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Thread: some question about humidity% & moistent content

  1. #1

    Default some question about humidity% & moistent content

    i saw many post about keeping our cam. at 40-50 humidity% (less water),
    is to prevent it from growing fungus ...
    but as i know tat diff. temp. in diff. humidity% = to diff moisture content...
    so 40-50% means for the temp. in our living environment (sg)?
    thks

  2. #2
    Moderator Octarine's Avatar
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    Default Re: some question about humidity% & moistent content

    Erm... the correct term is "Relative Humidity" - which expresses the dependency of the maximum absolute amount of water per air volume from the air temperature. There is no difference in terms of RH between 50%RH at 22C or 50% at 30C - both is fine for cameras. RH does not refer to any temperature - but needs the temperature stated to be complete. RH is used because it's easier to understand - and all what is needed is to stay away from higher levels or 100% where the dew point is.
    EOS

  3. #3
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    Default Re: some question about humidity% & moistent content

    What Octarine said is right.
    Cold dry air or hot dry air is still dry air. The main purpose is to keep our camera in a 'slighty dryer than our atmostphere' environment.

    Bear in mind that not to push the RH too low for the cabinet. Plastics & rubber parts will be damaged.
    N D300 | N D50IR | N80-200mm | N18-105mm | T11-16mm | T17-50mm | SB600 | N MB-D10

  4. #4

    Default Re: some question about humidity% & moistent content

    Quote Originally Posted by Octarine View Post
    Erm... the correct term is "Relative Humidity" - which expresses the dependency of the maximum absolute amount of water per air volume from the air temperature. There is no difference in terms of RH between 50%RH at 22C or 50% at 30C - both is fine for cameras. RH does not refer to any temperature - but needs the temperature stated to be complete. RH is used because it's easier to understand - and all what is needed is to stay away from higher levels or 100% where the dew point is.
    but 50%RH at 22C is 8g/kg
    as for 50%RH at 30C is 13g/kg
    so is still ok?

    think i saw the dry cabinet sold at ntuc got both RH% & temp.
    so wats the temp. for?
    thought is for us to check the moisture content...
    Last edited by alvinslchek; 10th December 2009 at 07:45 PM.

  5. #5

    Default Re: some question about humidity% & moistent content

    Quote Originally Posted by DellSuperman View Post
    What Octarine said is right.
    Cold dry air or hot dry air is still dry air. The main purpose is to keep our camera in a 'slighty dryer than our atmostphere' environment.

    Bear in mind that not to push the RH too low for the cabinet. Plastics & rubber parts will be damaged.
    Hi,

    Was wondering.. what would be too low a value for the RH? I read somewhere that fungus can grow at even 20%rh... So it juz dawns on me what would be the correct setting. =)

    Thanks.

  6. #6
    Senior Member CS TAN's Avatar
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    Default Re: some question about humidity% & moistent content

    Quote Originally Posted by alvinslchek View Post
    but 50%RH at 22C is 8g/kg
    as for 50%RH at 30C is 13g/kg
    so is still ok?

    think i saw the dry cabinet sold at ntuc got both RH% & temp.
    so wats the temp. for?
    thought is for us to check the moisture content...
    I think 24C and 35C is not going to make that much difference inside the small dry cabinet. Perhaps if you take Singapore as a whole, the difference will be great.

    Anyway, people using dry cabinet and kept it around 40-45% RH are quite happy with it. So far, I have not heard people complaining about getting fungus which is the main objective of using dry cabinet, right?
    Canon 5D Mark II | 24-105L | 35L | 85L II | 135L | Samyang 14mm 2.8

  7. #7
    Moderator Octarine's Avatar
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    Default Re: some question about humidity% & moistent content

    Quote Originally Posted by alvinslchek View Post
    but 50%RH at 22C is 8g/kg
    as for 50%RH at 30C is 13g/kg
    so is still ok?
    All camera manufacturers state the storage conditions as relative humidity, and in addition they state the temperature range. I've never seen any absolute value - which would overload most users I guess. So 50%RH @0C is valid as well as 50%RH @30C, the absolute amount is irrelevant. As mentioned: it's important to maintain moderate conditions, that's the reason for 40-50%RH.

    think i saw the dry cabinet sold at ntuc got both RH% & temp.
    so wats the temp. for?
    thought is for us to check the moisture content...
    It's nothing but a reading, the temperature cannot be regulated. If you wish do your own calculation of absolute amount of water in the air.
    EOS

