The Must Have Tool for Strobe Users

The Must Have Tool for Strobe Users

A few months ago, wedding photographer and Fstoppers writer, Trevor Dayley made a post about his favorite thing in his camera bag. Spoiler - it was a tilt shift lens, and the work he was able to produce with it made for some interesting and beautiful wedding and engagement photos. However, Trevor and I shoot entirely different styles, so what's my favorite thing in my camera bag?

It's simply, the Neutral Density filter. Being a strobist and commercial photographer, it is the one thing that I use on every single one of my photo shoots. I literally have 6 of them sitting in my camera bag right now, used primarily as backups if nothing else. So what is an ND filter and how do I use them?

What is a Neutral Density Filter?

As a portrait photographer, the best way I can describe a neutral density filter as is a pair of sunglasses for your lens. In other words, it blocks light from entering your lens, and the amount of blockage depends on the stop rating of the ND filter. A (good) ND filter won't provide any color shift to your photos, do any fancy tricks on its own, or alter your photos in camera.

So why would you want to block light from coming into your lens? Simple, for the same reason you want to shoot at ISO 100 and not ISO 400 on a bright sunny day. By reducing the amount of light that enters your camera, you're able to slow your shutter down and/or open your aperture wider for the shots. This becomes particularly handy when using off camera lighting, as it allows you to maintain the 1/200th of a second shutter, while opening up your aperture to get a shallower depth of field.

So in layman's terms, if I'm using an ND filter that is 5 Stops, that allows me to drop my shutter or aperture five stops total. So if I was shooting a session outdoors on a bright sunny day using the settings 1/200sec and f/11 (To expose the background correctly), with a 5 stop ND filter, I'd now be sitting at 1/200sec and f/2.0.

Why Do I Do This?

The biggest reason is balance. You'll often find that if shooting natural light on a clear sunny day, you're going to be left with white, or near white skies. This is simply because the sky is overexposed, and has lost all detail in it as a result. When firing with strobes, if you want to exposure the sky, you'll have to "beat the sun" in terms of strobe power, leaving you with an image that is exposed, but at a high f-stop, pushing everything in focus, and losing interesting focal planes. An ND Filter will let you expose the background completely, while allowing you to use your strobes to correctly expose the foreground, all while being able to select your aperture (since your shutter speed will be maxed out at 1/200 a sec). By using ND Filters, suddenly my super sharp f/11 image with everything in focus has a nice bokeh at f/2 to compliment the image and give it a more professional look.


Types of ND Filters

Generally speaking, there are three types of ND filters. The first, is the standard ND filter. These filters provide a specific stoppage of light, and that cannot be altered whatsoever. These will have a variety of filter sizes and stop numbers, and will be of much higher quality than the other option, which is Variable ND filters.

What a variable ND filter is, is a ND filter that covers multiple stoppage levels depending on how much you turn the filter's dial. They typically vary from 2-stops of light, to 9-stops. Because of how these work, the quality of them is reduced, and a strange purple or green vignette can come from them when shooting at higher filter stops. However, these filters still work great for everyday use, and provide excellent image quality if they're a higher quality brand. Because of the versatility of these types, they do typically cost a bit more than your standard ND filter.

The third is the ND filter (in my opinion) built specifically for landscape photographers, which is the gradient ND filter. Much like the name suggest, the Gradient ND filter will only provide a stoppage of light for a portion of the filter, gradually increasing stops as it gets closer to the edge. This is useful when trying to match the exposure of the sky with the exposure of the foreground, and particularly helpful with landscape photography during sunny days.


So Which One Do I Prefer?

I am a believer in the Variable ND Filter personally. Despite reducing the image quality and creating fringing caused by the filter, I still find the problems to be minimal, especially when using a higher brand filter. I also often manual focus, meaning that I'm still able to create incredibly sharp images, assuming my eyes are working right.

