[Poll] Do you use a CPL? Why or why not?

[mercaptan]

I'm trying to gauge the relative usage of CPLs on dash cams (and figure out if they are worth buying).

As an avid photographer I never leave home without one. I've got 5 or 6 in various sizes for my DSLR and know the pros/cons pretty well.

So is the trade off of minimized reflections / more consistent exposure worth having less available light with the CPL?

Please share your comments, thanks!

 

[USDashCamera]

I think I am going to start using mine again, but I stopped because I was too lazy to take it on and off. I might now just only put it on when it is very sunny out midday.

 

[kamkar]

Never used it as i dont mind the reflections in my windscreen, if i was making travel logs it might be a different thing, but for everyday use i dont need it.

 

[Street Guardian USA]

Here's a comparison video I made:

 

[Nigel]

I have some aluminium air vents in the centre of my dashboard and the reflections from them are really annoying and in sunshine completely obscure part of the view so I don't really have much choice other than to use a CPL or paint my air vents black. I always use the CPL as even without the air vents, it still improves the colours and contrast of the image and makes it easier to encode the movement into the video signal freeing space in the data stream for extra detail. The only disadvantage I can see is that it increases the amount of motion blur but when motion blur becomes an issue it normally needs more than just CPL removal to cure the issue.

 

[niko]

I have few CPL filters for many dashcams, some are original, some are DIY made, but why I am NOT using them, - because of one reason: "convenience" of attach / detach for night / day. For night driving , need to remove CPL for better video result, then next day need to attach it. Its not convenient on daily bases.
Second drawback is like @Nigel mentioned- slightly increases motion blur.
Yes, for still shots CPL is a very good accessory, but for everyday dashcam use it is not practical at this stage. Maybe one day there will be some more user-friendly CPL solution for dashams.

 

[jokiin]

The solution is available but it's just too expensive at this stage and for this application

 

[kamkar]

maybe some one should make a mecanical automatic CPL filter, just like the IR filters on CCTV cameras, and then have a light sensor engage & disengage the filter.

This offcourse mean that the dashcam will be bigger as CPL need to be in front of lens and not like IR filter in the socket.

 

[jokiin]

maybe some one should make a mecanical automatic CPL filter, just like the IR filters on CCTV cameras, and then have a light sensor engage & disengage the filter.

This offcourse mean that the dashcam will be bigger.

There are digital switched versions embedded between glass layers that can be turned on and off, still too expensive for this technology but give it time

 

[Nigel]

maybe some one should make a mecanical automatic CPL filter, just like the IR filters on CCTV cameras, and then have a light sensor engage & disengage the filter.

This offcourse mean that the dashcam will be bigger as CPL need to be in front of lens and not like IR filter in the socket.

Is that true? A CPL is flat and has no effect on the focus so I would have thought it could go at any point in the light path.

 

[kamkar]

well i am guessing, its just that when i have been using filters on regular cameras they have allways been in front of the lens.
If it could go in between the lens and the CMOS that would be nice, or as jokiin mentioned above

 

[jokiin]

well i am guessing, its just that when i have been using filters on regular cameras they have allways been in front of the lens.
If it could go in between the lens and the CMOS that would be nice, or as jokiin mentioned above

for reasons of practicality they are in front of the lens as you need to adjust them and take them on and off

 

[kamkar]

yes thats what i figuered too, not even sure if its possible to ajust a mecanical CPL filter from the factory, or if it need to be ajusted individual to the car/window.

Just trowing stuff around as usioal and its not all diamonds

 

[Nigel]

for reasons of practicality they are in front of the lens as you need to adjust them and take them on and off

For a dashcam you always want it vertical, so it doesn't need adjustment.

 

[jokiin]

For a dashcam you always want it vertical, so it doesn't need adjustment.

yes, but you don't always want it, still needs to come on and off

 

[Nigel]

yes, but you don't always want it, still needs to come on and off

Maybe you could combine it with a mechanical IR filter and remove both for the dark, put both back for the daylight?

 

[jokiin]

Maybe you could combine it with a mechanical IR filter and remove both for the dark, put both back for the daylight?

the biggest problem for anything like that if it's not automated is people forget to do it, even with CPL you see people that comment about not using it after a while as they get tired of taking it on and off, or just forget and end up not bothering, you're not catering to the enthusiast, they'd do it, it's Joe average that's the challenge

 

[kamkar]

I dident even try the CPL that came with my lukas once, to be honest i am not even aware of where it is right now, it is in some box for sure, but i have 10 of them here as i have only unpacked a little of my stuff when i moved here 3 - 4 years ago.

 

[NZDashcam]

Most of my driving is in the day so I will keep mine on. At night the x2 can cope. If I wanted to I could change to high instead of low in terms of the light balance, but the reduction of reflections is a substantial improvement to warrant the cpl

 

[DT MI]

well i am guessing, its just that when i have been using filters on regular cameras they have allways been in front of the lens.
If it could go in between the lens and the CMOS that would be nice, or as jokiin mentioned above

Not necessary for them to be in front of the lens. I have a large telephoto lens for photography (Sigma 300-800) where the CPL is inserted back near where the lens attaches to the camera.