Understanding ND filters, when to use, when NOT to use, etc...

[ButchA61]

Good afternoon,

Earlier today, I stopped at the local camera store in town, and asked about ND filters for my Nikon D3500 DSLR (which I brought with me). The clerk noticed I had the small DX 35mm f/1.8G prime lens on. I explained that it is my favorite, go anywhere, do anything, type of lens. Getting to the point, the clerk got out some 52mm filters, and sold me a Promaster Variable 2-9 stop ND filter.

I quickly ventured over to one of the public parks with one of those water fountains in a small pond. I setup my tripod on the wooden overlook/fishing pier, and focused squarely on the fountain at a shutter speed of 1/2 second, and very very carefully and steadily pressed the shutter button.

What do you think for a very first attempt at blurring a fountain with an ND filter? How dark can I go and/or how slow a shutter can I go?

 

[mreynolds767]

Sounds / looks like you have the hang of it.

For flowing water I often prefer a 1/2 second exposure time which is what you presented. Clearly shows the smoothness but still maintains motion.

if shooting a seascape with moving water or a water fall that would generally be my preference. Something slower like a pond or a lake I might up for a multi-second exposure as my first choice.

You can extend it greatly into the multi second range, even 30 or more seconds for such a scene. In those cases, it will really blur the moving bits out. Some love this look all of the time for all locations, I do prefer it some of the time but is fun to experiment with and see what you like best.

There is no right answer.

When you definitely don't want to use is when their is something you are trying to freeze with a high shutter speed to prevent blurring, think of a bird in flight, trees on a windy day or even those times when you want to freeze a big wave crashing. You also would have no benefit and a couple of side affects of using one when there is no movement in the scene. Clouds are still or there are no clouds and nothing else moving.

Not to rain on your parade but generally those variable ND filters are great for video and not so great for stills. Kind of like a swiss army knife of ND filters. Of course it is cheaper than buying a set of 3 different filters for 3, 6 and 9 stops but will not give you the same performance. As you get more experience with it you may find yourself always using one end of the spectrum so you can then later buy a single ND filter of a higher quality for the amount you like best. I recommend the brand Breakthrough Photography

If your camera has a 2 or 3 second delay timer setting use that, rather than try and press the shutter so carefully. Or get a timer/remote.

--
Online Gallery here
https://www.mattreynoldsphotography.com/

 

[Krusty79]

I have never used a variable ND filter, as I have heard of potential problems with them (vignetting & cross-hatching). But there is no limit on how long of a shutter speed you can use with them.

If you are interested in long exposures, you'll need a good tripod to do them right. Your image shows a little blur, but you can take it a lot further (with a tripod again). Using a remote shutter will help eliminate camera shake.

 

[petrochemist]

1/2s certainly works quite well for that fountain, taken at f/10 I suspect the filter wasn't very dark, but that does depend somewhat on the light...

For some shots I'll go to the maximum my camera handles without bulb mode. (That's 30s on most models & 60s on a few of mine). If trying to loose tourists from a crowded scene you can need longer times so they move enough to be lost.

Variable ND filters can give rise to issues especially with wider lenses, but if the dreaded dark X doesn't occur they generally serve pretty well.

WRT how dark, you can go as dark as you like - I've used ~18 stops reduction with welding glass to get serious reduction in lighting (not quite a ND as it gives a significant colour cast). With a DSLR stray light coming in through the viewfinder can be a problem - covering the viewfinder or just shading it with your hand/hat/head usually solves this.

Most ND filters (variable or not) reduce visual light but do little to infra red so shouldn't be used for photographing the sun (welding glass actually blocks more IR than visual light so the darker shades are safe for the sun - the reason I wanted 18 stops above).

Its not always for long exposures that you choose a ND, sometimes you might just want really wide apertures & find the shutter cant go fast enough - the lowest ISO on one of my micro four thirds bodies is 160, and the shutter maxes out at 1/4000s this proved beyond the range of my 50/1.2 projector lens (which has no aperture to close down). Usually just 1 or 2 stops is enough reduction to get things working...

Many of my ND filters are slot in types rather than screw on models. With these light getting round the back of the filter can be a problem, but I've never know issues like that with screw in types - just having filters the wrong size for the lens I've switched too....

 

[ButchA61]

Thank you all for the great replies. I have never used a ND filter before. I've always used CPL's and have a good understanding on how they work, when to use them, etc..

