Wednesday, May 26, 2010

CPL filter for dummies

Okay, I got myself a nice cheap Massa 77mm circular polarizing filter and tried it out today.

Few facts that I discovered for myself about CPL filters:

  • They remove some of light reflections
  • They darken the image
  • The image greatly depends on filter rotation on the lens

Here are two simple pictures that illustrate the principle behind the filter ( taken here ):

Now it must make sense that to achieve the desired "remove reflections" effect one must rotate the filter on the lens and asses the image in the viewfinder. Usually the filters are made that way so they can be rotated after being mounted on lens.

At last - couple of dummy images, one taken with and one taken without the CPL filter:

Note the sky reflections removed from windows of the building.

Monday, May 17, 2010

Amazing stuff - OpenStreetMap, NaviComputer, Holux M1000C

I bought a chineese Holux M1000C GPS reciever / logger and set up my prehistoric Acer n311 to run NaviComputer on it. OpenStreetMap is an amazing thing, as much as NaviComputer is.

I hope my problems of finding my way around are gone for good. I`ll make sure to toss it into a car and will also take it on my trips for sure.

For now this is my typical track from home to work that i cycle twice a day on weekdays ( unless I`m too lazy and take subway instead )

Interesting fact: My average speed on a bicycle is 1 km/h more than it is when I`m struggling with traffic in my car! And it is 30% faster to cycle than take a subway.