{"id":2157,"date":"2015-02-16T13:36:05","date_gmt":"2015-02-16T13:36:05","guid":{"rendered":"http:\/\/www.richardmudhar.com\/?p=2157"},"modified":"2015-07-10T08:55:54","modified_gmt":"2015-07-10T08:55:54","slug":"canon-ef-100-400-l-lens-fungus-attack","status":"publish","type":"post","link":"https:\/\/www.richardmudhar.com\/blog\/2015\/02\/canon-ef-100-400-l-lens-fungus-attack\/","title":{"rendered":"Canon EF 100-400 L lens fungus attack"},"content":{"rendered":"

note – this is a Mk 1 version of the Canon EF 100-400 L<\/em><\/p>\n

A working photographer uses their lenses all the time and probably never runs into this. I was into bird photography for a while, about eight years ago, and had the Canon EF100-400 IS L like every other wannabe bird photographer. In between now and then the field has separated the sheep from the goats – real bird photographers use longer primes, because the birds are always at the long end of any zoom. Or they use astro scopes on manual focus \ud83d\ude09<\/p>\n

\"Lapwings<\/a>
Lapwings landing<\/figcaption><\/figure>\n

Anyway, I take time out from birds and photography, because life gets in the way, and I stow the lenses in a relatively cold room. A couple of years back I figured I’d take some long lens pics, and get greeted by this<\/p>\n

\"Lens<\/a>
Lens fungus. Nasty<\/figcaption><\/figure>\n

which makes me curse. Mainly on the front element, though a starting spot on the inner element, which is part of the IS mech. The inner part is magnified by the biconvex front element. The spotty crap is on the inside of the front element, the fine filigree round the edge on the front of the front element.<\/p>\n

Markus Keinath is probably right<\/a> –\u00a0 the classic way this grows is<\/p>\n

In my view, glass fungus forms especially with rarely used items stored in leather cases. This often happens with gear passed on after someone’s died. The camera owner maintains his photographic equipment, and keeps everything neatly in the camera bag. Eventually for some reason he doesn’t take pictures any more, the camera is still packed away a few years , and then sold.<\/em><\/p>\n

The frequency of the glass fungal occurrence I would describe as high – in unused lenses , microscopes , probably binoculars. At flea markets, many of the old glass optics are contaminated with fungus. Optical devices that were in use until recently , are rarely contaminated with fungus, unless they are often used in humid conditions.<\/em><\/p>\n

Markus Keinath – any errors of translation are my own<\/em><\/p>\n<\/blockquote>\n

So this lens was used in the field and Britain is not the driest country in the world, many of these birds were on coastal areas, and i stored it in the lens case in a drawer close to the floor. There’s not much more that I could have done wrong from Zeiss’s words on the subject<\/a>. Oops<\/p>\n

Fungus does well with:<\/p>\n

Relative humidity of at least 70% (more than 3 days)
\nNo or little airflow
\nDarkness
\nNutrients (textile lint, traces of grease, varnish, dust and dirt)
\nTemperatures between 10 and 35\u00b0C<\/p>\n

[…]<\/p>\n

Do not use containers made of leather, textiles or wood for storage.<\/p><\/blockquote>\n