How long can lenses safely survive in a dry box?

**akptc** · 03-04-2021, 08:18 PM

Like many Pentaxians, I have accumulated more gear than I have time to use. The unused and rarely used lenses live in dry boxes at 35% average humidity. What is the smart thing to do to make sure they remain in great condition? Can they just sit there for years and be fine? Should I take them out from time to time and expose them to sunlight just in case? Fungus is a concern of course but also things like SDM - I am told to exercise the 300/4 from time to time otherwise the SDM may not work when I need it. All input will be greatly appreciated.

**UncleVanya** · 03-04-2021, 09:17 PM

Sdm exercise is nothing scientific. It may help. It may just be magical thinking.

Paul the Sunman · 03-04-2021, 09:20 PM - **1 Like**

Do you really have the DA*300 packed away in limbo?

stevebrot · 03-04-2021, 10:06 PM

Originally posted by Paul the Sunman

Do you really have the DA*300 packed away in limbo?

Is that a hint there is a forever home waiting for it Downunder?

Steve

**ramseybuckeye** · 03-05-2021, 02:40 AM

Maybe I’m wrong, but I was under the assumption that what you are doing may be the ideal method of storage.

**JensE** · 03-05-2021, 03:41 AM - **1 Like**

Some occasional mechanical movement for lubricated parts (focus, zoom, some aperture mechanics parts in some lenses) is advisable.

**termy** · 03-05-2021, 04:27 AM

Originally posted by akptc

Like many Pentaxians, I have accumulated more gear than I have time to use. The unused and rarely used lenses live in dry boxes at 35% average humidity. What is the smart thing to do to make sure they remain in great condition? Can they just sit there for years and be fine? Should I take them out from time to time and expose them to sunlight just in case? Fungus is a concern of course but also things like SDM - I am told to exercise the 300/4 from time to time

35% RH seems way too low i think.

Setting it at range of about 50% to 55% should be just about right.

**gordon_l34** · 03-05-2021, 05:06 AM

Hi,

I have all of my dehumidifiers set at about 50% RH as I have been lead to believe that down around 35% RH it dries the grease out in the lens and above 60% RH that is when our friendly fungus can grow!

Regards,
Gordon.

ChristianRock · 03-05-2021, 07:19 AM

Originally posted by stevebrot

Is that a hint there is a forever home waiting for it Downunder?

Steve

If there isn't... here in the state of Georgia there's a place where the DA*300 could get some regular exercise

Seriously though, 50% humidity should allow it to be kept for a long time with no issues.

**Bob 256** · 03-05-2021, 08:54 AM

Low humidity has little affect on grease since humidity is a measure of water content in air which doesn't affect the rate at which grease solvents evaporate. Lower humidity won't introduce any bad effects (unless you have dry skin to worry about) so going below 50% is probably better than 50% for long term storage (it makes fungus growth less likely). Grease does dry out over long periods, but that's because it loses some of its original solvent base. You can reduce this evaporation if keep the lenses cool (hint: don't store your lenses where they will get hot). Also, bagging the lenses in sealed (zip-lip) poly will prevent long-term storage dust issues but be sure to include a desiccant in the sealed bag and check those once in a while for depletion (some moisture can migrate through poly).

**jatrax** · 03-05-2021, 09:23 AM - **1 Like**

I have any number of Takumar lenses that were stored at room temperature and humidity for 30 years or so with no ill affects. The lenses that I have handled that developed fungus did so (IMHO) not because of storage but because they were put away wet. I cannot prove that but it does make some sense. A normal home environment, healthy to humans is dry enough that fungus does not develop on walls, floors etc. So it is not going to develop on lenses either. But if you get something wet, put it in a closed camera bag so the moisture cannot escape readily, then yes you get fungus.

So rule number one is to never, ever put your gear away damp or wet. Leave everything out on a counter in free air until it is completely dry. The use of a dry box or other mechanical drying system will certainly work also. And if you frequently are shooting out in the wet a dry box would be a good investment to dry your gear when you come in.

According to information published by the EPA mold growth can happen if relative humidity is 60% or above. They suggest keeping home humidity in the 30 to 50% range with 45% being ideal for human health. Too low can cause health issues as well.

So a dry box at 35% will certainly prevent fungus growth indefinitely but it could be set at 40 or 45% to achieve the same result.

