Seemolf DMC-FZ5, ( Xacti E6,
Canon A70,
Nikon FM-2
)
My offical site is here:
http://freenet-homepage.de/seemolf/
mare tranquilitatis
--- click the pictures to enlarge them in a separate window ----
A walk on the beach.....
Nothing spectacular, just water and stones:
A camera obscura would be nice at this moment.
....or a camera with more than 8 seconds of exposure!
My new filter helped in this case: ND4, factor 10000, 13 steps (aperture)
...and combining 4 pictures helped me with long exposures: 24sec. eff. - last picture
The choices of filters are shown at the end of this page
Blurring the motion
These lenses can be used for direct photography of the sun (ND4, not NDx4!!!!).
(!!! only for the camera, our eyes need ND5 -Baader sunfilter- or more !!!)
With different cameras they are used for long sky shots.
Exposures of one minute or more let the moving people disappear in a crowded city.
...and we have the chance to shoot lightning at daylight.
These are the choices:
B&W filters and Neutral Density factors
common
name |
article |
neutral
density |
f stops |
time
factor |
transmission |
diff.
brands |
| NDx2 |
B&W 101 |
ND 0.3 |
1 |
2 |
50% |
hoya,hama e.a. |
| polarizer |
|
|
1.8-2.5 |
appr. 4 |
appr. 25% |
|
| NDx4 |
B&W 102 |
ND 0.6 |
2 |
4 |
25% |
hoya,hama e.a. |
| NDx8 |
B&W 103 |
ND 0.9 |
3 |
8 |
12.5% |
hoya,hama e.a. |
| NDx4 + NDx8 |
|
ND 1.5 |
5 |
32 |
3% |
hoya,hama e.a. |
| |
B&W 106 |
ND 1.8 |
appr. 6 |
100 |
1% |
|
| NDx4 + NDx4 + NDx8 |
|
ND 2.1 |
7 |
128 |
0.8% |
hoya,hama e.a. |
| |
B&W 110 |
ND 3.0 |
10 |
1000 |
0.1% |
|
photo
sun filter |
Baader |
ND 3.8 |
appr. 13 |
10 000 |
0.01% |
|
| |
B&W 113 |
ND 4.0 |
13 |
10 000 |
0.01% |
|
| astroSolar |
Baader |
ND 5.0 |
16.5 |
100 000 |
0.001% |
|
| |
B&W 120 |
ND 6.0 |
appr. 20 |
1 000 000 |
0.0001% |
|
| |
|
|
|
|
|
|
variable 77mm
ND2x-8x |
singh-ray |
ND 0.3-0.9 |
1-3 |
2-8 |
50%-12.5% |
|
| 2 polarizers |
|
|
4-?? |
16-?? |
6%-?? |
|
Baader filters are square folia that have to be fixed.
They are sold for telescopes.
Arithmetic:
If you combine these lenses, simply add the stops and multiply the factors mentioned above.
So NDx8 + NDx8 give you 6 stops, factor x64 and 1.56% transmission.
But most neutral gray filters are not coated, it is not a good idea to combine them.
Exposure
This is an example for the changes in exposure, starting with daylight: f/8.0 t:1/125
A B&W110 needs 8 seconds of exposure with the same aperture
Usage: look for the exposure time of the test picture in row: "0"
and find the new time under your used filter
Take a test shot and find the perfect exposure time.
These times are just a hint, your camera may need slightly different times.
Especially analogue cameras need a correction (Schwarzschild Effekt).
B&W Filters - Exposure
| |
|
NDx2 B&W101 |
NDx4 B&W102 |
NDx8 B&W103 |
B&W106 |
B&W110 |
B&W113 |
B&W120 |
| aperture/stops |
0 |
1 |
2 |
3 |
6 |
10 |
13 |
20 |
| 1,4 |
|
1/8000 |
1/4000 |
1/2000 |
1/250 |
1/16 |
1/2 |
32sec |
| 1,8 |
1/8000 |
1/4000 |
1/2000 |
1/1000 |
1/128 |
1/8 |
1sec |
64sec |
| 2,0 |
1/4000 |
1/2000 |
1/1000 |
1/500 |
1/64 |
1/4 |
2sec |
2min |
| 2,8 |
1/2000 |
1/1000 |
1/500 |
1/250 |
1/32 |
1/2 |
4sec |
4min |
| 3,5 |
1/1000 |
1/500 |
1/250 |
1/128 |
1/16 |
1sec |
8sec |
8min |
| 4,0 |
1/500 |
1/250 |
1/128 |
1/64 |
1/8 |
2sec |
16sec |
16min |
| 5,6 |
1/250 |
1/128 |
1/64 |
1/32 |
1/4 |
4sec |
32sec |
32min |
| 8,0 |
1/128 |
1/64 |
1/32 |
1/16 |
1/2 |
8sec |
64sec |
1hour |
| 11,0 |
1/64 |
1/32 |
1/16 |
1/8 |
1sec |
16sec |
2min |
2hours |
| 16,0 |
1/32 |
1/16 |
1/8 |
1/4 |
2sec |
32sec |
4min |
4hours |
| 32,0 |
1/16 |
1/8 |
1/4 |
1/2 |
4sec |
64sec |
8min |
8hours |
| 64,0 |
1/8 |
1/4 |
1/2 |
1sec |
8sec |
2min |
16min |
16hours |
| |
1/4 |
1/2 |
1sec |
2sec |
16sec |
4min |
32min |
32hours |
| |
1/2 |
1sec |
2sec |
4sec |
32sec |
8min |
1hour |
64hours |
| |
1sec |
2sec |
4sec |
8sec |
64sec |
16min |
2hours |
|
| |
2sec |
4sec |
8sec |
16sec |
2min |
32min |
4hours |
|
| |
4sec |
8sec |
16sec |
32sec |
4min |
1hour |
8hours |
|
| |
8sec |
16sec |
32sec |
64sec |
8min |
2hours |
16hours |
|
You will notice that most of the long exposures show "warm" colours.
These extreme filters don't block the light below 660nm effectively.
The B+W-UV/IR-interference-blocking filter 486 in front (!) of the ND filter
removes this effect.
Crossing two polarizers should be a good trick too.
Two identical polarizing filters should give a perfect adjustable gray filter.
....I have tried my polarizers: they were not good enough!
Most of the long exposures are taken of wet surfaces.
The reflections add to the mystic effect. Polarizers can eliminate these reflections.
I needed a manual exposure, the camera did not like the dark environment.
Adjustments have to be taken without the filter, there is a dark screen otherwise!
So I take a test picture and calculate the necessary aperture and time.
Caution: SLRs need a cap on the view finder!
..and don't forget to look at this inspiring thread:
Reichert-ultra long exposures
Wikipedia neutral grey wiki
Variable polarizers?:NDx2-x8 variable singh-ray
Thanks for visiting my pages! Have a nice day - Sven
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© 2005-2007 Seemolf last update 4.mar.07 08:00
