Polariser V Nd V Gnd

[The Vulcan]

I'm permanently battling with the extreme light over here especially when I'm using my lenses wide open for OOF.

Currently I'm using a pola filter to achieve this which enables me to get an acceptable EV from my GF1 which is "limited" to 1/4000th shutter speed

Without the fitted pola I'm stuck at (say) f4-f5.6 which I don't want - too much DOF

The problem is it also changes the reflections, contrast and colours which I sometimes wish to retain

So, my question

Is a 3x ND better than a pola or what about a GND - I also read about soft and hard - what does that mean?

I've never used either an ND or a GND and would welcome any users advices and experiences.

Thanks

[Sunny Valentine]

Guess an ND (Neutral density) filter is exactly what you need here. Try to get good quality glass, as some cheapos really do alter the color apart from reducing the amount of light.

A GND filter is something slightly different: It has a graduated effect, going from clear on one side to a gray density on the other side, with either "soft" or "hard" (i.e. smaller or larger areas of graduation) in the central area in between. You need this for instance for landscape pix where you want to specifically reduce the brightness of the Sky, without touching the land part. Here you use a GND, and have the transition area at the horizon. Depending on the shape of the horizon, a soft or hard transition produces better results. Imagine a shot of the ocean with the sky above; here you have a clearly defined Horizon, and can use the 'hard" one. An alpine landscape where the horizon is ragged asks for a soft one.

Using a Polarizing filter is too much of a compromise, as it has other, most likely unwanted effects on the picture.

Sunny

[aeon]

I use ND2 ND4 ND8 (respectively they reduce light by 1stop 2stop and 3stop) they are neutral color so they will not affect the white balance, but be careful to buy a good one, most of the shops here in thailand sells a chinese brand that has very cheap ND filters but they are not so neutral, meaning that unless you get rid of it through custom settings on the white balance, you will get that tint.

The polarizer stop down but of course it reduce some reflected lights, and this effect can be unwanted on some case, but if you use the circular polarizer you can "minimize" the effect by turning it 90 degrees, however I think it stop down just around 1 stop.

I heard there are filters combined such as ND+CPL together so you get much less light and get rid of polarized reflections, very nice for watery images.

The GND is the gradual neutral density (it comes also in different strength as ND), and it has a gradient from dark to transparent (top to bottom) normally used to stop down the sky. Soft or hard is the way the gradient is distributed over the surface of the filter, soft means bigger gradient, the hard one it tends to grade from dark to transparent just in the middle.

Hope it is helpful.

Edited February 27, 2010 by aeon

[aeon]

Dude we answered at the same time

[The Vulcan]

Brilliant

Thanks Guys that's helped a lot

[eurasianthai]

I use ND2 ND4 ND8 (respectively they reduce light by 1stop 2stop and 3stop) they are neutral color so they will not affect the white balance, but be careful to buy a good one, most of the shops here in thailand sells a chinese brand

I also have been pondering for quite some time about buying or not ND filters, the light is just too bright in Thailand.

Where did you buy them Aeon? In Thailand?

What brand would you recommend?

[aeon]

I use ND2 ND4 ND8 (respectively they reduce light by 1stop 2stop and 3stop) they are neutral color so they will not affect the white balance, but be careful to buy a good one, most of the shops here in thailand sells a chinese brand

I also have been pondering for quite some time about buying or not ND filters, the light is just too bright in Thailand.

Where did you buy them Aeon? In Thailand?

What brand would you recommend?

not much choice of filters in bangkok, the ones I bought here are from a french brand called cokin, they are ok and price is ok too, and I bought them at capa at fortune mall. Just avoid nd from tyan or thayn or similar chinese brand, they are cheap but tint everything very strongly. If you are looking for highend brands such as tiffen etc, I had no luck in bangkok, but if you can find please recommend me where.

[The Vulcan]

I use ND2 ND4 ND8 (respectively they reduce light by 1stop 2stop and 3stop) they are neutral color so they will not affect the white balance, but be careful to buy a good one, most of the shops here in thailand sells a chinese brand

I also have been pondering for quite some time about buying or not ND filters, the light is just too bright in Thailand.

Where did you buy them Aeon? In Thailand?

What brand would you recommend?

not much choice of filters in bangkok, the ones I bought here are from a french brand called cokin, they are ok and price is ok too, and I bought them at capa at fortune mall. Just avoid nd from tyan or thayn or similar chinese brand, they are cheap but tint everything very strongly. If you are looking for highend brands such as tiffen etc, I had no luck in bangkok, but if you can find please recommend me where.

Fotofile are selling Heliopan - usually made from Schott glass (ala Schneider etc) - needs checking though as they also do a cheaper version.

[aeon]

I just experienced something weird by adding more than 1 nd filter (particularly when adding the nd8) it seems there is a magenta color cast, but the filters if used one by one visibly they don't cast any color. I thought was the nd8 that wasn't so neutral but I was wrong. I did some research and the phenomena seems to be related only to digital cameras (on film this doesn't happen) and seems related to the nd filter that is unable to filter infrared colors together with the other colors of the spectrum, and also the infrared filter of the camera sensor, so the light is stopped down but more you stop down more the infrared color are prominent. Anyone has experienced this? how did you managed to work out this? White balance could help but is annoying to do everytime I add more filters.

[astral]

I used to use a polariser to cut reflections and enhance skies, but have go out of the habit.

Perhaps time to try again?

[RAZZELL]

http://www.singh-ray.com/

http://singhray.blogspot.com/

And take your pic

RAZZ

Edited March 15, 2010 by RAZZELL

[aeon]

I never tried singh ray filters but it seems to happen even with that brand of nd filters, I did a quick search on google (key words: singh ray nd magenta cast) and there are many pages of forums describing the same problem when stacking dense nd filters together. The problem as I said before seems to be the sensibility of the camera sensor combined with the limitations of the filters to filter infrared colors.

[RAZZELL]

I never tried singh ray filters but it seems to happen even with that brand of nd filters, I did a quick search on google (key words: singh ray nd magenta cast) and there are many pages of forums describing the same problem when stacking dense nd filters together. The problem as I said before seems to be the sensibility of the camera sensor combined with the limitations of the filters to filter infrared colors.

You know what the answer is then...Photoshop!

RAZZ

[aeon]

yes or trying to compensate with less level of magenta in a custom white balance, but both photoshop and this solution are a fix but not a solution to the problem...

the funny/crazy thing is that with the same filters in the same scene and same light people don't get the magenta cast on canon 20d or film camera but they get it on canon 5dmk2 and canon 7d.

Maybe a different (less powerful) infrared filter in the sensors of these latest cameras?

Edited March 16, 2010 by aeon