How to Store Cameras and Lenses So They Don't Grow Fungus
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Fungus is the one form of damage that gets worse while you're not using a lens. Everything else — scratches, dents, wear — happens when you're handling it. Fungus happens in the cupboard.
Short answer
Fungus needs moisture, darkness, still air and time. Take away the moisture and the problem largely goes away.
- Aim for moderate humidity rather than as dry as possible
- Don't seal gear in a bag or a closed case with damp air inside
- Let air move, and use the gear — equipment that gets handled rarely grows fungus
- Never put a camera away damp
What fungus actually needs
Spores are everywhere, all the time. You can't keep them out and it isn't worth trying. What you can control is whether they find conditions to grow in:
- Moisture — the main one, by a long way
- Darkness and still air — a closed bag is close to ideal for growth
- Something to feed on — dust, skin oils, traces of grease and old lubricant
- Time — months of undisturbed storage, not days
Remove any one of those and growth is much less likely. Moisture is the one you have the most control over.
Aim for the middle, not for bone dry
Keep storage humidity in the moderate range — roughly 30–50% relative humidity, with around 40% being the figure most often given as the sweet spot. That's dry enough to discourage fungus without going to extremes.
Very dry storage is often said to be hard on lubricants, leather and rubber parts over long periods. Whether or not you take that seriously, there's no benefit in chasing the lowest possible number: fungus is already unlikely well before that.
An inexpensive hygrometer is worth more than any accessory here, simply because it tells you whether you have a problem at all. Plenty of people discover their storage is fine and they never needed to buy anything.
The worst places to store gear
- A zipped camera bag. Padded, dark, sealed, and it holds whatever humidity was in the room when you closed it. Bags are for carrying, not for storing.
- A leather ever-ready case, long term. Leather holds moisture and it sits directly against the camera. They're lovely to use and to display — just don't leave a camera stored inside one for years.
- Basements, garages, unheated rooms. Cool, damp and undisturbed.
- Sealed plastic boxes with nothing to control the moisture inside. An airtight box is only as dry as the air you shut in with it.
Three setups that work
1. A dry cabinet. An electric cabinet that holds a set humidity. It's the no-thinking solution and the one serious collectors use. The cost is real, so it makes most sense once the value of what's inside justifies it.
2. An airtight box with desiccant and a hygrometer. A sealed plastic container, silica gel inside, and a small hygrometer so you can actually see what's happening. Cheap, effective, and it scales — one box per shelf.
3. An open shelf in a room you live in. In a dry climate this is genuinely fine. Rooms that are heated, ventilated and used tend to stay in a reasonable range, and moving air is unfriendly to fungus. This is also the setup where you're most likely to pick a camera up and use it, which helps more than any box.
Using silica gel properly
- It has a capacity. Once saturated it stops working, and a saturated packet sitting in a sealed box is doing nothing at all.
- Indicating types change colour when they're spent, which takes the guesswork out.
- Many types can be dried out and reused — follow whatever the packaging says rather than a general rule, since types differ.
- Don't let it touch the glass. Keep packets loose in the box, not pressed against a lens.
Habits that matter more than equipment
Dry it before it goes away. A camera that's been out in rain, mist, snow or heavy humidity should sit out in the open air for a few hours before it goes into any container. Sealing damp gear is exactly how fungus starts.
Use your gear. Cameras that get picked up, carried around and exposed to moving air simply don't grow fungus the way forgotten ones do. The lenses that turn up with heavy fungus are almost always the ones nobody touched for twenty years.
Caps on, both ends. Not for fungus specifically — it keeps dust out, and dust is one of the things fungus feeds on.
Take the batteries out if a camera is going away for months. That's a different problem, but the same shelf.
Look at your lenses occasionally. Shine a light through from the back and look at the internal glass. Once or twice a year is enough to catch something early, and early is the only time it's easy.
Japan's climate makes all of this more relevant than it is in dry countries — more on that in why used cameras from Japan are usually in better condition.
What if a lens already has fungus?
Two practical points.
Keep it separate. Whether fungus spreads easily between lenses in storage is argued about, but the cost of storing an affected lens apart from the rest is zero, so there's no reason to take the chance.
Get it assessed rather than guessing. Light growth can often be cleaned by a technician. Growth that has been there a long time can etch the coating, and cleaning it then leaves a mark. Either way it's not something to attack yourself with household chemicals — the coating is the part you can't replace.
You also don't need to panic about a small amount. Plenty of lenses with minor internal marks take perfectly good photographs. What matters is whether it's growing.