A couple shots from the Memphis Zoo last weekend

[petpoor]

Here is a few shots that I took at the Memphis zoo this past Sunday. I had alot that really turned out lousy and was curious if my camera store gave me good advice or not... I am using a U.V. lens and they also sold me a polarizing lens. He told me to leave the uv lens on and just screw the polarizing one on top of it so in essence I am shooting through two extra pieces of glass.... is this going to cut down on my light so much that shutter speeds slow so bad that I get images that are just not super sharp ???? Some of the bad pics I even used the railing as a makeshift tripod and they still just did not have the pop that I thought they should,,, but hey I am still learning this stuff so I could be wrong.
Tom

Now this is my kind of Lizard :eek1:

I think this guy stayed out too late Saturday nite lol

 

[spline9]

I often use the UV and Circlular Polarizer combo but only in bright outdoor conditions. The UV is mostly used to protect your lens and its good that you have one. If anything happens to the glass, it will happen to the UV instead of your lens. Good insurance.
The CP is used to reduce reflections/glare. It has an effect on reflected light. I'm no expert but it works great. It can also enhance the color of the sky (if youre pointing perpendicular to the sun). It is a dark filter so it will reduce a significant amount of light to the lens so use it only when you know it will benefit the shot. Otherwise, leave it off unless you intentionally want it to be a tad darker (ie: in really bright situations or if you want a longer exposure)
The best thing to do with the CP is to play with it while aiming it at a glass (or anything with a high reflective property) and adjust the polarizer. You will see the reflections adjust. You can also point it at the sky (at a 90 degree angle to the sun) and rotate the lens. You will notice the sky's color change. This helps a lot if you need to adjust the sky according to the foreground or to make the clouds pop out more.

I'm a total amatuer with no training so this is what I've picked up on my own. If anybody has a better explaination of its operation feel free to pipe in. I'm always looking for ways to improve my skills.

 

[gregr]

The uv filter won't block a significant amount of light but the polarizer blocks approximately 1.5 stops- that is indeed significant. A tripod will make a huge difference in the sharpness of your images (although the pics you posted look sharp to me) but you always have to be aware of your shutter speed. If the subject isn't moving you have no worries but if it is you have to use a shutter speed that is fast enough to get sharp results- this is seperate from the issue of using a fast enough shutter speed to avoid camera shake when you're not using a tripod.
The general rule of thumb is sharp results are probable (again, this has nothing to do with getting a sharp shot of a moving subject) when you use a shutter speed that is at least 1/focal length-- for example, if you're using a 300mm lens you need a shutter speed of at least 1/300 to get a sharp handhelp picture. Of course that is only a general rule but it gives you a place to start.
Back to the polarizer issue-- if your camera tells you the settings are f5.6 and 1/500 for a properly exposed picture and you then add the polarizer the same shot will now be f5.6 and 1/180, which is going to be iffy if you aren't using a tripod.
Of course there are things you can do to get a fast enough shutter speed in that situation (raise the iso, use a bigger aperture etc) but at least this example gives you an idea of the implications of using that filter.
Greg