[aquashankar]

Gentlemen,

After reading many lens reviews in detail, I finally bought a Vivitar manual focus 50mm f1.7 off ebay for the K100D Super. It cost me all of $50 and came in a good condition. I began getting much sharper images than the only other lens I have; an old Pentax FA SMC 28-200mm lens which is not bad but nothing great either in low light. The Vivitar being a manual focus lens, has a higher learning curve to get the focus and timing right. The images are excellent inspite of the average rating the lens has received on this forum. It suffers at apertures lower than 2.8. I did not have any other benchmark to compare as I do not have the newer 18-55mm kit lens either.

Checking the other lens reviews on this site, I found glowing reviews for the Pentax M 50mm f1.4. The sample images posted by the members are just great. I searched again and found one on ebay again for $60. I had high expectations the day it arrived and began clicking in all earnest. However, I found the inner most lenses to have what seems to be a wierd substance (the photo below). All the photos taken with this lens have a white haze on them and the centre focus is much harder to obtain than the Vivitar. I then found the video showing the process of disassembling the lens but even this video did not show how to take apart the inner most lenses where the actual problem might be. Below is the photo of the innermost lens after removing the outer lenses from both ends.



Below are also two photos taken with both lenses without any editing. Both were shot at f8 with a shutter speed of 1/30. Would the masters please advise? Or is the Pentax M a goner?



I do not know how to remove these two inner lenses and clean them if that is the issue. Any advice would be most welcome.

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Last edited by aquashankar; 07-02-2012 at 05:14 AM. Reason: typos

[MysteryOnion]

Sorry to say, but that is fungus.

The disassembly is not very complex thing... just some details that need to be check before you start.

If you have removed the rear most group, the usual infected lens is the final element facing the aperture blades. This is the only true air space and this is the same for the front group.

It has been a while be, but I recall the last lens is not secured? You could tip it out, but have a clean soft surface to work on... and launder that work surface after the element is washing or soaking as to not spread spores back. For better control of the spores, dowse the entire lens in straight dishwashing soap and wash in cold water over a catch basin in case it slips. Microfiber cloth is the best way to quickly clean surface for re-installation of element. Use surgical gloves washed of talc. If the fungus was not living long on the surface, it should come clean. If it was there for some time, it may have already eaten or etched the surface.

[kh1234567890]

Youtu.be

Youtu.be

Don't worry about 'spores'. They are everywhere anyway. The lens fungus will not suddenly spread over everything. Use cold cream to clean fungus off the glass surfaces (borrow some from you wife/girfriend etc). Apply generously, leave for a while, wipe off. Do not worry about damaging the coating, it is tougher than you think. Clean all glass with lens tissue etc., keep your dust blower handy as you re-assemble otherwise insignificant bits of fluff will bug you forever more.

[aquashankar]

Just as I feared. is it worth trying to clean it now? I intend to open the lens myself as I do not know anyone in Hyderabad who cleans Pentax lenses. If the fungus can be removed, it would still make a great lens to keep.

I will again try opening but since the last scrubbing with the cloth did not work, I think I have to see if I can further open it. I removed the lenses from the front and the back till I got to the lens facing the aperture. Since I bought this off ebay, I do not know how long the fungus has been there.

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Last edited by aquashankar; 07-02-2012 at 06:07 AM. Reason: text did not render at first. I saw the entire message only on refresh after posting

[aquashankar]

kh1234567890: thank you for the link. I have seen that video and come to the point where he removes all the lenses except the inner most ones. The video does not show how to remove them and that's where I'm stuck too unless there are no more lenses to remove and the fungus has etched the lens.

I will do as you say now. I will open the lens again (3rd time now) and apply the cold cream as you said and pray that it is on the aperture side and hopefully comes off. I have the microfibre cloth too and if it gets cleaned, I will be most happy.

[MysteryOnion]

Cool video on disassembly, but the cleaning part is a little vague or not very cautious on spore spreading.

"...inner most." could you give a snapshot of where you are now if not the image above?

Otherwise, it looks like the last piece is the retainer sleeve for the last element at the rear. It will look like a single thick tube, but it is a retainer.

[kh1234567890]

Sorry, I've not taken one of these to bits myself. It should be like so :

Where is the fungus ?

[MysteryOnion]

Sorry, I've not taken one of these to bits myself. It should be like so :

If I were at home right now, I would not mind cracking open one of my M50 1.4 to show, but thanks for the diagram of the optics kh1234567890.

Where is the fungus ?

Common place is the point where the two cupped sides face each other.
That is the aperture space and a most probable place a spore could creep in over time.
As pointed out in a thread about fungus infections in general, the lens in not a hermetically sealed vessel.
Fungus could make it through a slight gap on the outer retainer and grow and climb in.


I've cleaned many fungi-ed optics in the past and have cleaned quite a few 50mm with assorted fungus points. My weapon of choice for prevention is GSE (grapefruit-seed-extract) on the optics to soak for a while, if the UV light does not kill the spores first. I do think the GSE will neutralize them on the glass, but I have not wanted to apply to painted metal parts. The non-optical parts are set under a halogen light with the UV filter removed as to give them a good scorch. If you use the halogen, be careful of over-heating, this can cause the grease to separate and make an oily set of aperture blades.

[jatrax]

I searched again and found one on ebay again for $60.

Despite all of the wonderful advice above what you should do is return it to the seller for a full refund. Unless they stated that it had fungus you should not have to accept a non-functional lens. That is not an expensive lens, and is available just about every day so unless you are trying to learn lens repair you are wasting your own time.

