On 30/3/06, Manuel Magalhães, discombobulated, unleashed: >Hi Cotty, >is it possible to convert the lens to PKA fit? > >Thanks, > >Manuel
That's an interesting one. I would say yes - and no. The register distance (distance between film/sensor plane and back of lens is 44mm on the Canon. On Pentax it's 45.46mm. On a 'normal' lens this would mean losing infinity focus without a costly and degrading optical adapter. But the EF MP-E 65mm macro is no 'normal' lens. <http://www.tanchung.com/canon/efmpe65mmf28macro1to5.htm> It would be totally practical to engineer a K mount for it - - except - - that one would have no control over the aperture. The OEM system is controlled electronically from the camera. To lose that electronic control would mean either leaving the f-stop 'welded' open or closed (or indeed anything in between). Fully open and you can focus but you get no depth of field. Fully closed down (f/16) and you get depth of field but you can't see a dicky-bird, even with focussing lamps on. You need the max aperture of f/2.8 to focus. It might be possible to engineer a simple mechanical lever that could be used to open and close the aperture manually, or it might not. A much better option would be to get Canon film or digital camera to go with the macro.... HTH Cheers, Cotty ___/\__ || (O) | People, Places, Pastiche ||=====| http://www.cottysnaps.com _____________________________
