learning about the CLP

[Al Drake]

With the introduction of more dash cams that are using the CPL(circular polarizing lens) it is important to learn as much as possible about this filter. In this video towards the end there is a list of which brands are recommended and which should be avoided and why. The reason I like the LUKAS LK-7900 ACE vs. the Finevu is the LUKAS uses a standard 37mm threaded CLP and allows one to purchase a quality lens and avoid vignetting
http://www.google.com/#hl=en&sclient=ps ... 20&bih=929

There are some CPL lens that are not true rotating polarizers and must be avoided as they can not be adjusted which is very important.
http://www.ebay.com/gds/Circular-vs-Lin ... 386/g.html

Another way of avoiding vignetting is to use a larger size filter(CPL) with a step up adaptor to make the lens overlap assuring there are no visible edges.

http://www.amazon.com/Adorama-Step-Up-A ... B0002GVX7Q

This is only an example and not a recommendation. The best option is to pay for the best CPL you can afford. Something that can last a lifetime if properly cared for. These quality filters do not degrade the quality of the video and will give amazing results.

Good luck and have fun.
Al.

 

[Swordfish]

A polarizer can actually degrade video when used through some windows, especially those that contain a layer of plastic. It will cause weird psychedelic rainbows, so think twice before using one. It's also pointless at night because it cuts as many as 2 stops of light. Since we're talking about filters, I also would advise against using UV filters especially at night because it causes glare and ghosting. There's also not much need of protecting the camera lens because it's inside your car anyway and mostly stationary.

 

[Al Drake]

A polarizer can actually degrade video when used through some windows, especially those that contain a layer of plastic. It will cause weird psychedelic rainbows, so think twice before using one. It's also pointless at night because it cuts as many as 2 stops of light. Since were talking about filters, I also would advise against using UV filters especially at night because it causes glare and ghosting. There's also not much need of protecting the camera lens because it's inside your car anyway and mostly stationary.

I couldn't disagree more. The inside of a car can be the dirtiest and dustiest place you will ever see. I am always cleaning and dusting my dash. I'd rather clean my UV filter than clean the surface of my dash cam lens. You can adjust the CPL so it has little effect. I've never read anything to back up your claim. Can you provide a cite? I have been using cameras for decades and am a member of several camera forums.

http://www.dpreview.com/forums/

I just searched your wording and claims and found nothing.
http://www.dpreview.com/forums/post/39682198

The best thing to do is try one and see for yourself. Do you have one that does what you claim? Can you provide a mfg. of this product and some photos to post?

 

[Swordfish]

A polarizer can actually degrade video when used through some windows, especially those that contain a layer of plastic. It will cause weird psychedelic rainbows, so think twice before using one. It's also pointless at night because it cuts as many as 2 stops of light. Since were talking about filters, I also would advise against using UV filters especially at night because it causes glare and ghosting. There's also not much need of protecting the camera lens because it's inside your car anyway and mostly stationary.

I couldn't disagree more. The inside of a car can be the dirtiest and dustiest place you will ever see. I am always cleaning and dusting my dash. I'd rather clean my UV filter than clean the surface of my dash cam lens. You can adjust the CPL so it has little effect. I've never read anything to back up your claim. Can you provide a cite? I have been using cameras for decades and am a member of several camera forums.

http://www.dpreview.com/forums/

I just searched your wording and claims and found nothing.
http://www.dpreview.com/forums/post/39682198

The best thing to do is try one and see for yourself. Do you have one that does what you claim? Can you provide a mfg. of this product and some photos to post?

Which one among my claims haven't you read about?

About rainbows, haven't you tried taking a photo through an airplane window using a polarizer? You will see the phenomenon I just mentioned. I have a video from the LK-7900 that shows exactly that, but it's too much effort (and bandwidth) to upload the file just to prove my point. It's looks exactly like this YouTube video.

And about glare and ghosting, haven't you read -- and experienced it yourself, since you claim to be a photographer? It happens when a non-image light reflects internally on lens elements before reaching the digital sensor. A UV filter, especially at night when you have streetlights directly in front, introduces an extra surface that can reflect light, giving you an image/video with a washed-out look.

I use several filters myself (CPL, UV, ND, Kodak Wratten gels, etc.) if only to protect my expensive lenses. I also don't normally shoot THROUGH windows.

