Nearly every Summar F2 lens I have seen has marks on the front surface of the front optic. The results from these lenses is very 'romantic' . They have very low contrast and the focus is so soft that it appears that you have been taking photographs in a mist. This can be desirable in certain instances , but to improve performace of the lens the only remedy is re-grinding and re-polishing the front , steep , surface of the front optic. The SUMMAR glass is softer than normal Leitz lenses and constant wiping with a cloth over many years leaves the surface pitted with tiny scratches . This abundance of fine marks disperses light entering the lens and the consequent result is similar to putting vaseline on a lens to give beneficial , enhancing results as in portrait photography. Before the lens can be restored the front lens element has to be removed from its mount. The glass is pressed into a brass mount and the edges 'peined-over' to secure it . After it is finally removed the optic is measured optically on a test-glass plate and a moire pattern obtained. It is then machine ground and polished before being coated with a broadband magenesium flouride anti-reflective layer .
|Re-polishing/Coating the front element on a Leitz Summar Lens
Restoration of the Summar lens front element
first job :
removing the front element
|The 'grub-screw' in the front ring between Wetzlar &
Summar is removed and the front complete with optic can be removed.
The glass element is fitted into the chrome-plated brass mount with a packing ring and the edges of the mount are 'peined-over' to secure the optic. To remove the glass it is necessary to turn-out the edge of the mount and remove sufficient metal to allow the ring & optic to be removed. It is then heated to 200 degrees C to soften the cement . When hot , the glass is pushed out from the front.
With the glass separated from the mount it is now possible to re-grind & POLISH THE FRONT SURFACE , then , after checking the curvature it is re-coated with magnesium flouride in a vacuum chamber .
Return to :
Free : MINOX battery modification
Leica Guide Price : Repairs
Restoring Body shell coverings