The Mechanics of MP Video Settings - all you need to know...

[Dr Dave]

After making a recent query to this forum, I went through the machinations of attempting to understand video setting with the Mavic Pro. You see, it's not enough to be simply able to fly the Mavic - if you want to capture footage - or take pictures - you need to know a little something about photography. I think I've got it figured out and wanted to share - no need for other Noobs to reinvent the wheel, ok?

First - a disclaimer: I am a noob here, but I do have some amateur photography experience - and I do have a relative who is a professional photographer and much of what I will state here has been vetted through him.

THE ESSENTIALS

Back in the days of emulsion based photography, you typically had 3 settings to consider:

• Film speed (ASA or ISO) - a higher ASA or ISO means the film is more sensitive to light which has a number of ramifications. Say for example, in low light settings, you might need a fast film (high ASA/ISO) to take a shot.
  • A higher ASA/ISO typically resulted in a more "grainy" image
  • In digital photography, the sensor plate is the equivalent to the film emulsion, but can be dynamically adjusted rather than replacing a roll of film.

• Shutter Speed - how much time the film is exposed, typically as a fraction of a second.

• Aperture - a diaphragm which determines how much light hits the film. You will hear terms like "f/16" or "f/8". The higher the "f" setting - or "f" stop - the smaller the diaphragm and the less the light at any given exposure. The "f" stop settings can go from f/22 (smallest opening) to f/1.4 (largest opening).

• The "f" stop settings are 22,16,11,8, 5.6, 4, 2.8, 2, 1.4
• From one "f" setting to the next, the amount of light doubles going (ex from 16 to 11) or is halved (from 11 to 16).
• "f" stop determines relative "depth of field". That is, how far can the camera resolve anything in front or behind the focused image. For example, when taking a picture of a subject in front of a scenic view, you would want to take the shot at a high "f" setting because depth of field is at infinity. A low "f" setting would have the subject in focus, but the scene behind would be blurred.
• A low "f" setting means that the camera is "fast", meaning that at basic daylight, a fast shutter speed will be required.

THE MAVIC PRO VIDEO CAMERA

These 3 settings still apply to the Mavic Pro as it relates to video camera but with one exception - and that is that the aperture is fixed at f/2.2. So there are only 2 other settings to manipulate (actually there are 3...sorry): shutter speed and ASA.

However, with video camera, you have one other factor - how fast the frames are shot - frames per second - or FPS. Depending on who you listen to, most DJI authorities seem to think that somewhere between 24 and 30 FPS is an ideal setting - you may need it faster or slower depending on circumstance, but 30 seems to be the sweet spot.

Your FPS setting helps to determine shutter speed, and there's a rule that your shutter speed should be twice your FPS, that is for 30 FPS, your shutter speed should be 1/60th of a second.

Now how do you determine ISO?

BASIC DAYLIGHT EXPOSURE

Professional photographers use a rule of thumb called the "Basic Daylight Exposure Guide". What this means that at basic daylight (a sunny day without clouds) it has been determined that:

At F/16, an image will be properly exposed with a shutter speed of 1/ISO
​

So, back to the Mavic Pro, if you have 30 FPS, your shutter speed is set at 1/60, on a day that has basic sunlight (sunny day without clouds), your ISO should be set at 60.

But there's a catch - and the catch is that the Mavic Pro has a fixed aperture at f/2.2. The distance between one "f" setting and another is called an f-stop. The distance from f/2.2 to f/16 is approximately 5.5 f-stops. The importance is that in order to properly set the exposure of the video, you must drop either the aperture (remember it's fixed) or the ISO (there's not too many to drop below 60).

So how do you address this problem?

ND FILTERS

This is why God created ND (neutral density) filters for the Mavic Pro - and you will notice they come as a set of filters anywhere from ND 4 to ND 32 - with ND4 correlating with 2 f-stop ND to 5 f-stop ND reduction accordingly. These filters - some of which are polarizing - reduce the amount of light from 2 to 5 f-stops reaching the electronic optical sensor. And note again - there is a method to the madness - it is not by chance that the greatest ND reduction is 5 f-stops. It almost appears to be done by design!

But here's the wonderful thing about the Basic Daylight Exposure - it applies at any given shutter speed or FPS - that is, at 24 FPS, your shutter speed would be set at 1/50, your ISO at 50, and you're still 5 f-stops over exposed for basic daylight exposure - or +5 BDE. What this means is that your set of ND filters can be universally applied according to the same rules at any FPS.

Here is a link to an explanation of Basic Daylight Exposure. If for example your were to be out on a cloudy day, you might drop your F stop settings to something less than 5, say ND 16, or 3 f-stop adjustments.

Kapish?

One other suggestion - when in doubt, underexpose rather than overexpose.

Hope this helps. Maybe make this a sticky - but that's up to ya'll.

Cheers!

DrD

 

[rockydog]

Your statement regarding f-stops and depth of field is back to front. A low f-stop, say f2, will give a shallow depth of field, and f16 will give a much greater depth of field. The reason that the Mavic has a large depth of field at f2.2 is because of the small sensor size used.

 

[Dr Dave]

Your statement regarding f-stops and depth of field is back to front. A low f-stop, say f2, will give a shallow depth of field, and f16 will give a much greater depth of field. The reason that the Mavic has a large depth of field at f2.2 is because of the small sensor size used.

You're right - I stand corrected. It is interesting that a large aperture setting as related to depth of field can be corrected by a smaller sensor. Never knew that.

My relative - the professional photographer - told me that the reason for a fixed aperture is because having it variable would add more weight. So having only 1 aperture coupled with a smaller sensor seems to be a feat of intentional engineering to minimize footprint.

What can you say - it's very well designed.

Cheers,

David

 

[Riblit]

Good explanation.
One point. ND is Neutral Density, not Normal Daylight.

24 fps comes from film type movies cameras. The shutter on these cameras rotated and opened for half a revolution.
See here for more detail and some pics.

30 fps is associated with the NTSC television standard, I won't go into why as there is a bit of maths involved and it's Sunday. Needless to say, in these days of Digital TV and progressive scan its irrelevant.

 

[CashCache]

Thanks for the detailed explanation. I spent a lot of time on this when I first got my Mavic since I was never into photography prior. The article below is what finally made it click for me.

Neutral Density or ND Filters Explained explained | Tutorial

 

[Dr Dave]

Good explanation.
One point. ND is Neutral Density, not Normal Daylight.

24 fps comes from film type movies cameras. The shutter on these cameras rotated and opened for half a revolution.
See here for more detail and some pics.

30 fps is associated with the NTSC television standard, I won't go into why as there is a bit of maths involved and it's Sunday. Needless to say, in these days of Digital TV and progressive scan its irrelevant.

Picky, picky, picky ...lol...jk

Thanks for the info - post is updated.

Cheers!

 

[Miro_vg]

Hello can anyone tell me why my shutter speed is always in red colour on video or pictures is always red