I have a Sigma 4.5mm 2.8 f/2.8 fisheye lens that I'm using to take hemispherical canopy photos. I intend to analyze the photographs in Gap Light Analyzer, but need to know the projection of the lens. The literature on the lens states that it has an equisolid angle projection, but that isn't an option on the menu. I've looked for other papers using this lens, but most don't include the program settings used. The ones that do state that projection information was obtained by the manufacturer or that they developed a custom projection. I emailed Sigma, but I don't think the person who replied understood what I was asking.
Does anyone have projection information for this lens that I can use in GLA? Thanks in advance. I'll post a summary of replies to the list. - Vanessa Beauchamp Towson University
