[moliuguy]

請問遮光罩係甚麼情況下最有用?
日光日白? 影夜景? wide? zoom?

[Martin@SEPHIROT]

It should be used when you want to block undesired light entering your lens.

For example, daylight directly entering your lens from high sky will cause image to look blur. Lens hood should be used to block that light.

Both wide and zoom lens should use a lens hood.

In night shot, it depends on the place you take your photo. If it's bright with different lighting(eg. flash from other camera, leon light), use it.

[Tiger I]

咁請問佢同偏光鏡既分別係邊?

[Martin@SEPHIROT]

PL filter is used to control incomming light source, not to block undesired light around you.

Or in a simple way to say, PL filter, as all filters does, alter the light source comming from your subject, no matter people, landscape, still-life; while a lens hood mainly blocks the light around the photographer's camera.

PL filter can reduce water or glass surface reflaction but a lens hood can't.

PL filter can reduced the non-polarized light from the sky and make the sky looks "bluer" and the lens hood have very very little effect on this.

Also, it is suggested to use a lens hood when using a PL filter. Though it is a little difficult to turn/set the PL filter with the hood on. As they are of different function, better use them both.

[Tiger I]

thank you, Martin@sephirot.

But 我想再問, 係我既認知當中, 偏光鏡既作用係block晒所有光, 除了由主體直直反射回來的光. 是否這樣?

如是, 那和遮光罩的用途便差不多 (剩講上面第一項用途).

另外, 如果偏光鏡和遮光罩一起用, 那進入鏡頭的光便會很少. 如使用一般家用數碼相機時用高iso, 出來的成像又會多noise. 請問一起使用這種方法是否只可以用於單鏡反光或數碼單鏡反光這兩種機呢?

[Martin@SEPHIROT]

Thank you for ypur question tiger.

The theory of PL filter is rather complicated related to physics, I can just explain some here.

Well light we see is actually waves. This should be understand, here, as "vibrating particles". Assume light comes directly in front. A single direction light source can have particles vibrating in different direction (ie. up and down, left and right or whatever possible).

PL filter blocks almost any other direction of vibrating particles and allowing only one direction of vibration to go through, depending on how you turn/set your PL. This is basically how it works.

However, a lens hood is not a optical instrument and can never "polarize" light.

For explosure, a lens hood will not decrease "correct light" entering lens, it just blocks unwanted light around you, also reducing the chance of lens flare. Not only you don't have to increase ISO or explosure value, it makes metering more accurate.

It is correct that PL takes up quite a lot of light, from 1 to 2.5 F-stop, depending on brand, setting and situation.

"Use them both" can be applied to any camera.

Remember don't try to replace hood with PL. First they are of different function. Secondly, the more filter you use, the lower image quality you get. PL can be counted as 2 filters already. Use it only when you need to.

Keep the hood on your lens whenever possible.

[ccleung1]

你試過fog (霧)鏡嗎?

下次試o下,o吾用遮光罩, 鏡頭向著強烈燈光,
慢慢移至燈光剛剛離開畫面, 拍照.

用遮光罩再試一次.

很好玩的!!

[Cheese]

想問一下 A80加了wide鏡仲可唔可以加52mm的遮光罩
即係dcfever賣的那款
http://www.dcfever.com/showroom/catalog.php?categoryID=13

[Martin@SEPHIROT]

to ccleung1:

I tried it long time ago, when I was still a student. I remember I was in a country park, early in the morning, should be before 10 am.
Fog filter was borrowed from a classmate of photography club.
The light in this case came thru trees and reach my camera, quite a direct light as I pointed the lens a bit upward.

The effect without lens hood is better in this case. The fog filter increase and soften the lens flare and produced a romantic mood.
I'm not the one who think of doing it without a hood, just my friend told me it feels better and I try!

Every rules can be broken in terms of creation!

It's great to hear you having fun!

[Martin@SEPHIROT]

To cheese:

Sorry that I don't know much on this issue. I can just do some guess works.

As the wide angle lens should be mount on the same place as the hood, you probably can't mount 2 options on one same place. I don't know if this is correct as I have never used a A80.

Moreover, lens hood is designed to match different focal length. Unless the 52 mm hood is designed for use on wide angle, it should not fit it in general.

The above are all just gussing from experience. I suggest you to ask the sales person of any trusted photography store. I got some friends in Boardway, timesquare, they are all very helpful and glad to give you a helping hand on this issue.