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by dhanson on Thu Jan 05, 2017 5:29 pm
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Yesterday I was out trying to photograph a Snowy Owl. It was -6F (wind chill -20 or so) - not the worst I've been out in. 
I was shooting from the car with a D810/200-500. The car was turned off. 
On the second stop I made for the SNOW the autofocus would not lock onto anything. 
This morning I checked the lens/camera inside and it worked like a dream. Pics sharp SOOC. 
I've never had a lens or this camera not function properly in the below zero temps we get here. 
Is this a lens problem with the 200-500?
Or was it residual heat from the car?
Or user error…
Any help appreciated
Thanks
 

by ricardo00 on Thu Jan 05, 2017 5:46 pm
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dhanson wrote:
Yesterday I was out trying to photograph a Snowy Owl. It was -6F (wind chill -20 or so) - not the worst I've been out in. 
I was shooting from the car with a D810/200-500. The car was turned off. 
On the second stop I made for the SNOW the autofocus would not lock onto anything. 
This morning I checked the lens/camera inside and it worked like a dream. Pics sharp SOOC. 
I've never had a lens or this camera not function properly in the below zero temps we get here. 
Is this a lens problem with the 200-500?
Or was it residual heat from the car?
Or user error…
Any help appreciated
Thanks


Please don't take this the wrong way, but is it possible you had some condensation on the front glass part of the lens?  Sometimes going from cold to warm some water vapor condenses on the glass (ie. if the lens was cold and then you brought the lens inside the car) and the camera gets confused about what to focus on.  Just a thought.
richard
 

by dhanson on Thu Jan 05, 2017 6:05 pm
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Not taking the wrong way :)
Open for any suggestions or help
I did check the front of the lens. It's a habit as often I'm shooting in blowing snow (no blowing snow yesterday tho).
Thanks
 

by E.J. Peiker on Thu Jan 05, 2017 7:00 pm
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It could have also been condensation on the rear element, the drop in filter or the camera mirror which has to be completely clear for the AF to function.  The fact that you were shooting from in the car with the lens out in -6 and the camera at a warmer temp almost guarantees that condensation somewhere in the system caused this unless you didn't use heat in the car and the car and gear was cold soaked which is unlikely at -6.
 

by dhanson on Thu Jan 05, 2017 7:41 pm
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EJ - I've always photographed the same way from the car. I've never had the autofocus not lock in so was wondering if it was the lens (the Nikon 200-500). This is the first winter for that lens.
I do use the heat while traveling from site to site but once there the car is off. While traveling the camera is in the bag.
The lens is on the camera from the time I leave home.
If it is condensation - do I need to do something to keep from happening again? Or clean it up now? There are dry packs in the bag.
It's disturbing not to be able to rely on the camera/lens.
Thanks for help
 

by E.J. Peiker on Thu Jan 05, 2017 7:52 pm
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All it takes is a little more humidity (higher dew point) then what you have had in the past...
 

by Woodswalker on Fri Jan 06, 2017 8:50 am
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There are so many variables at play here. Radiant heating from the sun striking a snowy landscape can be a problem. Heat from the vehicle's interior is an obvious one but there's also heat around the vehicle. The exhaust system and engine emit heat. Best to sit for awhile and allow things to cool but again heat waves on the landscape could be a factor. There are days when I just throw up my hands at distant shots, birds on the snow etc.
 

