Nearly ruined an hour long exposure because of dew

I was out at Cherry Springs State Park in Pennsylvania last month trying to get the Milky Way. About 45 minutes into a 60 minute exposure, I checked my camera and the lens was completely fogged up. I had a dew heater in my bag but I thought I wouldn't need it since it was only August. Now I keep one on the lens no matter how warm it is. Anyone else forget about dew until it's too late?

2 comments

2 Comments

spencer_ross3d ago

Honestly, I think you're overcomplicating this. Dew is just part of the game when you're shooting nightscapes, and carrying a heater for every single warm night sounds like overkill. You could have just wiped the lens with a microfiber cloth, let it dry for a minute, and restarted the shot. I've had dew mess up a 20 minute exposure before, but I just took it as a lesson to check conditions better. Do you really want to lug around extra gear for something you might avoid by checking the dew point forecast first?

tarab543d ago

Wiping it off in the middle of a long exposure is going to mess up the shot even worse, not fix it. @spencer_ross once the fog hits the glass, that image is toast if you touch it mid capture. A dew heater is lightweight and runs off a USB pack you probably already bring for your intervalometer. Checking the dew point is smart planning, but it's not foolproof, especially in places like Cherry Springs where the humidity spikes fast after sunset. Better to have the heater on and not need it than lose an hour of data.