45

A sheet of glass or plastics will typically have internal stresses. For glass and some clear plastics these lead to the birefringence patterns you see, when you shine (partially) polarized light on them and then view them through a polarizing filter. You can try this out by either using two polarizing filters, one in front and one behind, or holding such an ...


22

When light bounces off a relatively nonconductive surface it becomes partially plane polarized, meaning the light tends to have the same polarization direction. Polarizing filters can be used to counteract glare/reflections, by orienting the filter at 90 degrees to the polarized reflection so that it get filtered out. If you orient the filter so that it is ...


20

You're probably comparing a linear polariser with a circular polariser. The linear polariser is a basic filter that only passes light waves polarised in a particular direction. That works either way round, and you can combine two of them to produce a variable density filter - by rotating the second polariser, it passes most of the light when the polarisation ...


18

Absolutely you can. Many square filter holders are specifically designed for this: The Lee Filters systems (Sev5n, 100mm) have optional front threaded rings designed to hold a polarizer in front of the ND filter(s). The NiSi 70mm and 100mm square filter holders feature a specially-made thin polarizer filter meant to stack behind the ND filters, closest to ...


13

I think you can only get subjective answers on this, different things will appeal to different people. I'll give you my experience. I have a polarising filter on my main lenses rather than a UV. If it's low light, or I otherwise don't need it, I remove it temporarily, but it always goes back on. I use the polarising filter all the time, so I don't like ...


12

Absolutely, the best ones are worth every penny. While I cannot say I tried every polarizer out there, I tried over a dozen and kept the 4 best ones. My favorite by far is the Hoya HD Circular Polarizer which lets one full stop more light than every other polarizer. This is an import advantage since more light lets you shoot at lower ISOs and faster shutter-...


11

Unless you put a polarizing sheet on the lamps, no effect (other than the global ND effect inherent in these filters), except if there is a reflection on the ground from them, then the reflection will be attenuated. The polarizer removes the reflections from non-metallic surfaces and the stars are direct light from emitting sources. Since the stars ...


11

It is possible and useful - and sometimes even crucial. Look at this example of a squid: http://en.wikipedia.org/wiki/Glass_squid It shows a picture with and without a polariser filter.


11

When we speak of typical ranges of "high transmission" polarizing filters, we do not mean "this filter might be -2/3 stops and that filter might be -1 1/3 stop." What we mean is that "the same filter can vary between 2/3 to 1 1/3 stops" based on the various directions of the polarization of the light it is filtering. These typical ranges are based on using ...


10

I would look into the Lee Filter Foundation Kit, based on the needs you specified. Lee makes a very solid, and less bulky, filter system similar to Cokin's, and it will more than adequately accommodate your need for LOTS of ND filtration, 100mm filters, graduated neutral density, and if you don't mind spending the money, glass and high quality glass (rather ...


10

There are several problems with some of the answers you have already received. First, little of this effect is due to polarized reflections from the car itself. The reflection needs to be at a more glancing angle to get significant polarizing selection. Most of the reflections in this image are steep enough to not make much difference to the polarization ...


9

That's because there is no set "starting position". You simply rotate it until it is blocking whatever angle the glare is coming in at. Adjust by how it looks. You will see glare either increase or reduce as you turn it, when you get to the angle with the least glare (or whatever visual look you are looking for), you have it set correctly. That's all ...


8

This question already has nice answers. I'll just address one sub-question inside your question. Namely: I can see why this might be the case and that for the most part that it might be undesirable, but is it really that much of a problem? Yes, it can be a problem. Painfully obvious in this photo of mine: Here the reason is not only the wide angle of ...


7

The only source of light under water is the light that is refracted from the outside. Also there is a fact that the light that is refracted into the water surface will be partially polarized.Partially polarized meaning that the refracted light has all planes of electromagnetic vibration other than the plane of vibration of the reflected light at the surface ...


7

A circular polarizer wouldn't directly create noise. The noise is a function of the sensor and exposure settings. Better filters help capture better images but better filters don't prevent noise. In this case, underexposure (an effect of the polarizer) may be the reason for noise in that sample image. Additionally, if you're noticing it more when you shoot ...


