Once the door is opened, within a fraction of a second, ~99% of the air inside will mix with the surrounding air, somemore there is disturbance introduced to the inside environment (placing of lens inside). Unless the cabinet have very small opening like that of a coke bottle. Even then, there will be significant exchange of air once the cap is opened.
Consider the rate of diffusion, how long does it take for the person on one corner of the room to detect a German gas released at the other corner of the room? 1 sec? 2 sec?
I also experienced this. My dry cabi's RH rised these few days due to the rain.
For my case.. I think it is due to my dry cabi being placed near to the window.
When there is rain, the air will come in through the windows, thus, the RH in the room will rise. Therefore, causing the RH in the dry cabi to rise.
anywyas, whenever open dry cabinet door, sure will let in moisture.
don't worry so much, fungus isn't some magic growth formula creature, it isn't going to explode once your humidity levels go beyond the specified range that is supposed to stop fungal growth or curtail it!
Logically, the RH inside the dry cabinet should not fluctuate in rainy days. The likely reason that will cause this is it not air tight. If one switch off the power on this bad cabinet, it should shoot up to high RH fairly fast in few hours in such situation.
If I were you, buy another hygrometer and put inside shelf to check if everything is uniform. Unreliable quality cabinet IMO.
My camera and 3 lenses were out of dry cab the whole day yesterday. Then how? Jialat liow lor? :cry: :bsmilie: :bsmilie:
No need to worry so much about a surge in humidity after you open the door. Its normal.
If it doesnt surge, probably you dont need a dry cab, because the outside humidity is same. hehe.
Please, 'lah, a dry cabinet is not a "Quick Drier" and no camera needs such a treatment. Dry cabinet is for long term storage, beyond days and weeks and the RH refers to the long term average RH for storage. The fluctuation due to opening the door is meaningless in that context. Rushing with your gear and opening the door only increases the chances of dropping something.