Fungus inside my Arriflex 16ST Door Optics

[Ivan DImitrov Alexandrov]

I just found that there is fungus at least in the first element of the optics of the viewfinder in my Arriflex 16ST. There doesn’t seem to be any fungus in the prism of the body itself. Im worried it may spread to the lenses. Is this a serious issue? There doesn’t seem to be any noticeable effect on the viewing as the image is sharp and fairly bright. 

[Dom Jaeger]

There can often be a little fungus in old viewfinder optics. The issue is more that it can spread across the affected optic rather than infect other lenses. Fungus spores are more or less everywhere, they just need the right environment to grow. Ideally, you should get the viewfinder optics cleaned, but as long as you keep the camera well stored, and perhaps air it out in the sun every now and then, it should be ok. Make sure the camera case itself isn’t damp or mouldy. You can use desiccant sachets or similar.

Same goes for any lenses you have, avoid storing them in dark, musty, damp or humid environments, and air them out regularly. UV light tends to kill or at least retard fungal growth.

I wouldn’t worry about lenses getting infected just by mounting them to the camera. 

[Ivan DImitrov Alexandrov]

On 4/7/2024 at 9:52 AM, Dom Jaeger said:

There can often be a little fungus in old viewfinder optics. The issue is more that it can spread across the affected optic rather than infect other lenses. Fungus spores are more or less everywhere, they just need the right environment to grow. Ideally, you should get the viewfinder optics cleaned, but as long as you keep the camera well stored, and perhaps air it out in the sun every now and then, it should be ok. Make sure the camera case itself isn’t damp or mouldy. You can use desiccant sachets or similar.

Same goes for any lenses you have, avoid storing them in dark, musty, damp or humid environments, and air them out regularly. UV light tends to kill or at least retard fungal growth.

I wouldn’t worry about lenses getting infected just by mounting them to the camera. 

I put a dehumidifier and I left my camera in a tripod outside the case. So RH around my camera is now 36-40%. I also pointed the viewfinder for around 10 minutes to the sun. I hope is gonna be fine for now. Thanks!