For sale is an early Leica Collapsible Summicron 5cm F2 in Leica in Thread Mount. This is a “Hot-Glass” lens that uses thoriated glass. This lens was “sun bleached” to reduce the amount of yellowing in the glass. It was then cleaned and relubed after this process. The optics are very clean for a Summicron of this vintage, see close-ups of the front element. My other Summicron was like wax paper before going to Focalpoint. Cosmetically it is in EX+ condition. This lens would be perfect for black and white film, or for the new M9 monochrome. On a color camera, it will produce a slight yellow cast which can be corrected using color-balance. Thoriated glass was used for its low-dispersion properties: the Infrared Focus index for this lens is within the F2 DOF marks. Not an “APO-Summicron”, but it does not get much better than that. Price: $540 shipped within the United States, $565 anywhere else via International Priority Mail. Paypal, Personal Check, Money Order. I reserve the right to hold shipment until check/MO clears. Return policy: returns must be made within 10 days, refund for the price of the item will be given after receipt. Postage cost is not refundable. Front cap and plastic rear cap included. If you need an IR cut filter for use on an M8, I will include one for an extra $30.