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Stan Yoder · 01/14/08, 03:11 AM

[quote=rtphotos;452726]I recently won a Summitar (ca.1949) in really nice condition. It didn't come with a hood, but I wanted to protect the lens' glass which I understand is quite soft and also prone to flare.

I dunno how soft the glass is, but the coating surely is soft. Leitz had to use the drip method of coating, since Zeiss had the patent on the vacuum-deposition process, which produced a harder coating. When the patent expired (I believe c.1960), Leitz turned to vacuum coating.

The drip coating is the cause of the "cleaning marks" so often found on older lenses. Also, drip coating dried out in time, and, under magnification, the surface looked like parched earth.

01/14/08, 03:11 AM	#9 (permalink)
Stan Yoder Benutzer Join Date: 05/24/07 Posts: 55	Re: Lens hoods for IIIf/5cm lenses [quote=rtphotos;452726]I recently won a Summitar (ca.1949) in really nice condition. It didn't come with a hood, but I wanted to protect the lens' glass which I understand is quite soft and also prone to flare. I dunno how soft the glass is, but the coating surely is soft. Leitz had to use the drip method of coating, since Zeiss had the patent on the vacuum-deposition process, which produced a harder coating. When the patent expired (I believe c.1960), Leitz turned to vacuum coating. The drip coating is the cause of the "cleaning marks" so often found on older lenses. Also, drip coating dried out in time, and, under magnification, the surface looked like parched earth.