[uttam.hathi]

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I would return it. The new DA 300mm F4 goes for $700 on ebay so just barely more than what you would pay for the lens+ fixing it. Not to mention that your time has to be worth something as well and that the lens witch etched coating will not be as good.

---------- Post added 01-12-15 at 05:46 AM ----------

example Pentax Da SMC AF 300mm 1 4 F4 Ed If SDM Telephoto Lens Digital EX | eBay

agree, unless u believe in restoring which is an expensive hobby

[Obin Robinson]

One thing I forgot to mention is that any time you go into the endeavor of cleaning your own optics make sure you wear powder-less latex gloves on your hands. There is no point in cleaning off fungus only to leave an oily fingerprint.


obin

[uttam.hathi]

One thing I forgot to mention is that any time you go into the endeavor of cleaning your own optics make sure you wear powder-less latex gloves on your hands. There is no point in cleaning off fungus only to leave an oily fingerprint.


obin

this is correct

---------- Post added 01-13-2015 at 07:15 AM ----------

This is actually not a particularly bad case of fungus. The only one that really might be affecting image quality is pic 2, which looks like vaporized lubricant deposits (haze) that have been attacked by fungus.

$500 (half regular used retail value) is definitely already a fair price for this lens, even with the undescribed fungus. Once it's apart, the cleaning won't add significantly more labor costs. Also bear in mind that the flashlight test tends to make things look far worse than they actually are.

If you choose to proceed yourself, ABSOLUTELY DO NOT FOLLOW UTTAM'S ADVICE. Bleach is bad news, and acetone is even worse, since it will decement doublets and remove blackening from the sides of lenses. Warm water and gentle dish soap, followed by a distilled water rinse is the best way to go. He's also wrong about fungus "infecting" other parts of gear. Fungal infections are caused by latent spores that are everywhere in the environment. Fungal growth is solely a condition of the humidity and temperature conditions a lens is stored in. If the barrel smells of mold/mildew, once all the glass is out, seal it in a large airtight container with a slow release chlorine dioxide packet (available at RV supply stores). This will kill any live fungus in the barrel and get rid of the smell without the need for disassembly.

Alternately, I can do it for you at a much lower price than you will get form a repair shop. If interested, let me know. I'd even consider buying it from you to clean up for myself.





Disagree. The SMC coatings are much more resistant to etching than pretty much anything else out there. Looks cleanable. I have never heard of arsenic used to clean fungus, and frankly, one would have to be an idiot to use it. The peroxide often used is household strength, so that's not really a concern, either.

---------- Post added 01-12-15 at 09:48 AM ----------

Recoating is definitely not needed, and doing so would only degrade the optical characteristics.



---------- Post added 01-12-15 at 09:52 AM ----------



Not really in terms of financial investment. The only real investment is the time it takes to develop the requisite skills.

i say from what i practice, i have clearly stated avoid doublets with any liquid, the lens elements are pictured on the lens itself here in F* 300, there are kinds and kinds of bleach, i said fabric bleach used in clothes and what i have suggested is wiping not keeping it soaked, soaking over period will damage coating even with ordinary tap water. fungal spores may be present otherwise but with known fungal infected lens its a bad idea to keep gear stored together, sorry dcshooter i differ. DO NOT KEEP GEAR IN chlorine dioxide over a period of time use it for very short burst as- thats BLEACH -"http://en.wikipedia.org/wiki/Chlorine_dioxide
Uses[edit]
Chlorine dioxide is used for bleaching of wood pulp, and for the disinfection (called chlorination) of municipal drinking water.[11][12]:4-1[13] As a disinfectant it is effective even at low concentrations, because of its unique qualities

[uttam.hathi]

@transam879 If u have cleaned the lens and photographed the process pls do post pictures

[transam879]

If u have cleaned the lens and photographed the process pls do post pictures

I actually sent it to a forum member to be cleaned. It turned out that one of the doublet elements was separating so that had to be repaired as well. Expect to have the lens back in a week or so. He said it cleaned up well and there didn't appear to be any etching from the fungus.

[uttam.hathi]

grt y would soon have one of the grtest 'portable' 300mm lens, any possibility the other forum member can post pictures of how to remove the front element

[transam879]

any possibility the other forum member can post pictures of how to remove the front element

No photos but this is what he told me, "I'm happy to walk you through the removal of the front element. It's a simple retaining ring with two spanner slots. I used a Flat-head type spanner (SK Grimes brand, my personal favorite) to remove the ring after applying MEK to soften the thread locker used on it. Simply turn counter clockwise until it pops out."

[uttam.hathi]

tks thats i grt confirmation

[bassek]

Pics of the lens before/after would be great...

Seb

[starjedi]

I actually sent it to a forum member to be cleaned. It turned out that one of the doublet elements was separating so that had to be repaired as well. Expect to have the lens back in a week or so. He said it cleaned up well and there didn't appear to be any etching from the fungus.

I see. Your picture 2 and 3 indeed suggest lens separation.

[transam879]

Pics of the lens before/after would be great...

** WARNING ** Not for the faint of heart **

The before pics of the lens are at the beginning of the thread. Here is the after pic. Yes, devastation, to put it mildly. The Post Office apparently dropped the box during shipping and it didn't mix well with very cold temperatures despite the lens being very well packaged. After the cleaning, and minus the Postal damage, the lens seemed to have been restored to outstanding condition. The front element looks the worst but there are also some internal elements that have 2-3 straight cracks in them as well. I took a quick shot of a test chart and was surprised to see the image it produced. At the very least, a lesson that minor front element scratches and internal dust, really aren't that big of a deal....and of course, it reiterates the importance of adding insurance.

[Driline]

So now what?

[transam879]

So now what?

Wait for the claim to be processed from the Post Office and start the search for another F* 300.

[noelpolar]

Sorry to hear..... the world doesn't need one less F*300!

Someone will probally offer to buy the tripod foot now......

[crewl1]

Wait for the claim to be processed from the Post Office and start the search for another F* 300.

Sorry to inform that I have heard it is next to impossible to get the post office to make good on insurance claims, but I wish you all the best.
I hope you have good friends at your local USPS office.