ND's are quite often (to my understanding) considered like putting a nice pair of Ray Ban sunglasses on your DLSR!

So.... that photo of the small pond and fountain was very first attempt at understanding how they work. I was able to lightly blur the sprinkling water of the fountain, but yet still keep things relatively in focus.

The more I read articles and tips from people on here, the more it starts to sink in! What a great site!

 

[Bender79ita]

You use an ND filter when you want to take a shot with specific settings, but the light is too strong for the settings you wish to use and relevant highlights cannot be recovered from the raw file due to excessive overexposing.

Generally you use an ND filter also to stay below f9 (APS-C with 24mp) to avoid diffraction.

Often this requires using a tripod to avoid having the image ruined by shake, like it happened in the picture you posted, that is clearly shaky.

A variable ND filter is particularly useful when dealing with water. You can set your camera to Aperture Priority, set the desired aperture, and dial in the shutter speed by adjusting the VND filter. Try and see what shutter speed results in the best effect for you or the situation.

You can or might want to stack a Circular Polarizer filter if you wish to make the water transparent, although this works mostly with still water.

A few examples of different shutter speeds in regards to water.


ND64 (IIRC)


ND1000 (IIRC)


With polarizer, IIRC


ND64

 

[petrochemist]

You can or might want to stack a Circular Polarizer filter if you wish to make the water transparent, although this works mostly with still water.

There's no point stacking a CPL with a variable ND (which are made using two polarisers) but the combination with standard ND filters can work well.

 

[Bender79ita]

You can or might want to stack a Circular Polarizer filter if you wish to make the water transparent, although this works mostly with still water.

There's no point stacking a CPL with a variable ND (which are made using two polarisers) but the combination with standard ND filters can work well.

How do you get rid/activate the polarizing effect from a VND?

I've read about this VND polarization things a few times but I never remember having a polarizing effect when I used VNDs. I've moved to fixed NDs for a few years now as I was never satisfied with the VNDs for stills and don't even have one for testing now.

Still curious to know how it works though :-D

 

[J Peters]

If trying to loose tourists from a crowded scene you can need longer times so they move enough to be lost.

This reminded me of a trip to Pompeii in 2016. I took a tripod, ND filter, and used a long exposure to get shots of the ruins with all the people removed. Some shots had a single solitary figure in them......another photographer doing exactly the same thing from the opposite direction!

 

[petrochemist]

You can or might want to stack a Circular Polarizer filter if you wish to make the water transparent, although this works mostly with still water.

There's no point stacking a CPL with a variable ND (which are made using two polarisers) but the combination with standard ND filters can work well.

How do you get rid/activate the polarizing effect from a VND?

I've read about this VND polarization things a few times but I never remember having a polarizing effect when I used VNDs. I've moved to fixed NDs for a few years now as I was never satisfied with the VNDs for stills and don't even have one for testing now.

Still curious to know how it works though :-D

The only way to get rid of the polarizing effect of a VND is to take it away. It's not much good for getting the effect you want, unless you set it to the minimum darkness then unscrew the filter till it's aligned right. I don't recommend trying it unless you really need a polariser & only have a VND handy.

In normal use (ie not at their palest) VNDs have two separate planes of polarisation, making it very difficult to see the effect, but adding a third one doesn't gain anything.

Generally light is a mixture of all directions of polarisation, the first polariser blocks any of these polarisation vectors that don't match it's alignment, just leaving the component perpendicular the that. The second layer then blocks any portion of this transmitted light thats does not match it's alignment. If both layers are exactly 90 degrees out of alignment the combination should block all light, if they're perfectly aligned the second layer effective does nothing.

Adding a third layer does nothing as any combination of the three can be matched with a different combination of the first two.

CPLs come into their own when the incoming light is already partly polarised by reflections etc that are part of the subject. Natural polarisation like this is quite common but often quite a way from complete. Combining a polarised light source & a lens mounted polariser can allow extra levels of fun/control lighting subjects behind glass (without seeing the light reflected on thew glass - though other techniques are usually better for this) or viewing stress patterns in plastics.... see

https://flic.kr/p/27yect2

for an example.

 

[Bender79ita]

You can or might want to stack a Circular Polarizer filter if you wish to make the water transparent, although this works mostly with still water.

There's no point stacking a CPL with a variable ND (which are made using two polarisers) but the combination with standard ND filters can work well.

How do you get rid/activate the polarizing effect from a VND?

