[thehabit]

I picked this 50mm 1.4 up for $10 with a somewhat broken MX body, missing its hot shoe, rewind lever that i replaced with a broken k1000's, and needs new foam. I thought I had made a complete steal as everything looked good, until I noticed this oily haze. I've tried searching forums archives and web pages for this issue. I haven't been able to find a similar photograph or explanation. I know the issue beyond repair (in between elements), but I no longer own a digital Pentax, and cannot test it, so maybe someone with experience knows how image quality will be? Thanks in advance for taking time to look and diagnose! I included some images of the MX for kicks, it seems like it would have been a great camera new.

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Last edited by thehabit; 06-26-2015 at 03:59 PM.

[sergysergy]

I would say it is fungus and it looks bad enough to affect the quality of the pictures.

[jawsy]

I'd say it's fungus. The doughnut shape could simply be caused by the fungus growing where the light strayed through the lens in storage.

[marcusBMG]

+1 only way to find out if it might clean off is to open the lens. Shouldn't be too difficult, it looks from the pic like its on the second or third element, should only mean getting in the front. I'm sure s/o else will have gotten into this lens and be able to brief you.

[thehabit]

Interesting, I didn't suspect fungus, it disappears when looked at straight on and isn't visible with a light shining through while dust still is. Either way I am sure I'll end up taking it apart at some point. Thanks for the input so far I appreciate it!

[Not a Number]

Difficult to tell which surface it is on from the 2D pictures. If it is on the outer surface of the front element I'd think it is just water spots from condensation.

[thehabit]

Found a video on dismantling it, will do so tonight. It seems much easier than I thought to get to that front element. If interested in seeing how a 50mm 1.4 is dismantled, here it is!

Video: The Systematic Disassembly of a Pentax 50mm F/1.4 Lens | Popular Photography

[thehabit]

All done, all clear. I still find it a little hard to believe it was fungus, fungus was easy to detect in thrift lenses when I lived in south Florida earlier this year, it's something you rarely expect buying glass in south California as this piece was... Either way it is all clean now, with no etching as you would usually always expect from fungus stricken elements... Thanks for the suggestion to dismantle it marcusBMG, it worked!

[sergysergy]

awesome news!
enjoy your 'new' lens

[marcusBMG]

Thanks for the suggestion to dismantle it marcusBMG, it worked!

You''re welcome
PS apropos that video I would comment:
1. always have a white cloth/sheet on the table. Otherwise you will soon learn the hard way as a vital screw skitters off never to be found again.
2. always have pen and paper to make quick notes. Even simple things like what way up a ring or shim goes, as well as vital things like element orientation. Potentially saves a lot of time and trouble.. And a black pen of the type for writing on CD's to mark the edges of more symmetrical elements with eg an arrow.
3. dont have the habit of handling the glass with your hands. Have gloves and micro-porous cloths handy for that.
4. Rear caps make good pots for eg bayonet screws. Best not to mix screws up, separate and label (though with a simple lens like the 50mm its not usually a problem).