imagei

That's what I do. I have a separate entry for when I'm using a focal reducer (with reduced focal length and the reducer info in the Lens Make and Lens Model fields). For example there's a preset called 'Primotar 135/3.5' and another called 'Primotar 135/3.5 (reduced)'. In the second case the 'Lens Model' field reads 'Primotar 135mm f/3.5 (Exakta); Lens Turbo II'. If you're on OSX there's a great little app called 'Exif Editor' by Martin Novák which I use for this purpose. It has a preset editor so you can have a convenient list of all your lenses in a dropdown box. Then it lets you select shots visually and apply all the changes in one go.