Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-10-2012, 10:52 AM   #1
Forum Member




Join Date: Apr 2011
Photos: Albums
Posts: 92
Possible fungus in a 50mm f1.7

Ok so a very vague post here as I do not have an image of the 'offending' lens. Story is this, got a great offer on an smc a f1.7 50mm.The low price seems to be based on a desire to shift some old camera bits for the family and not make a killing out of my LBA and all sounds genuine. Taken off a Pentax body right out of the shop in preference to a zoom and stored in its leather box for however many years, the vendor is the owners daughter and says in all probability it has never been used from new. She describes the condition as absolutely mint. But I've asked her to give it a more detailed once over mentioning the risk of fungus.

I speak to her later and she states there is one spot inside the lens that cannot be cleaned from the front or the rear element. So we both look at google images of fungus and she concedes it doesn't look like the typical patterns. I'm thinking it's more likely internal dust or a glass defect. But is either likely in a never used lens ?
It's a giveaway at £20 and although a day trip to collect I could no doubt recoup my losses on a lens that mint versions of regularly hit £80.

I can't help thinking I've introduced the new concept of fungus and she's found something that isn't a worry but she thinks is.
Advice ? Do I go for a spin to her town and make my own decision or walk away now ?

Regards Rob.

05-10-2012, 11:07 AM   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,259
We'll need a pic. It could be dust, but you never know.
05-10-2012, 11:10 AM   #3
Giveaway winner!
MysteryOnion's Avatar

Join Date: Dec 2007
Location: beantown
Photos: Albums
Posts: 933
Long term storage can be bad for the lens. As mushrooms grow up nice and healthy in a dark and moist environment, a lens deep in a case with a steady climate will be the same. Over time, if it is fungus, the lens coating will get eaten away and it leave behind a odd pattern. UV light can help to kill the fungus, but cleaning it out will be best. The common place for growth is the space adjacent to the aperture/diaphragm area. It is the only space the can get a tiny breath of air. Cleaning requires the use of lens spanners or it you rather not, it is a familiar procedure at most camera repair shops. The 50/1.7 is a good lens, but there are others out there. If the price to clean is greater than traveling to return, then there is the answer. If you would rather clean yourself, many here will offer instructions... including me.
05-10-2012, 11:24 AM   #4
Forum Member




Join Date: Apr 2011
Photos: Albums
Posts: 92
Original Poster
Yeah I realise the lack of an image is hindering this somewhat, she thinks it's too small to photograph. I've swotted up on Ken Rockwells page showing the various marks a lens can suffer and my gut feeling is that it's not fungus. I just put my year old fa50 1.4 to a light and there's dozens of tiny spots, all grease marks of course on the front element so I'm thinking crystal clear optics but one tiny spec of something is worth a punt. Ah well, I promised the kids a trip to the coast anyway so if it does turn out to be a ruddy great mushroom in the barrel I've not lost anything......

05-10-2012, 01:07 PM   #5
Site Supporter
Jean Poitiers's Avatar

Join Date: Apr 2011
Location: Lost in translation ...
Photos: Gallery | Albums
Posts: 16,551
A possible steal at £ 20 ...

Bonjour,

I would not hesitate really. I have a very good A 50/1.7 that I love ... a KEH purchase from the States.

Even if it's fungus, which could be doubtful, I would bet that you could resell for a small gain if it's a "worst case scenario" ... £20 = about 25€ which is a price that is worth a gamble.

Voilà ... my 2 centimes.

Bon courage, bon vent et bonne chance - John le Frog
05-11-2012, 03:23 AM   #6
Forum Member




Join Date: Apr 2011
Photos: Albums
Posts: 92
Original Poster
Ok so I'll get it tomorrow and post pics. Oddly I was talking about my fa 50 being a bit mucky so gave it a good clean then the flashlight test. Oh my it is FULL of dust ! Clearly on the internal optics and dozens and dozens of specs of the stuff.

