Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Any experience with negative temperature against fungus?
Post new topic   Reply to topic
Home   Equipment Care and Repairs
View previous topic :: View next topic  


PostPosted: Sun Mar 25, 2018 6:57 pm    Post subject: Any experience with negative temperature against fungus? Reply with quote
Question


From biology lessons at school I remember, fungus is quite weak against cold.
Any experience?
Could it make sense to put a lens with small fungus into a freezer for some time?


PostPosted: Sun Mar 25, 2018 9:37 pm    Post subject: Reply with quote
There is no negative temperature - only high or low Wink

Fungus and esp. fungus spores are extremely resistant, I doubt it will harm them.
It will grow back when the lens warms up again...


PostPosted: Sun Mar 25, 2018 10:46 pm    Post subject: Reply with quote
Cryopreservation is one of the methods to store fungal strains. For instance here they talk about survival rates of 60% to 100% and temperatures about -80C http://www.biomed.cas.cz/ccbas/Methods%20of%20Cryopreservation%20in%20Fungi.pdf. I am sure the end result depends on specific fungus, but in general as kds315 stated, it's hard to believe that this method of defungussing can be successful.

Here https://link.springer.com/article/10.1007/BF02915312 they find out that you can kill fungus by applying a series of freezing shocks. So just freeze and thaw your lens 32 times at a rate 10 000 C per minute and your lens will be fungus-free Wink


PostPosted: Mon Mar 26, 2018 4:40 am    Post subject: Reply with quote
Freezing could affect the lubricants in the lens, if nothing else. Use UV and a topical mixture (peroxide), and make sure there is minimal dust in the lens so the fungus doesn't return.


PostPosted: Mon Mar 26, 2018 8:39 am    Post subject: Reply with quote
Well I don't know about freezing but would think to kill anything living on earth would be to deprive it of any form of water.
When they have opened Egyptian tombs everything wasn't ruined by fungus, in fact in one tomb a wall of paintings had some black fungus and was considered to be a rushed job and not allowed to dry properly before sealing the tomb, well the fungus didn't survived because it ran out of moisture....if not, the paintings would have been completely ruined.


PostPosted: Mon Mar 26, 2018 11:59 am    Post subject: Reply with quote
I own FAR too many lenses and have been in a battle against fungus for a number of years.

The fungus is winning.

Water deprivation through use of silica gel has been, for me, an unreliable avenue of attack. I believe in the ability of UV to destroy fungus DNA. My problem is exposing the inner elements of my lenses to UV, given that most of it is absorbed by the outer lens elements.

My bottom line so far: fungus is a serious PITA and is not a good thing at all.


PostPosted: Mon Mar 26, 2018 2:52 pm    Post subject: Reply with quote
guardian wrote:
I own FAR too many lenses and have been in a battle against fungus for a number of years.

The fungus is winning.

Water deprivation through use of silica gel has been, for me, an unreliable avenue of attack. I believe in the ability of UV to destroy fungus DNA. My problem is exposing the inner elements of my lenses to UV, given that most of it is absorbed by the outer lens elements.

My bottom line so far: fungus is a serious PITA and is not a good thing at all.


Desiccants such as silica gel work well, but only if they are maintained. They will get saturated and then don't do anything further - this is common with the tiny packs most people use.
We have things at work that are MUCH more prone to moisture damage than lenses. These are kept in air tight containers with at least 50g desiccant, and the desiccant is dried every month (in an oven at over 100C for at least an hour).
I tend to use metal packs of silica gel (or Molecular sieve) for my camera bags, unlike the usual paper bags (which are held together with hot melt glue) these can be readily regenerated.

Cold will typically make fungus dormant, it won't kill it. From what I've read UV is only effective on the fruiting bodies not the spores.

Fortunately it's not to much of an issue here in the UK, as I don't regenerate my silica often enough for tropical conditions.


PostPosted: Mon Mar 26, 2018 3:40 pm    Post subject: Reply with quote
And keep lenses & silica gel in airtight containers, such as Pelican case. To keep space moisture-free, not to try dessicating World.