Wheatfield · 03-05-2021, 09:27 AM

Originally posted by akptc

Like many Pentaxians, I have accumulated more gear than I have time to use. The unused and rarely used lenses live in dry boxes at 35% average humidity. What is the smart thing to do to make sure they remain in great condition? Can they just sit there for years and be fine? Should I take them out from time to time and expose them to sunlight just in case? Fungus is a concern of course but also things like SDM - I am told to exercise the 300/4 from time to time otherwise the SDM may not work when I need it. All input will be greatly appreciated.

I live in a drybox climate, so no worries about fungus. I've had lenses in storage for decades (literally), and they are just fine and dandy. The biggest problem you will likely have is lubricants drying out causing slow aperture response.

**Apet-Sure** · 03-05-2021, 11:51 AM - **1 Like**

Originally posted by ChristianRock

here in the state of Georgia there's a place where the DA*300 could get some regular exercise

And in North Carolina.....

**akptc** · 03-05-2021, 07:44 PM

Originally posted by Paul the Sunman

Do you really have the DA*300 packed away in limbo?

I know, it's a travesty

---------- Post added 03-05-21 at 20:46 ----------

Originally posted by termy

35% RH seems way too low i think.
Setting it at range of about 50% to 55% should be just about right.

Thank you, I was not quite sure about this number.

---------- Post added 03-05-21 at 20:47 ----------

Originally posted by Wheatfield

I live in a drybox climate, so no worries about fungus. I've had lenses in storage for decades (literally), and they are just fine and dandy. The biggest problem you will likely have is lubricants drying out causing slow aperture response.

Indeed I am worried about that.. will start with higher humidity setting at 40-50% and occasional exercise of the lenses.. I guess that's all that can be done..

Wheatfield · 03-05-2021, 07:58 PM

Originally posted by akptc

I know, it's a travesty

Don’t sweat it. I have a 77mm LTD and an A*85/1.4 in storage.
I suspect I’m going to burn in h**l for that.

03-04-2021, 08:18 PM	#1
akptc Site Supporter Join Date: Feb 2008 Location: USA Photos: Gallery Posts: 771	How long can lenses safely survive in a dry box? Like many Pentaxians, I have accumulated more gear than I have time to use. The unused and rarely used lenses live in dry boxes at 35% average humidity. What is the smart thing to do to make sure they remain in great condition? Can they just sit there for years and be fine? Should I take them out from time to time and expose them to sunlight just in case? Fungus is a concern of course but also things like SDM - I am told to exercise the 300/4 from time to time otherwise the SDM may not work when I need it. All input will be greatly appreciated.

03-05-2021, 07:44 PM	#14
akptc Site Supporter Join Date: Feb 2008 Location: USA Photos: Gallery Posts: 771 Original Poster	Originally posted by Paul the Sunman Do you really have the DA300 packed away in limbo? I know, it's a travesty ---------- Post added 03-05-21 at 20:46 ---------- Originally posted by termy 35% RH seems way too low i think. Setting it at range of about 50% to 55% should be just about right. Thank you, I was not quite sure about this number. ---------- Post added 03-05-21 at 20:47 ---------- Originally posted by Wheatfield I live in a drybox climate, so no worries about fungus. I've had lenses in storage for decades (literally), and they are just fine and dandy. The biggest problem you will likely have is lubricants drying out causing slow aperture response. Indeed I am worried about that.. will start with higher humidity setting at 40-50% and occasional exercise of the lenses.. I guess that's all that can be done.. Last edited by akptc; 03-05-2021 at 08:47 PM.*

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03-04-2021, 09:17 PM	#2
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,403	Sdm exercise is nothing scientific. It may help. It may just be magical thinking.

03-04-2021, 09:20 PM - 1 Like	#3
Paul the Sunman Pentaxian Join Date: Aug 2011 Location: Melbourne Photos: Gallery Posts: 4,843	Do you really have the DA*300 packed away in limbo?

03-04-2021, 10:06 PM	#4
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Paul the Sunman Do you really have the DA*300 packed away in limbo? Is that a hint there is a forever home waiting for it Downunder? Steve

03-05-2021, 02:40 AM	#5
ramseybuckeye Site Supporter Join Date: Apr 2009 Location: Hampstead, NC Photos: Gallery Posts: 17,292	Maybe I’m wrong, but I was under the assumption that what you are doing may be the ideal method of storage.

03-05-2021, 03:41 AM - 1 Like	#6
JensE Site Supporter Join Date: Dec 2015 Location: Leipzig Photos: Gallery \| Albums Posts: 1,969	Some occasional mechanical movement for lubricated parts (focus, zoom, some aperture mechanics parts in some lenses) is advisable.