Currently, a cameras downfall is the inability to work with off camera lighting beyond 1/200th of a second (with the exception of hyper syncing). With lower ISO speeds (ISO 50 for example) modern cameras are often able to counteract that issue, but most times, it's not nearly enough. So if you want to be a lighting snob, and still get that great shallow depth of field, ND Filters are a must for shooting in bright conditions.

The current brand of Vari-ND filter I use is the Fader II, by Light Craft Workshop. I bought it for its price point, and quality that it does produce. When stacking ND filters, I have noticed some strange color toning coming from it, but for its normal use, it works wonderfully and works exactly how I'd need it to. This strange color toning is known as 'X Factor' and will occur on all Variable ND filters at one point or another, especially when staking them to achieve 12+ stops (like I was doing).


The Top Brands of ND Filters

For normal ND Filters, Lee, B&W and Hoya are all considered the Mercedes-Benz of filters. They're pricey, especially given that they're nothing more than a tinted piece of glass, but they have some of the highest quality available for ND Filters (Often filters on your camera will soften your images slightly). For Variable ND Filters, there is far more varying opinions. Here is a list I have built based on personal experiences and reviews that I've researched on the internet.


Regular ND Filters Variable ND Filters
1. Lee Square Filters 1. Schneider True-Match Vari-ND Filter
2. B&W Circular ND Filters 2. Singh-Ray Vari-ND
3. Hoya Circular ND Filters 3. Genus ND Fader Filter
4. Tiffen Circular ND Filters 4. Light Craft Workshop Fader ND Mark II
5. Formatt Square Filters 5. Heliopan Variable Gray ND Filter


Also, be sure to check out Jaron's review of the Fotodiox Wonderpana - a ND system for Wide Angle Lenses.

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Zach - Just curious, do you use studio strobes or speedlites with this technique? What was used for the example photos? Wondering if a speedlite has enough power to produce results in the sunny conditions after cutting down on the exposure with the ND filter.

Zach Sutton's picture

I use studio strobes for virtually all my work. I wish I could give you some insight on using speedlights with this technique, but I'm just not sure. Sorry.

No problem, I figured speedlites wouldn't push enough power in direct sunlight but thought I'd ask the question in case that's what you were using. Which brand strobes are your weapon of choice?

Ett Venter's picture

I can answer this for you -

I use and ND filter and speedlights in bright light conditions and the speedlights do a pretty good job. Sometimes they're not powerful enough, so I use 2 or 3 of them in the same softbox and that usually provides MORE than enough power. Like WAY more than enough. I don't think I've ever needed more than 3 lights at 1/8th or 1/16th power. So 2 lights would comfortably do the job as well.

David T's picture

lol @ David Hobby himself calling y'all out on this one...

David T's picture

from Twitter: @strobist: That moment when another website essentially rewrites a post of yours from 3 years ago & genericizes your company's name in the headline. :/

Zach Sutton's picture

Apparently strobist is a trademarked name. :-

Today I Learned.

You probably should have mentioned Cokin Filters, their square grad filters probably have a greater variety than any other brand that I know of. They have a variety of gradiants and also have colored grad filters and some odd special use ones. The filters are plastic but seem to be of good optical quality. And are far cheaper than any other brand.


Zach Sutton's picture

As I mention in the post, I don't ever use grad ND filters at all. So I figured it was best not to talk about them much, since I don't know that much about them.

If you do, you're welcome to write a post about it, send it to one of our editors and we might be able to post it up as a Guest Feature. Cause it already sounds like you know a whole lot more about it than I do.

I think I might take you up on the offer. Tho I use the same variable ND that you use, most of the time now days.


sadly cokin WAS a great manufacturer (french if I recall correctly) but has since been bought by chinese manufacturer.

I bought one lately and the 4 stops full ND filter was litterally BLUE. Had to push the correction to the extremes to get a normal look and even then it was sooooooft.

