Neutral Density Filters

[bouwy]

Thanks for your comments guys.

[Busted Knuckles]

I am on the quest for ND and was thinking about this very item.

At 10 stops you start to get issues from infrared, so you might consider a hot mirror to reflect the IR. They are more very expensive, but it will save you from increased fringing, flare, and inaccurate color due to infrared. (Normal ND filters only block regular light, not IR, so a 10-stop ND increases the I.R. by one thousand times.)

I found an industrial optics company that appeared to do the very high end filters, etc though the pricing actually seemed pretty reasonable. They had two types of ND, absorption vs. reflecting. I was going to give them a call and discuss if the reflecting would be Visible and near infra red to address this very issue. Then I got to wondering - why aren't any of the of the NDs in the photo world mirrored - they all appear to be absorption i.e. non mirror/reflecting

Any of the high science guys have thoughts on this? I "demo'd" an inexpensive variable and found even at its least setting to reduce sharpness and warm color cast - sent it back. I am thinking a 3 or 4 stop and then a 10 stop set should do the trick. Many comments that a 1 or 2 stop is largely a waste of glass.

Also any comments on brand? other than you get what you pay for.

[Squidy]

Hey guys,

I've noticed a few people mentioning adding a CPL in front of an ND filter. Is this a standard practice? I'm just curious because I'm still learning but have been told "never ever ever" to do it, but if you guys are doing it it can't be that bad? What are the benefits of stacking the CPL on an ND?

[HDNitehawk]

Hey guys,

I've noticed a few people mentioning adding a CPL in front of an ND filter. Is this a standard practice? I'm just curious because I'm still learning but have been told "never ever ever" to do it, but if you guys are doing it it can't be that bad? What are the benefits of stacking the CPL on an ND?

I suppose one negative is you loose a little IQ with every filter you stack.
I have done it with graduated ND's.
I suppose an advantage would be if you needed to add another stop or so and don't have another ND to stack. I have done this.

Maybe there is an effect I haven't heard of, maybe someone will weigh in with it.

[Squidy]

Ahhhh ok, I guess that would make sense. I'm probably using the filters wrong as the pictures I take with ND filters end up looking too contrasty... Maybe it's a problem that I forgot to take off the UV or something.

[Busted Knuckles]

how may stops is the filter and what camera settings?

I would think that you need to be shooting RAW and in Manual - don't let the camera do anything automatically.

[Squidy]

Yeah I shoot in raw and usually in manual... but I just realised I may have had auto iso on... that could be a part of it

The filter I was using was a Hoya ND4, and the other one was a Fotar (which was way, way worse than the Hoya)

[Jonathan Huyer]

Hey guys,

I've noticed a few people mentioning adding a CPL in front of an ND filter. Is this a standard practice? I'm just curious because I'm still learning but have been told "never ever ever" to do it, but if you guys are doing it it can't be that bad? What are the benefits of stacking the CPL on an ND?

Oh I use a polarizer with a solid ND filter all the time... it works brilliantly, especially when you're trying to shoot a waterfall and there's too much light to get adequate blur. The polarizer takes out the glare in the water and the bright spots on the rocks, so the two filters together are indispensable. Here's an example... it also happens to be a 3-shot HDR, but I used the dual-filter setup.

[conropl]

I am not a big fan of stacking filters, but there are times when you have to (or should).

For example, shooting water falls... the wet rocks tend to have a lot of glare as well as glare from the water; so you need the CP to cut that glare, and the CP also helps enhance the colors in the surrounding leaves. You would also need the ND to get a better motion blur out of the moving water. This combination also works to blur water (waves) at the beach, and yet cuts the glare from the water.

There are other times when you want to use the CP to get the blue in the sky to show up better or to get the clouds to be more defined. If this is around sunset, then a Grad ND mat be in order as well to keep your foreground from being nothing but a silhouette.

Stacking two filters is not too big of a hit to IQ.

Edit: It looks like Jonathan already answered while I was typing.

[Squidy]

That has got to be one of THE best shots I've ever seen, it's also EXACTLY what I want to do... and unfortunately exactly what I can't acheive