Set me straight - ND Filters

[Texbow]

If my normal setting is an aperture of F4 on a sunny day and I place a ND 8 PL filter on my lens, as a general rule should I change my aperture setting to F-2 due to the ND 8 PL's filters impact to the filming?

 

[CanadaDrone]

There are no rules, it is entirely dependent on each individual scenario. A ND8 at F4 is the same exposure as a ND16 at F2.8 which his the same exposure as a ND32 at F2.0. You cannot select F2.0 though at all, the maximum aperture is F2.8.

Assuming you want the shutter speed to be 1/60 (double the frame rate) you use whatever ND filter you need to in order to get the shutter speed to 1/60 relative to the scene brightness, your ISO (always leave this at 100) and your chosen aperture.

Also you should not really be using PL filters for generic flying, you need carefully planned flight paths without any deviation relative to the angle to the sun unless you want uneven footage.

PL's have no effect on aperture whatsoever, they are entirely separate. You don't change your aperture because you are using a NDPL. A NDPL8 is going to reduce the light hitting your sensor by 3 stops regardless of the fact that its polarized. The problem with polarized filters on drones is that the level of polarization cannot be adjusted in the air so you get uneven footage anytime you change the drone's angle to the sun, which will pretty well be any movement deviating from a carefully planned straight line. A NDPL is generally not a filter you want to leave on all the time like you can with a normal ND filter.

 

[Thomas B]

Texbow said:
“If my normal setting is an aperture of F4 on a sunny day and I place a ND 8 PL filter on my lens, as a general rule should I change my aperture setting to F-2 due to the ND 8 PL's filters impact to the filming?”

Not exactly... put on the filter. After the aircraft and controller are on set ISO to 100 and shutter to 30/sec. Look at your screen image. If you like it, cool. If not either change the filter, remove the filter, or consider the other 2 adjustments. The settings given will induce a little motion blur... like you see things in movies or on TV. Play with it from there. In PHX I usually start with an ND16 filter and sometimes use ND 32 except when very early or very late. Still images will have motion blur at these settings, so you may have to adjust shutter speed to 1/60 or above. The filters let you expose longer.

With polarizing be sure to rotate it while looking through it so you know the position for best light transmission before installing it. Unless I’m imagining a body of water I don’t use then. With water they drastically reduce surface reflection so you can see into the water,

Hope this helps. See below:

 

[afarkas]

F4 alone does not mean anything. Is it F4 at what ISO and what shutterspeed?
If you put an ND filter, you does not need to decrease the apperture... You can decrease the shutterspeed, or decrease the ISO as well
Its a relation between those factors, not one factor alone

 

[Texbow]

There are no rules, it is entirely dependent on each individual scenario. A ND8 at F4 is the same exposure as a ND16 at F2.8 which his the same exposure as a ND32 at F2.0. You cannot select F2.0 though at all, the maximum aperture is F2.8.

Assuming you want the shutter speed to be 1/60 (double the frame rate) you use whatever ND filter you need to in order to get the shutter speed to 1/60 relative to the scene brightness, your ISO (always leave this at 100) and your chosen aperture.

Also you should not really be using PL filters for generic flying, you need carefully planned flight paths without any deviation relative to the angle to the sun unless you want uneven footage.

PL's have no effect on aperture whatsoever, they are entirely separate. You don't change your aperture because you are using a NDPL. A NDPL8 is going to reduce the light hitting your sensor by 3 stops regardless of the fact that its polarized. The problem with polarized filters on drones is that the level of polarization cannot be adjusted in the air so you get uneven footage anytime you change the drone's angle to the sun, which will pretty well be any movement deviating from a carefully planned straight line. A NDPL is generally not a filter you want to leave on all the time like you can with a normal ND filter.

