Monday, July 25, 2011

First Circular Polarizer Photo

VIA 6420 leads the Hudson Bay
VIA 6420 leads VIA 6407 and the rest of VIA 693 (the Hudson Bay) out of Winnipeg, Manitoba.

This is my first shot with my new circular polarizer.

What does a polarizer do? Well... it's hard to explain and I don't totally understand it. Sunlight is unpolarized, meaning that the light waves vibrate in a variety of directions ("planes"). However, sunlight that reflects off a nonmetallic object is polarized. A polarizing filter only allows a certain "plane" of light through. Turning a circular polarizer adjusts what "plane" of light is allowed through to the camera, so reflections can be blocked.

The end effect is that contrast is higher (skies are darker, for example, as you can see above). Also, a polarizer can help cut through haze as much of the haze is reflected light.

There are some interesting images here showing the difference between non-filtered and filtered images.

PhysicsClassroom.com has a good tutorial on polarization of light.

I bought a Hoya PRO1 58mm polarizer. There are cheaper polarizers, such as this Hoya model. The differences include multi-coating (to reduce lens flare) and construction (plastic vs. metal frames). It's all in what you are looking for.

7 comments:

roldac said...

Wow, the colour saturation really makes the picture jump out at you. I use a ND filter on bright days but I will definitely try a polarizing filter in the future. Thanks Train Geek...you are educational in both trains and photography :)

Eric said...

Steve, I had a great sunny afternoon through northern Ontario and into Manitoba, with polarizer images in this post. The fall colours really popped on that day with the filter:

http://tracksidetreasure.blogspot.com/2009/03/vias-vestibule-view-heading-west-to.html

Nice VIA photo, plus the deer. Good to see you're not afraid to spend some doe or even a few bucks on good photo equipment.
Eric

Train Geek said...

A neutral density filter is very useful on bright days, especially when trying to shoot a low shutter speed or get a shallow depth of field. I don't have one yet but I plan to get one or two. Is yours graduated or constant?

Train Geek said...

Eric, try not to fawn over the photo gear!

Eric said...

I herd you there, Steve :)
Eric

roldac said...

I have ND2,4,8. They are constant, got them cheap on ebay, just a few bucks each, I like them. There is such a wide range in prices (some up to $100) it is hard to know what to buy so I go cheap for now. Also, how do you know how to adjust a circular polarizing filter, do you rotate till the glare goes away in the viewfinder?
roldac

Train Geek said...

Yes, you rotate it... you can tell by the sky. When it gets evenly dark, stop.