the lens kept fogging up. any ideas??
so i went to the dark site. and ran into a bit of a problem
- Thread starter MarkM10431
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Temperature variation. Taking a lens from warm indoors or heated car into cold weather can cause condensation to form.
what is the 'dark site'?
I'm assuming a place for celestial viewing.
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- #5
it's more weather. the camera and lens were set up just before sunset, and were out in the ambient for 2 hours. it was the typical air temperature bouncing around the dew point.
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- #6
were you using a lens hood? oddly enough those can help out, they act like a dew shield in mild fluctuations...some astronomers use insulated or even heated covers/hoods to further keep condensation at bay on large optics in more unstable environments like you describe, though that might be a bit higher cost with heating elements, and power, etc.
you might test a couple hand warmers strapped around the lens.
a trick I do is to use a lens hood then place a blanket over my entire setup similar to a rain hood setup and that has seemed to work for me.
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- #10
new mount, new solutions for dew M42, Comet Lovejoy and Andromeda
these were all cropped from images taken 30S ISO 1000-1250 F2.8-F4
these were all cropped from images taken 30S ISO 1000-1250 F2.8-F4
Nice. Motorized mounts?
Keep warm!
Keep warm!
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- #12
yes I settled on a iOprton Smart Eq pro mount. i have some learninga ns some adjustments tp make but otherwise i'm very happy
super.
especially liked andromeda, you nailed it.
what lens?
especially liked andromeda, you nailed it.
what lens?
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- #14
70-200 f2.8. I'm actually very unhappy with andromeda. I think I need to lower the ISO, raise the Fstop and take longer shots.
Excellent work.
I live out in the middle east, so taking my camera in the car with the AC on full, then stepping out into 40c and 80% humidity is a nightmare. Camera and lens fog up in seconds. So now, I warm my gear up using the car heater to bring it upto an acceptable level. Either that, or keep it warm then put in some sort of insulated bag or box while you travel.
I live out in the middle east, so taking my camera in the car with the AC on full, then stepping out into 40c and 80% humidity is a nightmare. Camera and lens fog up in seconds. So now, I warm my gear up using the car heater to bring it upto an acceptable level. Either that, or keep it warm then put in some sort of insulated bag or box while you travel.
Keep in mind that the camera and lens are losing heat via radiation. They send out infrared photons at the energy level for their current temperature. Since the universe is, on average, quite cold, the camera is not receiving as many, nor as energetic, of photons back. This means the net radiant heat movement is out of the lens, cooling it over time. This will drive the temperature of the lens down below the surrounding air temperature. That's often enough to push the lens below the dew point, and condensation results. The reason lens hoods can help is that the lens hood radiates photons based on its current temperature (which is quite a bit warmer than space), some of which hit the lens, so it helps the net energy balance of the lens stay closer to neutral. Additionally, there's a whole range of products in the amateur astronomy hobby designed to ever so slightly warm optics so they stay above the dew point. Might be worth investing in a simple setup for your camera.
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