Two CPL filters used together to replace ND filter - 未名空间MITBBS历史存档

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Two CPL filters used together to replace ND filter

Two CPL filters used together to replace ND filter# PhotoGear - 摄影器材

j*82010-04-19 07:04

1 楼

I found the following tip from web.
Tip: use a polarising filter
A polarising filter offers a similar light reducing option as a Neutral
Density 4x filter. Add two polarisers together and you can get an infinitely
variable ND from 4x to very strong (almost black) by rotating the front one.
Has anyone on this board used this tip? Will it works.
I already have on Hoya MC pro1 digital CPL and thinking to get another
cheaper Hoya CPL from ebay to avoid to buy a set of ND filters.
How about this one?

l*a2010-04-19 07:04

2 楼

not good.

infinitely
one.

【在 j****8 的大作中提到】

: I found the following tip from web.
: Tip: use a polarising filter
: A polarising filter offers a similar light reducing option as a Neutral
: Density 4x filter. Add two polarisers together and you can get an infinitely
: variable ND from 4x to very strong (almost black) by rotating the front one.
: Has anyone on this board used this tip? Will it works.
: I already have on Hoya MC pro1 digital CPL and thinking to get another
: cheaper Hoya CPL from ebay to avoid to buy a set of ND filters.
: How about this one?

j*c2010-04-19 07:04

3 楼

CPL容易偏色，可以对着草地试试看

j*82010-04-19 07:04

4 楼

Which ND filter is most commonly used for taking water falls?
ND filters and their exposure factors
2x one stop
4x two stops
8x three stops
64x six stops

k*t2010-04-19 07:04

5 楼

The first one needs to be a linear pol. two cir pols will not work.

l*a2010-04-19 07:04

6 楼

unless you hook them up face to face

【在 k****t 的大作中提到】

: The first one needs to be a linear pol. two cir pols will not work.

j*82010-04-19 07:04

7 楼

you can not turn linear polarized filer, can you?

【在 k****t 的大作中提到】

: The first one needs to be a linear pol. two cir pols will not work.

c*y2010-04-19 07:04

8 楼

why not?

【在 j****8 的大作中提到】

:
: you can not turn linear polarized filer, can you?

j*82010-04-19 07:04

9 楼

I never have linear filter. Just guess by key word " Linear".
Then if it can turn, what different between LPL and CPL?

【在 c********y 的大作中提到】

: why not?

c*y2010-04-19 07:04

10 楼

CPL has a quater wave plate

【在 j****8 的大作中提到】

:
: I never have linear filter. Just guess by key word " Linear".
: Then if it can turn, what different between LPL and CPL?

k*t2010-04-19 07:04

11 楼

CPL has one more piece behind the polarizer: quater wavelengh to turn the
linearly polarized light into circularly polarized light.

【在 j****8 的大作中提到】

:
: I never have linear filter. Just guess by key word " Linear".
: Then if it can turn, what different between LPL and CPL?