I have cleaned fungus from a number of lenses and unless it is in the glue bonding elements together or has etched the glass it can be cleaned easily assuming you can disassemble.

As noted above, forget about spores and fungus re-growing. Spores are in the air we breathe and almost always any fungus on an older lens has been dead for years. Fungus can only grow in a very narrow environmental range. It requires warm moist air, darkness and something to feed on. Without all those things it dies. It will not miraculously re-grow or spontaneously infect your other gear. All of your gear is already infected, but nothing will grow without the right environment. Keep your lenses in a dry environment, make sure if they get wet you dry them properly and you will not have fungus problems. Put a wet lens in a warm dark closet in the basement and you will have a nice crop of fungus.

[GibbyTheMole]

Despite all of the wonderful advice above what you should do is return it to the seller for a full refund. Unless they stated that it had fungus you should not have to accept a non-functional lens. That is not an expensive lens, and is available just about every day so unless you are trying to learn lens repair you are wasting your own time.

Yep. I would return it. Also, if the seller didn't disclose the fungus in the ad and they absolutely refuse to take it back, file a claim with PayPal. Be thorough in your correspondence with PayPal. I bought a lens from an eBay seller in which she said it was clear glass and mint condition only to find when I got it that it had a severe (like worst I've ever seen) case of fungus. I took photos of the fungus in the lens as well as some very blurry photos with the lens and sent them to her, politely explaining that though I was sure it was just an oversight on her part, that it was a useless lens because of the fungus, and she replied that she wouldn't take it back because you could still see light through it, and I was too picky. (She was the biggest idiot I have ever dealt with.)

So, without corresponding further with her, I filed a claim with PayPal, including links to photos of the fungus and our complete e-mail exchange. PayPal refunded me in full within 48 hours. After PayPal refunded my money, I got another e-mail from the idiot seller asking that since she had graciously decided to give me the refund, would I leave her positive feedback? I left her feedback, alright.

So my advice to you is:

1) Take photos of the fungus and send them in your e-mail to the seller politely explaining what the deal is, and ask for a full refund. Be nice, & don't accuse them of anything.
2) If they refuse, don't tell the seller you're going to file a claim. That gives them the opportunity to retaliate. Just upload the fungus photos somewhere like imageshack or flickr & file a claim with PayPal, including the links to the photos and your complete, unedited e-mail correspondence.
3) Don't wait. You only have 30 days to file a claim.

Of course, if the seller disclosed the fungus in the ad, you're kinda stuck.

Good luck,
Bobbo :-)

[kh1234567890]

Despite all of the wonderful advice above what you should do is return it to the seller for a full refund. Unless they stated that it had fungus you should not have to accept a non-functional lens. That is not an expensive lens, and is available just about every day so unless you are trying to learn lens repair you are wasting your own time.

I would agree with this. Having a go at taking lenses to bits is only really worth it if you'd paid next to nothing for it and you don't mind binning it if you can't get it all back together again. It is not difficult with old lenses but hardly worth it if you can pick up a mint example instead.

I have cleaned fungus from a number of lenses and unless it is in the glue bonding elements together or has etched the glass it can be cleaned easily assuming you can disassemble.

And reassemble

As noted above, forget about spores and fungus re-growing. Spores are in the air we breathe and almost always any fungus on an older lens has been dead for years. Fungus can only grow in a very narrow environmental range. It requires warm moist air, darkness and something to feed on. Without all those things it dies. It will not miraculously re-grow or spontaneously infect your other gear. All of your gear is already infected, but nothing will grow without the right environment. Keep your lenses in a dry environment, make sure if they get wet you dry them properly and you will not have fungus problems. Put a wet lens in a warm dark closet in the basement and you will have a nice crop of fungus.

It is refreshing to read some sensible advice instead of Internet myths !

[aquashankar]

Where is the fungus ?

The fungus as mentioned by MysteryOnion is in the centre between the twocupped lenses.

If I were at home right now, I would not mind cracking open one of my M50 1.4 to show, but thanks for the diagram of the optics kh1234567890.

I will pm you on this for some help if I am stuck with the lens after escalation and redressal by ebay and the seller.

Despite all of the wonderful advice above what you should do is return it to the seller for a full refund. Unless they stated that it had fungus you should not have to accept a non-functional lens. That is not an expensive lens, and is available just about every day so unless you are trying to learn lens repair you are wasting your own time.

I have cleaned fungus from a number of lenses and unless it is in the glue bonding elements together or has etched the glass it can be cleaned easily assuming you can disassemble.

Thank you for the advice. I have mailed the seller back asking for a refund as he clearly stated “no fungus” in the ad. I agree it is not an expensive lens but finding one in India is a little more difficult than the West as this is the land of Canonika.

And yes, I totally enjoyed learning to take apart the lens to understand its functioning. I’ve learnt how to clean the glass properly. I’ve learnt how the aperture works and the need to be precise when putting it back together. Most of all, I learnt to catch that little ball bearing which loves to run away when removing the aperture ring. :-)

But since I was unable to get to the root cause, I have asked for a refund. Let’s see what comes out of it.

Don't wait. You only have 30 days to file a claim.

Of course, if the seller disclosed the fungus in the ad, you're kinda stuck.

Thank you for the detailed note. I do not purchase much on ebay and I did not know about the 30 day threshold for filing a claim. It is 33 days as of today and I’m not sure what will happen next. I kept thinking it was dust and not fungus. The seller disclosed the dust but clearly said “no fungus”.I kept thinking the photos were poor due to the photographer’s (myself) ability.I will keep this in view from now on to ask immediately especially as this is one active forum with so many helpful members.