About dust, the answer to your concern about damaging the lens is called a blower.

P.S. You need to read more outside dpreview, where members are mostly gear heads and seldom go outside to shoot (of course, I'm generalizing). :-*

If you're interested, you can read about filter-causing lens flare here: The Filter Flare Factor
And here too: Understanding Camera Lens Flare

 

[Al Drake]

A polarizer can actually degrade video when used through some windows, especially those that contain a layer of plastic. It will cause weird psychedelic rainbows, so think twice before using one. It's also pointless at night because it cuts as many as 2 stops of light. Since were talking about filters, I also would advise against using UV filters especially at night because it causes glare and ghosting. There's also not much need of protecting the camera lens because it's inside your car anyway and mostly stationary.

I couldn't disagree more. The inside of a car can be the dirtiest and dustiest place you will ever see. I am always cleaning and dusting my dash. I'd rather clean my UV filter than clean the surface of my dash cam lens. You can adjust the CPL so it has little effect. I've never read anything to back up your claim. Can you provide a cite? I have been using cameras for decades and am a member of several camera forums.

http://www.dpreview.com/forums/

I just searched your wording and claims and found nothing.
http://www.dpreview.com/forums/post/39682198

The best thing to do is try one and see for yourself. Do you have one that does what you claim? Can you provide a mfg. of this product and some photos to post?

Which one among my claims haven't you read about?

About rainbows, haven't you tried taking a photo through an airplane window using a polarizer? You will see the phenomenon I just mentioned. I have a video from the LK-7900 that shows exactly that, but it's too much effort (and bandwidth) to upload the file just to prove my point. It's looks exactly like this YouTube video.

And about glare and ghosting, haven't you read -- and experienced it yourself, since you claim to be a photographer? It happens when a non-image light reflects internally on lens elements before reaching the digital sensor. A UV filter, especially at night when you have streetlights directly in front, introduces an extra surface that can reflect light, giving you an image/video with a washed-out look.

I use several filters myself (CPL, UV, ND, Kodak Wratten gels, etc.) if only to protect my expensive lenses. I also don't normally shoot THROUGH windows.

About dust, the answer to your concern about damaging the lens is called a blower.

P.S. You need to read more outside dpreview, where members are mostly gear heads and seldom go outside to shoot (of course, I'm generalizing). :-*

If you're interested, you can read about filter-causing lens flare here: The Filter Flare Factor
And here too: Understanding Camera Lens Flare

Thank you for teaching me something I was unaware of. However these are rare events and not effects that have turned the positive attributes of CLP filters on their heads. No one normally shoots through glass windows other than the users of dash cams. This is the reason that the use of the CLP is beneficial. The whole idea is to reduce reflection while no other method has proven effective. The small examples you have provided are just that. Very small and completely rare. I, myself, have never experienced any of them and found the science of polarizing light to be very desirable.

As far as cleaning the lens is concerned the blower is only one method alone and not completely effective. This is why other methods are still used.

In the end it's really up to the individual to decide like anything else.

 

[Swordfish]

Take note also that a wide-angle lens already has a tendency to polarize light, which gives you that deep blue sky. But if your aim is really to reduce reflections, then you will have to live with the nuances I mentioned, especially the rainbow effect.

 

[george55321]

I did daytime shots with my Lukas 7900 and the filter installed, pictures have glare from my dashboard. I guess the filter and my windshield disagree with each other.
George

 

[Al Drake]

Take note also that a wide-angle lens already has a tendency to polarize light, which gives you that deep blue sky. But if your aim is really to reduce reflections, then you will have to live with the nuances I mentioned, especially the rainbow effect.

That rainbow effect you are referring to is not something common what-so-ever. "Living with it" is in no way a reality. You seem to be fixated on totally debunking the used of a CLP. I have never seen such an effect and suggest it is something very rare.

Like I stated, it is up to the individual to decide. If you are so dead set against in then so be it.

 

[Al Drake]

I did daytime shots with my Lukas 7900 and the filter installed, pictures have glare from my dashboard. I guess the filter and my windshield disagree with each other.
George

I've found that whatever glare I have is lessened when I use the CLP I have. What brand are you using and have you tried adjusting it?

 

[Swordfish]

Take note also that a wide-angle lens already has a tendency to polarize light, which gives you that deep blue sky. But if your aim is really to reduce reflections, then you will have to live with the nuances I mentioned, especially the rainbow effect.

