Neutral Density Help

sohotrightnow

Ok so for my next roadtrip to Banf, Jasper, and Glacier National Park, I'm gonna get a neutral density filter. Only problem is, that not sure which one to get. So i'm gonna be using it for flowing water, and waterfalls. It will be 77mm for my Sigma 10-20mm. Now it will be in june so it should be pretty bright. But I don't know if I should get a 4x, 8x, or a 64x. Please tell me from personel experience what will be the best for the time of year, and flowing water. :dunno

Thanks,
Hansel :thumb

P.S. What brand or in particular filter will be the best, i'm looking for good quality for rougly $200 or less. Needs to be for Wide Angle lens also, so I don't get too much vignetting. Thinking B+W or Hoya will be good. Can't afford a Singh-Ray right now, so that will have to wait.

Shane422

I can't comment on how strong you should go, but look into the Cokin type filters (P size). Then you can buy one filter to fit all of your lenses. You then merely need a $8 adapter for each lens. Another advantage is that if you use a Split ND filter, you can move the transition to different parts of the frame.

sohotrightnow

Ya, I was considering the Cokin, but the only thing is, is that I will be hiking quite a bit and don't want to have to worry to much about bumping it etc. Also, it seems that Nikon is coming out with more and more 77mm so I shouldn't have a problem with it matching up with new lens's. And I should be getting a bunch of new lens's by the end of the year. And Ya, im still considering the grad in cokin, but i'm not sure right now. The input is appreciated.

Thanks,
Hansel

mr peas

Those filters will be expensive for 77mm and above, yikes! Listen to Shane and look into buying a Cokin filter set, it would be P series for something that size. I've used a 4x and 8x on flowing water and w/ infrared filters, 8x has a dramatic almost opaque look when you look through the filter, I think you can get by with 4x and then stopping down or putting on a circular polarizer on top of that. Also, watch out for filter stacking, may cause vignetting when you add two or more filters, especially at the wide end of a WA lens.

Go to www.2filter.com for a great selection on filters, they're usually on sale. I've bought 80% of my filters from them, great customer service (they actually answer their phones!).

You may also get lucky buy buying from Chinese vendors on Ebay, I dont think there are any 'copies' roaming around of these filters, but then again there's always that gamble. But I've seen prices on Ebay that were about 30% cheaper than that of from domestic vendors. I would go w/ 2filter still just to know that you'll be getting what you're ordering.

Hoya.. B+W.. both great filters. Singhray has that multipurpose ND filter, super expensive though.

Try using a Circl. Polarizer first and see if you can grab the effect your looking for. Personally, too much water flow for me loses the nice hard texture of water; the balance between all flow and frozen looks best at least to me.

But definitely go to 2filter, call them up and ask them questions, you'd be surprised on how much they know about this stuff!

Art Scott

sohotrightnow wrote:

Ya, I was considering the Cokin, but the only thing is, is that I will be hiking quite a bit and don't want to have to worry to much about bumping it etc. Also, it seems that Nikon is coming out with more and more 77mm so I shouldn't have a problem with it matching up with new lens's. And I should be getting a bunch of new lens's by the end of the year. And Ya, im still considering the grad in cokin, but i'm not sure right now. The input is appreciated.

Thanks,
Hansel

There is another thread on here that expalins why NOT to use Cokin ND filters but also states that Coking filter holders are great.....actually coking ND filters are not true ND bit a blue I think.....the other thread has photos of different filters......I be looking at Singh Ray or B+W something along those lines......I like most of Cokins special effects filters but for ND no.....Cokins CP would probably be very good also in the "P" size.....then it would also be a 1 size fits all lenses

Good Luck

mr peas

Art Scott wrote:

There is another thread on here that expalins why NOT to use Cokin ND filters but also states that Coking filter holders are great.....actually coking ND filters are not true ND bit a blue I think.....the other thread has photos of different filters......I be looking at Singh Ray or B+W something along those lines......I like most of Cokins special effects filters but for ND no.....Cokins CP would probably be very good also in the "P" size.....then it would also be a 1 size fits all lenses

Good Luck

I've never heard of that. Link us Scotty!

sohotrightnow

Price wise what can i get more for my money with, with good quality? Cokin Or Circular?

gus

sohotrightnow wrote:

Price wise what can i get more for my money with, with good quality? Cokin Or Circular?

Just out of interest...Singh-Ray has a Variable ND filter which i have been eyeing off for a long time. It aint cheap though.

sohotrightnow

Ya I have been looking at that too, but need to save up a while. In the long run it's worth it, but right now i'm not rich enough :cry.

Art Scott

Unfortunately filters is an area that can really make or break a photo when purchasing budget filters.....if you get lucky you'll find a good one, once in a while......over the years I have used some very odd ball and homemade filters but they weren't ND's.....they were special effects....motion blur...rainbow....star (now I want very good glass stars just like ND's) center focus (cut out in ctr with a swirl or some thing girls wanted in model portfolios in the 80's) came from spiratone and cokin......