Thank you for the info. I'm new at this and have noticed without and with filter comparative videos. It seems that those using filters get a more pleasing video with less glare and richer color (filiming over a beach or lake as an example). My hope (maybe unrealistic) is that I could find a general purpose setting with a filter that may not be perfect in all cases but still in the majority of the time improve my videos. I may get there but for now I do not see myself getting advanced enough to analyze ideal lighting conditions for each filming. Maybe the answer is a ND without PL or no filter at all. Still learning.

 

[Texbow]

Thomas, Thank you. This is a big help.

Texbow said:
“If my normal setting is an aperture of F4 on a sunny day and I place a ND 8 PL filter on my lens, as a general rule should I change my aperture setting to F-2 due to the ND 8 PL's filters impact to the filming?”

Not exactly... put on the filter. After the aircraft and controller are on set ISO to 100 and shutter to 30/sec. Look at your screen image. If you like it, cool. If not either change the filter, remove the filter, or consider the other 2 adjustments. The settings given will induce a little motion blur... like you see things in movies or on TV. Play with it from there. In PHX I usually start with an ND16 filter and sometimes use ND 32 except when very early or very late. Still images will have motion blur at these settings, so you may have to adjust shutter speed to 1/60 or above. The filters let you expose longer.

With polarizing be sure to rotate it while looking through it so you know the position for best light transmission before installing it. Unless I’m imagining a body of water I don’t use then. With water they drastically reduce surface reflection so you can see into the water,

Hope this helps. See below:View attachment 63692View attachment 63693

 

[Thomas B]

Thomas, Thank you. This is a big help.

Welcome. Also check out some YouTube videos on it, especially if you’re a visual learner. The name of one is on the bottom of one of the images in my post. Look at others too. You’ll see small variations. And a few that are very different. PolarPro has s good video series about ND as well as NDPL filters on their website.

 

[Mossiback]

For the Mavic Pro: A "general rule" regarding video; ND4 for low-light (sunrise/set), ND8 for cloudy days, and ND16 for sunny days. ND32 or 64 may be needed for bright sand or snow.

For a picture you want a fast shutter speed to freeze motion. You would use a ND filter if you wanted motion blur (moving water, traffic, etc) or a ND polarizing filter to reduce reflections and increase saturation.

 

[russellg]

I use a ND4 on cloudy days, ND8 on partial cloudy, and ND16 on sunny days and I let the camera do all the thinking. My videos look pretty good (at least to me they do). I ordered an ND 32 and ND64 just to experiment with, I need some decent weather to do more testing, like Sunny warm days not these cold rainy days they have been the norm lately.

 

[MGVision]

I use a ND4 on cloudy days, ND8 on partial cloudy, and ND16 on sunny days and I let the camera do all the thinking. My videos look pretty good (at least to me they do). I ordered an ND 32 and ND64 just to experiment with, I need some decent weather to do more testing, like Sunny warm days not these cold rainy days they have been the norm lately.

Really want to know if you will ever need ND32 on extremely bright sunny day with no clouds.
I bought single ND16 freewell filter, hope it will do the trick.

 

[kilomikebravo]

macius: I live in South Texas and the sun can get mighty bright down here. Consequently, on a day like you described, I would put an ND16 on the camera and then with the aircraft on the ground and stationary, I set the shutter speed appropriately for the frame rate I plan to use and then I begin tweaking the aperture. If I can't use f4 due to overexposure, I get out the ND32. I would estimate that I use the ND32 80 percent of the time in the summer so I consider that one to be as necessary as ND8 and ND16. As you have no doubt read, ND filters are not necessary for photos unless you want to do long-exposure photography. Otherwise, you simply increase the shutter speed at f4 for stills.

 

[CanadaDrone]

Just be careful coming up with a "rule". As I said earlier, it depends on so many factors that there is no catch-all. Changing aperture, ISO, or shutter speed can also completely alter what ND filter you need even if the conditions are identical. Selecting a ND filter based on conditions is something you can do quickly and easily before flying, and it will be the correct one every time. If you just blindly throw on a ND8 because that's what you did last time, you might end up having to bring the drone home to swap it. The nice thing about the M2P at least is the variable aperture gives you one full ND filter step worth of leeway on both sides of the exposure if you shoot in F4 without affecting the image too much.

