My DIY $6.45 CPL filer for my A119

[RCPilot]

Dave regarding the A119 do you think buying the CPL when it is released a good idea, will it really cut down the glare What percentage of reduction would it approx. cut down?

My experience with the 2 very low cost lenses I tried was about 75% reduction in glare. My dash is real bad. I've been tempted to get a black dash cover for it. If I don't use polarized sun glasses when driving the reflections and glare drives me nuts.

I was just thinking... my son is an Optometrist. His optician shop cuts down lenses every day. Why don't I buy a glass PL or CPL camera filter for a few quid and have him cut it to size? Hey, I wonder if he can cut to a 17mm x 16mm rectangle with rounded corners!

I think PL would be better as a CPL may delaminate when the edge is being cut (ground) away.

I'll ask him tonight...

Keep in mind that just a few degrees off and the effectiveness of the CPL lens drops quite a bit. If you cut it rectangular, you have to be sure you got it lined up 100% correct the first time. With a round lens you can easily rotate it to get it set to the optimal position.

 

[doru3160]

With a round lens you can easily rotate it to get it set to the optimal position.

That's right, and I filter fitted with double-sided tape, and I am not sure I got the optimal position. The next attempt will be mounted adjustable.

 

[Nigel]

Keep in mind that just a few degrees off and the effectiveness of the CPL lens drops quite a bit. If you cut it rectangular, you have to be sure you got it lined up 100% correct the first time. With a round lens you can easily rotate it to get it set to the optimal position.

But if you cut it rectangular and keep the edges parallel to the polarisation direction then it is easy to see (or measure) if it is a few degrees off when you fit it without even testing it.

Dave regarding the A119 do you think buying the CPL when it is released a good idea, will it really cut down the glare What percentage of reduction would it approx. cut down?

Depends on the car and the angle of the glass. On a vertical windscreen it will do almost nothing, on a car it may remove as much as 95% in the centre of the image reducing to about 30% at the left and right edges.

 

[DavidUK]

There's a minimum diameter for cutting lenses. He's going to find out tomorrow. I've given him a test filter to try out.
Yes, I figured circular is best too.
I bought some 2mm dia x 1mm round magnets off eBay. They had 2mm x 0.5mm too.

 

[TonyM]

@DavidUK & @RCPilot have you tried your DIY filters on the A119 at night?

 

[Sutton]

But if you cut it rectangular and keep the edges parallel to the polarisation direction then it is easy to see (or measure) if it is a few degrees off when you fit it without even testing it.


Depends on the car and the angle of the glass. On a vertical windscreen it will do almost nothing, on a car it may remove as much as 95% in the centre of the image reducing to about 30% at the left and right edges.

Thanks for the reply

 

[DavidUK]

@DavidUK & @RCPilot have you tried your DIY filters on the A119 at night?

Not yet, I just received all the bits for my experiment (shim washers; magnets) but haven't worked out the best way to do what I was thinking about!
Will have a play at the weekend. My son says minimum filter cutting diameter is 30mm so that's out. May also buy some PL or CPL film for mobile phones OR the real Viofo CPL might be on sale beforehand??????

It's fun fiddling with these DIY projects anyhow.

 

[Sutton]

Not yet, I just received all the bits for my experiment (shim washers; magnets) but haven't worked out the best way to do what I was thinking about!
Will have a play at the weekend. My son says minimum filter cutting diameter is 30mm so that's out. May also buy some PL or CPL film for mobile phones OR the real Viofo CPL might be on sale beforehand??????

It's fun fiddling with these DIY projects anyhow.

I still say this forum created a monster How did you get to be so exceptionally brilliant. I do not understand half of your technical experiment. Good for you

 

[DavidUK]

How did you get to be so exceptionally brilliant.

...by getting old?

 

[Gibson99]

...by getting old?

That's certainly not the case for everyone who gets old... Just ask my wife!

 

[DavidUK]

You might even try holding the filter up to your eye and rotate it to minimize the glare then mark the top and install.

