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**Henrico** · 08-26-2014, 08:21 AM

Bought me an oldie goldie, the K24 f2.8, which looks obviously mint with super clear outer glass. Unfortunately it suffers of flare caused to two inner elements close to the blades. A closer inspection makes me think it's oil, the structure of the pollution is pretty uniform, as if it's sprayed over the surface. The bigger outer lens elements seems very clean to me. It's very good visible shining a bright light straight through the lens.

What's your opinion on this? Dissasambling and cleaning with isopropanol?

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**grahame** · 08-26-2014, 08:49 AM

Unfortunately, it looks element separation. The glue between two element decayed and formed little bubbles. Hope you can other return the lens or you hadn't spent too much on it.

lytrytyr · 08-26-2014, 08:55 AM

Originally posted by Henrico

What's your opinion on this? Dissasambling and cleaning with isopropanol?

Welcome to the forum!

The K24/2.8 has a cemented pair of elements (third and fourth).

See this diagram from Boz Dimitrov's site:

If the problems with your lens are the result of deterioration of the cementing,
cleaning with isopropanol won't help at all.

But I'm no expert in lens repair,
so I can't be sure that this is the actual problem with your lens.

**Henrico** · 08-26-2014, 09:05 AM

Fortunaly not that much. I think I will keep it and might use it for special morning misty effects....

The two garden pictures were taken with sunshine straight in the lenses, to express the extreme flare effect. Avoiding that this little beauty produces soft but tack sharp pictures one stop down...

**grahame** · 08-26-2014, 09:25 AM

Well, you get a 24/2.8 soft lens. the SMC-FA 28/2.8 soft is expensive to have :-)

Tanzer · 08-26-2014, 09:51 AM

Looks like fungus to me.

I've seen element separation around the edges of cemented elements. I don't think I've seen separation so uniformly distributed. I could be wrong.

If it is element separation, then you won't risk anything by opening it up, or having a professional give it a try.

wombat2go · 08-26-2014, 10:33 AM

Henrico,
i have exactly the same lens. it had an appearance in the glass like your 4th photos, and the images from the lens had halo and haze. I sent the lens to Pentaxforum member dcshooter for repair. The condition was corrected by cleaning ( I understand re-condensed lubricant on the glass) and he was able to return the lens to top condition. it is now takes very good photos.

Perhaps this model of lens had a different lubricant as I have a few other similar vintage lenses here , different focal length , that do not show the problem

You can send a personal message to dcshooter.

**grahame** · 08-26-2014, 11:25 AM

lens separation/ delimitation could lead to anything like rainbow color splitting; nice looking leave or flower shape just like fungus, or evenly distributed small dots.
Unless you have the equipment to separate the glass, polish them and reapply the resin to glue them appropriately, separation/ delimitation is very hard to deal with.

Joojoo2010 · 08-26-2014, 11:40 AM

Not look like fungus/oil to me

manntax · 08-26-2014, 11:42 AM

Speaking from my experience with this lens - it was some oily residue with many small dust particles glued to it - lens has been serviced for exactly the same reason and after that all the misting is gone - so I say go for it - either yourself if you know how or ask somebody who does this sort of thing ( after all this lens is still fairly sought after and can be expensive ) and go for it! The dust was located in-between the glass elements where aperture blades are - which would explain that since dust is omnipresent so to speak and could have easily gotten inside the mechanisms of aperture and from there onto the glass.

Good luck!
,,,
'>' manntax

**Henrico** · 08-27-2014, 02:34 PM

Thanks for your advices!

A closer inspection of both sides of the lens in bright light with a magnifier shows there ar obviously two different surfaces infected, one in the front-group, one in the back-group. So I get pretty convinced it is condensed oil, it looks as many tiny drops on the glass. Last year I cleaned the blades of my M 35mm f2.0 and those inner lenses also were a bit affected with condensed oil.

So I'm best gonna buy me a lens spanner, try to remove the front group in one part, to reach the inner elements close at the blades and clean them up. Has anyone experience in disassembling this lens?

Despite some reservations on the lens reviews I am pretty impressed by the sharpness this lens produces already now. It's close to my 28 mm K. This 24 mm also has a very nice look & feel, it's more a "M" than a "K", so I definitely will adopt it in my collection of old full frame glass....

alexcam · 09-03-2014, 10:06 AM

Originally posted by Henrico

Thanks for your advices!

A closer inspection of both sides of the lens in bright light with a magnifier shows there ar obviously two different surfaces infected, one in the front-group, one in the back-group. So I get pretty convinced it is condensed oil, it looks as many tiny drops on the glass. Last year I cleaned the blades of my M 35mm f2.0 and those inner lenses also were a bit affected with condensed oil.