03-05-2021, 04:27 AM	#7
termy Loyal Site Supporter Join Date: Jan 2019 Posts: 1,154	Originally posted by akptc Like many Pentaxians, I have accumulated more gear than I have time to use. The unused and rarely used lenses live in dry boxes at 35% average humidity. What is the smart thing to do to make sure they remain in great condition? Can they just sit there for years and be fine? Should I take them out from time to time and expose them to sunlight just in case? Fungus is a concern of course but also things like SDM - I am told to exercise the 300/4 from time to time 35% RH seems way too low i think. Setting it at range of about 50% to 55% should be just about right.

03-05-2021, 05:06 AM	#8
gordon_l34 Loyal Site Supporter Join Date: Sep 2008 Location: Brisbane, Australia Photos: Gallery \| Albums Posts: 779	Hi, I have all of my dehumidifiers set at about 50% RH as I have been lead to believe that down around 35% RH it dries the grease out in the lens and above 60% RH that is when our friendly fungus can grow! Regards, Gordon.

03-05-2021, 07:19 AM	#9
ChristianRock Pentaxian Join Date: Jul 2013 Location: People's Republic of America Photos: Gallery \| Albums Posts: 9,910	Originally posted by stevebrot Is that a hint there is a forever home waiting for it Downunder? Steve If there isn't... here in the state of Georgia there's a place where the DA*300 could get some regular exercise Seriously though, 50% humidity should allow it to be kept for a long time with no issues.

03-05-2021, 08:54 AM	#10
Bob 256 Site Supporter Join Date: Jun 2008 Location: Idaho Photos: Gallery Posts: 2,375	Low humidity has little affect on grease since humidity is a measure of water content in air which doesn't affect the rate at which grease solvents evaporate. Lower humidity won't introduce any bad effects (unless you have dry skin to worry about) so going below 50% is probably better than 50% for long term storage (it makes fungus growth less likely). Grease does dry out over long periods, but that's because it loses some of its original solvent base. You can reduce this evaporation if keep the lenses cool (hint: don't store your lenses where they will get hot). Also, bagging the lenses in sealed (zip-lip) poly will prevent long-term storage dust issues but be sure to include a desiccant in the sealed bag and check those once in a while for depletion (some moisture can migrate through poly).

03-05-2021, 09:23 AM - 1 Like	#11
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	I have any number of Takumar lenses that were stored at room temperature and humidity for 30 years or so with no ill affects. The lenses that I have handled that developed fungus did so (IMHO) not because of storage but because they were put away wet. I cannot prove that but it does make some sense. A normal home environment, healthy to humans is dry enough that fungus does not develop on walls, floors etc. So it is not going to develop on lenses either. But if you get something wet, put it in a closed camera bag so the moisture cannot escape readily, then yes you get fungus. So rule number one is to never, ever put your gear away damp or wet. Leave everything out on a counter in free air until it is completely dry. The use of a dry box or other mechanical drying system will certainly work also. And if you frequently are shooting out in the wet a dry box would be a good investment to dry your gear when you come in. According to information published by the EPA mold growth can happen if relative humidity is 60% or above. They suggest keeping home humidity in the 30 to 50% range with 45% being ideal for human health. Too low can cause health issues as well. So a dry box at 35% will certainly prevent fungus growth indefinitely but it could be set at 40 or 45% to achieve the same result.

03-05-2021, 09:27 AM	#12
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,981	Originally posted by akptc Like many Pentaxians, I have accumulated more gear than I have time to use. The unused and rarely used lenses live in dry boxes at 35% average humidity. What is the smart thing to do to make sure they remain in great condition? Can they just sit there for years and be fine? Should I take them out from time to time and expose them to sunlight just in case? Fungus is a concern of course but also things like SDM - I am told to exercise the 300/4 from time to time otherwise the SDM may not work when I need it. All input will be greatly appreciated. I live in a drybox climate, so no worries about fungus. I've had lenses in storage for decades (literally), and they are just fine and dandy. The biggest problem you will likely have is lubricants drying out causing slow aperture response.

03-05-2021, 11:51 AM - 1 Like	#13
Apet-Sure Site Supporter Join Date: Dec 2015 Location: Goldsboro North Carolina Photos: Gallery \| Albums Posts: 2,861	Originally posted by ChristianRock here in the state of Georgia there's a place where the DA*300 could get some regular exercise And in North Carolina.....

03-05-2021, 07:58 PM	#15
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,981	Originally posted by akptc I know, it's a travesty Don’t sweat it. I have a 77mm LTD and an A85/1.4 in storage. I suspect I’m going to burn in h*l for that.