I don't need a circular pol. filter... right?

Nytmair · Dec 13, 2004

I just wanted to double check and make sure this is the right filter (the price seemed low so I wanted to see if it would be ok.

For my camera (panasonic fz20) I am going to get an adaptor that allows me to use 62mm filters/lenses. Now, becuase it's not an SLR camera, the lens does not rotate to focus, it's all within the camera. I will be able to use a cheaper/linear polarizing filter becuase of this, correct?

Here's the one I am looking at since I've heard good things of Hoya.
[ame]http://www.amazon.com/exec/obidos/tg/detail/-/B00006I5BU/qid=1102965344/sr=1-5/ref=sr_1_5/104-0817538-0043911?v=glance&s=photo[/ame]

OR...

This is a kit from Tiffen that has the polarizor, a UV filter (which is the other lens I am going to get), and a warming filter.
[ame]http://www.amazon.com/exec/obidos/tg/detail/-/B00005061L/qid=1102966074/sr=1-1/ref=sr_1_1_etk-photo/104-0817538-0043911?v=glance&s=photo&n=502394[/ame]

Would that be the best bet to buy since it has the 2 i want plus the extra warming for a pretty good price? Does it matter if I use a circular filter when I don't need it since my lens/filter isn't going to be moving?

Thanks for any help

ferny · Dec 13, 2004

A linear polarizer still rotates. Otherwise you wouldn't be able to change what it is polarising. It'd either be on or off all of the time. Linear and circular relates to the construction of the filter itself.
The general rule of thumb is, with auto-focus SLR's you need a circular. With digital cameras a linear one will do.

That is my understanding of it. I'd just buy the circular one myself. I don't think they're that much more expensive are they?

Nytmair · Dec 13, 2004

well the one in that kit (the 2nd link i posted) is a circular.... so I figure i'll get that kit since it has the 2 filters i was planning on getting in the first place.

Jamie R · Dec 13, 2004

Coming from Buffalo, I'm sure you'll appreciate that the trend for polarisrer+warming filters came about through the Moose Filter. This trend for sickly sweet hypersaturated and very false looking filters really hammered wildlifers and landscape photographers in the 1990s.

You may really regret not having a separate warm up filter, and also feeling disabled by a warm-up polariser when you don't want the warm-up for cool blue shots of the sea, beach, or other things watery, such as Niagara Falls. The weirdo colours from these combinations make me feel I'd rather be jumping off the Niagara Falls like the Lady of the MIst.

Nytmair · Dec 13, 2004

well that kit I posted comes with 3 separate filters:

- UV protector filter
- Circular polarizing filter
- 812 color warming filter

So the polar/warming aren't combined like you seem to think. So don't go jumping in the falls just yet

Jamie R · Dec 13, 2004

That looks okay as a basic intro set - nothing wrong with that. Can I take my lifejacket off now?

Tiffen isn't as well regarded across the Atlantic although they aren't much different to the standard Hoya filters.

Don't know the Panasonic camera you speak of - if it has autofocus or a spot-meter, your focussing and metering will both be messed up. It's safer sticking to a circular polarising filter kit.

Hope that helps.

ksmattfish · Dec 13, 2004

Linear polarizers are for manual focus cameras.

Circular polarizers are for auto focus cameras.

Jamie R · Dec 13, 2004

It's a bit more complicated than that Matt.

If a camera uses a sophisticated metering system, including 'splitting off beams of light' to measure differential exposure, then a circular polariser is required. Otherwise the polarised split beam going to a 5% portion of the exposure meter becomes drastically confounded.

The theory boggles me. Wish someone could explain it to me too....

Axel · Dec 13, 2004

ksmattfish said:
Linear polarizers are for manual focus cameras.

Circular polarizers are for auto focus cameras.

ANd what happens if you use a linear on a Auto-Focus SLR? Won't it work?

fadingaway1986 · Dec 13, 2004

I thought you just got a circular for an auto-focus, and a linear for a manual...

I think the camera can't focus through the linear?

Not sure if thats right though?

Jeff Canes · Dec 13, 2004

fadingaway1986 said:
--I think the camera can't focus through the linear?--

Yes, your 100% right on that

ksmattfish · Dec 13, 2004

Jamie R said:
It's a bit more complicated than that Matt.

If a camera uses a sophisticated metering system, including 'splitting off beams of light' to measure differential exposure, then a circular polariser is required. Otherwise the polarised split beam going to a 5% portion of the exposure meter becomes drastically confounded.

The theory boggles me. Wish someone could explain it to me too....

Name one manual focus camera that won't work with a linear polarizer.

Name one auto focus camera that will work (focus correctly) with a linear polarizer.

Not to be too much of a smart ass, but I think it is as simple as that for most folks. :wink:

The metering systems you are talking about only come in modern camera designs, in other words, auto-focus cameras.

ferny · Dec 14, 2004

It has something to do with the mirrors in an SLR. The light changes when going through the linear and for the auto focus system most use they struggle with this light. So you need a circular one. Because most digicams don't use mirrors there isn't a problem.
Well, that is what I've read from experienced and knowledgeable digicam users.

I would look into it more for you (and me) but right now I'm waiting for the toilette so I can have my shower. I'm in a bit of a rush.

Jamie R · Dec 14, 2004

"Name one manual focus camera that won't work with a linear polarizer."

The Contax RTSIII with a linear polariser, along with every other camera with a narrow spot meter will have a higher percentage error due to the linear polariser. This is mostly because it's spot meter is around 3mm of the screen area or approximately 1%.

It's not that they don't work: the error margin becomes unacceptably high and mitigates against the extra effort of spotmetering. Thus metering with a polariser, leads to under/over exposure errors.

In the 1970's with manual centre-weighted cameras, camera designs were much simpler. Guess things change...not necessarily for the better.