 

[Cymruflyer]

F4 alone does not mean anything. Is it F4 at what ISO and what shutterspeed?
If you put an ND filter, you does not need to decrease the apperture... You can decrease the shutterspeed, or decrease the ISO as well
Its a relation between those factors, not one factor alone

I think you mean to Increase the ISO. Decreasing it would make things even darker.

 

[Cymruflyer]

Thank you for the info. I'm new at this and have noticed without and with filter comparative videos. It seems that those using filters get a more pleasing video with less glare and richer color (filiming over a beach or lake as an example). My hope (maybe unrealistic) is that I could find a general purpose setting with a filter that may not be perfect in all cases but still in the majority of the time improve my videos. I may get there but for now I do not see myself getting advanced enough to analyze ideal lighting conditions for each filming. Maybe the answer is a ND without PL or no filter at all. Still learning.

When you see those great videos, they are not as a sole result of the filter they are using. A filter may help but it they were shooting in RAW, or D-cine, they would still need to do post as in colour correction. That is what helps the most to get good looking footage, but doing colour correction only if you know what you are doing. Because Like HDR settings, there are some people who know what they are doing and others who just hear HDR and then way over saturate their colours making it look so unreal it begins to turn ugly.

As in HDR, colour correction and filter choice and settings, there is no "One Setting Works For All" otherwise we would all have fantastic looking photos and videos.

 

[CanadaDrone]

I think you mean to Increase the ISO. Decreasing it would make things even darker.

I think he just means that putting on a ND filter is only one small part of the exposure equation. You can change ISO, Shutter speed, and aperture regardless of what ND filter you're using and get dramatically different results. Put another way, the ND filter in no way determines what individual settings you need to use. They are separate, but work together. You would never want to put too much ND filter on, to the point where you had to increase ISO or lower the shutter speed below 1/60 to compensate.

I think the most important thing for people to do is determine is the settings they want to use BEFORE selecting a ND filter, and then you don't have to worry about any of that. Ideal settings are fairly constant - for example I know beforehand that I always want to fly at F4, ISO100, and 1/60 shutter. Leave those settings alone, and select the ND filter accordingly, based on scene conditions.

You don't want to come at it backwards, for example, you don't want to put on a ND8 just because, and then fiddle with settings to get a correct exposure after the fact, which will almost certainly be less than ideal.

 

[paulatkin73]

Really want to know if you will ever need ND32 on extremely bright sunny day with no clouds.
I bought single ND16 freewell filter, hope it will do the trick.

well, for winter days with a lot of snow nd32 works better. if you use M2P you have way more freedom as you have an adjustable aperture and any aperture from wide open - 2.8 down to F6.3 is sharp and usable. sharpest one is F4. F8 and smaller apertures will reduce sharpness, so, 6.3 or 7.1 is really an aperture limit that provides best image.

for most sunny days a ND16 filter in combination with F4 aperture works just fine on 1/60 shutter. so, you set your video to 4K30 mode, switch to manual and set F4 with 1/60 and fly. in most scenarios it produces better image compared to shutter mode as in latter it will play with aperture to adjust the brightness - you can also do that, but it may produce a situation where it will be noticably unpleasant to see your clip getting darker and brighter and so forth as it will be continuously flipping aperture up and down.

so, realistically, a minimum of filters you need are ND4 and ND16. then you will have options to set either 4K30 or 4K24 mode, setting shutter to 1/50 or 1/60 and playing with aperture from F2.8 to F7 you can accommodate almost any lighting situation.

keep iso at 100.

also, i do not promote them in any way, but i have now filters from 3 different brands and this f.stop also seems to be OK. it mounts a bit tighter than tiffen, but seems to be an OK quality. you can try that if you do not want to spend $150 for best ones.

https://www.amazon.com/Fstop-Labs-M...23ZCWDCES8W&psc=1&refRID=MAHP4NJDV23ZCWDCES8W

 

[Texbow]

I think he just means that putting on a ND filter is only one small part of the exposure equation. You can change ISO, Shutter speed, and aperture regardless of what ND filter you're using and get dramatically different results. Put another way, the ND filter in no way determines what individual settings you need to use. They are separate, but work together. You would never want to put too much ND filter on, to the point where you had to increase ISO or lower the shutter speed below 1/60 to compensate.

