What good would a neutral density filter give me?

[GoingUp]

I already have a circular polarizer and UV filters. I'm unsure what a neutral density filter would give me.

I'm off to Nepal for 3.5 weeks on March 21st. Will be getting all of the way up to 18,000 feet. Should I also add a neutral density filter?

Thanks!

 

[fuzzybabybunny]

NDs lower the amount of light that reaches your sensor, allowing you to use slower shutter speeds.

Two situations come to mind:

1. You want to blur something, requiring a slow shutter speed. This slow shutter speed may be impossible to attain with high levels of available light. Think moving water or moving car lights.

2. The scene is so bright that even at your lowest ISO and fastest shutter speed and smallest aperture you're willing to stop down to for sharpness, you still get an overexposed picture. This is probably extremely rare or impossible under normal circumstances.

 

[montanafan]

Fuzzy, you'd know a lot more about this than me, but Gobadgrs said that he was going backpacking in the Himalayas. Wouldn't the combination of the sun, snow, and clouds/fog possibly create a situation like you described in #2? Would the neutral density filter help prevent blown out whites and overexposure from the combo and glare? Just wondering if that would be one of the unusual circumstances where a neutral density filter would come in handy.

 

[fuzzybabybunny]

Yeah, I was thinking about this too... but I'm not so sure. I mean, I think I've taken photos of the sun without ND filters. I'm not too sure if snowfields would actually be bright enough to limit the camera in this fashion.

It's still a nice filter to have though, regardless. I've used mine a total of probably 4 times, but each time the pictures would have been utterly impossible without them.

 

[soydios]

hmm...the brightest sunlight I've ever encountered at more mundane elevations with ISO200 is EV17.
come to think of it, I was actually shooting at that today. ISO200, between 1/5000th-1/8000th shutter, f/4.0 shooting baseball at 1pm. I shot at those settings to minimize the amount of highlight clipping.
so, stopping down to f/11 (which is the diffraction limit for most sensors these days) that gives you a shutter speed of 1/1000th at ISO200. assuming your camera has a base ISO of ISO200 and fastest shutter of 1/4000th, that means you've got two stops of flexibility before your highlights start clipping. if you've got a higher-end SLR then you should be able to use ISO100 1/8000th shutter, getting you two more stops of cushion for a total of four, and making an ND filter less necessary.
in your situation, I would buy a 3-stop ND filter so you can play with depth of field even in extremely bright situations.
if you're serious about taking landscape shots at those high altitudes, then you should buy perhaps a 2-stop graduated ND filter to darken the sky. polarizing filters don't play nice with wide angles. this is what you get: half the sky passing through the polarizer, and half the sky not: http://photos.anands.net/Album...wy1/slides/Hwy1000.jpg

EDIT: I just read your other thread on picking lenses. your 40D can use ISO100 and 1/8000th shutter, so you're in the clear. unless you want to do shallow depth-of-field shots in obscenely bright daylight, you should be fine.

 

[randomlinh]

The other scenario is if you're like me and love shallow DOF. I find myself not being able to use f2.8 or lower quite a bit on bright days. I really need to get one.. just dunno which one yet.

 

[ElFenix]

don't forget you lose a couple stops just using the polarizer, which is likely to be on your camera a whole lot up there.

 

[Jawo]

I've been thinking about getting a ND filter as well and have been looking around some. What really confuses me is the difference between the circular ND filters and the split ND filters (beyond the obvious). Can you get a split ND filter in circular format?

 

[fuzzybabybunny]

Originally posted by: Jawo
I've been thinking about getting a ND filter as well and have been looking around some. What really confuses me is the difference between the circular ND filters and the split ND filters (beyond the obvious). Can you get a split ND filter in circular format?

I'm not sure if you can get them in circular format, as this would be pretty goofy to use. The ones I've seen are always in square form. They slide into a square bracket that screws on the lens which allows you to adjust the up and down of the "split" to match your framing.

 

[GrJohnso]

I've used Cokin's A Series for their splits and full 2 stop ND filters. I want to get an 8 stop, but hasn't happened yet... They are the square, slide in, etc... You can rotate them as needed for what'ev reason you have.... Splits are great for scenic shots with bright skies, dark waters, etc... Just line them up on the skyline and instant dynamic range! The fulls ND filters are handy for water photos where you really want to slow things down. You can get some amazingly silky smooth tidal shots during the day along the coast, dreamy rivers and waterfalls, etc...

There's a company out there that makes a variable ND filter, but for $250-$350... You can dial in 2-8+ stops with a single piece of hardware... Don't remember who made it, as the price wiped it from my brain...

I think Cokin may be dropping the A-Series filters, or at least my local camera shop is... They are only good up to 62mm filter mounts, but that covers over half my lenses at least... They can be found for pretty cheap these days... Sure, they take up a little extra room in the bag, but... Nice options to have...

 

[OdiN]

Originally posted by: fuzzybabybunny

Originally posted by: Jawo
I've been thinking about getting a ND filter as well and have been looking around some. What really confuses me is the difference between the circular ND filters and the split ND filters (beyond the obvious). Can you get a split ND filter in circular format?

I'm not sure if you can get them in circular format, as this would be pretty goofy to use. The ones I've seen are always in square form. They slide into a square bracket that screws on the lens which allows you to adjust the up and down of the "split" to match your framing.

I have a circular "split" ND filter.

They are called graduated ND filters. It's only useful if you can line the shot up with the bright part being in the top half of the image. I also have cokin style ND filters - you still want to get graduated ND's for cokins and not try to use a regular and just position it.

There are various versions of graduated ND's also - you can have a soft gradation in the middle or a harder gradation - softer blends the secene better while harder is going to be useful for something with a very well defined horizon line like an ocean/beach where the sky is overpowering the foreground.

 

[PHiuR]

ND's are also good for shooting fairly wide open with high iso film or when it's too bright out.