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ND Filter meter App?

JayTea26

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Can you recommend an IOS App in which I can just point my iPhone at the sky and determine appropriate ND filter for various frames and shutter speed. I'm getting tired of trying to select filter via trial and error.
 
It’s a good idea.

For me - I set my exposure on the ground first. Pointing the Drone in the direction of my shot let’s say. That way I can change filters before I launch,

Secondly this hard and fast rule of exactly double shutter speed to frame rate is overstated. All we are trying to do with ND filters is give a natural motion blur. Yet say you are shooting at 25fps and a decent exposure is at 1/80s shutter speed. Yes it’s not double exactly, but it still has a very good natural motion blur, with that in mind. These days I can pretty much guess ND filters spot on beforehand,

Whilst aiming for the 180°shutter rule, I’m happy a little bit either side, Note in bright conditions I also am happy to bump ISO up to say 200/400 (so leaning towards a stronger ND if unsure). In low light though I will forego motion blur for less noise, and lean the other way.

So with that in mind I have in my mind a set of conditions I’ve become pretty good at judging.
-Super sunny high noon bright scene ND32 (snow, highly reflective ocean)
-Sunny bright cloudless day ND16
-bit of cloud cover shot away from sun, bright early in sunsets & sunrises ND8
-cloudy overcast midday, later in sunsets/sunrises and/or with a touch of cloud. ND4 to nothing
-low lighting no ND ever we do not want noise

I’d imagine after using your app You will become adept at judging it by eye anyways after awhile too. That would speed up the learning process.

I think the main takeaway with ND & video is that especially in really bright scenes your motion blur will be super unnatural. These are the conditions in which the ND is super beneficial. Lower light you can get away with it more and not being perfect but pretty close will be barely perceptible anyways. Experiment for yourself see if you can tell between say a perfect 180° shutter rule shot and one that is just a couple of stops away.

My post was all about video but the same basically applies for adding motion blur in photos with ND filters. If you can guess to get around the 180° rule then add subtract filter strength accordingly.
 
Thank you very much for the detailed reply. Exactly what I needed.

In fact, I took a screenshot of it for my future quick reference.

Just one question...do you point the drone lens at the sky only and use the over exposure bars to judge exposure?
 
Thank you very much for the detailed reply. Exactly what I needed.

In fact, I took a screenshot of it for my future quick reference.

Just one question...do you point the drone lens at the sky only and use the over exposure bars to judge exposure?

I basically frame the shot as per what I think I’ll be shooting,

For example, if it’s a top down, then I’ll hold the drone and point camera down having mainly the ground in frame.

If I’m doing say a half sky half land I will set it up accordingly.

You would also consider am i shooting into the sun, with it behind, to the side, etc. the reality hard one is say a long pan that has the light coming from different angles.

Mind you I can pretty much eyeball how much filter is needed now. I did it like a guessing game before I even got the drone out for a little while by challenging myself and thinking about it regularly I got good at guessing quickly, I also do the same for all my cameras. Mind you they are more forgiving with aperture not being fixed.
 
Can you recommend an IOS App in which I can just point my iPhone at the sky and determine appropriate ND filter for various frames and shutter speed. I'm getting tired of trying to select filter via trial and error.

I use My Lightmeter Pro. Set it at f/2.8, ISO 100 and let it tell you the suggested shutter speed. Then determine how many stops of filter you need to put the shutter speed where you want it with the same EV. I.e., if it suggests a 1/1000 shutter speed and you want 1/60, you need a 4 stop filter. (1000 - 500 - 250 - 125 - 60 = 4 stops)
 
You should minimize ISO, ie keep it at 100 if possible. Even the M2P with the best sensor still has a lot of noise If you up ISO. You can reduce the aperture (increase the number) to 5.6 then as said above, add the ND filter as needed. If u get in the air & feel that everything is overexposed (use the histogram) then double the shutter speed. U can always add motion blur in post.
 
One can carry a small 18% gray card and use it as the target to measure the lighting brightness in front of the camera while on the ground. Then as above calculate the number of stops needed to reduce shutter speed. This can also be done on the MP 2 to select the ND needed to achieve an exposure with the desired f stop and shutter combo. And yes strive to keep the iso to 100.
 
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Both you guys are right on ISO however. It’s also important to understand that tis is more important in low light.
Darker images reveal more noise.

ISO is sensor amplification in a simple sense. A great analogy is say a digital audio recording device with a microphone.

If the sounds you are recording are really quiet (dark images/low light) you need to turn up the gain (iso). In doing so you start to hear the hum of noise soundfloor gets raised. And that is all the noise is on a digital camera too. It’s the amplification of te sensor so that you see te raised soundfloor.
With that in mind in dark areas (quiet) it’s easier to see (hear) the noise then light areas,

So with that in mind. If you are in flight on a good light scene and getting perfect exposure requires a bump up in ISO 200 is fine in good light. it’s so much easier then landing and changing a ND filter. Same with adding a touch more or less shutter speed.

It frustrates me all around the internet that the 180° Shutter rule has to be stuck too religiously. I urge people to experiment or themselves try an ISO bump a not quite 180° shutter angle. I can make a blind test video I reckon, see if you guys can tell which is which.

In the end the story, the actual scene, the feeling, is first & foremost.

And yes with these small sensors always try and keep the iso as low as possible. Lol.
 
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Depending on the kind of flying you are doing, motion blur is rarely an issue. It matters only when there are very rapid changes in the frame which can cause visible strobing, which is very annoying. For the kind of flying I normally do, I set the ISO at 100, and adjust the shutter speed to get the correct exposure. Often the shutter speed goes above 1/1000 sec. The images are very clear, as the high shutter speed completely stops any movement.

If you are flying 10 feet or lower to the ground, or flying with the camera pointed sideways at high speeds or similar situations, strobing may be a problem.
 
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It’s a good idea.

For me - I set my exposure on the ground first. Pointing the Drone in the direction of my shot let’s say. That way I can change filters before I launch,

Secondly this hard and fast rule of exactly double shutter speed to frame rate is overstated. All we are trying to do with ND filters is give a natural motion blur. Yet say you are shooting at 25fps and a decent exposure is at 1/80s shutter speed. Yes it’s not double exactly, but it still has a very good natural motion blur, with that in mind. These days I can pretty much guess ND filters spot on beforehand,

Whilst aiming for the 180°shutter rule, I’m happy a little bit either side, Note in bright conditions I also am happy to bump ISO up to say 200/400 (so leaning towards a stronger ND if unsure). In low light though I will forego motion blur for less noise, and lean the other way.

So with that in mind I have in my mind a set of conditions I’ve become pretty good at judging.
-Super sunny high noon bright scene ND32 (snow, highly reflective ocean)
-Sunny bright cloudless day ND16
-bit of cloud cover shot away from sun, bright early in sunsets & sunrises ND8
-cloudy overcast midday, later in sunsets/sunrises and/or with a touch of cloud. ND4 to nothing
-low lighting no ND ever we do not want noise

I’d imagine after using your app You will become adept at judging it by eye anyways after awhile too. That would speed up the learning process.

I think the main takeaway with ND & video is that especially in really bright scenes your motion blur will be super unnatural. These are the conditions in which the ND is super beneficial. Lower light you can get away with it more and not being perfect but pretty close will be barely perceptible anyways. Experiment for yourself see if you can tell between say a perfect 180° shutter rule shot and one that is just a couple of stops away.

My post was all about video but the same basically applies for adding motion blur in photos with ND filters. If you can guess to get around the 180° rule then add subtract filter strength accordingly.
Terrific information, thanks for taking the time to lay it all out.
 
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