I'll be using Lee/Cokin for Graduated ND filters when I get around to it.
GNDs are different from regular ND
ND is consistent throughout
GNDs go from light to dark ==> check out Jakes pics of his camera with the filters on it ==> An Introduction to Neutral Density Filters and Why You Need Them for Landscapes | Photography Forum

 

[D-B-J]

I sat in on a presentation for the D750 last night, and it looks like the camera I'll be purchasing after the new year, so anything I purchase now will be intended to support the 77mm lenses then.

Can you explain the wide-angle adapters? I suppose you need those with wide-angle lenses, but how do they work? It's in addition to the holder and the lens itself?

Can you point me to specific items either on the LEE site or B&H, perhaps? Of course I could search (and I have), but I figured a direct pointer would be the easiest way to explain...

And are you an amateur? Or do you use these as a pro? I could probably afford the $400 as an amateur, but I'm not sure I'm actually going to be using this one filter all that often - still have to buy a UV and polarizer after this....

I guess I consider myself a semi-professional photographer. I have paid gigs. I've sold some prints. But it is DEFINITELY not my sole source of income nor do I rely on it. I should add that I'm REALLY into landscapes, and love to spend money on gear. I'm a gear junkie. So while the Lee system works for me, it may be overkill and over priced for someone who isn't going to use the filters on a weekly or daily basis like I often do. See the link Astro provided below for a ton of info on filters [emoji106][emoji106]

 

[astroNikon]

Just figure out how much you will use it and if will improve your photography (both your enjoyment of it and your photos).

You may not want to spend a ton on a full Lee System. A FilterDude/Lee combo might do. Or you might go for a lower Cokin system.

There's not much where I live where I can use a good GND for the price. So I haven't bought one yet.
My primary subjects is usually a bit farther up in the sky from landscapes where my lens is 2500mm and 85lbs.

But if you think you'll enjoy it and use it alot I'd say go for it. The Lee filters can't be matched by many for quality.
The darker filter you get the higher quality you want.

 

[dannylightning]

I did a long exposure in the middle of the day on a waterfall with no filter, very bright sunlight that day. the photo was over exposed, I used light room to bring down the exposure and it actually looked pretty good. I got the effect that I wanted with the water. the exposure on that one was not very long but it did smooth out the water.

I had to take several photos of this to get one that was not over exposed too much. this was just a experiment to see if I could do it but it worked with some editing, out of several pics only one of them was able to be fixed in light room, the rest were all way over exposed to the point where they cold not be fixed up and made usable.

this experiment kind of has me wondering if a 3 stop filter would do the job for that basic smooth water look.

 

[astroNikon]

waterfalls aren't bad depending upon where it's at - basically how much sky is there and location of sky, clouds etc.

f/22 or 32 etc can give some pretty good long exposures for testing. That is what I did initially.
The NDs really let you take into account any situation and not use the aperture where you may get distortion.

The GNDs really come into play in instances such as evening when the sun is setting or sunrise. The foreground is unadequately exposed. The GND is good here where as there is little ND on the foreground and more on the horizon.

or water on a beach/rocks on an ocean ... etc. plenty of uses. The only beaches I have here are for small inland lakes.