7

The difference is in the depolarizer filter that is on the back side of a circular polarizer filter, and which side you turn towards the screen. A linear polalizer filter shows the behaviour number 1 regardless of which side you have towards the screen. It works the same in both directions. A circular polarizer filter shows the behaviour number 1 when you ...


7

Yes, you are looking at the wrong number. Since the filter screws to the front of the lens, the only number that matters is the diameter of the filter thread, not the focal length of the lens. Look at the front end of the lens. Around the glass is a ring with text on it. One number will have a symbol a little like Ø next to it, probably 52. This is the ...


7

Use a polarizing filter, which will filter out light polarized in a certain direction (turn the filter until the desired effect is achieved). This works, because reflected light is polarized in the plane of the surface it is reflected from. Note that the sky's blue is also polarized, you'll see a distinct graduation when you look at different angles to the ...


7

If you want to get the effect without photoshop trickery there are couple of factors to think about. Generally reflections off of medium boundary (like water) are governed by Frensell equations that predict that the amount of reflected light is dependent on the orientation of the reflective surface and the polarization of the incoming light. The effect of ...


7

Is the Cokin 173 filter just a backwards CPL? No. The effect is similar to mounting your polarizer backwards, but much more pronounced on the Varicolor filter. Here is what my Hoya HD CPL looks like at 0° and 90° polarization angles, when oriented for correct mounting (male threads towards camera): Note that this is NOT a variable-ND filter. In the right ...


7

Many polarizing filters have a marking like this — either a triangle or a dot or something. You'll get maximum effect if you align the camera so you're pointing in a direction roughly perpendicular to the sun in the sky and the mark is pointed at the sun. This doesn't need to be exact, but it's an easy starting point. Of course, with through-the-lens ...


6

Hard to know from your post, but note that a CP filter will loose you between 1 and 2 stops of light, depending on it's setting. This significantly reduces the amount of light reaching both the sensor and the all important autofocus system. If you have a variable aperture lens, this means that longer focal lengths have a smaller maximum aperture and ...


6

Is there a simple way of quickly swapping a circular polariser between lenses (of different filter diameters)? Not really. The simple solution is to have a polarizer for each lens so you don't have to swap them in difficult conditions. The cost-effective solution is to do as you are currently doing and use step down rings. Magnetic filter holders and ...


6

The polarizing filter (should be called a polarizing screen) is likely the most valuable optical filter you can possess. The polarizing screen mitigates reflections. It does not work on all surfaces but it works on most. You can use it to diminish annoying reflections on glass and on water. This filter darkens a blue sky making clouds stand out without ...


6

The obvious answer is that the light from a rainbow, or at least the portion that is fitting in your viewfinder at the time you are rotating the polarizer, is all polarized in the same direction.¹ That is, the light reflecting off of millions of water droplets falling in the atmosphere is polarized in the same way by the more or less uniform shape of those ...


6

You can use a polarising filter on any lens. However, using a "directional" filter like a polarising filter or a graduated neutral density filter on a lens where the front element rotates when it focuses is a bit of a pain: you get the scene lined up, rotate the filter so that it's where you want it, focus... and then the filter rotates, so you have to ...


5

Besides Singh-Ray, which are extraordinarily expensive, Tiffen and Kenko and others also make variable ND filters. Some call them "faders". The problem with them compared to fixed ND filters is that they can create strange color casts and banding (even with the top of the line Singh-Rays) and as Stan said, being composed of polarising filters they have ...


5

Do you use more than one filter size? To me, that's the biggest reason for going with systems like Cokin P. I have numerous lenses, and they each have their own filter size. I would go broke trying to duplicate all my filters for all my lenses! Or, a different way of looking at it is that if you get a new lens that has a different filter size, for the cost ...


5

The brand of filter does make a difference according to the LensTip polarizing filters test. My experience bears this out -- my B+W circular polarizer is clearly better than my Tiffen. It's also worth noting that I've discovered second-hand that more than a few filter sellers on eBay are selling counterfeit name-brand filters for low prices.


5

Obviously the two filters have totally different uses so you can't say one is strictly better than the other, but if you only buy one filter I'd say a polarizer is more useful as it cuts through the haze, enhances skies etc. it will also act as a 1 stop ND. Provided your camera goes up to 1/8000s you should be absolutely fine without an ND. The only use for ...


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