LINKY WAS ASKED FOR.......SO ...... HERE IS LINKY TO ARTICLE FROM OTHER THREAD

HOPE THIS HELPS

Gud nite all.............

sohotrightnow

For the Cokin would i need to get the z series, since I'm using the 10-20mm sigma. Or would the P series still work without much vignetting.

Miguel Delinquento

I just came back from a week in the very bright Arizona desert. I found a whole bunch of Cokin ND and Polarizing filters used for a few bucks apiece. The "P" size served me quite well and I used it on a Pentax 12-24mm 77mm sized lens with zero vignetting.
Though my used stash came with a filter holder I ended up not using it--I just held each filter slab in front of my lens as appropriate to the effect I was seeking. I didn't notice any color casting, but since I shoot RAW that's easily fixed anyway.

M

Art Scott

Here is the link to Gate's Rest.....the thread with the original and a vry nice photo done with a 3x grad ND.............

gluwater

Just get the 77mm ND 8x and 77mm Circular polarizer. Make sure you get the slim CP for the ultra wide angle. Also get step down rings for when you want to use those filters on smaller filter size lenses. I use B+W and have been very pleased. They are not cheap though, especially the slim CP. That should give you about 5 stops if you stack them. You will probably see vigneting if you stack them at 10mm but that is what PS is for, it's such an easy fix that it's not even worth worrying about. Also with stacked filters at 10mm you may actually see the edge of the filter in one or more corners. I do when I use the Canon 10-22. But I have stacked three on it and just cloned or cropped slightly. It gets you images like this:


This was with a 10-22, 8x ND, 4x ND, and CP stacked with overcast skys. I believe it was 30 seconds.
Make sure you don't go cheap on the CP, you will not be happy with the results.

Robinivich

BTW guys, the fancy shmancy singh-ray filters probably consist of 2 polarizers that rotate on one another.

I think it should be pointed out that since linear polarizers went out when they introduced metering and autofocus via beam splitting, you can get a pair of them to screw together for not much more than the cost of a single good UV filter.

I'm actually seriously tempted to go and do exactly that tomorrow. There's some complicated and goofy physics that goes on with circular polarizers, at least, complicated and goofy to the layman (me), but I believe linear is dead simple by comparison, and also cheap. Mind you, loss of metering would be annoying, so I'm uncertain how best to proceed, anyone with better grades in physics want to jump in?

gus

Robinivich wrote:

BTW guys, the fancy shmancy singh-ray filters probably consist of 2 polarizers that rotate on one another.

Ive heard that however what about stopping down to an 8 ?

mr peas

gus wrote:

Ive heard that however what about stopping down to an 8 ?

More CPs..duh!! With all of our CPs combined we can summon Captain CP!

gus

gluwater wrote:

Thats a great photo nick I hadnt seen that one.

I just bought a normal 77mm screw on ND (#4 i think ) for my trip in a few weeks. I will see if i like it & if so i will take the dive into some better stuff.

SloYerRoll

Robinivich wrote:

BTW guys, the fancy shmancy singh-ray filters probably consist of 2 polarizers that rotate on one another.

Not probably. Definately.

gus

SloYerRoll wrote:

Not probably. Definately.

Will this do 2 to 8 stops variable ?

Robinivich

(For people who don't want to read a mini-novel)
Yes, two CP filters, appropriately aligned, can go from 2 stops straight through to opaque, not just 8 stop ND filter, lens cap kind of opaque.
(Here endeth the lesson, for more intrepid or bored readers, follow along )



Here's my understanding: Considering light as a wave, waves can go up and down, or side by side (plus everything in between). A polarizer only lets waves going a particular direction go through. If you then put another polarizer, set at 90 degrees, behind the first polarizer, the only light that gets through the first is light that can't get through the second, so it blocks 100% of the light.

At any less than 90 degrees, a portion of light oscilating in the right direction will get through, so the effect is adjustable from ~2 stops to impermeable, two polarizers at EXACTLY 90 degrees will let through as much light as your lens cap

As a bonus, when two polarizers are exactly aligned, the second one will only filter out as much light as the coatings reflect, it will have no additional effect, so two polarizers can go from 2 stops or even less light reduction, to opaque (significant because unlike ND filters, simply stacking polarizers doesn't mean you lose another couple stops, first you need to twist 'em).

Singh-ray doesn't reccomend filtering more than 8-stops, I'm guessing that's because at this point you're so close to opaque that the wavelengths aren't getting through evenly, and you get goofy colour effects (not a "Neutral" density filter anymore). However, not having seen these myself yet, I'd be interested in seeing the effect.