I think the most important thing for people to do is determine is the settings they want to use BEFORE selecting a ND filter, and then you don't have to worry about any of that. Ideal settings are fairly constant - for example I know beforehand that I always want to fly at F4, ISO100, and 1/60 shutter. Leave those settings alone, and select the ND filter accordingly, based on scene conditions.

You don't want to come at it backwards, for example, you don't want to put on a ND8 just because, and then fiddle with settings to get a correct exposure after the fact, which will almost certainly be less than ideal.

Really appreciate your feedback and this was most helpful. I do understand that those great images and videos are a result of post production edits in LR and other software. I expect that I may get to the level of effort at some point but for now your point about just leaving my settings alone and testing the impact of the filter is what I needed to hear. I like the footage I'm getting without the filter (just returned from the Amazon) but have plans to use the drone in Fort Lauderdale in a few weeks and with so much water I'm curious about using a ND PL filter to help with the water glare. Thanks again for your input.

 

[Texbow]

well, for winter days with a lot of snow nd32 works better. if you use M2P you have way more freedom as you have an adjustable aperture and any aperture from wide open - 2.8 down to F6.3 is sharp and usable. sharpest one is F4. F8 and smaller apertures will reduce sharpness, so, 6.3 or 7.1 is really an aperture limit that provides best image.

for most sunny days a ND16 filter in combination with F4 aperture works just fine on 1/60 shutter. so, you set your video to 4K30 mode, switch to manual and set F4 with 1/60 and fly. in most scenarios it produces better image compared to shutter mode as in latter it will play with aperture to adjust the brightness - you can also do that, but it may produce a situation where it will be noticably unpleasant to see your clip getting darker and brighter and so forth as it will be continuously flipping aperture up and down.

so, realistically, a minimum of filters you need are ND4 and ND16. then you will have options to set either 4K30 or 4K24 mode, setting shutter to 1/50 or 1/60 and playing with aperture from F2.8 to F7 you can accommodate almost any lighting situation.

keep iso at 100.

also, i do not promote them in any way, but i have now filters from 3 different brands and this f.stop also seems to be OK. it mounts a bit tighter than tiffen, but seems to be an OK quality. you can try that if you do not want to spend $150 for best ones.

https://www.amazon.com/Fstop-Labs-M...23ZCWDCES8W&psc=1&refRID=MAHP4NJDV23ZCWDCES8W

Thanks very much Paul. Your explanation is very helpful. The light bulb is starting to come on.

 

[paulatkin73]

Really appreciate your feedback and this was most helpful. I do understand that those great images and videos are a result of post production edits in LR and other software. I expect that I may get to the level of effort at some point but for now your point about just leaving my settings alone and testing the impact of the filter is what I needed to hear. I like the footage I'm getting without the filter (just returned from the Amazon) but have plans to use the drone in Fort Lauderdale in a few weeks and with so much water I'm curious about using a ND PL filter to help with the water glare. Thanks again for your input.

make sure you set video format to dlog-m 10bit. that will give you 12 stops of the dynamic range and will allow to correct exposure, to some limit, in the post processing - same way as with DNG files. 8bit color is less forgiving and will require more accurate exposure set.

 

[BlueRidge]

PolarPro makes a free app that will calculate the weather, your shutter speed, and tell you which ND filter to use or to not use one at all. It's pretty cool with weather, sunrise, sunset, KP index, and other useful info...