DIY Fader ND - CP+LP

Z

zm15

Well-known member
I went the route of using a circular polarizer and screwing on a linear polarizer in front of it.

I've never used any type of fader, so I have nothing to compare it to and was hoping I could get some help.

It doesn't stop all the light like you see some demo videos of a real Fader ND filter, and sometimes it seems to give a greenish tint to the picture when i really stop down the light.

Are these thing normal at all for a real fader? Will the filter stop all the light?

I used a Zeikos circular polarizer, and a tiffen linear polarizer.
 
attach the circular polarizer after the linear polarizer. You need to be able to rotate one filter while the other stays put, thats how the fader nd works.

circular polarizer is a linear polarizer that can be rotated.
 
rovanpera said:
attach the circular polarizer after the linear polarizer. You need to be able to rotate one filter while the other stays put, thats how the fader nd works.

circular polarizer is a linear polarizer that can be rotated.
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I tried this and it does not work. It only works when I do camera -> circular polarizer -> linear polarizer

Both the circular and the linear polarizer rotate.

I'm curious if a real Fader ND filter goes completely black when rotating and stopping out the light?
 
I've been doing a little reading on the subject and just using 2 linear polarizers is fine on m4/3s cameras since there is no phase detection autofocus.

A whole bunch cheaper and better quality too (ie a cheap LP is far better than a cheap or even middle range CPL)
 
Dazza said:
I've been doing a little reading on the subject and just using 2 linear polarizers is fine on m4/3s cameras since there is no phase detection autofocus.

A whole bunch cheaper and better quality too (ie a cheap LP is far better than a cheap or even middle range CPL)
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I've read that it takes both a circular and linear or it will not fade, is this true? any video examples of this?

Is a DIY fader with a circular and linear supposed to go completely black and stop out all the light like a name brand Fader ND?
 
No it fades just fine with 2 linear polarizers, if you have 2 CPL it doesn't fade as much. The reason why alot of people don't use 2 LP, is that for most DSLR camera systems the polarized light stops autofocus and metering from working properly. Having a CLP before the lens "realigns" the light a bit so those features can still work. The best CPL will always be worse than the best LP due to the added complexity.

Back in the days of manual photography LPs were a lot more common as there was no need for CPLs, I think most cinematography uses LPs too

I've never tried a real variable ND filter so I can't comment on that.
 
Dazza said:
No it fades just fine with 2 linear polarizers, if you have 2 CPL it doesn't fade as much. The reason why alot of people don't use 2 LP, is that for most DSLR camera systems the polarized light stops autofocus and metering from working properly. Having a CLP before the lens "realigns" the light a bit so those features can still work. The best CPL will always be worse than the best LP due to the added complexity.

Back in the days of manual photography LPs were a lot more common as there was no need for CPLs, I think most cinematography uses LPs too

I've never tried a real variable ND filter so I can't comment on that.
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Thanks for the reply Dazza. I'm using it with a GH2 in movie mode, so with contrast based autofocus i think it's ok.

I'm curious, when you use your two LP's, does it stop out all the light completely? Or at least a large amount?

Is there a slightly blueish tint to it as you fade as well?
 
Not quite completely but almost. Yes unfortunately polarizing filters can cause slight colour casting, at certain angles
 
Dazza said:
Not quite completely but almost. Yes unfortunately polarizing filters can cause slight colour casting, at certain angles
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Gotcha, looks like I might have better luck with 2 linear polarizers. Mine doesn't even go close to being completely black. I must have done something wrong.
 
I made these in Dec. 2009 using a Canon HV30 as a test since I had a circular and linear Polarizer to play with. I was thinking of getting a Fader ND myself for my GH2 but have read mixed reviews and people complaining about the plastic filters, green casts, soft image above 100mm, etc. I'm wondering if two glass Polarizers would be better for sharpness and will run some new tests as soon as I get a 62mm linear Polarizer. There's two versions:

Version 1:

Version 2:
 
Dazza said:
The best CPL will always be worse than the best LP due to the added complexity.
.
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I Just decided to folly the DIY Vari ND path and got a good Marumi Super CPL (is 5mm thin??) http://www.amazon.com/gp/product/B003QSG0HK/ref=oss_product
and a Hoya LPL http://www.amazon.com/gp/product/B00009R9ED/ref=oss_product

I had a hard time finding good info on LPL reviews, but there was a great CPL review here: http://www.lenstip.com/115.4-article-Polarizing_filters_test_Results_and_summary.html

Wondering if you could answer a couple Q's i've got on the subject:

1. For my GH2, would I really be further ahead, as far as image quality, ND filtration depth (and polarization effect?) as well as far as reduced profile to return the Marumi CPL and get a second LPL?
2. Having a CPL and a LPL gives me Variable ND filtration PLUS standard polarization in one package, like the Singh Ray Vari ND DUO, correct?
3. during all my reading, it seems that some ppl were unscrewing and reversing one of the filters inside one of their polarizers, but i couldn't understand why.

