Originally Posted by
Pere Casals
Your symmar says in the front 210mm 5.6 in white, but also says 370mm f/12 in green.
210mm 5.6 is the normal configuration. If you unscreew the front cell of the lens you have a 370mm f/12. Diafragm has two scales, one in white and the other in green, one for each configuration.
Convertiible lenses have fromt and/or rear cell corrected independently, so you can split the lens in 2 halves, and each half can be used alone, with less performance than what the whole lens has,
but still usable.
regards
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