by Mark Picard on Fri Jan 06, 2017 10:53 am
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It has been my experience that a lens/camera will not condensate if the combo goes from warm to cold (as in taking your camera outside from your house/vehicle into the cold. But it will condensate if the gear is cold and you bring it into the warm (as in from the cold outside into the warm house/vehicle. So that might be your starting point. Maybe the lens gets cold hanging out the car window while shooting and when and if you bring it back into the car it condensates a bit from the warm car/cold lens. I would imagine that if you were shooting with the lens outside  (attached to your window mount) that it could suffer from this problem in that it could be getting cold enough outside to feel the effects of the heat generated by your idle car. Do you bring the lens into the car for any period, such as to warm up a bit by rolling up the window in between shootings? Those glass elements (many of them in a 200-500mm) do get extremely cold while hanging out the window at those temps. To me it wouldn't take much heat to condensate from a minimum of exposed  heat. I always put the front lens cap back on if I'm not actually shooting to help avoid this problem. If you do figure it out, please post your results, as many of us shoot in similar conditions. 
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by dhanson on Fri Jan 06, 2017 5:30 pm
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Mark
If I figure anything out, I will post results but don't hold your breath :)
I have no clue what I did differently.
I did wonder if it was the 200-500. I wondered if the build of the lens is different so that it's impacted by cold weather more than my other lenses.
I'm careful about condensation but maybe I messed up this time.
I wish I knew.
Missing the photos of the snowy owl was frustrating but not something that is horrible for me -- I have plenty of chances during the winter close by.
But I've been getting reports of great grays and I don't want to squander that opportunity.
Contemplating the 150-600 sigma sport …
Thanks for comment/help
 

by E.J. Peiker on Fri Jan 06, 2017 5:47 pm
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I think the point isn't that you did something different but rather that atmospheric conditions may have been different then what you previously experienced. These differences can be subtle.
 

by ricardo00 on Fri Jan 06, 2017 9:24 pm
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Phrasing the question slightly differently, would some lenses be more prone to condensation problems than other lenses? For example, could the materials they are made with effect how rapidly they cool off and hence make it more likely to result in condensation when they are brought into a warm, humid environment? As someone who contemplates switching from my Nikon 500mm f/4 to the Nikon 200-500mm lens and occasionally experiences this problem, I would love to know this! My worst experience with condensation was in humid Borneo where going from the air conditioned room out to the extremely humid outside caused lots of condensation. Since one wanted to be ready to shoot once you got outside, keeping the camera and lens in a plastic bag was not an option!
 

by ChrisRoss on Sun Jan 08, 2017 3:31 am
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Thermal mass is the big thing, the bigger the lens elements the longer they take to cool off. Adding some insulation will help. Consider adding a lens coat, the neoprene will slow down down heat loss. Wrap your lens hood with closed cell foam. Consider doing the whole lens. You can get closed cell foam sheet which is about 6mm thick or so which would be ideal. You could cut sheets that form rings and hold them on with rubber bands avoiding the parts you need to access. Mightt take a bit of trial and error to come up with something that doesn't get in the way. Lens coat make a cover for this lens so probably the simplest option.

I have an astronomical telescope and the secondary mirrors are small pieces of glass and prone to dewing. My top end which is the top of the tube is lined with such foam. It is extremely rare for mine to fog while others on the field are out of action. I put it down to the insulation provided by the foam
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by Karl Egressy on Mon Jan 09, 2017 10:02 am
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When we shoot from the car, my wife and I, all the pictures are soft for the first 5-10 minutes.
As the temperature inside of the car is + 20 degrees Celsius and about -12 to -15 degrees Celsius outside
there is an air flow through the open window which causes the aforementioned problem.
Also not all days are the same. There could be heat shimmer when your target is on the snow, ice, water etc.
even in winter.
If the sun is strong and the air is dry, then the snow start evaporating which can be a source of problems as well.
Shortly, it is not camera/lens error, not user error, it is a complex environmental effect.
 

by Chas on Tue Jan 10, 2017 3:02 pm
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If the AF continued to hunt, It could be a combination of low contrast and use of a non-cross type AF point, and even more so with converter use.
This is especially, true with cameras other than the new 1DX Mark II, and 5D4.

The 1DX Mark II is AF amazing in this regard!

See...http://cpn.canon-europe.com/content/news/canon_publishes_the_af_setting_guidebook_for_eos-1d_x_mark_ii.do

Best,

Chas
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