Wednesday, July 14, 2010

Wide-Field Large Format Astrophotography

Photographer Danny Spence has tackled a very difficult job, photographing the Milky Way with a large format camera. Difficult in nature due to slow lenses inherit in large format work, Danny uses films with low reciprocity failure to make the most of his exposures. In this case, 4x5 Fuji Acros 100 film was employed. A 180mm lens set at f/8 and a 15 minute exposure captured the wonderful star fields of the Summer Milky Way in Sagittarius as well as parts of Scorpius and Ophiuchus. The field of view is about as wide as a standard camera lens, but with telephoto resolution!

Making the exposure is challenging enough, but to make a difficult task even harder, the large camera must be mounted on a clock driven equatorial mount to keep the stars from trailing. Keeping a large camera on track as the Earth turns can be supremely difficult; as the clock driven mount moves the camera and lens across the sky, Danny makes small adjustments to the tracking while looking through a guide scope to keep stars in perfect registration as the film is exposed.

Enlarged section of the original 4x5 negative. Because the negative is very large, small sections can be seen to hold lots of detail. The resolving power of large format still rivals digital in sheer resolution. Click on images for larger size.

Although shot in a fairly light polluted sky, Danny's image gives us a tantalizing hint of what is possible when a seldom used method is given a chance to show what it is capable of. Danny is working on refining the process and hopes to get out under a clear dark sky when the opportunity arises!
All Photos Courtesy Danny Spence, All Rights Reserved.

1 comment:

  1. The 180 mm lens on a 4 x 5 inch film, 101 mm X 127 mm, should produce an enormous feld of view (FOV) - much, much larger than a "standard" (50 mm??) lens on 35 mm film.

    Bob G