Trouble with fogging lenses at night

phildaintith

phildaintith

Suspended / Banned
Messages
325
Name
phil
Edit My Images
No
Ok, well i shoot alot at night using long exposures sometimes upto 40 minutes long, but a problem which has always been happening is the lens fogging over and dew collecting everywhere (tripod, camera body etc) now i use L lenses so im not too woried it getting into my camera, its just annoying when i have to end a shoot because my lenses fog over...

Has anyone else ever experienced anything similar and how to combat it? i'm guessing its to do with the lens/camera getting to air temperature so that dew/condensation can occur ?

would attatching some kind of hand warmer around the camera possibly help stop this?
 
One trick which I'm told works is to bodge up one of those little fans that are supposed to help keep you cool in summer so it keeps the air moving over the surface of the lens. If you're anything like many of us, you'll have an old, cheap tripod somewhere and that'll be an ideal support for the fan.
 
Telescopes have something called dew heaters which may be the kind of thing you're after.
I don't know if you can get them specifically for camera lenses but it's worth investigating.
 
orac said:
Telescopes have something called dew heaters which may be the kind of thing you're after.
I don't know if you can get them specifically for camera lenses but it's worth investigating.
Click to expand...

A quick Google should turn up some simple DIY equivalents. All that's really needed is a battery, some resistors and a means of mounting it.
 
I'd imagine those cotton bags with oats/rice or whatever it is in them, that you warm in the microwave could do the trick nicely. Get a few, rest one around the lens, the other on the camera body to keep it warm.
 
neil_g said:
but isnt the camera being warm vs the cold air the issue?

i thought the key is to equalise the temps?
Click to expand...

Cold camera/lens in warm, damp air = instant condensation. Warm camera/lens in cold air shouldn't induce the same.
 
one way of reducing the effect is to make a dew shield out of camping mat. Worked a treat on my Nifty Fifty... Then, using a hair dryer (you can get 12v battery versions) on cool, low speed blow will remove any dew build up... (I can't afford dew straps and controller at present, so the OH's hairdryer works a treat on my scopes, no complaints from the neighbours about the noise either so far at 0200).
 
I concur with John. I don't have dew heaters on my telescope, but a quick whiz with a 12v portable hairdryer from time to time keeps the dew at bay.
 
phildaintith said:
Ok, well i shoot alot at night using long exposures sometimes upto 40 minutes long, but a problem which has always been happening is the lens fogging over and dew collecting everywhere (tripod, camera body etc) now i use L lenses so im not too woried it getting into my camera, its just annoying when i have to end a shoot because my lenses fog over...

Has anyone else ever experienced anything similar and how to combat it? i'm guessing its to do with the lens/camera getting to air temperature so that dew/condensation can occur ?

would attatching some kind of hand warmer around the camera possibly help stop this?
Click to expand...

Yes it would! but you need to get the heat to the lens, so I would suggest strapping it to the lens somehow or alternatively buying a heater strap, but then you would need a power source to run it from! If you heat the camera? it's likely to increase noise :thinking: Ideally you want the camera as cold as reasonable and the lens a few degrees above ambient temp.

jgs001 said:
one way of reducing the effect is to make a dew shield out of camping mat. Worked a treat on my Nifty Fifty... Then, using a hair dryer (you can get 12v battery versions) on cool, low speed blow will remove any dew build up... (I can't afford dew straps and controller at present, so the OH's hairdryer works a treat on my scopes, no complaints from the neighbours about the noise either so far at 0200).
Click to expand...

A hair dryer is fine but requires a power source which is not always available :thinking: also a dew shield would be pointless on a wide angled lens :shrug: Although the OP doesn't mention the lenses he's using ... His sig suggests wide angle lenses :cool:

Those disposable crunchy style hand warmers wrapped in a sock and taped to the lens are perfect!
 
neil_g said:
but isnt the camera being warm vs the cold air the issue?

i thought the key is to equalise the temps?
Click to expand...


I think it is too ... :D

Heaters .. blimey, lots of hassel with little reward Im thinking. ;)

In my mind ... Dew or condensation of water vapour begins when the temperature of air is lowered to that days dew point and beyond.

So either both the air and camera have to be above or below the dew point to stay clear of dew … if either the camera or air are either side of the dew point then whilst the temperatures balances out dew will form.

The best way to get around dew is to let your equipment reach the same temperature as the air in which your going to be taking photographs.
 
Forbiddenbiker said:
I think it is too ... :D


The best way to get around dew is to let your equipment reach the same temperature as the air in which your going to be taking photographs.
Click to expand...

That doesn't work. I take my scope out an hour or so before intending to use it, to allow the air inside the tube to match ambient (it prevents air currents within the tube).

