Neutral Density Filters

[Kayaker72]

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

...I assume you checked your exposure, set your focus, then added the filter, then made a 10 stop adjustment to your speed......

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.

iND. My 7D is able to meter fairly accurately with the 6-stop ND filter on a lens. I hear that is a little hit or miss and that some cameras have issues metering with a 6 stop filter on. It works with my 7D. So, I didn't follow the technique above. Really, my technique was pretty standard in that I metered in camera with the filter on.

The first waterfall I shot with the camera resting on my hand which was resting on a rock ledge. I shot it at 1/4 sec, f/5.6 at ISO 100 at 24 mm. With the 4 stop IS on the 15-85, that was sufficiently stabilized. The shot at Niagara, I shot at 1 sec f/20, ISO 100 mounted on a tripod. The f/20 is more narrow than I would typically want to go, but without a 10-stop ND filter, it was necessary.

As for the people in the second shot, they really didn't move much within the 1 sec exposure. I think it would be pretty hard to "vanish" people at Niagara. They tend to stand there for long periods of time watching the falls and someone usually takes their place by the rail the second they move.

[neuroanatomist]

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?

Spot on about technique. FWIW, I use an iPhone app called Longtime Exposure Calculator to determine exposure adjustment.

A variable ND could be used like that - focus first then darken. I've avoided them for two reasons: not quite dark enough, and more importantly the 'Maltese cross' artifact seen at ~24mm and wider angles (related to the uneven polarization you get with a CPL on an ultrawide lens, since a variable ND is basically stacked polarizers).

[M_Six]

Another good (and long) guide on ND filters in general here.

[btaylor]

Hi mate,

I use the B+W 10 stop ND filter on my 5D2. You will struggle to meter accurately and will definitely not be able to use autofocus. BUT - you get 30s + exposures in bright daylight so it's a tradeoff I'm willing to make. You'll get a warmer colour temperature as well but if you shoot in RAW then it's easy to fix in post. Here's a couple of examples for you:


Downstream East Leichardt by Ben__Taylor, on Flickr


Simpson Desert Series # 2 by Ben__Taylor, on Flickr



Cheers,

Ben

[iND]

Someone with some more optics or physics experience may be able to answer this questions.

What would be the effect of stacking a CPL filter (circular polarizer) under a linear polarizer filter: Could this serve as a poor mans Varible ND filter?

[Daniel Browning]

Could this serve as a poor mans Varible ND filter?

Yes. That is how the Singh-Ray Vari-ND works.

[Dr Croubie]

Someone with some more optics or physics experience may be able to answer this questions.

What would be the effect of stacking a CPL filter (circular polarizer) under a linear polarizer filter: Could this serve as a poor mans Varible ND filter?

I've got one of those reversal adapters, 72mm male to 77mm male thread, intended for macro work revering a lens and mounting another lens on the front (which i've never actually tried, I should one day).
Instead, I tried mounting two CPLs front-to-front (so Circular Pol faces the sky and faces the sensor, Linear Pols face each other), to try emulating a Vari-ND. It didn't work too badly (I never used it too much because soon after that I got my ND400), but at the darkest settings it went a bit (a lot) purple.
So using a Linear Pol facing the sky (in either direction) and CPL facing the sensor (in the normal direction) should work just the same, but seeing as it wasn't designed as such you'd probably get some weird colours. Worth a test though...

[iND]

Does anyone have experience with the 4x6 handheld ND graduated filters by LEE and SINGH-RAY?
Not for extended exposures but for lanscapes to bring out detail in the sky?
If you do 'for most purposes' how many stops would you recommend on this type of filter.
They are about $100 each (Lee has a soft ND grad filter kit .3 .6 .9, 1-2-3 stops) for about 240.
The Lee are not glass (some type of resin) but that means they are less likely to break.
I like the 4x6 so you can adjust the soft area to the scene and not the scene to the filter.

Other recommendations?

[conropl]

Does anyone have experience with the 4x6 handheld ND graduated filters by LEE and SINGH-RAY?
Not for extended exposures but for lanscapes to bring out detail in the sky?
If you do 'for most purposes' how many stops would you recommend on this type of filter.
They are about $100 each (Lee has a soft ND grad filter kit .3 .6 .9, 1-2-3 stops) for about 240.
The Lee are not glass (some type of resin) but that means they are less likely to break.
I like the 4x6 so you can adjust the soft area to the scene and not the scene to the filter.

Other recommendations?

For sunsets/sunrises the DR (dynamic range) is large and you will need the 3 stops to get decent results, and at times it does not seem enough. I have 0.3, 0.6, & 0.9 and use them mainly early morning or evening (low light / high DR situations), so I use the 3 stop 99% of the time. The only time I have used a 2 stop was mid-day to get a little more detail in the sky, to get more of the blue in the sky, and yet get the blue water refection. I am not sure I would buy the 1 stop again if I had to do it over unless it was part of a kit and it was basically free (which was the case when I bought them).

By the way, Grad ND's really make a big difference in the quality of a sunset/sunrise shot. There is a lot of talk about being able to do the same thing in PP, but with the filters you can do it without the noise associated with pushing your DR in PP... so the results are much cleaner.

I do not have Lee, but would like to some day.

[HDNitehawk]

I have to say +1 for conropl's advice for sunsets. Most of what I do falls in the area that he referred to as "mid-day" so +2 is seems to be the most used. Ideally a person would have all three filters, and then you could stack the 1, 2 or 3 and have combinations up to 6 stops.