Polarized filter for a70?

[cheewooi]

Hi,
I plan to get a polarized filter for my a70, i don't know anything about filter but I juz know dat the polarized filter will make the photo looks nicer by limiting the light pass thru the lenses. i need to know more about polarized filter? is there anyone know about this? i browse some web site and i saw there's 2 type of polarized filter - linear and circular? for Cokin filter. what the difference between these two? And another question is, how do i mount the filters on my a70?

thanks

[juno]

there has been a previous thread discussing the use of polarizers. check this thread >> http://photography-on-the.net/forum/showthread.php?t=15859

you will also need the LA-DC52 lens adapter for your A70 before you can make use of a filter or other attachment accessories.

[stopbath]

Try this link for more information than you can digest in one sitting on polarizers:

http://www.cliffshade.com/dpfwiw/filters.htm#polarizers

In fact the whole site is very good regarding digital cameras in general:

http://www.cliffshade.com/dpfwiw/index.htm

[cheewooi]

Thanks for yours recommendation,
I plan to get Cokin circular polarization filter. Does anyone using it?Can show me the resulf of the Cokin Filter? To use the Cokin circular polar filter, we need a Cokin Mount Braket for Compact camera to mount the a70 since the A70 doesn't have place to screw in the filter. Is there any possibility to mount the filter without getting the Cokin Compact Camera filter bracket?Another problem is if I get the a70 52mm Lense Adapter, is it possible to mount the filter onto the lense adapter?

Thanks

[Servant]

I just bought a kenko polarizer (LINEAR) for my A70 for $17.99 and it seems to work fine. No problem with the auto focus that I can tell and the light metering doesn't seem to have any troubles either.

Here's a picture I took with it:

http://home.wi.rr.com/servantseven/waterfall%20polerizer800.jpg

[cA70]

So polarized filters just let alot less light in i'm guessing?

Are these thing's expensive? $17.99 what currency?

I play with alot of long exposure shot's at night, can u get different stength ones? Are they cariable or the same every time?

One last thing, does the camera have any trouble focusing with it?

[cheewooi]

To Servant,
You are using Kenko linear polarizer? How do you mount your polarizer on your a70 lense? Did u use the 52mm Lense adapter to mount it? I keen to know coz da Cokin Digi Shoe Lense Adapter are a bit bulky to carry around?


To cA70,
If you not sure whether a70 support linear polarizer, it's better to get a circular polarizer, it's bit more expensive than linear one and it won't affect the AF light and metering! I am from Malaysia, a Cokin brand filter cost me around RM34.50 till RM54.50 (if converted to US dollar is around USD$9.07 till USD$14.32) depends on what kind and type of filter. Typically there are 2 kind of filter available from Cokin - Square and Round filter)!

[Servant]

ca70 wrote:
So polarized filters just let alot less light in i'm guessing?

Are these thing's expensive? $17.99 what currency?

I play with alot of long exposure shot's at night, can u get different stength ones? Are they cariable or the same every time?

One last thing, does the camera have any trouble focusing with it?

Polarizers do two things:
1) they cut down the reflections from things like water and windows (this is the primary purpose)
2) they cut light (about two stops) just like an Neutral Density filter does

The price I paid was in US Currency - sorry I didn't specify that.

Not sure if a polarizer would be useful at night; maybe with a good flash.

[Servant]

cheewooi wrote:
To Servant,
You are using Kenko linear polarizer? How do you mount your polarizer on your a70 lense? Did u use the 52mm Lense adapter to mount it? I keen to know coz da Cokin Digi Shoe Lense Adapter are a bit bulky to carry around?


I bought the LA-DC52C Canon A70 adapter (52mm) for $15 US.

[cheewooi]

Thanks for your reply Servant,
here's another problem, let say if i get my LA-DC52C lense adapter, can i fit any 52mm filter to this adapter? is the adapter tread universal to all 52mm adapter especially Cokin filter? Did anyone out there using Cokin Filter together with this LA-DC52C lense adapter? I need to know wheter is it compatible b4 i get my adapter and filter.. Thanks..

