Using a ND1000 neutral density filter

The K&F Concept 10 stop ND1000 filter

Neutral density filters let you use longer exposures or wider apertures by stopping some light getting into the camera during your shot.

A range of filters at lower densities let you make more effective use of flash in daylight and wider apertures – for thinner depth of field.

Once you get to filters like this ND1000 – the uses change.

Keith has been trying a ND1000 filter from K&F Concept

The ND1000 neutral density filter

At it’s simplest, the filter just blocks light – how much?

Well, that’s given in the table below, but look at this photo taken of a ceiling lamp in my home.

I’m holding the filter in my hand – note how in the unfiltered shot, the lampshade and part of the bulb are exposed correctly. The ND filter cuts so much light (10 stops) that you can clearly see the filament of the interior halogen bulb. [click to enlarge]

Only about 1/1000 of the light is getting through the filter

The 10 stop difference means that if I needed a 1/1000s exposure for a shot, the filter would lengthen this to 1 second.

This gives a clue to the typical uses of such filters – long exposures.

ND filter ratings are described in a number of ways – this table shows the gradations up to our ND1000 example

Note that you need better than ND5000 to photograph the sun with liveview. Nearer to ND100,000 for safely looking at it. You also need to be sure that the filter is not letting damaging levels of UV or IR through. The gist of this is that if you want to look at the sun, get a specialised solar filter.

Filter build quality

The filter is a low profile one, so when fitted to my TS-E24mm shift lens, there were no edge vignetting issues even at full shift.

The filter is hard and anti-reflection coated. There were no ghosting issues from bright light sources, suggesting that the glass is of good optical quality.

During testing I noticed no obvious colour shifts that were not handled by the auto white balance of the camera (a Canon 5Ds).

Whilst there is no direct vignetting from the edge of the filter, shifting the TS-E24mm to get a wider view gives a slight vignetting from the oblique angle the light is passing through the filter. I’d suspect this wouldn’t be a big issues until you got down to 16mm or so with a normal lens

Remember that I’m using a shift lens – more info if you’re unfamiliar with them

This shot is a composite of two shifted images each six seconds exposure [click to enlarge].

The vignetting darkens the top of the shot – not a problem usually with the sky, and easily fixable if I wanted

When I first looked at the image I was concerned with a lack of sharpness.

It turned out that the small footbridge I was on flexes quite a bit with people walking over it.

The six second exposure has given a slight softness to the water that may help with some shots.

The blur from vibration over a long shot like this is actually quite amenable to sharpening, such as here with Focus Magic

Remember that I’m using a 50MP camera (~80MP total in the image above), so this is fine for web use, but definitely not for my architectural clients ;-)

One of the uses for this filter is in my architectural photography where I want to give a blur to people, whether to make them less clearly identifiable or simply for a sense of movement.

You need to experiment and take quite a few shots. Results are always somewhat unpredictable.

The same view of Leicester City centre at one second and six seconds. [click to enlarge]

Some people don’t move much.

This view (0.4 second) of two competing food outlets gives a sense of movement and isolates those stopping for any reason. [click to enlarge]

There is no shortage of detail (100% crop – no special sharpening).

A cafe I stopped at (10s) [click to enlarge]

Both these shots show how little people sometimes move in 10 seconds.

About the filter

The filter was from K&F Concept who have a range of ND filters in different sizes

With such a filter, you just can’t see through the viewfinder any more, so it’s composing with the rear screen or, as I did, put the filter on just before you want to shoot.

If using a DSLR you should be aware that light coming in through the viewfinder will completely throw your camera metering – for me this is something to use with manual setting only.

I’m not a big fan of misty waterfalls and beaches from long exposures, but we’ve none of them round here anyway…

What such a filter does let you explore is the varied dynamic elements of a static world.

Great for my architectural work, and fun to try out too.

Just beware of the new-toy effect where you start thinking everything benefits from long exposure (it happens with any new photo technique, just beware of it ;-)