Thursday, 27 September 2007

Sigma 15mm FE arrived today

The first thing needed was a comparison of angle of view. How wide is this lens with the DX sensor?
Being a fisheye lens the normal angle of view ratios dont apply. With a rectilinear lens you just multiply by the crop factor so a 15mm film rectilinear = 15 * 1.5 = 22.5mm on the D80. A 15mm fisheye is much wider than a 15mm rectilinear lens.

Nikon Coolpix 5000 with WC-E68 wide converter - TOP
Nikon D80 with Sigma 15mm FE - BOTTOM

The Coolpix wide setup gives the same angle of view as a 19mm lens on a full frame camera.
Calculation - 7.1mm Coolpix = 28mm film, multiplied by .68 (Wide adapter) = 19mm

D80 with Sigma 15mm FE gives a slightly wider horizontal view (maybe like an 18mm lens on film) and slightly less vertical view. So the equivalent would be about a 12mm rectilinear lens.
Calculation - 18mm divided by 1.5 (Crop factor for D80) = 12mm

Pay no attention to image quaity. Coolpix image cropped top and bottom from 4:3 to 3:2.


  1. Excellent comparison. Very interesting to read this blog! :-)

  2. thanks for the compare for Sigma 15mm.