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	Username   Password FM Forum Rules Canon SLRs, primes, and zooms lenses reviews FM Forums | Canon-mount SLRs | Join Upload & Sell    end    Archive 2012 · cold weather infinity focus question

mstout Offline • • Upload & Sell: On p.1 #1 · cold weather infinity focus question This may be a dumb question. Going to Alaska in couple weeks hoping for Aurora photography. Have been fine tuning focus and marking lens barrel at infinity focus so I do not have to worry about it in the dark. One of the lenses used is a samyang 35/1.4, there is a 1 mm difference between perfect focus and mush. I am using a first gen 5D without live focus. Does anyone know if the 50-80 degree temperature difference between here and there is likely to cause any changes to lens and therefore focus? I may not have the ability to test much in the field. Thanks in advance. Michael Feb 09, 2012 at 11:24 PM

ragsn_old_iron Offline • Upload & Sell: On p.1 #2 · cold weather infinity focus question Chimping might be your only choice, take a shot and then review magnified. I shoot in the cold and at night too and know what you mean with perfect focus and mush, it is crazy how close the two are on lenses like the 24 TS-E II as well. Besides an angle finder, I would chimp, temperature does make a difference in focus for sure in my experience, and live-view has made all the difference with night shooting, especially in the cold so I don't accidentally breath on the viewfinder and turn it in to a frost bomb and lose time trying to clear that off too. Have a safe trip. Feb 10, 2012 at 01:34 AM

mstout Offline • • Upload & Sell: On p.1 #3 · cold weather infinity focus question I was afraid of that, thanks. Never really missed live view on 5D until I used it on my T2i. Won't buy another without it, may upgrade just for that. Chimping probably is the best option but have been disappointed in past with what looked in focus on playback magnified but was terrible on full sized monitor back home. oh well. Thanks again Feb 10, 2012 at 02:52 AM

TrojanHorse Offline • • • • Upload & Sell: On p.1 #4 · cold weather infinity focus question Would you please report back and reveal your findings? I'm going in July. And how are you liking that samyang on your 5d? Feb 10, 2012 at 04:54 AM

Ariel Bravy Offline • • • • • Upload & Sell: Off p.1 #5 · cold weather infinity focus question ...shrinkage? Can you get another object to focus on in the dark? Say a flashlight a good distance away that you can both focus on and is far away enough to count as infinity focus. Feb 10, 2012 at 06:11 AM

Dave Bachrach Offline • • Upload & Sell: On p.1 #6 · cold weather infinity focus question Hi Michael, I'm not familiar with your lenses, but here's what I did last year with my Canon zoom lens. When I got to Fairbanks I went outside while it was daylight and pre-focused the lens to infinity using a distant object at the widest zoom angle. This can even be done in an urban setting by using a street sign, street light or other distant object. Infinity on my zoom lens is anything over 30 meters, so basically 100 yards. Then I used the blue painters masking tape to tape the focus ring to the lens barrel so it wouldn't move and left the lens on the body so it was ready for shooting that night. The temperature can make a difference, however I would be surprised if don't have time to do a focus test in Alaska before you shoot auroras. Be sure to use a lens hood to help keep frost from forming on the lens and remove any filters that might be on the lens. But above all dress warm! I hope the auroras come out for you! Dave Feb 10, 2012 at 06:52 AM

mstout Offline • • Upload & Sell: On p.1 #7 · cold weather infinity focus question Trojanhorse- I will post when we return. About the samyang, without any focus confirm light, focusing looking through the viewfinder is hit and miss, have to bracket when at 1.4. I know it can be chipped but consensus is that is not reliable. However, when in focus, I am impressed. At 1.4, it is sharper than my previous wide angles which are my only frame of reference- 17-40, 24TSE (I), 15-85 and Tokina 11-16 when wide open. In fact, stopping down does not improve it much more. I will post a couple of 100% crops over the weekend. Ariel- How great is that? A shrinkage joke right after a trojan post! I have done the flashlight or laser pointer at night but without focus confirm or live view it is tough to get perfect. There is quite literally less than 1 millimeter margin of error when focusing this thing at 1.4, even on an object over 100 yards away. Dave- thanks, that is what I am planning on doing. Regarding frost, was planning on keeping camera hooded while waiting. Have you any experience taping handwarmer to camera to preserve battery? Read that a couple of places. Any favorite spots when you went? Thanks to all, Michael Feb 10, 2012 at 01:37 PM