Actually, I remember finding something awesome that uses this principle, it's called a Rapatronic camera, and it uses this polarizing effect to allow the shutter to take the shortest exposure times possible, for things like nuclear weapons tests. Can you imagine dialing your camera to 1/100000000 of a second?

http://en.wikipedia.org/wiki/Rapatronic_camera

Getting back on subject, if anyone reading this happens to have a pair of circular polarizers (say you needed different sizes for different lenses) would you mind playing with them a bit for us? All I have is one B+W CP, my sunglasses, and the LCD monitor I'm typing this on. I'm finding that with the circular polarizer it's very dependent on which direction the CP faces, which could be significant for this experiment, it'd be irritating if a male-male or female-female adapter were required for this to work.

claudermilk

I've been looking at NDs myself lately. I am probably going to go the 4x4 route with a Cokin Z holder (I already have the Lee 4x4 B&W gel set for my MF rig). Not sure of whose filters to get though. 2filter has Tiffen, HiTech, Lee, Formatt. I hear the HiTech resin filters are nice, and they are the best prices; anyone have experience with these? The glass filters are scary expensive.

Cuong

Robinivich wrote:

... Getting back on subject, if anyone reading this happens to have a pair of circular polarizers (say you needed different sizes for different lenses) would you mind playing with them a bit for us?...

It'd be interesting to see how this comes out.

Cuong

SloYerRoll

gus wrote:

Will this do 2 to 8 stops variable ?

Yes.

Robin did a good job explaining it. I think there are some inherent issues w/ stacking ND's to make a variable ND though. Light travels in waves, dependant on which part of the light wave is allowed to travel through the ND filter, your shot will be exposed differently. So if your whole rig was (jsut as an example::) straight up and down, then you turned BOTH filters 45deg. The light that would be allowed in the shot would be of a different intensity.

I know more about light dynamics that ND filters though unfortunately. So all this is theory, but educated theory at a minimum.

sohotrightnow

So could i put a linear polarizer on a Singh-ray warming polarizer to make a good neutral density? Or would I get weird colors, or would I not get enough light in?

SloYerRoll

Your starting to mix too many things. It would probably work, but you definitely want to shoot RAW to adjust for WB changes. I don't know what other wackiness happen w/ warming filters.. Never used em..

Best bet is to buy an ND filter that fits your needs or a commercial off the shelf (COTS) solution for variable density.

-Jon

Robinivich

I'm not sure exactly what makes a "warming" polarizer, from what I read it sounds like basically a polarizer that doesn't cut the light as much, probably polarizes somewhat less (that is, always lets through some light regardless of polarization).

In any case, stacking polarizers you should be able to get an adjustable ND effect, the only catch being that with circular polarizers, there seems to be some directionality, it only gets a true polarizing effect on light travelling one direction. As I've said, I'm not sure exactly how the directionality works, if it's just in CPs not LPs, etc.

As far as how much light gets through, try and remember, polarizers don't exactly "absorb" light, in theory, you could stack 10 polarizers, and if they were all aligned correctly, they'd let through as much light as the first one on its own. Of course, in practice no filter is 100% transparent.

As for colour, I'd go by what singh-ray themselves say here, between 2 and 8 stops reduction the effect will not distinguish between colours, after that theres so little getting through (8 stops = 1/256th of the inbound light passes, or 0.3%) that some spectra may have more trouble than others.

Cuong

I was intrigued by this discussion, so I decided to try it out. I'm more interested in the actual light attenuation effect than the color balance at this point. I used a Cokin and a Quantaray CP filters (remnants from the film era). To achieve the variable density effect, both filters must face the same direction. If one of them is reversed, there'd be no variable density effect. As suspected from the theory discussed, maximum density is achieved when one of the filters goes through a 90 degrees rotation from a minimum density position.

Here are my results:

#1. ISO 1600, f/5.6, 1/20 sec


#2. ISO 1600, f/5.6, 1/6 sec - about 1/8 turn of front filter - about 2 stops slower than #1


#3. ISO 1600, f/5.6, 2 sec - about 1/4 turn of front filter - about 6 stops slower than #1


Cuong

claudermilk

Interesting test. Might I suggest a modification to the process? Set the camera to M and leave the ISO, shutter, and aperture on one setting, then take the shots as you rotate. I think that will show the effects much better.

SloYerRoll

claudermilk wrote:

Interesting test. Might I suggest a modification to the process? Set the camera to M and leave the ISO, shutter, and aperture on one setting, then take the shots as you rotate. I think that will show the effects much better.

I thought I'd see a much more drastic change w/ those numbers.

Cuong

claudermilk wrote:

Interesting test. Might I suggest a modification to the process? Set the camera to M and leave the ISO, shutter, and aperture on one setting, then take the shots as you rotate. I think that will show the effects much better.

The approach you suggest would show exactly what I see thru the viewfinder as I rotate one of the CP filter. I was interested in finding an estimated difference in exposure between minimum and maximum density effect. That's why I posted the exposure data. Actually, I should post pictures showing the effect as seen in the viewfinder along with the exposure data to obtain a correctly exposed picture. I'll try to do that by tomorrow.

Cuong