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Filter query - PL or not?

metaphase

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Been looking at getting filters for my MA - have found plenty of threads debating the relative merits of the different manufacturers (so won't open that hornet's nest!) but am keen to get a feel which type folks find they use most?

Each manufacturer has different packs and I'm trying to avoid getting a whole lot of filters I don't then use - I was thinking ND/PL 8+16+32 seem a reasonable combo but was wondering if there was any reason to not get the PL versions and instead go for the straight NDs? (obviously I could spend more and get them both, but I'm trying to avoid unnecessary spend!)

My thinking was that the PLs could be adjusted to either be cutting down reflections or not, if set to the latter then are they much different from an equivalent straight ND, however I'm wondering if that then gives any problems when, for example, moving around a subject in a circle? I'm used to the concept of PL filters, but more from the DSLR world so interested what issues folks have found when using on a drone.

Thanks :)
 

gnirtS

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PLs are only useful if you adjust it preflight and film from *exactly* the same camera to subject angle in the air. Therefore, only really useful for photos.
They cause issues in video with varying exposure as the camera turns around, light and dark patches of sky and so on.

Also, if you're going to be taking 360s or panoramas you definitely dont want a polariser on.

I'd get a set of NDs that aren't polarised for video and a single polariser that isnt ND in case you want to take still photos utilising it.
 
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CanadaDrone

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PLs are only useful if you adjust it preflight and film from *exactly* the same camera to subject angle in the air. Therefore, only really useful for photos.

I'd get a set of NDs that aren't polarised for video and a single polariser that isnt ND in case you want to take still photos utilising it.
This is not true - they can be very useful for video, and lots of drone pilots use them successfully for video. You just need to have your flight path planned out beforehand and do the video pass without changing your angle to the sun, which is not difficult to do. You run into the exact same problem with stills as you do video - polarization changes as soon as you change your angle relative to the sun.

Polarization is one of the very few things that post processing software cannot even come close to replicating, which makes them even more valuable to have when the situation calls for it.

I definitely wouldn't be leaving a PL on all the time but they absolutely have their place for video, and there is no substitute.

Also, chances are you will want polarization more often when it is bright out, so for filters an ideal set for most scenarios IMO would be ND4, ND8, ND16, ND32, ND16PL, ND32PL.
 
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metaphase

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Also, chances are you will want polarization more often when it is bright out, so for filters an ideal set for most scenarios IMO would be ND4, ND8, ND16, ND32, ND16PL, ND32PL.
Thanks - sounds like a good combo, frustratingly can't see anyone offering that sort of spread. I see in the USA PP offer custom models but $14.99 for one-month shipping to the UK (plus customs fees and the weakness of GBP in general) doesn't make them that appealing - will keep searching on Amazon to see what I can find!
 

CanadaDrone

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Thanks - sounds like a good combo, frustratingly can't see anyone offering that sort of spread. I see in the USA PP offer custom models but $14.99 for one-month shipping to the UK (plus customs fees and the weakness of GBP in general) doesn't make them that appealing - will keep searching on Amazon to see what I can find!
Yeah Polar Pro is what I was going to suggest - they let you put together a convenient 6-filter custom package. I am in Canada so I am not sure what your best options are in the UK to be honest.

If you never fly at dusk/dawn you can probably forego the ND4 as well if you're looking to save a bit of money, and/or start with only one NDPL filter until you get the hang of things. ND 8/16 are the most commonly used and ND32 will likely be needed if you travel to tropical places or fly in bright areas with light colored landscapes.
 
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CanadaDrone

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UV filters are largely useless and can cause more harm than good - they were designed for the film days. All modern optics and digital sensors have UV coatings on them already. On digital sensors they can sometimes cause an unpleasant color cast that adds more work to remove in post processing. I'd skip that one personally, and if you want a protective filter (I think the front element is plastic anyway), go with a standard glass one if you can find it rather than UV.
 

Lady Rover

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Hi everybody, I found a set of filters with ND, ND-PL, CPL and UV.

As per the previous posting, UV is not needed.

I understand ND and ND-PL.
Still, what is a CPL filter?

Secondly, there is also a set which gets just pushed onto the original lens rather than unscrewing it. Is that a good solution?

I aprecciate your comments,

Franziska
 

johnnyinak

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Hi everybody, I found a set of filters with ND, ND-PL, CPL and UV.

As per the previous posting, UV is not needed.

I understand ND and ND-PL.
Still, what is a CPL filter?

Secondly, there is also a set which gets just pushed onto the original lens rather than unscrewing it. Is that a good solution?

I aprecciate your comments,

Franziska
CPL refers to a circular polarizing filter. It consists of 2 coated glass elements that when the outer element is rotated it polarizes to different degrees. This leaves me to wonder how what they call a ND-PL could function properly without a circular rotating element. As you already have no need for the UV, this sounds like marketing from a sub par company. I have found that more for less is usually not a good option. I am not an authority or judging any product or company, but I can not regret purchasing Polar Pros in the beginning!
 

CanadaDrone

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Hi everybody, I found a set of filters with ND, ND-PL, CPL and UV.

As per the previous posting, UV is not needed.

I understand ND and ND-PL.
Still, what is a CPL filter?

Secondly, there is also a set which gets just pushed onto the original lens rather than unscrewing it. Is that a good solution?

I aprecciate your comments,

Franziska
CPL is just another term for what most people know as polarizers. There are both circular and linear polarizers, so the term "CPL" is used to differentiate. Linear polaizers have the same effect but are not common in the photography realm because they prevent normal operation of certain autofocus systems.

A ND-PL is just a ND filter with polarization stacked onto it, and it will have to have a rotating element. A CPL on it's own usually cuts 1-2 stops of light (equivalent to a ND2 or ND4 roughly).

It's much easier to have screw-on filters for the Mavic Air, in my opinion. Not only are they secure, but it is extremely easy to swap them. The outer ring that you remove on the Mavic Air to use filters actually has no glass in it, it's strictly for cosmetics or to protect the filter threads. I wouldn't want to be putting push/pull force on the gimbal all the time either when installing/uninstalling - more room for error than if you were gently threading on a filter. Further to this, I am not sure how you would push on a filter securely without putting a big fingerprint on it - with a screw on filter this will never happen if you do it properly. Same when it came time to remove it.

I'd suggest not getting a CPL or ND-PL until you completely understand how polarization works, as it makes for very limited flight paths. Polarization is strongest 90 degrees from the sun and completely eliminated 180 degrees from the sun. The payoff can be great, but if your angle to the sun changes at any time during the flight it will change the look of your video footage, so you cannot change directions without changing the look of your footage - not as convenient on a drone.

Many companies offer UV filters but it is 100% unnecessary and just a money grab. Some people associate a "protective" filter with a UV filter, which may be why they are marketing it as such but it's still misleading.