ND filter experts wanted

[olof Ekbergh]

I have used ND8 and it looks like it should be ND16 so the green sugarbeet has all the color, now it has like water shine white on it from the above and I cannot get anything from it in post. I manage to get rid of the gray in post by increasing contrast. And it looks good for low fly video here but from the above the video simply does not have color, it is too bright I guess.

I dont get you guys who say that you work in manual mode and then you say that you change the exposure. I cannot change exposure in manual mode, only in Auto.

So when you go in manual mode you change ISO in order to get the EV to 0 ?

When in manual mode, you use iso or shutter speed (as well as ND filter before takeoff) to set your exposure according to the histogram and the way the monitor looks. This is done using the right wheel on the TX. By turning it you increase or decrease iso or shutter speed, by pushing down on the wheel you switch witch one is effected by the wheel. It is crude but it works well.

So before takeoff you decide on what ND filter to use (if any) then set exposure using histogram and it will stay set, the EV is not used in manual mode at all.

If you notice that the histogram looks wrong when flying, just adjust the shutter speed so it looks right, picking the right ND filter usually makes it possible to shoot 1/60, 1/80 or 1/100 shutter and get correct exposure for 30p. If out of that range land and change to a different ND, or remove it if it is too dark.

This is a not as nice as a real video camera with built in ND's and variable aperture but it works well enough. In the future we may see continuously variable ND filters like in the Sony FS5, that would be a very nice solution for MR's. This is a electronically variable ND not the dual polarizer type that is very problematic for several reasons, one being vibration that could cause it to change while flying. But some have reported using them successfully here and on other boards. I think the added weight is also a problem for the gimbal on the P3P's.

 

[Karanba]

I have realised that in Manual mode I can brighten the video with ISO and darken with shutter speed. I thought that I must stay on 1/60 for 30fps and then I got EV +1.0 or more sometimes and that is why my videos went too bright and lost color.

Which does more for quality, increased ISO from 100 to max 400 or increasing shutter speed from 1/60 to max 1/100 ?

I am thinking to put darker ND filter like ND16, I can then easily come to EV 0 from minus EV with increasing ISO. Or go with ND8 and darken the video with shutter speed increase.

Which one should look better ? Just in case I need to decide in the air. Or go wIth Auto and put ND16 or something which will give good EV. In Auto is says 8" for shutter speed, what is that ?

 

[olof Ekbergh]

I have realised that in Manual mode I can brighten the video with ISO and darken with shutter speed. I thought that I must stay on 1/60 for 30fps and then I got EV +1.0 or more sometimes and that is why my videos went too bright and lost color.

Which does more for quality, increased ISO from 100 to max 400 or increasing shutter speed from 1/60 to max 1/100 ?

I am thinking to put darker ND filter like ND16, I can then easily come to EV 0 from minus EV with increasing ISO. Or go with ND8 and darken the video with shutter speed increase.

Which one should look better ? Just in case I need to decide in the air. Or go wIth Auto and put ND16 or something which will give good EV. In Auto is says 8" for shutter speed, what is that ?

You should always try to keep iso as low as possible, increasing iso will add noise (or grain as it is sometimes referred as). If the ND8 still has you at a 1/250 shutter speed then go to ND16.

As long as you do not fly very fast close to objects or pan quickly upping the shutter speed is OK but I try not to go above 1/100 for 30P video. It will cause the "Private Ryan" effect very stroby jarring effect.

The best thing is just experiment try different settings and see what you like best. IMHO the framing and subject are really the most important, and being very smooth with all your moves.

Just go out and play with different settings, you will figure it out.

Fly safe and have fun...

 

[snerd]

The histogram is invaluable to get a good exposure. Learn how to use it to get it right. Try to get it as spread out as possible, with it not bunched to either side.

That's a very basic lesson, but a start. Exposure is ISO, Shutter Speed and Aperture. We can't control the Aperture on the drone camera, so yes, you adjust the ISO and Shutter Speed to get a good histogram and better video.

 

[snerd]

Here are some bad histograms.

 

[Karanba]

Thanks guys, I will try to use it but I dont have the time to do it on every flight coz I am recording working machines. I will try ND16 and then put it on Auto and see what it says, then go back to Manual and tune it with ISO and shutter, I thought that shutter must be fixed all the time to 2xfps and now I see that I can go to 1/80 or 1/100 max if needed and the video will still look great.

 

[dmark1867]

In snerds post the top histogram is good, the other 2 are bad.

I use gel ND filters and use this to adjust my exposure (go to 54 seconds)

I have found that for me personally what works best is to put everything in manual, figure out what ND filter I need.
Then I switch it back to auto. When flying I would rather just focus on flying.

And when doing reveals etc the lighting can change so quickly I personally feel I get better results using auto then me trying to constantly adjust.

Also this video I did

If you go to 1:31 and watch the drone fly around the pier, see how much the lighting changes.
(Please disregard the macro-blocking/pixelation, another topic)

If I were shooting in manual I do not think the shot would had been usable.

Further it was an automated flight using litchi and my tablet rebooted mid-flight and would and I had no screen to look at to make the adjustments.

So for me this is what works best.