Any way to increase motion blur in 25p video already shot at 1/2000 second?

That's what NDs are for, exactly. Use the low tech solution. It's the best.

Doing this in post production is an expensive and risky operation: you have to buy the software, you have to learn how to use it, you may be terribly disappointed by the results.

Or, of course, it may turn out that you love look and learn to rely on your new tools for much more experimentation as your work on other projects.

I have not kept up with pixel-level processors that will create motion blur from razor sharp images. Hopefully someone will be back shortly with a suggestion about an effect that can simulate motion blur.

It's possible to create a template in Motion that can be moved to FCPX but this relies on things actually moving while the shutter is open, it does not create trails behind pixels.

https://www.youtube.com/watch?v=UJfrWDkWHE4&feature=youtu.be

Ian R. Brown wrote:

ND filters probably are the best solution but there are a great many complex shooting variables that can make them a PITA to someone like me who is new to their use. So the idea of being able to add blur at leisure, over a coffee etc., is very seductive.

Sorry no one else had jumped in to correct me or to give you better advice. This is unbelievably complex software, huge computational and rendering resources using motion tracking at a pixel level and motion prediction in order to create blur—and to get the directional blur correct—where only razor sharp edges exist.

The thing about neutral density filtration is it's been around forever. It's predictable, reliable, and inexpensive. Variable NDs are convenient but the polarization might be unwanted. The section on ND filters in every "how to shoot killer video with your DSLR" book is readily understood, the ND factor is a denominator; ND2 is half the light (one stop), ND4 is 1/4 light (two stops) &c. You need 6 stops (ND64) to go from 1/2000 to 1/30 second shutter speeds. That's going to be two NDs stacked, a 16 and a 4 or two 8s.

From around the web:

here are two common ways of quoting ND filter strengths, and one less common:

• 2x, 4x, 8x, etc. Sometimes these are referred to as ND2, ND4, ND8, and so on. These refer to the amount by which the light is diminished. An ND2 filter halves the light, while an ND8 filter reduces it to one eighth.
• 1 stop, 2 stops, 3 stops etc. Sometimes these are referred to as EV, for exposure value. These are probably the most convenient measurement because they tell you how many stops they'll adjust your exposure by.
• Numbers like 0.3, 0.6, 0.9 etc. These are basically just 0.3 x the number of stops of EV. These are less common.

Each stop of exposure value refers to a halving of light, so:

• 1 stop = ND2
• 2 stops = ND4
• 3 stops = ND8
• 4 stops = ND16

And so on.

Stacking multiple ND filters adds stops, and multiplies strength values.

So, ND500 sounds like a lot, but it'd be the same as stacking an ND16 and an ND32 (16 x 32 = 512; manufacturers round it to 500).

Variable neutral-density filter[edit]

The main disadvantage of neutral-density filters is that to be entirely flexible in your shooting you need to carry a range of different NDs. This can become an expensive proposition, especially if using screw filters with different lens filter sizes, which would require carrying a set for each diameter of lens carried (although inexpensive step-up rings can eliminate this requirement). To counter this problem, some manufacturers have created variable ND filters. These work by placing two polarizing filters together, at least one of which can rotate. The rear polarizing filter cuts out light in one plane. As the front element is rotated, it cuts out an increasing amount of the remaining light, the closer the front filters comes to being perpendicular to the rear filter. By using this technique, the amount of light reaching the sensor can be varied with almost infinite control.

The advantages to this are that you get multiple ND filters in one package, the disadvantage is a loss of image quality caused by both using two elements together and by combining two polarizing filters.

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Hello Ian,

Screwing on filters is one of those things that usually make it too much trouble to use a filter. 😠

Have a gander at these things:

http://www.xumeadapters.com/

I've been using these for a few years and they simply work and don't fall of. ✅

Depending on how many you need and size, there are Pro kits available, that just means you buy a bunch for less.

Now it easy to stick filters on/off, Luv 'em. 🙂

The link keeps cycling back to this thread, so type it in manually. Seems to be an ASC issue. Loungies were discussing it recently.

Al

Ian R. Brown wrote:

Ideally you need to focus the camera spot-on which can only be achieved properly without an ND fitted. The action of screwing on the ND filter is then highly likely to upset the delicate focusing position of the camera lens. Even if you use a variable ND and focus at its minimum darkening, the focus could again be upset when rotating the ND to a darker position.

When we shoot DSLR video, we head out with stacked NDs and polarizers as our normal configuration. We boost the display brightness and activate the focus aid to achieve perfect focuson the Nikon.

One of the things I really miss about my old 35mm Nikons is the split-image rangefinder focusing screen. Focusing was never hit or miss; it was absolutely deliberate.