Dave Bachrach Offline • • Upload & Sell: On p.1 #8 · cold weather infinity focus question mstout wrote: Trojanhorse- I will post when we return. About the samyang, without any focus confirm light, focusing looking through the viewfinder is hit and miss, have to bracket when at 1.4. I know it can be chipped but consensus is that is not reliable. However, when in focus, I am impressed. At 1.4, it is sharper than my previous wide angles which are my only frame of reference- 17-40, 24TSE (I), 15-85 and Tokina 11-16 when wide open. In fact, stopping down does not improve it much more. I will post a couple of 100% crops over the weekend. Ariel- How great is that? A shrinkage joke right after a trojan post! I have done the flashlight or laser pointer at night but without focus confirm or live view it is tough to get perfect. There is quite literally less than 1 millimeter margin of error when focusing this thing at 1.4, even on an object over 100 yards away. Dave- thanks, that is what I am planning on doing. Regarding frost, was planning on keeping camera hooded while waiting. Have you any experience taping handwarmer to camera to preserve battery? Read that a couple of places. Any favorite spots when you went? Thanks to all, Michael Michael, No I have not tried the handwarmer trick. However, I did not have any problems with the battery in my 7D even at -10 to -30 degrees. I did keep my spare in my shirt pocket so it would be warm. The two places that I went to around Fairbanks were Murphy and Pedro Dome. Dave Feb 10, 2012 at 02:39 PM

Rune Offline • • Upload & Sell: Off p.1 #9 · cold weather infinity focus question mstout wrote: This may be a dumb question. Going to Alaska in couple weeks hoping for Aurora photography. Have been fine tuning focus and marking lens barrel at infinity focus so I do not have to worry about it in the dark. One of the lenses used is a samyang 35/1.4, there is a 1 mm difference between perfect focus and mush. I am using a first gen 5D without live focus. Does anyone know if the 50-80 degree temperature difference between here and there is likely to cause any changes to lens and therefore focus? I may not have the ability to test much in the field. Thanks in advance. Michael Hi Michael! Very interesting question! One of my interest is trying to take picture of the nightsky and moon, and from different tries and experiments, I have concluded that it helps to "temperate" the equipment before I start... so I leave the camera and lens outside in the cold for an hour or so before I start to photograph. So to answer your question, yes I do believe the focus will change with "extreme" temperature changes... If I were you, and I hope this doesn't sound dumb, I would have taken out the battery, pre-focused your lens and dumped your equipment in the freezer for a good while... quickly take it out, put it on a tripod, take some pictures, take out the memory card, put the whole stuff back in the freezer, analyze the pictures, and try again if necessary... the equipment is safe in the cold... living in Norway I have never had a problem, just be careful bringing your stuff back in... heat it up again sloooowly.. in a plastic bag many recommend... or normally I just leave it overnight in my camerabags... never had a problem... Good luck in Alaska! I would love to go one day too! Feb 10, 2012 at 05:29 PM

David Baldwin Offline • • • • Upload & Sell: On p.1 #10 · cold weather infinity focus question For focussing on the night sky don't waste your time on a camera without live view. Rent a 5D2 for your trip and get some great pictures. Forget focussing scales, fancy focussing screens, AF etc. Its live view, end of discussion. Live view focus at 10x on a bright star near the middle of your viewfinder. I do it all the time and it works a treat - but note I said a BRIGHT star. Feb 10, 2012 at 07:32 PM

Mike V Offline • • • Upload & Sell: Off p.1 #11 · cold weather infinity focus question It's not just the lens but the mount as well that is effected by the temperature. The camera mount will be made of some sort of cheap stainless steel that changes size with temperature. Feb 11, 2012 at 03:32 AM

mstout Offline • • Upload & Sell: On p.1 #12 · cold weather infinity focus question Rune, that is a great idea, a little embarrassed that I did not think of it. Thanks. David, like I mentioned earlier, I will not buy another camera that does not have live view, more useful than almost any other feature I can think of. But it would bug me to spend the money on a rental and leave a perfectly good camera at the house that is already paid for and takes very fine pictures. I have failed it many more times than it has failed me. Not really logical but there you are. Lots of excellent photos taken without live view in the past. I will muddle through the best I can. (Am renting a zeiss though!) thanks again for all suggestions, Michael Feb 11, 2012 at 04:00 AM

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