Alley in Pisa, Italy

by Lars Kotthoff

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Today I have tested my Hitech Pro Stop 10 ND filter for Lee holder. And I am somehow shocked. It was morning 10.

enter image description here

Please, can someone help me, how to use it. :) By the way, I have lost the tech info on exposure times list, maybe someone can photo and include it to your answer, I will be every appropriated.

ADDED

I have resolved this issue :):

enter image description here

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For future reference: What was the problem? –  Matt Jun 20 '12 at 13:36
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3 Answers 3

up vote 7 down vote accepted

The general approach I use with ND filtration is to compose and meter your scene first without filtration. I also use the Lee filter holder, which has the handy feature that allows you to clip/unglip the actual filter holder to/from the lens adapter fairly easily. The general process to expose for any amount of ND filtration, including the Big Stopper or other large-stop filter, would be as follows:

  1. Attach the Lee filter adapter ring to lens. Set camera to Manual mode.
  2. Fully meter the scene at a fixed ISO of 100:
    • Evaluative metering will work well with average scenes of relatively balanced tonal range. (Make note of shutter speed.)
    • Selective spot or partial metering will often be necessary with scenes of divided contrast or uneven tonal range. (Make note of shutter speed.)
    • If you are also using Graduated ND to compensate for contrast, meter highlight, midtone, and shadow areas to determine total dynamic range
      • Set aside the shutter speeds for graduated compensation in a later step.
  3. Compose scene in-camera without filtration.
    • Adjust aperture here if necessary for artistic/stylistic effect.
  4. Apply ND filtration and compensate shutter speed:
    • Multiply the shutter speed by the filtration factor:
      • This is easy to calculate. Take 2 to the power of the number of stops of ND filtration:
      • If applying a 2-stop/0.6 ND filter, multiply shutter speed by 22, or 4
      • If applying a 10-stop/3.0 ND filter, multiply shutter speed by 210, or 1024
  5. Apply Graduated ND (GND) filtration (Optional):
    • GND filtration should not be compensated for in-camera, as the intent is to mitigate highlights for a given exposure.
    • The amount of GND filtration necessary in stops can be computed as follows:
      • Divide the longer shutter by the shorter shutter.
      • Take the log of the shutter speed quotient
      • Divide the first log by log(2)
  6. Apply white balance correction (Optional):
    • If you are using a considerable amount of ND filtration, strong color casts may appear
    • These can be corrected in post, however they are often EXTREME, and may not be fully correctable
    • To ensure viable correction in post, compensate in-camera first (according to manufacturer's recommendations and settings)
      • Lee BigStopper tends to cast very, very blue...so set WB to around 10k or more
      • HiTech 10x ND also tends to cast rather blue, so a setting near or even above 10k might still be needed
      • Other brands may cast very magenta or violet-blue, some cast very green or yellowish

If you have a smartphone with a calculator, computing these is extremely easy in the field. You can also try to memorize a few things to help you quickly arrive at rough settings without the need to use a calculator. Here is a table of ND stops filtered to shutter speed multipliers (Ratios provided for Lee/Singh-Ray filter users...just add up all the fractions of your ND filter stack):

 ND Stops | ND Ratio | Multiplier
==================================
     x1   |    0.3   |       2
     x2   |    0.6   |       4
     x3   |    0.9   |       8
     x4   |    1.2   |      16
     x5   |    1.5   |      32
     x6   |    1.8   |      64
     x7   |    2.1   |     128
     x8   |    2.4   |     256
     x9   |    2.7   |     512
     x10  |    3.0   |    1024
----------------------------------

Example Scenario #1: Simple ND filtering

You wish to photograph a serene river scene, completely blurring out not only the motion of water, but also the slight rustling of the leaves of the trees, creating a very dreamy style of photograph:

  • The scene has roughly even tone, no GND filtration is needed
  • You use evaluative metering, and compensate down by 1/3rd of a stop
    • Aperture f/8
    • ISO 100
    • Shutter meters at 2 seconds
  • You want to apply 6-stops of ND filtration (1.8 ratio)
    • Shutter speed needs to be increased by a factor of 64: 128 seconds, or about 2 minutes

Example Scenario #2: Complex ND+GND layered filtering

You wish to photograph a cloudy coastline just after sunset, blurring the soft waves to a fog and flattening clouds. You need to compensate for the sun, which is just below the horizon and brightly illuminating the sky relative to the sea.

