Fungus on SMC-FA 80-320

Just took out my SMC-FA 80-320 for a go with the SMC-F 1.7x AF adapter on the K10D...

Managed 540mm handheld at 1/50s using SR - amazing!

But... I've got a spidery bloom growing behind one of the front elements, and several spores that have landed on the element around it. Thankfully the lens was isolated from the rest (and probably where it grew the mold).

Hoping that it was behind the front element, I used a steel vernier guage as a lens spanner to unscrew the front element... and the contamination is behind the second element and it looks like the whole thing needs disassembling

The lens was second hand (about £90) and may even have had the spores there from the beginning, so I don't want to spend a great deal having it fixed (and of course, there's no guarantee as it could resurface). Does anyone have any suggestions?

Failing that the SMC-DA 50-200mm is looking very attractive as a replacement until the 60-250mm arrives But I did sooo like the 8-blade bokeh of this lens, and its very long range!


Matt

Matt,
Many are waiting with eager anticipation for the "new" lenses. I hope I am wrong but I think the price will come as a shock and put them out of the reach of many. Think of the premier lenses for full frame. I could be wrong but I would think these are the replacements. They disappeared from the european websites a while ago and are almost impossible to find in the US although still listed there.

The 16-50 fills the same space as the 28-70/2.8 had, the 50-135 the same space as the 80-200/2.8. The 60-250 doesn't have an exact predecessor but think of the 250-600/5.6. These were all fixed aperture high quality zooms and well into 4 figure sums even in the US. As I say I hope I am proved wrong but I suspect each will be at least £1000! I also think that it tends to show the whatever others may think, if the K1D arrives, it will not be full frame. If this was their intention, Pentax would not be dropping the earlier full frame premium zooms and introducing these other than perhaps at the wide end.

As far as your "present" problem, The 50-200 are nice lenses and can be found at less than £100 now. If you do need longer, what about the 100-300 which are also very cheap at the moment.

Kim

Kim,

You might well be right about the new zooms, but, given the low price of the K10D and the fact that nowadays manufactured items cost much less than they used to, I think there are grounds for hoping that the new lenses will be somewhat cheaper than the old.

My Z1-P cost much more in 1994 than my K10D did last week. And yet the K10D is more complex and better built.

Pentax have shown that they are much more price-aware than they used to be, and they have seen that low prices translate into good sales.

I'm hoping that the new lenses will be affordable.

G

That's why I said £1000 not the £1500 plus that the older ones were. They may try to price them just under the 4 figure sum so that it looks better. The 18-55 would be entry level at around £100, 16-45 for the enthusiast which is around £350 (some are discounting) which would put a well corrected fixed f2.8 at around 2 1/2 - 3 times the price. That would match with the previous price structures. As you know, I think the 28-70/2.8 is a fantastic lens and I was very very lucky to get a near new one for around £400. I would dearly love a "digital" replacement but I don't think I will be able to afford it. Electronic sensors have come down a lot in price but the glass hasn't changed that much even though the smaller sensor is slightly easier to correct for. Think of the number of comments about the present range of DA lenses distorted at the wide end. If these are * lenses, Pentax will try to correct that and that is still going to cost.

Kim

Kim,
I'm aware of the probably price premium of the stars...
Yes, the 50-200 looks a good bet - can't find it for £100 though SRS seem the best price I can find.

However, are there any possible options for my 80-320? Would slow baking at a lowish temp kill the spores (and hopefully not the lens)? If not, can anyone recommend a repair centre that's worth ringing for this kind of job?

Matt

Both Robin at Harrow technical and Michael Spencer have cleaned older MF lenses for me, Michael being the slightly more reasonable.

The usual method to kill the spores is something like ammonia or other liquids wiped onto the affected elements. The last thing I would try would be "baking". you are more likely to affect the grease and the outgassing could lead to sticky blades and other problems.

Kim

I think it would be a fine line between killing the spores and melting your lens.

Dan

Weeeell,

The SMC-DA 50-200 caught me. Chris from SRS is winging one to me for tomorrow, so I'll have something else to review

The SMC-FA 80-320 I will try the "sunshine" treatment... if we ever get any And I'll isolate it and save it for the odd occasion when I need super telephoto.

Matt

Actually a fungus affected lens is unlikely to infect other lenses as it is very unlikely to grow to the point of fruiting and spreading spores. The atmosphere is full of fungal spores in any case - the chief cause of fungus on lenses is inapropriate storage. If they are sealed in boxes it can create the kind of damp climate that allows the spores to grow. Oddly, one of the worst places to store a lens from this POV are the plush lined leather cases that were provided with older Pentax lenses!

http://www.chem.helsinki.fi/~toomas/photo/fungus/

Tony - there's one spidery growth plus a few other "spots" on the same element. Whether they came from the spidery growth, or whether they originated from the same source as the growth (and haven't had a chance to flourish) I don't know.

In any case, I'm isolating this £90 len from the other (much) more expensive lenses Better safe than sorry! But I'll bear your comment in mind!

Matt

Matt, don't dispair, the 80-320 is a nice lens but once your 50-200 arrives you wont miss it too much. The 50-200 is a thing of beauty, and it makes my 80-320 feel very clunky.

Hi Matt,

I'm getting out of lurking mode to give another vote to the DA 50-200. The one thing I like the most is its size. I'm not really a tele-guy, but everytime I travel, this one goes in the bag as it doesn't really take too much space.

For example, we went to Montreal on Xmas and I thought I woudn't have any use for a tele in a city, but then we went to this Biodome (kind of indoor zoo), and all of the sudden the 50-200 had a nice run.

BTW here are the photos (the DA 50-200 are the ones with animals at the end of the set ):
http://www.flickr.com/photos/13185735@N00/sets/72157594443950208/

Thanks everyone!
Can't believe how small the 50-200 is
Will put it through its paces in a few days
Matt

I too have sucumbed to the 50-200mm disease (another sale for SRSChris - next day delivery too, well done mate). Astonised at how small it is. Now where did I put it.........?