I've read about this VND polarization things a few times but I never remember having a polarizing effect when I used VNDs. I've moved to fixed NDs for a few years now as I was never satisfied with the VNDs for stills and don't even have one for testing now.

Still curious to know how it works though :-D

The only way to get rid of the polarizing effect of a VND is to take it away. It's not much good for getting the effect you want, unless you set it to the minimum darkness then unscrew the filter till it's aligned right. I don't recommend trying it unless you really need a polariser & only have a VND handy.

In normal use (ie not at their palest) VNDs have two separate planes of polarisation, making it very difficult to see the effect, but adding a third one doesn't gain anything.

Generally light is a mixture of all directions of polarisation, the first polariser blocks any of these polarisation vectors that don't match it's alignment, just leaving the component perpendicular the that. The second layer then blocks any portion of this transmitted light thats does not match it's alignment. If both layers are exactly 90 degrees out of alignment the combination should block all light, if they're perfectly aligned the second layer effective does nothing.

Adding a third layer does nothing as any combination of the three can be matched with a different combination of the first two.

CPLs come into their own when the incoming light is already partly polarised by reflections etc that are part of the subject. Natural polarisation like this is quite common but often quite a way from complete. Combining a polarised light source & a lens mounted polariser can allow extra levels of fun/control lighting subjects behind glass (without seeing the light reflected on thew glass - though other techniques are usually better for this) or viewing stress patterns in plastics.... see

https://flic.kr/p/27yect2

for an example.

Oh I see, so as they allow light-blocking adjustment by a combination of polarization with each other, there is always some degree of polarization going on.

IIRC polarization removes rainbows, so it might be best not to use VNDs if you're shooting one!

Street photographers might be intrested in the glass transparency thing. I'm too shy for it :-D

 

[Bender79ita]

If trying to loose tourists from a crowded scene you can need longer times so they move enough to be lost.

This reminded me of a trip to Pompeii in 2016. I took a tripod, ND filter, and used a long exposure to get shots of the ruins with all the people removed. Some shots had a single solitary figure in them......another photographer doing exactly the same thing from the opposite direction!

If you're into this kind of thing, Nisi makes a 32000 15 stops ND that is very good for getting several minute exposures in full daylight.

You can average a bunch of frames shot with a timelapse in photoshop aswell, but there's sort of a romanticism in doing it with filters instead, IMO. Kind of film days style.

 

[dsjtecserv]

You can or might want to stack a Circular Polarizer filter if you wish to make the water transparent, although this works mostly with still water.

There's no point stacking a CPL with a variable ND (which are made using two polarisers) but the combination with standard ND filters can work well.

How do you get rid/activate the polarizing effect from a VND?

I've read about this VND polarization things a few times but I never remember having a polarizing effect when I used VNDs. I've moved to fixed NDs for a few years now as I was never satisfied with the VNDs for stills and don't even have one for testing now.

Still curious to know how it works though :-D

The only way to get rid of the polarizing effect of a VND is to take it away. It's not much good for getting the effect you want, unless you set it to the minimum darkness then unscrew the filter till it's aligned right. I don't recommend trying it unless you really need a polariser & only have a VND handy.

In normal use (ie not at their palest) VNDs have two separate planes of polarisation, making it very difficult to see the effect, but adding a third one doesn't gain anything.

Generally light is a mixture of all directions of polarisation, the first polariser blocks any of these polarisation vectors that don't match it's alignment, just leaving the component perpendicular the that. The second layer then blocks any portion of this transmitted light thats does not match it's alignment. If both layers are exactly 90 degrees out of alignment the combination should block all light, if they're perfectly aligned the second layer effective does nothing.

Adding a third layer does nothing as any combination of the three can be matched with a different combination of the first two.

CPLs come into their own when the incoming light is already partly polarised by reflections etc that are part of the subject. Natural polarisation like this is quite common but often quite a way from complete. Combining a polarised light source & a lens mounted polariser can allow extra levels of fun/control lighting subjects behind glass (without seeing the light reflected on thew glass - though other techniques are usually better for this) or viewing stress patterns in plastics.... see

https://flic.kr/p/27yect2

for an example.

Oh I see, so as they allow light-blocking adjustment by a combination of polarization with each other, there is always some degree of polarization going on.

IIRC polarization removes rainbows, so it might be best not to use VNDs if you're shooting one!

To the contrary, a polarizer can be used to enhance rainbows!

