Polarized Lens

alisonbull

Do circular polarized filters remove enough glare and increase sky detail to warrant purchasing one? Do you need a separate one for each individual lens, and if so, can you recommend a filter for a 35 mm f/1.8 and a sigma all in one lens? Thank you

Haggis

The answer to polarized filter is yes, you do need one. The size of the filter diameter depends on the lens, eg 52mm 58mm 62mm etc. I have various lenses and 3 sizes of filters. I bought 3 polarized filters of these sizes for convenience. To be honest some of the cheaper ones on the bay are in fact excellent, others terrible. It is worth getting the recognized make like Hoya, and even second hand is worth thinking about.
Yes the filters remove glare from water and other surfaces, and darken skies, but remember the rule, polarizing filters should be used at right angles to the sun. In other words, line up your elbow to the sun. Just a guide rather than a rule.
You can buy adaptor rings allowing you to use, lets say, a 77mm filter on a 52mm lens filter size, but this is not the most fun way to start a shoot.

Your second question an all singing all dancing lens,
Sigma 18-250mm f/3.5-6.3 DC MACRO OS HSM, or a Tamron 18-200mm f/3.5-6.3 Di 2 VC Model b018n
On the subject of filters, I always put a UV filter on a lens to protect the glass from accidents.

bruto

A polarizer is one of the only filters that does something that can never be done in post processing. The way it does its job makes its effect very dependent on the direction of the light, as @Haggis notes, and because of that the results can vary from very little to dramatic. For reflected glare, it can make a very great difference, including making it possible to see through reflecting windows, or through the surface of water, in ways that nothing, including the naked eye, can do.

Some people get confused by the terminology. The "circular" in this case refers only to the manner in which polarizing takes place. Older linear polarizers look and behave just the same, but some AF and AE systems misbehave when they're used. If shopping for used filters, keep that in mind. "CPL" is what you want to see unless you're using a manual lens.

On many kit lenses and lenses with rotating front elements, a polarizer is a nuisance to use, since its effect is achieved by rotation, and AF can disturb it. Manual focus or back button focus make use on rotating-front lenses much easier, since once focus is achieved you can adjust the filter and the lens will not continue to rotate. Since I have been using back button focus for some time, I have a CPL on my kit 18-55mm, and it works fine. You just have to remember to adjust it for every new shot.

A polarizer can also cause somewhat odd color shifts in the sky when it's used on a very wide angle, because of the effect of sun angle. It's not a problem at longer focal lengths, and usually not a problem if there are clouds or other things to break up the sky, but at wide angle a clear blue sky may look patchy.

Some benefits are not immediately obvious, because we are not always aware of reflected glare until it's gone. Many scenic shots will benefit from it and things like foreground grass may appear sharper and more saturated when the glare is removed.

Ii would highly recommend getting a polarizer. Once you are used to using it, you may find you're using it more often than you expect.

Galan

If you never purchase another filter, the one filter that must be in your bag is the Polarizer.
Granted, GND's are as high on the list of tools for photographers, but the polarizer can accomplish things no post processing has been able to do to date, and that is to realign light rays.