bill kehoe
15-Oct-2009, 10:22
i just received a 300mm congo lens yesterday. coating much of the surface of the rear element closest to the shutter (ie. accessible) is a whitish haze that closely resembles the kind of calcium deposits hard water leaves on glass shower doors. it can be felt. as far as i can tell it is on the one surface only. the rest of the lens and shutter looks perfect. there were a few different-looking blotches on the inside of the front element but those cleaned right off with lens cleaner. the following nostrums gleaned from elsewhere on the web yielded no detectable results: windex with ammonia, vinegar, hydrogen peroxide, naphtha, isopropul alcohol.
the lens came from florida and because of deteriorated foam padding in an accompanying filter case, i suspect the lens was left in a car's trunk in the sun for an extended period of time, causing humidity to get inside the lens and leave some sort of chemical deposit. i don't really want the expense of a professional cleaning or the hassle of returning the lens. i'm thinking of trying a decalcifying cleaner but thought i'd seek other opinions before running that risk. any input would be appreciated. thanks for reading this.
the lens came from florida and because of deteriorated foam padding in an accompanying filter case, i suspect the lens was left in a car's trunk in the sun for an extended period of time, causing humidity to get inside the lens and leave some sort of chemical deposit. i don't really want the expense of a professional cleaning or the hassle of returning the lens. i'm thinking of trying a decalcifying cleaner but thought i'd seek other opinions before running that risk. any input would be appreciated. thanks for reading this.