I purchased 77mm for my 20mm 1.7, 50mm 1.4 FD and the 14-140 HD ... and a bunch of rings of course.. hope that was a good purchase!

Thanks.
 
I'm far from an expert on the matter

1. I wouldn't bother too much since there isn't a huge amount of price difference between them and judging from those reviews it seems to be a very good CPL. plus you'll be able to use it on other cameras in future that might require a CPL.
2. Yes from what I can gather, polarization should be able to be changed by just rotating the inner filter
3. Reversing a CPL was effectively turning it into an LP, these ppl had 2 CPL filters.

I'm sure you will be very happy with your purchase, variable ND filters are very very handy.
 
Great. Thanks Dazza.

1. With this setup then, am I effectively ahead of the game, compared to say a Lightcraft Fader ND Mark II? ie will this perform the same or better than a standard Vari ND filter, with that added bonus of also having ploarization effects ? Or is this DIY setup a compromise in some ways adainst standard Vari Nd's- ie. This won't give me as much light reduction as a standard Fader ND?

2. What is the standard "setup" , after i attach the CPL, followed by the LPL, how do I set them both to ZERO and then gently dial in the ND filters if i need them? I have read ppl put a rubber band on the CPL to hold it steady, but having these TWO variables is kind of confusing my noob approach to using ND filters. Plus, not having any markings on the sides, where to i begin?. Any startup advice would be appreciated.

3. assuming i have say, my 20mm 1.7 wide open on a sunny day, tons of bokeh and way too much light at 1/60th / f1.7, do i simply increase the ND filtration untill by GH2 meter reads good, or do i have to over/underexpose according to the meter?

thanks again - much appreicated!
 
iflight said:
Great. Thanks Dazza.

1. With this setup then, am I effectively ahead of the game, compared to say a Lightcraft Fader ND Mark II?

2. What is the standard "setup" , after i attach the CPL, followed by the LPL, how do I set them both to ZERO and then gently dial in the ND filters if i need them?

3. assuming i have say, my 20mm 1.7 wide open on a sunny day, tons of bokeh and way too much light at 1/60th / f1.7, do i simply increase the ND filtration untill by GH2 meter reads good?!
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1. I'm interested to hear opinions about this too.

2. You simply need to be able to rotate the outer filter relative to the inner one - so the elastic band (or whatever) is simply to stop them both rotating in tandem. You don't need markings to find minimum and maximum filtration - just look through the viewfinder/LCD and adjust the level of filtering until you like what you see.

3. Yes. Or until until a quick test shot looks good.
 
GrahamH said:
1. I'm interested to hear opinions about this too.
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OK great, thanks a lot.

Who will answer our question? Anyone? Is this setup at all a compromise over a standard Vari ND setup, or is it the mother of all Vari ND DUO for a fraction the price??
 
I'm not sure if I'm the only one that has this problem, but when I stack the linear on top of the circular, i start to get a blue cast when it begins to stop out the light. I have tried to flip flop the filters every which way, but am still having a hard time achieving the same light stops that you see in the name brand demos. Perhaps I'm just missing something. I don't believe there should be a blue cast on the filter, should just get darker.
 
hello,

after comparing the samples of stacking a LP + CPL vs. a Light workshop Fader ND 2, i decided to go with the LP + CPL combo as the Fader ND degraded IQ.

I already had a Hoya HD CPL so I ordered a cheap Tiffen linear polarizer (82POL). Despite the greenish tint from the cheap Tiffen, the light reduction was minimal compared to the fader ND. It perhaps cut out 3 stops of light. It seems the Fader/Vari NDs and some of the other LP + CPL samples cut out light to almost a pitch black.

Is this normal? or is there something wrong with the LP? Thanks!
 
I own a polarize filter already so was thinking about to buy a linear one and use it like an nd fader. Heard that some said it would be give sharper results after 50mm with this DIY ??
Anyway, my concern is if any of you guys did try that with 14mm and if you get any vignetting ( I dont have the slim version of the polarizer).
 
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