Bryan, i use cokin too. i face issues with it giving out different tints while stacking these and so it has been lying there for long. results are outstanding though. what i need to know is that if we expensive ones such lee or singh rays. shudnt we have no issues at all?

Zach Sutton's picture

Him and I discussed it privately and have resolved it. It was more of the use of the name Strobist, not so much about the ND filters.

There really is no need to open up closed doors on the topic.

John White's picture

It's nice to see you talked with him and are trying to settle the dust of everyone freaking out. Good job Zach

Singh-Ray variable ND filters are the ne plus ultra in the field. I've tried nearly every one on the market, including the Lightcraft Workshop Fader II...

Ett Venter's picture

Alright, so Zach, I'd love to share my own experience with this stuff.

I have a pretty similar style/approach to portraiture to you. Good lighting (I use speedlights though), shallow DoF, on location, etc. This calls for an ND Filter or HSS. My first approach was to go the ND route. So I bought the very ND filter you use (LCW). It's a great filter, but man, I've gotta be honest - the impact on image quality is more than something I can comfortably ignore. Not always, but sometimes. The impact on sharpness is what bugs me most. We all know there's a slight colour cast from filters like this, but that's not the end of the world. The impact on Sharpness, though, that really bugs me.

So then I decided to pick up a new set of speedlights that do HSS, and HSS is freaking amazing. Great light, high shutter speed, ZERO impact on image quality. So shooting that sort of thing through a good piece of glass - amazing. Only problem is that the lights have to fire at a higher power to do the trick. That adds a new annoyance because you either need to fire and wait for it to recycle, or you need to stick 2 or 3 lights into the softbox.

So I think I'm bouncing back to the ND route, but I'm just going to bite the bullet and hook up a few LEE filters. I've read some amazing things about them, and seen some amazing photographers use them too.

Thanks for posting! Great article focused on Variable ND's used for adjusting flash exposure. Very clear and easy to understand and put into practice.

does anyone know how the glass used in welders masks compares to ND filters, i want to filter my 14mm wa lens but a proper one is huge bucks, i did make an adaptor that took a ND grad but even the biggest i could find showed up as a circular image on ff sensor, but t works

Erin B.'s picture

They are green or bluish green in tint. (My dad taught me how to weld) And they are very dark - you can view a solar eclipse with a #12 and up. Maybe if you have a few 1200 WS mono lights to blast your subject with and want the pure green color.

ok so they are very dark and very green.............back to the drawing board, thanks Erin

Tyler Friesen's picture

You forgot about Tiffen Variable ND's, tests show they are actually fantastic.

Zach Sutton's picture

I've actually heard that, though I'm always a skeptic when it comes to Tiffen. They've done a good job at marketing themselves as budget equipment, so I always feel weird trying them out when I want the absolute best.

I'm currently saving my pennies for the Schneider True-Match Vari-ND Filter

Tyler Friesen's picture

Check out this video. It is not very scientific but some great examples of what the small differences are from filter to filter.

Well, please! When you buy that filter, you should tested and share, and if you want drama, test it with the very chepo Neewer Vari_ND, with a medium price filter and the Schneider. That would be very valuable for us.

These is the cheapo one, pretty popular with the Video folks.

Zach Sutton's picture

How much money do you think I'm making!? :-p

Graham Marley's picture

Just did this Saturday, I started shooting with a variable ND and strobe this year and I can't look back.. I need to clean up the blue in the shadows and whatnot, but just thought I'd throw it up there. Thanks!

Great article ! The only thing i'm missing is the mention of the New kid on the block the Genustech Eclipse vari-ND filter! Only on the market for a couple of months but no-strong colorcast or great loss of sharpness like i.e. the LCW Fader II, but still at the same pricepoint as the LCW ! :) Check it out:

Could I get the same results with a mirrorless camera that can shoot at high sync speeds?

Did it a few times with a Fuji X100S . . . although that is technically more of a "large-sensor-compact" than a mirrorless.

thats the exact camera I am thinking of getting for shots like it would work?