DO Lenses - Sharpness issues in the cold?

DanCarr

I'm New Here
Apr 15, 2015
15
10
Last year on a very cold day (-30F) I had some issues with my 400mm f/4 DO II. I simply could not get a sharp shot. At the time I thought I must have dropped it earlier in the day without realizing it because everything was so soft and it looked like the lens was screwed.

Strange thing is, when I got the lens home and warmed it up, the next day everything was fine and it continued to work well at normal temperatures. I know DO lenses are complex beasts so I was wondering if contraction in the cold has a different effect on them compared to other lenses. I have never had an issue with a non DO lens in low temps.

I posted on my blog to see if anyone else had experienced the same thing, and just today someone commented that with the same lens, they too had issues in the cold.

With my own single data point, I had sort of put the issue at the back of my mind as there wasn't enough to go on, but now my curiosity has been renewed with the news that someone else might have had the same problem.

Has anyone else experienced this? Either with a DO lens or maybe a non DO lens?
 

johnf3f

Canon 1Dx
Oct 25, 2012
913
15
Wales
I haven't heard of this potential problem, I wonder if any other users have encountered anything similar.
I am interested in the idea of downsizing to a lightweight 400/500mm lens so I would be interested to find out if this a common problem.
 

AlanF

5DSR
Aug 16, 2012
4,864
1,516
We don’t get weather as cold as Sam McGee experienced in Canada back here in the mother country.
 

fentiger

EOS 80D
Dec 26, 2015
155
43
England
you may have to let the lens cool down to outdoor temperatures, could be thermal currents inside lens causing that issue.
i know that is the case with astro telescopes, so maybe the same thing.
 
Reactions: ejenner

Don Haines

Beware of cats with laser eyes!
Jun 4, 2012
7,877
1,207
Canada
Don't be offended, but are you sure it wasn't fog/condensation. If the rear element fogged up in the cold you might not notice it. Just speculating.
Yes, cold air does not hold as much moisture as warm air, so it is very possible that as your lens cooled down, that some of the moisture left the air for a lens element. Try throwing a dessicant pack into your lens case.
 

DanCarr

I'm New Here
Apr 15, 2015
15
10
Don't be offended, but are you sure it wasn't fog/condensation. If the rear element fogged up in the cold you might not notice it. Just speculating.
Yeah I'm sure that wasn't it. At the time that thought occurred to me and I checked.
 

Don Haines

Beware of cats with laser eyes!
Jun 4, 2012
7,877
1,207
Canada
Yeah I'm sure that wasn't it. At the time that thought occurred to me and I checked.
interesting.... What temperature are we talking about? If you take the lens outside, how long does it work before things go soft on you?

Could it be a lubricant problem?
 

BeenThere

EOS 6D MK II
Sep 4, 2012
823
151
I’ve seen infinity focus shift slightly on wide angles (relative to focus ring setting) when going from warm to cold. Could there be a slight AF calibration change with temp? Another good reason to move to the R system where AF occurs on the sensor itself.
Could this be why Canon has held off releasing new DO lenses until mirrorless was available to solve the issue?
 

Viggo

EOS 5D SR
Dec 13, 2010
3,881
435
Yeah, not only DO lenses, all lenses expands and retracts in more extreme temperatures. I’ve used different AFMA with my lenses outside and in for ever, one for cold winter and one for indoor and sometimes one for very hot. It was a big issue with DSLR’s for me as it isn’t all that constant, so fine tuning is often needed.
 

awair

EOS T7i
Jan 3, 2013
92
6
photo.awair.net
I took a 4-hour walk in -20C a couple of years ago, can't remember which lens (but not DO), but everything appeared to come out sharp.

I do recall the camera (6D) couldn't autofocus on occasions because of the cold. However, with the shorter focal lengths this issue may not have been obvious to me.