So I'm best gonna buy me a lens spanner, try to remove the front group in one part, to reach the inner elements close at the blades and clean them up. Has anyone experience in disassembling this lens?

Despite some reservations on the lens reviews I am pretty impressed by the sharpness this lens produces already now. It's close to my 28 mm K. This 24 mm also has a very nice look & feel, it's more a "M" than a "K", so I definitely will adopt it in my collection of old full frame glass....

When I first bought this lens I was expecting a lot more from it, but I got it at a decent price.
After reading this thread, I decided to take a close look at my copy. Sure enough it had the same foggy look to it.
I was able to get the front group out but not the back. I cleaned the inside of the back group through the wide open aperture.
BIG DIFFERENCE!!!
I'd say it's sharper than my A and M 28mm f2.8 copies that I have.
Once you get the front cover ring off, a spanner wrench will take out the whole front group.
Good Luck!

lytrytyr · 09-03-2014, 11:18 AM

Originally posted by Henrico

This 24 mm also has a very nice look & feel, it's more a "M" than a "K"

The K24/2.8 was offered in catalogs and brochures along with the M series.
I'm guessing they didn't call it an M because it didn't have the standard 49mm filter thread of the (smaller) M lenses.

**Henrico** · 09-03-2014, 12:33 PM

Thanks Alex,

Yesterday I tried to open it up from the front side. I easily removed the name plate and started unscrewing the three tiny screws. Two of those went easy, one did not cooperate and I ruined that screw. I tried to drill it out but that was more difficult than I thought it was so I left it....

Question to you; is it necessary to remove those three screws to remove the front group, or do I only need to remove the narrow ring around the group? I tried to do that with two screwdrivers but failed to unlock it. So I doubt what to do now...

Don't pay attention on the dust under the front lens, I removed it to inspect those surfaces and they were not affected, I cleaned them quickly with a tissue but I have to repeat that with a dust free handkerchief .

alexcam · 09-04-2014, 06:35 AM

Originally posted by Henrico

Question to you; is it necessary to remove those three screws to remove the front group, or do I only need to remove the narrow ring around the group? I tried to do that with two screwdrivers but failed to unlock it. So I doubt what to do now...

Henrico,
You don't need to remove the screws.
Remove the first ring (just outside of the ring you removed to clean the first lens) and that will take out the whole front group.
I actually had to remove the first lens so I could get small needle nose pliers to access that lock ring....and it was tight! As I said before the back group was so tight I couldn't loosen it with those same pliers. I have to invest in a spanner wrench to do this correctly from now on.

As a side note this is probably the third lens I've taken apart and cleaned that improved the image quality. One being a no name 135mm f/2.8 and the other an M50mm f/2. By far the 24mm has seen the biggest improvement.

Good Luck!

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08-26-2014, 08:49 AM	#2
grahame Loyal Site Supporter Join Date: Aug 2011 Photos: Albums Posts: 2,041	Unfortunately, it looks element separation. The glue between two element decayed and formed little bubbles. Hope you can other return the lens or you hadn't spent too much on it.

08-26-2014, 08:55 AM	#3
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by Henrico What's your opinion on this? Dissasambling and cleaning with isopropanol? Welcome to the forum! The K24/2.8 has a cemented pair of elements (third and fourth). See this diagram from Boz Dimitrov's site: If the problems with your lens are the result of deterioration of the cementing, cleaning with isopropanol won't help at all. But I'm no expert in lens repair, so I can't be sure that this is the actual problem with your lens.

08-26-2014, 09:05 AM	#4
Henrico Loyal Site Supporter Join Date: Jun 2013 Location: Utrecht Photos: Gallery Posts: 255 Original Poster	Fortunaly not that much. I think I will keep it and might use it for special morning misty effects.... The two garden pictures were taken with sunshine straight in the lenses, to express the extreme flare effect. Avoiding that this little beauty produces soft but tack sharp pictures one stop down...

08-26-2014, 09:25 AM	#5
grahame Loyal Site Supporter Join Date: Aug 2011 Photos: Albums Posts: 2,041	Well, you get a 24/2.8 soft lens. the SMC-FA 28/2.8 soft is expensive to have :-)

08-26-2014, 09:51 AM	#6
Tanzer Veteran Member Join Date: Mar 2012 Location: Perrineville, NJ Posts: 1,375	Looks like fungus to me. I've seen element separation around the edges of cemented elements. I don't think I've seen separation so uniformly distributed. I could be wrong. If it is element separation, then you won't risk anything by opening it up, or having a professional give it a try.

