M2P - Video @ 2X Inverse FPS

[EricJT]

Too cold up here north of Toronto to try it out right now so:

Shooting video with my M2P at 30fps and using a variable ND filter....what would be the result of shooting at a shutter speed of 1/120 vs 1/60 using the variable ND filter to get the proper EV? Theoretically, I think 1/120 would result in sharper videos than 1/60.....any other significant differences?

 

[Not A Speck Of Cereal]

Why even use an ND filter? If you go 1/120 @ 30fps, it would indeed be sharper, but would not give you the desired motion blur (which is the reason you use an ND filter to slow-down the shutter speed). The classic cinematic look would require 1/60 @ 30fps for that look.

But if you want the sharper video, the more realistic look, then yes: you want a faster shutter speed. And faster FPS as well. In that case, an ND filter can be a hindrance (depending on the lighting).

Chris

 

[EricJT]

Why even use an ND filter? If you go 1/120 @ 30fps, it would indeed be sharper, but would not give you the desired motion blur (which is the reason you use an ND filter to slow-down the shutter speed). The classic cinematic look would require 1/60 @ 30fps for that look.

But if you want the sharper video, the more realistic look, then yes: you want a faster shutter speed. And faster FPS as well. In that case, an ND filter can be a hindrance (depending on the lighting).

Chris

Thanks, I should have stated the ND filter is only to ensure I don't blow out highlights. Another question.....as I keep upping the shutter speed and opening the aperture or reducing the ND filter strength, what will the video result be?

 

[brett8883]

Thanks, I should have stated the ND filter is only to ensure I don't blow out highlights. Another question.....as I keep upping the shutter speed and opening the aperture or reducing the ND filter strength, what will the video result be?

So this is a real variable ND filter or are we talking about a graduated filter here?

 

[Not A Speck Of Cereal]

Thanks, I should have stated the ND filter is only to ensure I don't blow out highlights.

So that's not really what an ND filter is for. It reduces light, but not just the bright parts -- it reduces ALL light (highlights and shadows). You can do the same thing with basic exposure adjustments: if you have blowouts (see the zebra stripes), reduce exposure, which could be just dialing down the exposure compensation.

An ND filter does exactly the same thing. The reason for using an ND filter is to reduce the shutter speed, but still have the SAME exposure as you would have without the ND filter. That's all it does.

Another question.....as I keep upping the shutter speed and opening the aperture or reducing the ND filter strength, what will the video result be?

Each frame will be a little sharper.

Chris

 

[EricJT]

So this is a real variable ND filter or are we talking about a graduated filter here?

I have the Freewell Vaiable ND filters.....they work well.

 

[brett8883]

I have the Freewell Vaiable ND filters.....they work well.

That’s kewl. Then yea to make video sharper you would increase the frame rate not just the shutter speed. ND filters are for making movement look less choppy and more fluid.

You can’t look at video like still photos. It just doesn’t work like that our brains don’t see individual frames so there’s more to it then making the frames sharper.

 

[Dave Maine]

Higher shutter speed is always going to create sharper images. Once you decide to get rid of motion blur, there is nothing keeping you from going to your drone’s maximum shutter speed. You don’t need the ND filter at all. All it does is give you a lower shutter speed, and 2 more glass surfaces which will inevitably reduce slightly the image sharpness.

 

[xspwhite]

The ND filter goes on in place of the glass cover, so you won't have two pieces of glass, but just one.

 

[Not A Speck Of Cereal]

Also, if you are going to use an ND filter (with an important addition for EricJT below in the last bullet item):

• My comments about what an ND filter above is for a normal ND filter (not graduated)
• Just a minor technicality: A normal ND filter does not "lower shutter speed". It's best to think of what it actually does, which is "reduce transmission of light through lens". That MAY mean that you lower shutter speed (which is the main intent for video), but of course you could always compensate with aperture and/or ISO
• If you are going to use a normal (not graduated) ND filter, the variable filters are the lowest quality. If they work fine for you, that's cool. But if you want better optics, don't use variable.
• Variable ND filters aren't really saving you that much time. To adjust it, you still have to bring the AC down to you, just as you would have to do to exchange non-variable ND filters.
• CONTROLLING BLOWN SKY: As I said in an above post, a normal (not graduated) ND filter will not help with that. However, a graduated filter will help with this, because it's only reducing light on the top half, allowing you to lower light for the sky, without dropping the foreground light into the shadows. I should have realized and mentioned that earlier, sorry. But note that this is mostly for STILL photography, not video, unless you shoot video without moving the lens around. Because moving the lens with a graduated filter on is going to look silly.

If someone still doesn't understand why one would use an ND filter for matching a slow shutter-speed with the proper frame rate, speak up and someone will post a tutorial. And if you're not trying to achieve that cinematic goal in video, why you should just take your ND filters off for video.

Chris

 

[Dave Maine]

Not if it is a clip on which many people use.

 

[EricJT]

Not if it is a clip on which many people use.

I assume you mean like the Mavic 2 Pro ND filters that you push in and twist on clockwise?