From: https://dashcamtalk.com/forum/threads/video-cable.21275/page-2#post-298639

Exactly what I did today, then blutack'd the filter in its makeshift holder to the lens housing, took some footage, rotated 5 degrees, took some more, etc.
This is the clip-on filter for £3 odd but it's flimsy plastic and already has some fine scratches (maybe there already). It has a 16mm x 1mm clear glass lens too, which may be useful if covered with CPL film - see below.

I've also experimented with cutting an old glass camera filter, which worked OK but it's not a PL one. It's about 2mm thick and I only have 3mm between housing and windscreen so a little tight. I'd have to work out the rotation before cutting a PL one square or rectangular (can't do a circle).

Otherwise, I've bought a 0.8mm x 20.8mm watch crystal off ebay and some mobile phone PL (or CPL) film, some 3mm x 0.5mm neodymium magnets, and some other bits. I'm almost up to £10 in total now!

 

[Gibson99]

I'm almost up to £10 in total now!

How will you afford your next tank of petrol??

 

[5Cowbells]

From: https://dashcamtalk.com/forum/threads/video-cable.21275/page-2#post-298639

Exactly what I did today, then blutack'd the filter in its makeshift holder to the lens housing, took some footage, rotated 5 degrees, took some more, etc.
This is the clip-on filter for £3 odd but it's flimsy plastic and already has some fine scratches (maybe there already). It has a 16mm x 1mm clear glass lens too, which may be useful if covered with CPL film - see below.

I've also experimented with cutting an old glass camera filter, which worked OK but it's not a PL one. It's about 2mm thick and I only have 3mm between housing and windscreen so a little tight. I'd have to work out the rotation before cutting a PL one square or rectangular (can't do a circle).

Otherwise, I've bought a 0.8mm x 20.8mm watch crystal off ebay and some mobile phone PL (or CPL) film, some 3mm x 0.5mm neodymium magnets, and some other bits. I'm almost up to £10 in total now!

You probably know a lot more than me by now, but sometimes different points of view help (or not). You won't be able to eliminate all reflections, because the reflections will tend to become polarized in a direction parallel to the physical orientation of the reflecting surface relative to you. You may want to target to reject reflections off horizontal surfaces, like the road surfaces directly in line with the camera pointing angle, to reduce reflections outside the car which may also minimize windshield reflections. If you are primarily trying to eliminate windshield reflections, target to minimize those reflections in direct line-of-site of the camera pointing angle, since the windshield is a curved surface. I would think that there should be two filter orientations for minimizing glare, 180 degrees of rotation apart, and you could use either.

Regards

 

[DavidUK]

I would think that there should be two filter orientations for minimizing glare, 180 degrees of rotation apart, and you could use either.

Are you talking 2 circular or 2 linear filters 180 degrees apart?

 

[Gibson99]

Are you talking 2 circular or 2 linear filters 180 degrees apart?

i think he's saying that you can use one filter in 2 different positions and get identical results. ie: orient filter for minimum glare, then mark the top of the filter as 12 o'clock. then rotate the filter so the mark is now pointing at 6 o'clock and you'll get identical results.

 

[jokiin]

once aligned the effect is the same 180 degrees out

 

[5Cowbells]

Are you talking 2 circular or 2 linear filters 180 degrees apart?

@DavidUK - No, I meant what @Gibson99 just said - https://dashcamtalk.com/forum/threads/my-diy-6-45-cpl-filer-for-my-a119.22144/page-3#post-298876

Regards,

 

[DavidUK]

Ah yes, that was fairly obvious, but no, I don't know much at all!

 

[jcs]

I just cut up some 3D glasses $1 from ebay. It worked fairly well for my A118, but wasn't necessary for my A119.

 

[5Cowbells]

I just cut up some 3D glasses $1 from ebay. It worked fairly well for my A118, but wasn't necessary for my A119.

Not sure how that works ...are they polarized? Lots of sun here, badly need a polarized filter (preferably clear) for A119. Patiently awaiting Viofo's product.