wavelength photography

multiple exposure sequence - technical details

The following is a detailed summary of the equipment and exposures used to create this multiple exposure sequence of the 2002 Total Solar Eclipse.

> Event
  • Total solar eclipse, 4th December 2002.
> Location
  • Near Lake Everard, South Australia
    (31o 25.95' South, 135o 21.24' East)
> Equipment
  • Pentax 645 medium format camera
  • 150 mm Pentax A f/3.5 lens (φ = 58mm, field of view = 17o x 23o)
  • Manfrotto tripod with weight bags (filled with sand)
  • Cable release
  • Hand held spot meter
  • Darkroom timer
> Film
  • Fuji Velvia ISO 50 transparency (120 roll film)
> Filters
  • Hoya ND 400 (+8 stops)
  • Hoya ND 8 (+3 stops)
  • Hoya ND 4 (+2 stops)
        Total = +13 stops (equivalent to 4.0 ND, filter factor = 104, but visually unsafe)

> Exposures

The table below shows the times and corresponding exposures:

Event
Time (ACST)
Shutter Speed
Aperture
Notes
1st contact
18:41:29
-
-
18:55:55
-
-
Sun placed in top corner of frame
1st photo
19:05:55
1/250
f/22-32
19:10:55
1/250
f/22-32
19:15:55
1/250
f/22-32
19:20:55
1/250
f/22-32
19:25:55
1/250
f/22
19:30:55
1/250
f/16-22
1/2 stop increase
19:35:55
1/250
f/16
1 stop increase
Totality
19:40:55
1/4
f/3.5-5.6
No filter
19:45:55
1/250
f/11-16
1 stop increase
19:50:55
1/250
f/11-16
1/2 stop increase
19:55:55
1/250
f/11
20:00:55
1/250
f/8
20:05:55
1/250
f/5.6
20:10:55
1/125
f/5.6
Last photo
20:15:55
1/30
f/5.6-8
Sunset
20:21:00
-
-
Sky exposure
20:24:00
1/500
f/11
No filter

> Notes
  • At 18:55:55 the Sun was placed in the top right corner of the viewfinder to allow it to track into frame before the first exposure. This was practised beforehand.
  • The 1/2 stop and 1 stop increases in exposure around totality were made to compensate for solar limb darkening.
  • A spot meter reading taken on the horizon during totality suggested an exposure of roughly 1/2 sec at f/5.6, however the actual exposure used (1/4 sec at f/3.5-5.6) was chosen in advance, making it about 1 1/2 stops under what the meter reading suggested.
  • The sky exposure, made after sunset, was taken at 4 stops under the meter reading and probably did not contribute much to the overall image. Most of the colour in the sky was therefore formed during the totality shot.