[cA70]

cheewooi: USD$14.32 isn't that much, so circular is better than a linear one?
Any reason so? and i have turned of the AF beam anyways so that wouldn't matter. UI was going on by the light entering in the lens, but i supose it would addapt to the changes so it should work fine.

Square and round, are they the phisical shape of just a name?



Servant: The water bit would be interesting, but my main purpose is to take a picture like the one posted above with the waterfall. A longer shutter without over exposure. Thanks for the currency check.

About the night, thats where i do my long shutter things so there not over exposed, i was looking for a filter so i could do those things during the day. At night you need the most amount of light you can get.


Can you get different levels of 'Polarize', like one that lets in less light than another?

How long can you get the shutter to stay open for during the day to get a shot like the waterfall?

[cheewooi]

cA70:
the circular polarizer filter is always compatible will all kinds of camera, if you not sure whether linear polarizer will affect your AF light, then better get a circular polarizer filter in the safe side. If not mistaken both the filter function is the same. Maybe you can check it out at http://www.cokin.com for more information regarding the filter. The square and round is physicall difference, but most of the polarizer or ND (neutral density) filter come in round shape so that you can adjust the filter according to the effect you wanted on the LCD screen or lense.

[cA70]

I've read some of the links that people have put on, its seems ths main use is for reflection. And the cliffside thing went into effects with them. What my main purpose was to let less light in so i can leave the shutter open for alot longer. Then do some blur effects with the camera, is this the right/wrong type of lens for that?

[Servant]

cA70 wrote:
I've read some of the links that people have put on, its seems ths main use is for reflection. And the cliffside thing went into effects with them. What my main purpose was to let less light in so i can leave the shutter open for alot longer. Then do some blur effects with the camera, is this the right/wrong type of lens for that?

It will serve that purpose just fine plus you get the bonus of canceling out the reflections. That's the reason I bought a polarizer (for the waterfall). I could have just got an ND filter but I figured why not get two in one.

[cA70]

That's good to hear!

How long can u then open up your shutter to with a polerized filter?

Now i've got another thing to research and buy.

[stopbath]

cA70 wrote:
That's good to hear!

How long can u then open up your shutter to with a polerized filter?

Now i've got another thing to research and buy.

A Polarizing filter will knock 'one to two' stops off your exposure. So that doubles or quadruples your exposure time. Compare the different brands offered at the store. Even between circular and linear of the same brand there may be differences in ND qualities.

An additional ND filter may be required depending on your scene and the available lighting (direct noonday sun, overcast, evening...)

[cA70]

So if i were to take it to f8, it would turn it to a f10-12?

Can u ad a filter ontop of that filter, is that what ur saying?

A70>polz>nd ?

[stopbath]

Not really. The A70 can not shoot at anything less than f8.

In auto or program mode, the camera will compensate and change aperture or shutter speed for the lower amount of light, but f8 will still be f8. In time mode, the aperture would open up in response to ND or Polarizer filters (not close down.)

You could stack as many filters together as you wanted. When stacking filter, if using cheap filters, you will degrade your image faster than with high quality filters as the abberations and defects multiply.

[cA70]

My origional plan was for just 1 filter to just get a slower shutter speed without over-exposure.

If i can do that with 1 i'm happy as larry.

And i do realise that the camera won't be able to change the numbers on the screen, but it would be equivelent of that is what i was geting at.

[stopbath]

Well sort of.

The f stop measures the ratio of light transmitted by the lens itself. By cutting the light from the source (with a filter) you're not affecting the ratio of light transmitted by the lens. Thus the f stop remains true, but you have changed the amount of light from the scene that hits the sensor.

The actual amount of light to cut down depends on your scene and the original light it has compaired to what you want it to have.

[cA70]

I supose u could view it as the same way u view a 3x zoom witha tele converter, still 3x but modified before hitting the lens.

