Photoclubalpha

Hi everyone,

I was baffled to see these deformed lines and contours when I took photos with a different sample of Sony 18-200mm only a few minutes ago. My Sony 18-200mm never showed such deformations, though I was agitated with its tendency to show excessive purple fringing.

Can someone who has seen this in a lens reason this out for me please? When does a lens act this way?

Thanks
Yildiz

100% crops from Raw files with no post-processing and the in-camera jpegs show the same artifacts as well.

aster wrote:I was baffled to see these deformed lines and contours when I took photos with a different sample of Sony 18-200mm only a few minutes ago. My Sony 18-200mm never showed such deformations, though I was agitated with its tendency to show excessive purple fringing.

Can someone who has seen this in a lens reason this out for me please? When does a lens act this way?

I could be wrong, but it looks like heat haze (or some other atmospheric distortions) to me, and nothing to do with the lens.

harveyzone wrote: I could be wrong, but it looks like heat haze (or some other atmospheric distortions) to me, and nothing to do with the lens.

Thank you fro the input Harveyzone.

I suspected the atmospheric conditions too since it is a very sunny day in Istanbul and light reflects in every direction but I've never seen this much deformation during any of my shootings before.

After reading your post I attached my CZ 16-80mm to the camera and here's the same building. Though naturally this lens has a shorter focal reach and the result may be due to that but there's no excessive visible deformation from the Carl-Zeiss.

Thanks
Yildiz

ps. I'll try the Sony 18-200mm once again when the clouds hide the sun creating an overcast lighting situation.

100% crop from unprocessed raw file:

It's been a long time since we had any weather capable of creating such effects here, but as Harveyzone wrote, the images are consistant with heat haze!

Philip

Hi,

Harveyzone and Philip;

I'll take your leads and say that the irrational-looking effects may after all be because of the bright sunlight bouncing off from everywhere. I waited for the clouds to cover the Sun and here's the latest result with the Sony 18-200mm:

There still are visible artifacts as the result of the haze but at least the lines aren't looking that 'electrified' as the first photo.

Thanks
Yildiz

100% crop ; 200mm ; Sony 18--200mm

Not so much the sun but the warm air rising off hot surfaces creates streams or air at diferent density rising through the atmosphere. try this shots again first thing in the morning while everything is still cool and you may see better results. also if you find a black car sitting in the sun and shoot the roof against a contrasting background you can actually get the camera to focus on it and you will see the effect clearly.

Wow, that's some haze effect Yildiz, it looks like the photos were taken through a sheet of ripple glass...we've got one of the brightest and hot sunlights around and I've never seen a mirage/haze anything like that bad in any of my building shots. Only thing that I can think of that might contribute is a very slow shutter speed...maybe, what were the exposure settings exactly? including ISO.
Greg

ps. Are you sure there wasn't some air conditioner/heat exchanger exhaust or hot roof close in line of, or near the direction of the shot?

Greg Beetham wrote:Wow, that's some haze effect Yildiz, it looks like the photos were taken through a sheet of ripple glass...we've got one of the brightest and hot sunlights around and I've never seen a mirage/haze anything like that bad in any of my building shots. Only thing that I can think of that might contribute is a very slow shutter speed...maybe, what were the exposure settings exactly? including ISO.

Exif is on them - 1/200, f/13, ISO 200.
Surely a slow shutter would even it out so that it would just seem blurred. A faster speed would freeze the ripples.
Remember that the images are greatly enlarged which will help exagerate it.

Yep you'r right Tom, 1/200 is fast enough too freeze the ripples most likely, and a slow slow shutter would turn them into a smudge, so my money is on some strong interference from an unseen heat exhaust of some sort at this point.
Greg

Hi everyone,

Thanks for all the suggestions which I'll pursue with the Sony 18-200mm to see how it will react to other heat and light conditions. I suppose a lens like the 70-400 G would be even better to observe the rippling effects the heat and perhaps the wind turbulances around the high-rise can cause.

Today, it was only 21 degrees Celcius in Istanbul but there was also a chilling strong wind that could easily disperse the heat haze into an zig-zaggy turbulance look. I also think that the white surfaces are the main cause for the intensity of these artifacts as they are more reflective of either heat and/or the strong bright light. You can see that white surfaces show more deformation than the other colours.

Tomorrow is expected to be 24 degrees Celcius during day hours, and I'll shoot more samples to see if the effects will be consistent in the future photos of this building. That should give a good idea.

Greg;

I can't recall at the moment if there actually is a heat-radiating building, structure or facility in front of that high-rise but if my memory serves me right, there are a few low-rise buildings and maybe tennis courts in that region. Next time I'm there I'll take a better look to see if there actually is a plant of some sort or a facility that emits excessive heat into the air.

Thank you all for the guidance! I definitely appreciate every word.

Yildiz

Yildiz, if the tennis courts are concrete or asphalt, that can be the source of your heat shimmer. In the summer we ofter get bad heat shimmer of of the roads here.

Dusty

See:

http://www.photoclubalpha.com/forum/vie ... ault#p4202

David

It's just that Yildiz said that the ambient temp was 21C, that is a cool day here, I would have thought too cool to produce any large amount of mirage effect...at 31C+ I wouldn't have any trouble believing some mirage troubles, but 21C..hmm...unless the cold breeze she mentioned is/was doing something...turbulence/conflict with the warmer air over the city maybe, also just how cold was the cold breeze? that could be the key.
Greg

Hi,

I can say that time of day doesn't make much of a differrence to the haze distortions for this building especially as this is the facade facing South which is the most affected by the Sun. The temperature at the moment is around 20 degrees Celcius and there's a slight wind. The white surface and and the distance from the building to the camera is most effective in this result. I think that each road that's covered with asphalt or flat roofs between the camera and the building have a constant impact on the results we see.

David, thanks for the link. I read it throughly.

Here are the shots from this morning; 9 am, 10 am and 11 am respectively. 9am photo definitely looks much better than the latter ones.

Sony 18-200mm; Exif is intact on the images.

9 am; South facade


10am; South facade


11 am; South facade

Hmm that's pretty bad alright Yildiz, all the edges look like they've been chewed by a rat, I guess the next thing too ask is, is there a filter involved? if so how is it without it? and do you have a good polarizer filter too try, just to see if that improves things, also I think you said you had two copies of the 18-250 available, do they both come up with similar results? And what about a big pair of binoculars on a tripod, or better yet a decent spotting scope on a tripod, at 20X you will definitely see mirage through the eyepiece if it's present.
Greg