  8. #8

    Default Re: some question about humidity% & moistent content

    Quote Originally Posted by Octarine View Post
    Erm... the correct term is "Relative Humidity" - which expresses the dependency of the maximum absolute amount of water per air volume from the air temperature. There is no difference in terms of RH between 50%RH at 22C or 50% at 30C - both is fine for cameras. RH does not refer to any temperature - but needs the temperature stated to be complete. RH is used because it's easier to understand - and all what is needed is to stay away from higher levels or 100% where the dew point is.
    Quote Originally Posted by Octarine View Post
    All camera manufacturers state the storage conditions as relative humidity, and in addition they state the temperature range. I've never seen any absolute value - which would overload most users I guess. So 50%RH @0C is valid as well as 50%RH @30C, the absolute amount is irrelevant. As mentioned: it's important to maintain moderate conditions, that's the reason for 40-50%RH.


    It's nothing but a reading, the temperature cannot be regulated. If you wish do your own calculation of absolute amount of water in the air.
    (All camera manufacturers state the storage conditions as relative humidity, and in addition they state the temperature range.)
    hi bro...
    where can i find infor about this...
    thks

  9. #9
    Moderator Octarine's Avatar
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    Default Re: some question about humidity% & moistent content

    Quote Originally Posted by alvinslchek View Post
    (All camera manufacturers state the storage conditions as relative humidity, and in addition they state the temperature range.)
    hi bro...
    where can i find infor about this...
    thks
    Your camera manual.
    EOS

  10. #10
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    Default Re: some question about humidity% & moistent content

    Most ppl will set it between the range of 40-45% RH.
    Too high, fungus might start getting comfortable.
    Too low, rubber and plastic will slowly get damaged.

    And most ppl recommend that you do not put ur equipments into the dry box/cabinet straight after usage.
    Let it dry a bit in your room before putting back into the box.

    But i heard somewhere that if the equipment is used regularly and not always stationary, eg inside the cabinet.
    Chances is that fungus growth will be lesser, not sure how true though.

    Hope this helps.
    N D300 | N D50IR | N80-200mm | N18-105mm | T11-16mm | T17-50mm | SB600 | N MB-D10

  11. #11

    Default Re: some question about humidity% & moistent content

    Quote Originally Posted by Octarine View Post
    It's nothing but a reading, the temperature cannot be regulated. If you wish do your own calculation of absolute amount of water in the air.
    i know the temperature cannot be regulated...
    but the RH% can...
    is not useless...

    Quote Originally Posted by Octarine View Post
    Your camera manual.
    c thought my manual, but cant find anything about it...
    nvm thks anyway

  12. #12

    Default Re: some question about humidity% & moistent content

    The quick answer is 40-50% in any temperature. The condenser works according to its meter. Unlike liquid thermometer which is affected by atmospheric pressure, conductivity meter is little affected in living environment.

    In 22C temperature of 39% or 30C temp at 39%, the condenser won't kick in. Unless you are keeping sensitive goods for fermentation and chemical, the temperature factor becomes crucial... switching between humdifier and dehumidifer.

    Where the season enters into winter, fungus is at bay. So in a typical room where temp drops to 22C because of aircon for few hours won't affect anything. Besides, you are working within safe % zone and temperature where fungus prevails.

    Quote Originally Posted by alvinslchek View Post
    i saw many post about keeping our cam. at 40-50 humidity% (less water),
    is to prevent it from growing fungus ...
    but as i know tat diff. temp. in diff. humidity% = to diff moisture content...
    so 40-50% means for the temp. in our living environment (sg)?
    thks

  13. #13

    Default Re: some question about humidity% & moistent content

    The reason why people say dry you equipment is not about RH problem but rather to clean and dry off any liquid to prevent corrosion as well as not to push the humdity in the box or cabinet to its max when you introduce wet item. Especially for those using dry agent like silica gel and calcium chloride which will exhaust fast if you introduce a wet item.

    Turning wheel never rusts. Fungus don't grow well in sunlight. When used, camera heats up driving moisture out. And people will clean used item frequently, thus less chance of dust build up and fungus. However an active cam left in warm dim moist area all the time will still get fungus on lens. Which is why keeping your shoes socks and feet dry prevents foot fungus.

    Quote Originally Posted by DellSuperman View Post
    Most ppl will set it between the range of 40-45% RH.
    Too high, fungus might start getting comfortable.
    Too low, rubber and plastic will slowly get damaged.

    And most ppl recommend that you do not put ur equipments into the dry box/cabinet straight after usage.
    Let it dry a bit in your room before putting back into the box.

    But i heard somewhere that if the equipment is used regularly and not always stationary, eg inside the cabinet.
    Chances is that fungus growth will be lesser, not sure how true though.

    Hope this helps.

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