marcomarks Loc: Ft. Myers, FL

I've noticed from time to time that if I'm in temperatures above 90 and it's very humid, my auto-focus and overall photo clarity seem to be a bit soft. I don't think it's the temperature because you CAN take crisp digital shots in a hot dry desert. I'm not sure if it's the lens, the camera electronics, or maybe the moisture in the air deflecting and fooling the auto-focus beam a little. It's also not just in the dSLR I have now. All auto-focus cameras I've owned over the years seemed to be that way except a 5MP Minolta DiMage 7 advanced point and shoot with fixed lens that I had for a couple years. It was always crisp in every environment. Of course, when shooting a car hood with heat waves rising from it, clarity of edges are going to be harmed. But I'm talking about even when shooting a subject in the shade without flash, or when it's overcast, on a hot and humid day.

I'd be interested in hearing whether others have experienced this phenomenon. Of course, I know you can override auto focus.

JimH Loc: Western South Jersey, USA

Humid air can play havoc with autofocus. And manual focus, for that matter. The water vapor deflects and scatters light rays and makes it difficult for both the camera's AF mechanism, and our own eyeballs, to resolve sharp edges and contrast. Try taking a picture parallel to the ocean while on a beach.

Yeah, humidity is a pain in the butt around here anyway.

marcomarks Loc: Ft. Myers, FL

Verification #1. Thanks!

I wish I was near an ocean and a beach right now... well maybe not those in NJ though. I heard what you guys got up there lately with Irene. Pew!

SharpShooter Loc: NorCal

macro, are you using those cheap Panasonic lenses?
Well, there's your problem :lol: :lol: Hey, just kidding.
I'd have to see hard evidence that humidity could be causing a focus problem.
The computer just takes the areas of contrast in the area of the little red square and moves the lens till they are the sharpest. It's more accurate than your eye. Have you check your software to see which focus point is locked and what it is locked onto?
Is it possible that your lens has a propensity to front/back focus? Read some real reviews on whatever lens you are using when you seem to have the problem. For example some Sigmas' are notorious for that. Good luck with it. ;-)
SS

marcomarks Loc: Ft. Myers, FL

Wow... it's looks like it's been almost three years since I posted in this thread last time. Are you late joining or just got back from somewhere? :)