04-08-2009, 08:36 AM #1
Finding Fungus & second hand lens inspection
i'm on the verge of a steep glass cliff..
i found a "very good" 70-300 f/4-f/5.6 G (no VR) which i want to take pics of my 5year old in his rugby team we just signed him up for.
i might go around and see the lens beofre i buy it. (i can get it for between US$50-US$70.
which is dirt cheap really.
how do i spot the fungus (even if there is a small amount of it?)
whatother signs should i be looking for? apart from scratches, and obvious external damage.. mounts or contacts..
i wouldnt know what specifically to look for..
04-08-2009, 10:40 AM #2
Jared - the second post in this thread is concise, but seems to be right on point. If not, I'm sure vandergus, inkista and/or someone else will chime in soon.
$50-70 US would sure be dirt cheap. Good luck.
EDIT: Now that I think about it some more, the thread that I posted originally is for a lens with an aperture ring. So, I'm not sure how you can check a G lens to see if the stops all "click" the right way. Sorry about that.
Last edited by Chip; 04-08-2009 at 11:08 AM.
04-08-2009, 12:22 PM #3
Well since you asked...
The best way to find fungus in a lens is to open it up to its widest aperture, then hold the lens up so you are looking through it into a direct light source like a lamp or overhead light. On lenses with aperture rings it's easy. Just select the largest aperture and look through. On G-type lenses it's a little different. When the lens isn't mounted, the aperture automatically stops down to it's smallest setting. If you look at the lens mount on the rear of the lens, you'll see a little pin sticking out that controls the aperture. As you move it back and forth in the slot, you can see the aperture in the lens open and close. So to inspect the lens, hold the pin in the position with the aperture wide open and look through the lens at a light source.
If you see something that looks like a mishapen snowflake, that's probably fungus. Looking through the lens like this will also help you see scratches on the front element more easily. Don't make to big a deal about fine scratches though. They won't show up as spots in you pictures or anything like that, but they may increase the chances of flare in certain situations.
The link Chip posted covers pretty much everything else as far as checking funtionality goes.
And as a general comment about the lens, don't expect miracles from it. For $50 bucks, though, it's probably worth it.
04-08-2009, 06:44 PM #4
Thank you Gentlemen, very much apreciated
i bought it
*slap on the hand*
will give it a health check when i go pick it up, so if its not exactly as described of if i see snow.. i'll walk away.
Phew.. just in time for the long weekend.
04-09-2009, 08:57 AM #5
well thanks guys
picked it up and all looks good, no scratches, zoom is smooth and no fungus/dust.
only minor thing is a bit of wear on the mount, and when searching for a focus its a gritty noise.. not smooth like the 50mm or 18-135
*shrug* oh well... cant cmplain for that price
04-09-2009, 10:43 AM #6
04-09-2009, 11:35 PM #7