PostPosted: Mon Mar 26, 2018 6:06 pm    Post subject: Reply with quote
visualopsins wrote:
And keep lenses & silica gel in airtight containers, such as Pelican case. To keep space moisture-free, not to try dessicating World.


Agreed

I use double seal freezer/refrigerator bags and include, for each lens, about four to five teaspoons of silica gel contained by a folded up paper towel pocket stapled closed. There is no silica gel spillage.

It is a sealed environment and should be bone dry. Only problem: apparently nobody told the fungus.

I really HATE fungus. It is a total PITA.


PostPosted: Mon Mar 26, 2018 7:28 pm    Post subject: Reply with quote
guardian wrote:
I own FAR too many lenses and have been in a battle against fungus for a number of years.

The fungus is winning.

Water deprivation through use of silica gel has been, for me, an unreliable avenue of attack. I believe in the ability of UV to destroy fungus DNA. My problem is exposing the inner elements of my lenses to UV, given that most of it is absorbed by the outer lens elements.

My bottom line so far: fungus is a serious PITA and is not a good thing at all.


Have you tried an anti-fungal cream, guardian? You know, like the stuff used for feet?

I've been using it to remove fungus for a few years now. As an experiment, on my Pentax PK lenses, I'm washing the cream off before re-assembly. On the Takumar's, I'm buffing off only, to see if any active resistance is created.

If you've tried everything else....

NB: As you can see above, I'm not experimenting on anything expensive.


PostPosted: Mon Mar 26, 2018 7:53 pm    Post subject: Reply with quote
guardian wrote:
visualopsins wrote:
And keep lenses & silica gel in airtight containers, such as Pelican case. To keep space moisture-free, not to try dessicating World.


Agreed

I use double seal freezer/refrigerator bags and include, for each lens, about four to five teaspoons of silica gel contained by a folded up paper towel pocket stapled closed. There is no silica gel spillage.

It is a sealed environment and should be bone dry. Only problem: apparently nobody told the fungus.

I really HATE fungus. It is a total PITA.


Double seal freezer/refrigerator bags are not air tight. Turkey bags are better sealed. Was the silica gel recharged prior? Any temperature variations?


PostPosted: Mon Mar 26, 2018 9:09 pm    Post subject: Reply with quote
visualopsins wrote:
guardian wrote:
visualopsins wrote:
And keep lenses & silica gel in airtight containers, such as Pelican case. To keep space moisture-free, not to try dessicating World.


Agreed

I use double seal freezer/refrigerator bags and include, for each lens, about four to five teaspoons of silica gel contained by a folded up paper towel pocket stapled closed. There is no silica gel spillage.

It is a sealed environment and should be bone dry. Only problem: apparently nobody told the fungus.

I really HATE fungus. It is a total PITA.


Double seal freezer/refrigerator bags are not air tight. Turkey bags are better sealed. Was the silica gel recharged prior? Any temperature variations?


Silica gel brand new. Yes there are temperature variations because it is an unheated room, very cold in winter, warmer in summer but never hot. My fungus grows just great in the cold.


PostPosted: Mon Mar 26, 2018 11:02 pm    Post subject: Reply with quote
guardian wrote:
visualopsins wrote:
guardian wrote:
visualopsins wrote:
And keep lenses & silica gel in airtight containers, such as Pelican case. To keep space moisture-free, not to try dessicating World.


Agreed

I use double seal freezer/refrigerator bags and include, for each lens, about four to five teaspoons of silica gel contained by a folded up paper towel pocket stapled closed. There is no silica gel spillage.

It is a sealed environment and should be bone dry. Only problem: apparently nobody told the fungus.

I really HATE fungus. It is a total PITA.


Double seal freezer/refrigerator bags are not air tight. Turkey bags are better sealed. Was the silica gel recharged prior? Any temperature variations?


Silica gel brand new. Yes there are temperature variations because it is an unheated room, very cold in winter, warmer in summer but never hot. My fungus grows just great in the cold.


Brand new doesn't mean dry. Also, I am loath to open up my dry cases in wet weather. I have special "from the field case" lenses I've used go into to dryout before being put into long term storage.

