Digital camera accessories

[csmith200]

 Hi:  Just getting familiar with my FZ18 and about to order some filters.  
 I'd much rather use a linear polarizer because it has a much stronger effect than a circular.  
 I know circulars are required for the auto focus on a SLR because of the beam splitter required for the optical finder.    Since the FZ18 uses an EVF will its' auto-focus work OK with a linear polarizer?  Also:  how critical is a thin polarizer for avoiding vignetting?

[ShutterbugGail]

Hi there and welcome to the Q&A Board!

Most compact digital cameras, such as the FZ18, do not have reflection mirrors, so either linear or circular polarizers can be used.

You will get vignetting at wide angle with a standard polarizer so a slim one would be a better choice. The FZ18 takes 46mm filters, and it can be difficult to find polarizers that size. One place I found slim polarizers was at B&H Photo.

http://www.bhphotovideo.com/

Hope you're enjoying your FZ18!

[bdery]

Hi and welcome. Here are some additional answers:

I'd much rather use a linear polarizer because it has a much stronger effect than a circular.

 
That is not correct, the effect is the same. A circular polariser IS a linear polarizer with an addd element.

I know circulars are required for the auto focus on a SLR because of the beam splitter required for the optical finder.

A circular polarizer is required for autofocus with a SLR or DSLR, correct. But it's not linked to the optical viewfinder, which doesn't have a beam splitter. That beam splitter is in the focusing system.

Since the FZ18 uses an EVF will its' auto-focus work OK with a linear polarizer?  Also:  how critical is a thin polarizer for avoiding vignetting?

The EVF is not linked to autofocus, but yes a linear polarizer wil work fine with your FZ18. I'd suggest you get a thin polarizer to avoid vigneting, but the tolerances on thickness vary for each camera. The best thing to do would be to visit a store and ask to test a few polarizers.

Here is additional information on polarizers:

http://www.digicamhelp.com/accessories/filters/polarizers.php

[csmith200]

Thanks for everyone's reply.  I do beg to differ on the opinion that circular and linear offer the same effect.  True, they both affect reflections and glare, but every circular polarizer I've used, and there have been several, offered a much more subtle effect--so subtle it was sometimes hard to notice.  The old linear polarizers I used on a manual focus SLR had a very marked effect, especially on skies and clouds.  These days circular polarizers are so much the norm I think many people have never used a linear.  I'd experiment by holding the linear polarizer in front of my camera but it disappeared along with my manual focus gear in a burglary about 20 years ago.

[ShutterbugGail]

but every circular polarizer I've used, and there have been several, offered a much more subtle effect--so subtle it was sometimes hard to notice.  

That's interesting. I've never heard that and always understood both linear and circular polarizers produce the same effect.

I do know there specialized polarizers, such as a warming polarizer. Here's two examples of specialized filters at the Tiffen site:

http://www.tiffen.com/ultrapol.htm

According to Tiffen:

"A Circular Polarizer is a linear one to which has been added,on the side facing the camera, a quarter wave "retarder."  This "corkscrews" the plane of polarization, effectively depolarizing it, eliminating the problem.  The Circular Polarizer otherwise functions in the same manner."

http://www.tiffen.com/polarizer_pics.htm

[engineerdude]

I just found this topic so I'm resurrecting it.   

I have an FZ18 and circular polarizer.  Unfortunately, when I use it I get this blue distortion where some of the sky looks bluer than other parts and it almost looks fake.  I should probably post a pic.  Anyway, I'm thinking that a linear polarizer will make the effect more "linear" and not like someone has a blue light just off the edge of the camera.  I guess this is what vignetting is.  I'll get one since they're fairly inexpensive and see how it does.

BTW, thanks Gail for all your info on this great site. I'm not only trying to take good photos but to be a good photographer. I think it all starts with thinking like one with all the great info on this web site going through my brain when I'm trying to set up a shot.  I guess its sort of like golf.  They say that when you're about to hit the ball, try not to have more than 20 things going through your mind at the same time.   

[ShutterbugGail]

Hi engineerdude and welcome!

Thanks for the kind words.

To avoid vignetting, consider getting a slim polarizing filter. It may be a bit difficult to find the filter size needed for the FZ18 (46mm). If so, try a local camera shop or an online site like B&H photo.

Here's some information on both linear and circular polarizers that should help:

http://www.digicamhelp.com/accessories/filters/polarizers2/


Related reading: FZ18 blog
http://www.digicamhelp.com/topics/camera-logs/panasonic-fz18/