Is it possible to change the amount of light to come through a filter?

Cause some times i'd want a quick shot, but no reflection of the water, other times there will be no water and i'm after a long shot during the day.

Servant:
I see u used >
Shutter Speed 0.4
Aperture Value 8.0

Is 0.4 the max u could go before over exposure? Although that is a very long time for a shutter to be open in bright sunlight.

[stopbath]

cA70 wrote:
I supose u could view it as the same way u view a 3x zoom witha tele converter, still 3x but modified before hitting the lens.

Is it possible to change the amount of light to come through a filter?

Cause some times i'd want a quick shot, but no reflection of the water, other times there will be no water and i'm after a long shot during the day.

Servant:
I see u used >
Shutter Speed 0.4
Aperture Value 8.0

Is 0.4 the max u could go before over exposure? Although that is a very long time for a shutter to be open in bright sunlight.

Yes, you teleconverter magnifies the image, then the lens does too.

I can't think of a filter that can 'dial in' light pass through value. You just have to stack filters.

[Servant]

cA70 wrote:
Servant:
I see u used >
Shutter Speed 0.4
Aperture Value 8.0

Is 0.4 the max u could go before over exposure? Although that is a very long time for a shutter to be open in bright sunlight.

Yeah, I believe that was the best I could do with the high noon sun. Here's one with a 1 sec shutter (altered big time but has a good blur effect):

http://home.wi.rr.com/servantseven/waterfall-one-sec-shutter.jpg

[cA70]

Alterd using photoshop?

Did u just make it darker?

Did u just use the one filter or stack them up?

[Servant]

cA70 wrote:
Alterd using photoshop?

Did u just make it darker?

Did u just use the one filter or stack them up?

Darkened and other enhancements such as color adjustment and sharpening using paintshop pro. Only one filter.

[cA70]

The origional waterfall, is that alterd at all or the origional?

When i shoot i prefer not to photoshop, is cheating is a way, but if u have to u have to.

[Servant]

cA70 wrote:
The origional waterfall, is that alterd at all or the origional?

When i shoot i prefer not to photoshop, is cheating is a way, but if u have to u have to.

Yes, I altered the first one too but the overexposure was not nearly as bad. I tend to make some changes to all my pics; that's what I love about digital - It gives me a good degree of control.

Bottom line: the polarizer DID allow me to get a much slower shutter and made for a decent blur.

[cA70]

Servant wrote:
Bottom line: the polarizer DID allow me to get a much slower shutter and made for a decent blur.

That was my whole plan!

[cheewooi]

Servant,
Did you try use 2 filters (polarizer and ND(neutral density) filter) together to take the waterfall photos?
I plan to get a Circular Polarizer and ND filter. I heard that there's about 3 types of ND filter - ND2, ND4 and ND8. ND2 have a F stop of 1 whereas ND4 and ND8 both have F stop of 2 and 3 respectively. which one is suitable for the a70?

thanks

[Servant]

cheewooi wrote:
Servant,
Did you try use 2 filters (polarizer and ND(neutral density) filter) together to take the waterfall photos?
I plan to get a Circular Polarizer and ND filter. I heard that there's about 3 types of ND filter - ND2, ND4 and ND8. ND2 have a F stop of 1 whereas ND4 and ND8 both have F stop of 2 and 3 respectively. which one is suitable for the a70?

thanks

I just used a single linear polarizer, I don't have any ND filters yet.

[dsylvak]

HI there..

see my post on this subject;.... short n sweet go for Kenko polarizer and lens adaptor. Works just as well as the Canon polarizer and filter.. slight different in price tho. You will love the results on either one.


keith

[dsylvak]

you should be able to mount (try holding hands!) the polarizing filter alongwith the adaptor...no problem

keith

[cheewooi]

to keith:
do you have a picture taken with kenko polar filter?
is it possibble to mount any filter with the canon a70 52mm lense adapter? it'll be a bit trouble some to hold the filter with one hand while another hand holding the camera...