Cooke Primoplane

The Cooke Primoplane, by the famous maker Taylor, Taylor and Hobson, is one of their many applications of the triplet design (three air-spaced elements) by Cooke.  Its remarkable how far they managed to stretch this simple layout, from little wide angles like this one, up to great big portrait lenses.  This 6″ version (152mm) equates to around 21mm on a “full frame” camera.  It’s designed for full plate and covers 10×8 only at portrait distance, but a similar version, with a slightly wider rear element, covers 10×8 comfortably.  

The Pink One was designed for this lens, although it now sports a 7″ Primoplane (equivalent to 24mm).  They’re great for environmental portraiture and landscapes/cityscapes.  A feature of wide angle lenses in this format is the relatively shallow depth-of-field.  On small cameras wide angle lenses tend to render everything sharp, regardless of distance from the camera.  On 10×8 a wide angle lens has depth-of-field similar to a short telephoto, so even a group portrait can have a lovely blurry background.