On a clear night, things like the scope, your car etc will drop in temperature quicker than the ambient air. When it drops below ambient is when dew starts forming. If it's cold enough, that dew will freeze, giving us frost.

If you start off with your gear already at ambient, dew is going to form quicker as it's temperature drops further.

If you can keep an object warmer than ambient, dew won't form, as the surface of the object remains above the dewpoint.
 
Last edited:
Agree that having your camera/lens at the same temperature as the air does not work. Just look at the cars windscreens in the morning.

I shoot mostly at sunrise and have this problem. I do use a rocket blower which gives me enough time to get one shot then i have to clear the lens again.

One thing i am tempted to try is Bob Heath visor spray. This stops the inside of my crash helmet visor from getting any condensation. I'm just not sure if it will damage the front element????
Maybe someone could try it and let me know:naughty:
 
Merc said:
One thing i am tempted to try is Bob Heath visor spray. This stops the inside of my crash helmet visor from getting any condensation. I'm just not sure if it will damage the front element????
Maybe someone could try it and let me know:naughty:
Click to expand...

I wouldn't. Those sprays put a mist of detergent onto the surface to reduce the surface tension of any condensation that forms so that it becomes a layer of water rather than droplets. So you'd be shooting through a layer of detergent and water...
 
Forbiddenbiker said:
I think it is too ... :D

Heaters .. blimey, lots of hassel with little reward Im thinking. ;)

In my mind ... Dew or condensation of water vapour begins when the temperature of air is lowered to that days dew point and beyond.

So either both the air and camera have to be above or below the dew point to stay clear of dew … if either the camera or air are either side of the dew point then whilst the temperatures balances out dew will form.

The best way to get around dew is to let your equipment reach the same temperature as the air in which your going to be taking photographs.
Click to expand...


No hassle with heaters at all, take about 10 seconds to fit ... providing you have a power source of course :)

The reason lenses suffer so badly is the big lump of glass at the front, which radiates it's own heat away very quickly. Keeping the camera cold is a good thing at night when doing long exposures, a warm camera causes noise!

I've left my camera out all night taking long exposures when the outside temp was -16C with no issues whatsoever! I used a small heater band on the 16-35L lens and it worked perfectly well :cool:
 
Scarecrow said:
That doesn't work. I take my scope out an hour or so before intending to use it, to allow the air inside the tube to match ambient (it prevents air currents within the tube).

On a clear night, things like the scope, your car etc will drop in temperature quicker than the ambient air. When it drops below ambient is when dew starts forming. If it's cold enough, that dew will freeze, giving us frost.

If you start off with your gear already at ambient, dew is going to form quicker as it's temperature drops further.

If you can keep an object warmer than ambient, dew won't form, as the surface of the object remains above the dewpoint.
Click to expand...


Yep, your right. soz OP. .... What I should have added is ...as long as you do the adjustment after the dew point has passed.
 
Splog said:
No hassle with heaters at all, take about 10 seconds to fit ... providing you have a power source of course :)

The reason lenses suffer so badly is the big lump of glass at the front, which radiates it's own heat away very quickly. Keeping the camera cold is a good thing at night when doing long exposures, a warm camera causes noise!

I've left my camera out all night taking long exposures when the outside temp was -16C with no issues whatsoever! I used a small heater band on the 16-35L lens and it worked perfectly well :cool:
Click to expand...

Really ok, just an kinda wrap thing on the lens then, that does sound easy I admit. ... Can a big car battery do the job then? most if us have a car right.
 
Forbiddenbiker said:
Really ok, just an kinda wrap thing on the lens then, that does sound easy I admit. ... Can a big car battery do the job then? most if us have a car right.
Click to expand...

Certainly can :) Some more info here
 
I 100% agree with Splog. :thumbs:
A dew heater band is the best solution if you want to keep dew from forming.
I use a Kendrick dew heater system on my telescope and photo gear and it works great.
There are a few diy projects on the net that work well too - and cheap to do if you're handy with electronics.
 
Astro said:
I 100% agree with Splog. :thumbs:
A dew heater band is the best solution if you want to keep dew from forming.
I use a Kendrick dew heater system on my telescope and photo gear and it works great.
There are a few diy projects on the net that work well too - and cheap to do if you're handy with electronics.
Click to expand...

Cheers Astro :thumbs: Some awesome shots on your Flickr :clap:
 
Thinking low-tech, would a hot water bottle suspended under the tripod not work? It could be refreshed from a thermos.

...Prepares for a flaming
 
exalto said:
Thinking low-tech, would a hot water bottle suspended under the tripod not work? It could be refreshed from a thermos.

...Prepares for a flaming
Click to expand...

It'd be more helpful strapped under your jacket :p

The objective or filter surface needs to be warmed so no, it wouldn't work.
 
You must log in or register to reply here.
Back
Top