08-26-2014, 10:33 AM	#7
wombat2go Veteran Member Join Date: Jan 2010 Location: Michigan Photos: Gallery Posts: 2,207	Henrico, i have exactly the same lens. it had an appearance in the glass like your 4th photos, and the images from the lens had halo and haze. I sent the lens to Pentaxforum member dcshooter for repair. The condition was corrected by cleaning ( I understand re-condensed lubricant on the glass) and he was able to return the lens to top condition. it is now takes very good photos. Perhaps this model of lens had a different lubricant as I have a few other similar vintage lenses here , different focal length , that do not show the problem You can send a personal message to dcshooter.

08-26-2014, 11:25 AM	#8
grahame Loyal Site Supporter Join Date: Aug 2011 Photos: Albums Posts: 2,041	lens separation/ delimitation could lead to anything like rainbow color splitting; nice looking leave or flower shape just like fungus, or evenly distributed small dots. Unless you have the equipment to separate the glass, polish them and reapply the resin to glue them appropriately, separation/ delimitation is very hard to deal with.

08-26-2014, 11:40 AM	#9
Joojoo2010 Veteran Member Join Date: Sep 2013 Posts: 306	Not look like fungus/oil to me

08-26-2014, 11:42 AM	#10
manntax Veteran Member Join Date: Jan 2012 Photos: Albums Posts: 1,972	Speaking from my experience with this lens - it was some oily residue with many small dust particles glued to it - lens has been serviced for exactly the same reason and after that all the misting is gone - so I say go for it - either yourself if you know how or ask somebody who does this sort of thing ( after all this lens is still fairly sought after and can be expensive ) and go for it! The dust was located in-between the glass elements where aperture blades are - which would explain that since dust is omnipresent so to speak and could have easily gotten inside the mechanisms of aperture and from there onto the glass. Good luck! ,,, '>' manntax

09-03-2014, 10:06 AM	#12
alexcam Forum Member Join Date: Jun 2009 Location: Long Island, New York Posts: 50	Originally posted by Henrico Thanks for your advices! A closer inspection of both sides of the lens in bright light with a magnifier shows there ar obviously two different surfaces infected, one in the front-group, one in the back-group. So I get pretty convinced it is condensed oil, it looks as many tiny drops on the glass. Last year I cleaned the blades of my M 35mm f2.0 and those inner lenses also were a bit affected with condensed oil. So I'm best gonna buy me a lens spanner, try to remove the front group in one part, to reach the inner elements close at the blades and clean them up. Has anyone experience in disassembling this lens? Despite some reservations on the lens reviews I am pretty impressed by the sharpness this lens produces already now. It's close to my 28 mm K. This 24 mm also has a very nice look & feel, it's more a "M" than a "K", so I definitely will adopt it in my collection of old full frame glass.... When I first bought this lens I was expecting a lot more from it, but I got it at a decent price. After reading this thread, I decided to take a close look at my copy. Sure enough it had the same foggy look to it. I was able to get the front group out but not the back. I cleaned the inside of the back group through the wide open aperture. BIG DIFFERENCE!!! I'd say it's sharper than my A and M 28mm f2.8 copies that I have. Once you get the front cover ring off, a spanner wrench will take out the whole front group. Good Luck!

09-03-2014, 11:18 AM	#13
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by Henrico This 24 mm also has a very nice look & feel, it's more a "M" than a "K" The K24/2.8 was offered in catalogs and brochures along with the M series. I'm guessing they didn't call it an M because it didn't have the standard 49mm filter thread of the (smaller) M lenses.

09-04-2014, 06:35 AM	#15
alexcam Forum Member Join Date: Jun 2009 Location: Long Island, New York Posts: 50	Originally posted by Henrico Question to you; is it necessary to remove those three screws to remove the front group, or do I only need to remove the narrow ring around the group? I tried to do that with two screwdrivers but failed to unlock it. So I doubt what to do now... Henrico, You don't need to remove the screws. Remove the first ring (just outside of the ring you removed to clean the first lens) and that will take out the whole front group. I actually had to remove the first lens so I could get small needle nose pliers to access that lock ring....and it was tight! As I said before the back group was so tight I couldn't loosen it with those same pliers. I have to invest in a spanner wrench to do this correctly from now on. As a side note this is probably the third lens I've taken apart and cleaned that improved the image quality. One being a no name 135mm f/2.8 and the other an M50mm f/2. By far the 24mm has seen the biggest improvement. Good Luck!

Misty 24mm.... Oil or Fungus ?

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