Recommend Neutral Density Filters?

[ilzho]

Hello:

I am in the market for a rectangular ND filter system. I am looking at getting a 3 & 6 stop nd filters.

I realize they can be very expensive and there are many different manufacturers (Cokin, Lee, Progrey, Hoya, B+W, Tiffen, etc.), but can you all recommend good ones and ones to stay away from?

Also, would you recommend graduated filters or the solid ND filter?

I am looking to expand my landscape photography and to better blur water and clouds, etc.

Thanks,

David

[RobertTheFat]

I suppose this isn't really relevant to your question, but why do you want to blur water and clouds? As a sometime seascape photographer, I think that's one of the last things I'd want to do. What am I missing?

[ilzho]

To show motion. 

Waterfalls, streams, lakes. Smooth water during a nice sunset.

I like to blur the clouds to show motion over a nice skyline, etc...

I can do this without ND filters up to a certain point. 

ND filters will make life a little easier for me.

I realize some of this stuff can be done in post processing as well.

[ebiggs1]

"I realize some all of this stuff can be done in post processing as very well."

This is one of the easiest editing techniques to learn.

[diverhank]

I'd recommend getting a square filter holder system - easier to put on and with less vignetting.  I'd get the 100x100 mm and not the 150mm (too expensive).  The two brands that are popular and I'm familiar with are Lee (Big and Little stopper) and formatt hitech.

If you haven't used these before...be mentally prepared for color changes and other effects.  I don't use graduated filters because I always bracket my shots and blend in post.

[TCampbell]

The key factor in filters is to have filters with good anti-reflective coatings to avoid "ghosting" (reflections) in the images.

Top brands in slide-in filters are companies such as Lee Filters, Formatt-Hitech, and Singh-Ray makes a few specialty filters (like their reverse ND grads which do well at sunsets -- I've noticed more companies coming out with reverse ND grads... Lee filters now has them as does Formatt-Hitech).  

B+W does make extremely good filters (they are definitely a top brand), but so far as I know they only make round "screw on" filters.  I don't think they make square/rectangular "slide on" filters.  

Cokin is a low-cost option.  If you're buying filters on a budget... they'll have the cheapest prices.

Filters do come in sizes... the 100mm or 4" wide size is the most universale.  Everyone makes a filter holder and filters in this size.  This means you can mix brands. 

If you're specifically thinking of blurring water, then you probably want a 10-stop ND, such as a Lee "Big Stopper".  But these are used a bit different than other filters.  The problem with 10 stops is that it is too dark for you to see to compose... meter... or focus.  When the filter is on the camera things will pretty much just look black.  You have to do the focus & compose with the filter off the lens.  If you used auto-focus to focus the shot, disable AF once the lens is focused.  Use manual mode and meter the shot, then manually adjust the shutter to 10 stops slower than your metered reading.  Slide the 10-stop filter on... then take the shot.

Regarding the "graduated" vs "solid".

"Solid" filters are meant to change your shooting conditions... 

For example... I've been out in mid-day sun and wanted to shoot a subject with a gently blurred background (I wanted to shoot at f/4).  The problem was... I needed to use fill-flash and that meant that my shutter was limited to the max flash-sync speed of 1/200th sec (unless I used high-speed sync mode).   This meant I was going to have to use a high f-stop and that meant I was going to have strong depth of field ... so much for background blur.

With a solid ND filter, I was able to bring down the light such that I could still use the fill-flash... but I could bring my f-stop down to f/4 at 1/200th sec and get the blur I wanted.

That's what I mean by "change your shooting conditions".  For any shot, there's a range of possible combinations of aperture & shutter speed (& ISO although if you're using an ND, you're already at lowest ISO).  The solid ND filter shifts that entire range of possible exposures down so you can use wider f-stops or longer shutter speeds than otherwise possible.

A graduated ND filter just shifts part of the frame.  The most common use of these is in landscape photography where the sky typically has considerably more light than the foreground.  If you bring up the exposure on the foreground, you end up over-exposing the sky.  If you expose for the sky, you end up with an under-exposed foreground.  The "graduated" ND filter lets you bring these back into reasonable balance so you can tone down the sky and bring up the foreground and everything looks much better.  It's "as if" you got a lot more dynamic range in your camera (without changing the camera).

Grads come in two flavors... "hard edge" and "soft edge".  If you look at a "hard edge" filter, the edge isn't actually "hard" (it's no a straight tint where you have clear, and then suddenly it's tinted)  Both fade in the tint.  But a "hard" edge grad fades it in very quickly.  A "soft" edge grad fades in more slowly.

If you have a shot with a fairly straight separation of sky vs. foreground, then a "hard" grad ND usually works best.  You slide the filter to put the grad edge on the horizon and take the shot.

Trouble happens if you use this filter when you have a very jagged horizon ... or foreground objects that crop up in into the sky section (buildings, trees, etc.)  A "soft" edge grad makes the change gentle enough that it isn't noticeable in the image.

There's also something called a "reverse" grad.  It's basically an inverted "soft" grad.  Normally in a soft grand, half of the filter is clear.  half the filter is tinted.  But the tinted half very gradually gets darker.  (so it's clear... then slightly dark, then dark, and darker as you get farther from the clear half).  Imagine if you flip that so that it gets very rapidly dark (like a hard edge) and then gently gets less dark.  These work well for sunsets where the sun is on the horizon (the brightest area).  You have a clar-half for the foreground, a very dark area for the sun at the horizon...and then the tint gets weaker as you get higher in the sky.

Some of these companies make filters with a dark band in the middle... these are meant for stacking... use a standard grad ND.. but slide the second filter in (the one with the dark band) and position the band at the sun to provide extra darkening).

There are LOADS of YouTube videos that demonstrate what you can do with these filters.

[ilzho]

Thank you so much. Great information.

[DanSF]

I realize you requested a rectangular ND filter system, but I use a Cokin that takes both of their rectangular and round filters. i got this two:

CA120 Cokin-A Grad ND 4x Hard-Edge and

CA121 Cokin-A Grad ND 8x Hard-Edge

I noticed you did not mention a variable ND, but I use that too, which lets me dial-in the ND I want but they are solid, and not graduated.

The graduated ND is good for landscapes when I want to sky to be get washed out, but the bottom (let's say the beach) looks normal, just like you said.  I used the solid ND to make moving subjects like cars or walking peoplle blur out using long exposures.

I got mine from Filter Find, who is a local specialist in filters.  http://www.filterfind.net/Home.html

but maybe he can still help you.  Since he specializes in filters, I got very good guidance, but I can help here if you need from my experience.

[RobertTheFat]

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@DanSFwrote:

I realize you requested a rectangular ND filter system, but I use a Cokin that takes both of their rectangular and round filters. i got this two:

CA120 Cokin-A Grad ND 4x Hard-Edge and

CA121 Cokin-A Grad ND 8x Hard-Edge

I noticed you did not mention a variable ND, but I use that too, which lets me dial-in the ND I want but they are solid, and not graduated. ...

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I'd love to hear the physics of a variable ND filter. The nearest thing I can conceive of is two consecutive polarizers. Am I missing something obvious?

[DanSF]

You're exactly correct. It's two polarizers rotating on a common axis.  That also causes potential problems with a mark that resembles the letter "X" at some settings.   The person from FilterFind told me that stacking a circular and a linear polarizer provides the same effect but it won't have the easy to rotate capability of a pre-configured variable ND Filter.

But for me, while experimenting, I'm willing to live with that given the convenience and it's fun to play with.  For people who do professional or precise work, I think they need to get a regular ND filter.