Neutral Density Filters

[iND]

I am looking at experimenting with black glass.

Does anyone have experience with ND filters in the 10 stop range?

I am looking for techniques, applications, and perhaps examples.

[Daniel Browning]

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.)

[M_Six]

I've been doing this lately. You can get some very cool images. I stacked a 3-stop ND, a 6-stop ND, and a 2-stop CPL for a total of 11 stops. It turns a 1/60 shot into a 30 second shot. ISO 100, f22, 30 secs

[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.

[iND]

Good input

Any ideas on how much you have to slow the shutter to remove moving people from a scene?

[neuroanatomist]

I usually aim for a 30s exposure to blur out pedestrians. Here's an example (apologies, I grabbed these from an old post on CR, and they were saved to my iPhone to post here, not sure what that'll do to them!). This is from my initial testing of the Schneider Optics' (parent company of B+W) 82mm 10-stop ND, which AFAIK is the only one available in that size as a round/threaded filter. These were shot on a 5DII with a TS-E 24mm f/3.5L II. The first is a 1/6 s exposure without the filter, the second is a 30 s exposure with the filter. During the second one, several pedestrians passed through the frame, and some cars as well. You can also see the warmer tone with the filter - could be corrected in post, but for this shot I think the warmer tone is preferable.

[Dr Croubie]

I've been playing around with a Hoya HMC ND400 ("Made by Tokina Co.") I got off ebay a while ago.
Focussing on Live-view isn't so hard, tripod is a must obviously, I haven't noticed any colour casting to speak of (I also have a Canon ND8, which makes everything a funky colour).
Here's a shot I took last weekend, about 100km NW of Melbourne. It's the -2/3EV shot of an HDR that I haven't processed yet, just batch-processed in DPP so pretty much the came as a camera JPG.
EFs 15-85 @ 15mm f/5.6, iso100, 10s exposure, ND400 stacked with a Heliopan CPL on top (love that 15-85 vignetting, even better with 2 filters, you can't see it because i've cropped it 3:1). The longer exposure really helped to blur out that damn duck that swam right through my shot (the trail it left behind isn't so bad). I'll re-process later on Landscape style and saturate the colours a bit more when i HDR it...

[Kayaker72]

The darkest filter I have is a 6-stop. But here are two shots I took with it last year:


Waterfall IMG_0382pp by kayaker72, on Flickr


Falls IMG_2704 by kayaker72, on Flickr

You can see the red hue others mentioned in both shots. This was still after adjust WB in post (DPP at the time). I probably could adjust reds only, but didn't.

[iND]

OK Great discussion, This is why I keep coming back to TDP.

First Neuroanatomist:
So it looks like a 30 sec exposure was adequate for that shot to remove the objects moving though the scene.
Good info, and you used a 10 step filter.
I assume you checked your exposure, set your focus, then added the filter, then made a 10 stop adjustment to your speed.
I assume you can not focus through a 10stop filter.
Am I close on the technique?

Do you have any comment on a Singh-Ray variable ND (2-8) filter ($340) or the less expensive Genus brand (I believe they have a 1-4 stop and a 2-8 stop)?
Would the variable allow focus through a smaller ND then rotated up and avoid screwing on the ND filter and chance moving the focus ring?



Second Kayaker72:
Can you comment on your technique? Is it similar to how I described above?
What were your settings for each of your shots?
Why do you think you got no motion blurr on the people in the second shot, I assume they moved during the exposure.


Dr Crouble.

I really like your shot? I think it came out fantastic. Is this a panorama or a crop?
Why did you choose f5.6 for such a deep scene?


Thanks for the discussion

FYI
Nice discussion on strobist on this topic

http://strobist.blogspot.com/2010/06...-of-field.html

[Dr Croubie]

Dr Crouble.
I really like your shot? I think it came out fantastic. Is this a panorama or a crop?
Why did you choose f5.6 for such a deep scene?

This is just a crop from a single shot, EFs 15-85 @ 15mm, and cropped. I did take a panorama with my Samyang 35, shot in vertical, i 14-shots to get around the lake, but I haven't stitched it yet. With stitching the Samyang I couldn't use a CPL obviously, so I chucked the 15-85 on so I'd at least have 1 CPLed shot (i love CPL effects on water and deep blue skies like that).

I normally put it on iso100, 3-shot bracket 1-stop apart, set the middle bracket to 16 seconds, so I get 8/15/30 second shots, then adjust the aperture until 15-seconds is at 0EV, in this case it ended up at f/5.6. Then I take 3x3 brackets, -4/3|-1/3|2/3 + -1|0|1 + -2/3|1/3|4/3 (and for those paying attention, yes I know that if +1EV is 30-seconds, +4/3EV will also only get to 30 seconds. Meh.) Sometimes I take 9 shots at 2-stop bracketing so I get 2/3-stop intervals which I seem to have done here. I don't know what happened, I must have gotten told to hurry up by the missus, but i've only got -8/3|-2/3|4/3 brackets for this shot.
Anyway, seeing as the Hyperfocal for 15mm/5.6 on crop is something like 2 meters, I just live-view MFed on something closeish.

I could have gone to longer speeds and deeper DOF with higher f/ stop, I did have my TC-80N3 in my pocket, but i've never tried bracketing with it (i'm sure I could, just adjust the time between each shot, but I prefer to HSC my shots so clouds don't move too much between shots).