It's only 9 months old !!!! I've heard some views on this that its's unacceptable and should be cleaned under warranty then also that 'these things happen' and all, even new lenses, can and will get dust inside. Thoughts ?
05-11-2012, 07:09 AM   #7
Giveaway winner!
MysteryOnion's Avatar

Join Date: Dec 2007
Location: beantown
Photos: Albums
Posts: 933
I've found that my old M80-200 was very dusty and the trombone action is a pumping action. I would wonder if bellow for macro users have the same problem?
05-12-2012, 11:18 AM   #8
Forum Member




Join Date: Apr 2011
Photos: Albums
Posts: 92
Original Poster
Ok here she is, 100% this is fungus but will quite happily accept someone telling me it isn't ! It's about the size of a pen dot when not magnified and seems to be a on a forward element. Otherwise this is as mint a second hand lens as I've ever seen. So the question is, what do I do next ?

Attached Images
View Picture EXIF
PENTAX K-5  Photo 
05-12-2012, 03:18 PM   #9
Giveaway winner!
MysteryOnion's Avatar

Join Date: Dec 2007
Location: beantown
Photos: Albums
Posts: 933
From here it looks like fungus.
05-13-2012, 12:50 AM   #10
Forum Member




Join Date: Apr 2011
Photos: Albums
Posts: 92
Original Poster
So I guess my choices are:
Sell.
Try to clean myself.
Have it cleaned.
Aside from this can I also ask is there any risk in how I handled it? I took of my current lens, mounted this on my camera, took 3 shots then removed it. My understanding is that it's storage conditions that grow fungus and cross infection from lens to body to lens would be impossible if it was only mounted for a minute.
05-18-2012, 04:38 AM   #11
Giveaway winner!
MysteryOnion's Avatar

Join Date: Dec 2007
Location: beantown
Photos: Albums
Posts: 933
Just to note that London Rob has opened an expanded version of this topic.
05-18-2012, 04:55 AM   #12
Site Supporter
Jean Poitiers's Avatar

Join Date: Apr 2011
Location: Lost in translation ...
Photos: Gallery | Albums
Posts: 16,551
Where ?

QuoteOriginally posted by MysteryOnion Quote
Just to note that London Rob has opened an expanded version of this topic.
Bonjour,

Could you give us a link? Couldn't find it at first glance ...

Salut, J Frog

EDIT - Never mind ... I think that I found it, alas.

Last edited by Jean Poitiers; 05-18-2012 at 05:05 AM.
05-18-2012, 05:41 AM   #13
Giveaway winner!
MysteryOnion's Avatar

Join Date: Dec 2007
Location: beantown
Photos: Albums
Posts: 933
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/186378-definit...us-thread.html

Sorry, that link didn't display... cut and paste fail
05-18-2012, 07:03 AM   #14
Pentaxian
ivoire's Avatar

Join Date: Mar 2007
Location: chicago burbs
Photos: Gallery
Posts: 3,368
From one that got rid of fungus in the early stages:

"Open the aperture as far as possible, and park the lens in bright sunlight, preferrably at noon. Orient the lens so light is shining directly down its optical axis. (Make sure the sunlight isn't being focused by the lens onto anything that will melt; and obviously don't do this with the lens mounted on a camera!) The UV component of sunlight will kill the fungus pretty quickly. This won't undo any etching of the coating or glass caused by the fungus, but it will get rid of the organism."
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
f1.7, fungus, lens, look, mint, pentax help
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to Remove Fungus: A 50mm F1.7 lens adr1an Do-It-Yourself 14 08-30-2012 04:04 AM
Fungus in my DA* 16-50mm & DA* 50-135mm davidt Pentax SLR Lens Discussion 32 03-01-2012 04:46 PM
Repairing/Cleaning Fungus-Ridden Pentax-M 50mm 1:1.7 iht Troubleshooting and Beginner Help 22 05-17-2010 06:30 AM
Pentax A 50mm f 1.7 with fungus value rockmaster1964 Pentax SLR Lens Discussion 18 08-11-2009 09:51 AM



All times are GMT -7. The time now is 02:42 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top