  • The scene has high contrast, so GND filtration is necessary
    • You spot-meter the sky near the sun, and get an exposure of 1/50th second
    • You spot-meter the sea near the horizon, and get an exposure of 1/3rd second
    • You spot-meter the rocky coastline, and get an exposure of 1 seconds
    • Total difference in stops between the sea and sky: @4 stops
      • log(1/3rd / 1/50th) / log(2) =
      • log(.3333 / .02) / log(2) =
      • log(16.6667) / log(2)
    • Total difference in stops between the sea and coast: @1 2/3 stops
      • log(1s / 1/3rd) / log(2) =
      • log(1 / .3333) / log(2) =
      • log(3) / log(2)
    • (Check) Total difference in stops between sky and coast: @5 2/3 stops
      • log(1s / 1/50th) / log(2) =
      • log(1 / .02) / log(2) =
      • log(50) / log(2)
    • Three levels of GND filtration necessary:
      • One 2-stop soft grad filter for the division between coast and sea
      • One 3-stop and one 1-stop hard grad filter for the division between sea and sky
      • Alternatively, drop the extra 1-stop hard grad if you are worried the sky may end up too dark with an additional 10-stop filter, or you intend to slightly under-expose to preserve highlights
  • You use center-weighted or partial metering on the sea:
    • Aperture f/8
    • ISO 100
    • Shutter meters at 1/4th
  • You want to apply a 10-stop BigStopper (3.0 ratio) or similar ND filter
    • Shutter speed needs to be increased by a factor of 1024:
      • 1/4s x 1024 / 60s/m =
      • 0.25s x 1024 / 60s/m =
      • 256s / 60 s/m =
      • 256 second or 4m 16s exposure time
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On top of this excellent answer, I'd also add: cover the eyepiece to prevent light leakage, which may explain the fogging in the two example photos posted. –  Nick Miners Jun 20 '12 at 13:04
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I've just started experimenting with a 9 stop ND filter. First, thing I've noticed is that just playing with the exposure really helps. Try 30 seconds, try a minute, try 15 seconds. See what looks good. Once you get your exposure set, then work on the scene. So don't worry about the missing list, just experiment. Right now I'd say you need more time since your image is too dark. (Or you can open up the aperture some.)

The second thing I notice is that your sensor appears to be dirty? Are you shooting well stopped down, like f22 or so? The more you stop down the more apparent sensor dirt becomes. I use a Delkin SensorScope. It was pricey but does a very good job.

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1) yes, you are right it was f22. 2) Have you tried SensorScope DSLR Camera Sensor Cleaning System (it includes SensorScope)? It seams to be useful thing ->> thank you, Paul! –  garik Jun 3 '12 at 15:45
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The same way as any ND filter I suppose :) Mine is an ND400 from Hoya and it is pretty consistent, so all I need as a basic calculator.

There is a FREE Android App on which calculates things for me. You first need to enter the strength of your ND filter and the metered exposure without the filer on. It then tells you how many seconds or minutes the exposure should be.

In the case of your 10-stop filter, multiply your exposure time by 1024 (or 1000 to simplify, the difference is 2% only so insignificant). This assumes you are keeping the aperture and ISO consistent of course.

Because you will get very long exposures for a 10-stop ND filter, you should be doing things in Bulb mode (either B on the Mode-Dial or the B shutter-speed in M mode). Bring an illuminated watch or much any cell phone will do.

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