Street photographers might be intrested in the glass transparency thing. I'm too shy for it :-D

Dave

 

[BBbuilder467]

You can or might want to stack a Circular Polarizer filter if you wish to make the water transparent, although this works mostly with still water.

There's no point stacking a CPL with a variable ND (which are made using two polarisers) but the combination with standard ND filters can work well.

How do you get rid/activate the polarizing effect from a VND?

I've read about this VND polarization things a few times but I never remember having a polarizing effect when I used VNDs. I've moved to fixed NDs for a few years now as I was never satisfied with the VNDs for stills and don't even have one for testing now.

Still curious to know how it works though :-D

It works like stacking one polarizer over another. Adjust one for the polarization and the other to add density. The types designed to do both use 2 rotating rings. The VND only has one.

 

[petrochemist]

IIRC polarization removes rainbows, so it might be best not to use VNDs if you're shooting one!

To the contrary, a polarizer can be used to enhance rainbows!
Dave

That's the wonderful thing about polarisers anything they can reduce they can also enhance just by twisting them round. For some reason this option is often missed out!

 

[Bender79ita]

Oh I see, so as they allow light-blocking adjustment by a combination of polarization with each other, there is always some degree of polarization going on.

IIRC polarization removes rainbows, so it might be best not to use VNDs if you're shooting one!

To the contrary, a polarizer can be used to enhance rainbows!

Street photographers might be intrested in the glass transparency thing. I'm too shy for it :-D

Dave

Are you sure? I used a ND64CPL ( link ) for this picture, I could see the rainbow disappear from the preview while adjusting the cpl effect... With the filter off, the rainbow had the same intensity as with the cpl adjusted off on the preview.

 

[dsjtecserv]

Oh I see, so as they allow light-blocking adjustment by a combination of polarization with each other, there is always some degree of polarization going on.

IIRC polarization removes rainbows, so it might be best not to use VNDs if you're shooting one!

To the contrary, a polarizer can be used to enhance rainbows!

Street photographers might be intrested in the glass transparency thing. I'm too shy for it :-D

Dave

Are you sure? I used a ND64CPL ( link ) for this picture, I could see the rainbow disappear from the preview while adjusting the cpl effect... With the filter off, the rainbow had the same intensity as with the cpl adjusted off on the preview.

Yes, I'm sure, I have done it to good effect. As Petrochemist noted above, a polarizer can be adjusted to both optimize and minimize its effects. So while you certainly can make the rainbow weaker, you can also make it stronger.

Dave

--

Galleries by David S. Johnston

www.pbase.com

 

[ButchA61]

Here's two more photos that I just took with my Nikon D3500 and the variable ND filter, on a tripod. I had my Samsung Galaxy with me and Nikon's app called "Snapbridge". Connecting up via Bluebooth, I used the feature called Remote Camera, and pressed the virtual shutter button on the app.

2 second shutter speed, ISO 100, and f/16 (I think). It worked! :-D

 

[Bob]

Good afternoon,

Earlier today, I stopped at the local camera store in town, and asked about ND filters for my Nikon D3500 DSLR (which I brought with me). The clerk noticed I had the small DX 35mm f/1.8G prime lens on. I explained that it is my favorite, go anywhere, do anything, type of lens. Getting to the point, the clerk got out some 52mm filters, and sold me a Promaster Variable 2-9 stop ND filter.

I quickly ventured over to one of the public parks with one of those water fountains in a small pond. I setup my tripod on the wooden overlook/fishing pier, and focused squarely on the fountain at a shutter speed of 1/2 second, and very very carefully and steadily pressed the shutter button.

You don't need to be so careful with the shutter button if you have a remote shutter release OR you set your camera to 'self timer' mode. You can set it for a 2-second self timer. That should be enough for any hand vibrations to settle.

What do you think for a very first attempt at blurring a fountain with an ND filter? How dark can I go and/or how slow a shutter can I go?

Since you have a tripod, there's no limit to the shutter speed. From the looks of your shot, 1/2 second still seemed fast. I would try 2 to 6 seconds - see how those comes out. Of course, you have to adjust your aperture and ND accordingly. Just experiment.
One thing about your composition. I would have moved the camera more to the left in order to level out the edge of the lake in the background. Because your background distance is not uniform, the trees on the left are further than the trees on the right. Thus, if you look closely, the trees on the left are blurrier as they fall beyond your depth-of-field. I would have thought f/10 would be sufficient, especially on a 35mm lens.

 

[Bob]

beautiful