That rainbow effect you are referring to is not something common what-so-ever. "Living with it" is in no way a reality. You seem to be fixated on totally debunking the used of a CLP. I have never seen such an effect and suggest it is something very rare.

Like I stated, it is up to the individual to decide. If you are so dead set against in then so be it.

Just because you don't have it doesn't mean it's rare. Aside from the glass, maybe the tint has something to do with it. About "debunking the use of a CLP (sic)" why would I do that when I use it under ordinary circumstances (not through a window)? I'm just saying it's not always ideal as you make it to be.

 

[Al Drake]

Take note also that a wide-angle lens already has a tendency to polarize light, which gives you that deep blue sky. But if your aim is really to reduce reflections, then you will have to live with the nuances I mentioned, especially the rainbow effect.

That rainbow effect you are referring to is not something common what-so-ever. "Living with it" is in no way a reality. You seem to be fixated on totally debunking the used of a CLP. I have never seen such an effect and suggest it is something very rare.

Like I stated, it is up to the individual to decide. If you are so dead set against in then so be it.

Just because you don't have it doesn't mean it's rare. Aside from the glass, maybe the tint has something to do with it. About "debunking the use of a CLP (sic)" why would I do that when I use it under ordinary circumstances (not through a window)? I'm just saying it's not always ideal as you make it to be.

Show me where I said it was ideal? To me it's a filter worth having. If you use it and you like it fine. If not then you won't use it will you? For me it works great in reducing the reflection as I drive 80 miles a day. So far I haven't seen any rainbow or any leprechauns.

 

[jokiin]

Show me where I said it was ideal? To me it's a filter worth having. If you use it and you like it fine. If not then you won't use it will you? For me it works great in reducing the reflection as I drive 80 miles a day. So far I haven't seen any rainbow or any leprechauns.

I know in the past I've had polarising sunglasses that I couldn't wear in some cars due to the horrible rainbow effect through the laminated windscreen yet other cars never caused a problem, I'd guess this is a similar sort of effect with these filters

 

[Al Drake]

Show me where I said it was ideal? To me it's a filter worth having. If you use it and you like it fine. If not then you won't use it will you? For me it works great in reducing the reflection as I drive 80 miles a day. So far I haven't seen any rainbow or any leprechauns.

I know in the past I've had polarising sunglasses that I couldn't wear in some cars due to the horrible rainbow effect through the laminated windscreen yet other cars never caused a problem, I'd guess this is a similar sort of effect with these filters

It has everything to do with the quality of the filter. Unlike sunglasses the CLP can be adjusted.

 

[Swordfish]

Show me where I said it was ideal? To me it's a filter worth having. If you use it and you like it fine. If not then you won't use it will you? For me it works great in reducing the reflection as I drive 80 miles a day. So far I haven't seen any rainbow or any leprechauns.

I know in the past I've had polarising sunglasses that I couldn't wear in some cars due to the horrible rainbow effect through the laminated windscreen yet other cars never caused a problem, I'd guess this is a similar sort of effect with these filters

It has everything to do with the quality of the filter. Unlike sunglasses the CLP can be adjusted.

It's more about the quality of the glass you're shooting through and less about the polarizer itself. A $200 B+W polarizer will still give you those rainbows if you shoot through glass with plastic.

You didn't directly say a CPL is ideal, but you never mentioned any potentially undesirable results from it, maybe because you've never experienced these yourself.

 

[george55321]

I got the one from Lukas themselves, it was included with my order. I took the filter off yesterday but did not review the SD card yet. Will do it tonight

 

[javr]

I live in area, surrounded by high mountains. As you can see in the video below, my camera is almost totally blinded by the light, that commes from above the mountains (description: I was trying to hide my car below a balcony in front of an approaching hail storm).

The camera has a "Night mode" adjustments:
- off
- auto night mode
- auto anti glare.

I didn't notice any difference between those three, or simply said: nothing works.
So I guess I need a filter. Since I know nothing about filters, what would you suggest ?
Thanks.

 

[Swordfish]

If the sun is directly in front of you, a circular polarizer won't help you. It could degrade your video by introducing flare. You could tilt the lens downwards if you're bothered by the light.

 

[javr]

You could tilt the lens downwards if you're bothered by the light

Before suggestion:

After suggestion:

Thank You.