Some questions about the A129 CPL filter.

[Andy555]

Do you guys think its worth getting CPL filters for both the front and rear?

Do you leave the filter on at all times or do you take it off at while driving at night?

Does the CPL filter help protect the lens from sun exposure/damage? Unfortunately, my car is almost always sitting outside in the sun, at home and at work. I guessing over time my camera lens will be affected from sitting in the sun all day and I was curious if another benefit of the CPL is that it could help mitigate some of this damage?

Thanks

 

[Nigel]

1. Depends on the car, if you have a vertical rear window then there is no point in a rear CPL, 45 degrees it does tend to help but it also depends on what there is that can reflect in it. Maybe wait until you find out if there is a problem before getting the rear one, and also test the front one on the rear to see if it helps.

2. I leave it on all summer, November is very dark here so I currently have it off all the time, will go back on in January or February.

3. I don't think the lens will suffer any noticeable damage within the lifetime of the camera, the sensor however will deteriorate over time, the colours in the colour filter may fade over time, a CPL will half the light level so will presumably double the useful lifetime of the sensor, it may also help to keep the sensor cool if half the sun's energy doesn't reach the sensor. The sensor will last for a few years before any deterioration is noticeable anyway, but if you live somewhere very sunny then it may be worth the protection.

 

[Tractor]

I have a hatch back and get no reflection form the rear cam unless the sun shines directly in the rear windscreen. If you are concerned about lens life it would be wise to fit a CPL.
It should protect the lens in the same way sunglasses protect your eyes. Sunglasses are recommended by most opticians but it's a decision you chose whether to wear them or not..

 

[Andy555]

1. Depends on the car, if you have a vertical rear window then there is no point in a rear CPL, 45 degrees it does tend to help but it also depends on what there is that can reflect in it. Maybe wait until you find out if there is a problem before getting the rear one, and also test the front one on the rear to see if it helps.

2. I leave it on all summer, November is very dark here so I currently have it off all the time, will go back on in January or February.

3. I don't think the lens will suffer any noticeable damage within the lifetime of the camera, the sensor however will deteriorate over time, the colours in the colour filter may fade over time, a CPL will half the light level so will presumably double the useful lifetime of the sensor, it may also help to keep the sensor cool if half the sun's energy doesn't reach the sensor. The sensor will last for a few years before any deterioration is noticeable anyway, but if you live somewhere very sunny then it may be worth the protection.

Thank you for the info, I live in a very sunny area so I will probably leave it on year around. And it is nice knowing the the filter could help protect the sensor.

 

[clicketyclack]

It should protect the lens in the same way sunglasses protect your eyes. Sunglasses are recommended by most opticians but it's a decision you chose whether to wear them or not..

The CPL is just a polarization filter that reduces glare from reflections. I don't think it has any UV protection properties, so I wouldn't equate this filter to sunglasses with regards to protection, outside being a physical layer in front of your camera/eye. Sunglasses only protect your eyes from light if they block UV wavelengths (a few sunglasses don't), which is important when wearing dark sunglasses as your iris gets larger and more susceptible to UV.

 

[Tractor]

The comparison to polarised sunglasses is to give an example of how a CPL works NOT an health matter. Its definitely the wearer's choice. UV protection on the lens of a plastic encased device is pretty pointless because the case would disintegrate well before lens goes blind.

 

[Nigel]

The comparison to polarised sunglasses is to give an example of how a CPL works NOT an health matter. Its definitely the wearer's choice. UV protection on the lens of a plastic encased device is pretty pointless because the case would disintegrate well before lens goes blind.

Hopefully our cameras use UV stabilised plastic since they sit in the sun all summer long!

The main reason for UV coatings on sunglasses is that modern glasses use plastic lenses and they need the UV protection for themselves, so actually quite similar!

 

[TonyM]

I have front & back CPL filters for my A129, although yesterday I decided to remove the front one for increased performance since so much of my driving is now in darkness or poor lighting conditions. Like Nigel, I will probably put it back on in January or February.

 

[DarthMaul]

I have front & back CPL filters for my A129, although yesterday I decided to remove the front one for increased performance since so much of my driving is now in darkness or poor lighting conditions. Like Nigel, I will probably put it back on in January or February.

I did the same starting yesterday, removed both CPLs. There is a clear improvement in image quality - more detail and better colours.

 

[Tractor]

Have you tried changing the EV values and keeping CPL on?

 

[Nigel]

Have you tried changing the EV values and keeping CPL on?

Main reason for removing them in the winter is that it halves the motion blur, increasing the EV instead would increase the motion blur!

 

[Tractor]

Good reason if the quality is important to you.

 

[Hilts]

I've past experience with a SG9665GC and an A119S both with and without CPLs. I found that the CPL had a detrimental effect on image quality (motion blur) making them unable to read number plates even at relatively low speeds & good light conditions. My personal preference is for sharp images, so I no longer use a CPL.
Living in West Wales we get lots of rain and poor light conditions, so I don't intend buying a CPL for my A129.

Personally I'd hold-off buying a CPL until you've run your A129 for a few months and had a chance to see whether you suffer from reflection issues... It may well be that you'll need CPLs for the sunny USA!!

 

[DarthMaul]

I detached the CPLs for the same reasons. I'd rather accept some dashboard reflections in exchange for lower motion blur and better image quality.

 

[Tractor]

Do not have the problem of not being able to read number plates and always prefer to have the CPL on. Very low angled windscreen that gives too many reflections without it.

 

[Svek]

I can read number plates from oncoming cars at 100km/h with my CPL filter,

however i still have some dash reflections... is there a right way up or something?

 

[Andy555]

I can read number plates from oncoming cars at 100km/h with my CPL filter,

however i still have some dash reflections... is there a right way up or something?

Yes, here's a video that shows the proper adjustment.