Have you measured humidity? There are inexpensive gauges, with high/low memory. Mine has an alarm clock.

Lens stored thus shouldn't grow fungus. Something is wrong here.


PostPosted: Tue Mar 27, 2018 12:08 am    Post subject: Reply with quote
kds315* wrote:
There is no negative temperature - only high or low Wink

Fungus and esp. fungus spores are extremely resistant, I doubt it will harm them.
It will grow back when the lens warms up again...


? How about -100C? Or -40F?


PostPosted: Tue Mar 27, 2018 8:12 am    Post subject: Reply with quote
visualopsins wrote:
kds315* wrote:
There is no negative temperature - only high or low Wink

Fungus and esp. fungus spores are extremely resistant, I doubt it will harm them.
It will grow back when the lens warms up again...


? How about -100C? Or -40F?


Moderately low, the first is 173.15K still quite a way from seriously cold Smile
I don't know about the second it's in an alien scale that has never made any sense to me, though there is a proper absolute temperature scale that uses the same increments.


PostPosted: Tue Mar 27, 2018 1:59 pm    Post subject: Reply with quote
DConvert wrote:
visualopsins wrote:
kds315* wrote:
There is no negative temperature - only high or low Wink

Fungus and esp. fungus spores are extremely resistant, I doubt it will harm them.
It will grow back when the lens warms up again...


? How about -100C? Or -40F?


Moderately low, the first is 173.15K still quite a way from seriously cold Smile
I don't know about the second it's in an alien scale that has never made any sense to me, though there is a proper absolute temperature scale that uses the same increments.


"Negative temperatures across Europe this morning..." said the weatherpeople...

I don't think I have enough clothing for -100C, or even -40F. lol

Quote:
The Fahrenheit scale is a temperature scale based on one proposed in 1724 by Dutch-German-Polish physicist Daniel Gabriel Fahrenheit (1686–1736).[1] It uses the degree Fahrenheit (symbol: °F) as the unit. Several accounts of how he originally defined his scale exist. The lower defining point, 0 °F, was established as the temperature of a solution of brine made from equal parts of ice, water and salt (ammonium chloride).[2] Further limits were established as the melting point of ice (32 °F) and his best estimate of the average human body temperature (96 °F, about 2.6 °F less than the modern value due to a later redefinition of the scale).[3] The scale is now usually defined by two fixed points: the temperature at which water freezes into ice is defined as 32 °F, and the boiling point of water is defined to be 212 °F, a 180 °F separation, as defined at sea level and standard atmospheric pressure.

By the end of the 20th century, Fahrenheit was used as the official temperature scale only in the United States (including its unincorporated territories), its freely associated states in the Western Pacific (Palau, the Federated States of Micronesia and the Marshall Islands), the Bahamas, Belize, and the Cayman Islands.[4] All other countries in the world now use the Celsius scale, named after Swedish astronomer Anders Celsius, defined since 1954 by absolute zero being −273.15 °C and the triple point of water being at 0.01 °C.[5] (Before 1954, the Celsius scale was based on 0 °C for the freezing point of water and 100 °C for the boiling point of water at 1 atm.)


https://en.m.wikipedia.org/wiki/Fahrenheit

Now I would say "heat" is always positive. Interesting l could also say "cold" is always positive.

There is no negative electricity -- only high or low. Laughing


PostPosted: Tue Mar 27, 2018 10:02 pm    Post subject: Reply with quote
visualopsins wrote:
And keep lenses & silica gel in airtight containers,


Do not remove them from those containers. Ever.
Otherwise the fungus will get them Very Happy


PostPosted: Wed Mar 28, 2018 8:25 am    Post subject: Reply with quote
visualopsins wrote:


I don't think I have enough clothing for -100C, or even -40F.


Not quite -100C but I've had Dry Ice (-78C) in the palm of my hand without the need for any gloves. Fortunately subliming CO2 held the solid away from actual contact with my skin.
Post new topic   Reply to topic
Home   Equipment Care and Repairs
Page 1 of 1