Painterly like distortion in background

Tighelander · 04-26-2014, 11:40 PM

I took this photo today, and the distortion is really noticeable in the background. What should be straight lines look like they've been dabbed on with a brush.
This is from a Tamron SP 60-300 Adaptall 2 on a K5IIs set at f/14, 1/800 with ISO 800
The close-ups are full size parts of the whole.

maltfalc · 04-26-2014, 11:43 PM

hot air rising from a bunch of cars and asphalt out in the sun.

Tighelander · 04-27-2014, 12:15 AM

Even on the houses in the background? Is it a bit of bokeh causing it?
The weather was cold, cloudy, and even rained a bit now and then. It rained quite a bit in the middle of the night.

**geomez** · 04-27-2014, 01:14 AM

That distortion looks a little high up for it to be hot air, espically given the described weather. I was just in Chula Vista a few days ago and the weather was jacket worthy.

That said, I'm dumbfounded.

Giklab · 04-27-2014, 02:01 AM

Originally posted by Tighelander

The weather was cold, cloudy, and even rained a bit now and then. It rained quite a bit in the middle of the night.

Weird. Still, has to be atmospheric, there's nothing the camera or lens can do to produce anything like that, except maybe extreme noise reduction.

**PJ1** · 04-27-2014, 02:06 AM

Looks like typical mirage effect to me. It is not really a matter of how hot it is but whether there are variations in air temperature. The light is refracted when it passes through air of different temperatures (that's why stars twinkle). The air rising off the car park is hotter but air movement means that it is not all the same temperature. Every little change in the temperature of the rising air cause a different amount of refraction so the image of things behind it to appear to swirl about.

Giklab · 04-27-2014, 05:55 AM

Originally posted by PJ1

Looks like typical mirage effect to me. It is not really a matter of how hot it is but whether there are variations in air temperature. The light is refracted when it passes through air of different temperatures (that's why stars twinkle). The air rising off the car park is hotter but air movement means that it is not all the same temperature. Every little change in the temperature of the rising air cause a different amount of refraction so the image of things behind it to appear to swirl about.

Nailed it. Didn't think of this before but you were shooting across a parking lot. Cars can heat up a surprising amount when in broad daylight, even if the external temperature is low. And as PJ1 said, you only need a difference in temperature.

Oldbayrunner · 04-27-2014, 06:30 AM

Yep I agree, I got this in the background the other day when I was shooting some horses in a field with my DA 55-300 WR on both my K5 lls and K50

K5 lls

K50

It's more noticable with the images larger.

normhead · 04-27-2014, 06:41 AM

Some people photoshop their images to get that effect, you got it for free....but better lenses do change the nature of it.... in side by side shooting at distance, it was more pronounced with my Sigma 70-300 and a Sigma 120-400 I sent back than with our Tamron 90 or DA 18-135.

stevebrot · 04-27-2014, 09:50 AM

Originally posted by maltfalc

hot air rising from a bunch of cars and asphalt out in the sun.

What he said. Atmospheric disturbance is a concern and a fact of life with any longer telephoto. The subject is not the only thing that is magnified.

Steve

Tighelander · 04-27-2014, 10:42 AM

Oh, one other thing I wanted to note is that the SR was turned off, and I was at 300mm.

Oldbayrunner · 04-27-2014, 10:43 AM

Originally posted by Tighelander

Oh, one other thing I wanted to note is that the SR was turned off.

SR on or off wont matter.

stevebrot · 04-27-2014, 12:30 PM

Originally posted by Tighelander

Oh, one other thing I wanted to note is that the SR was turned off, and I was at 300mm.

At 300mm on a sunny day with any distance in the equation, what you are seeing is expected.

Steve

6BQ5 · 04-27-2014, 04:00 PM

That distortion is definitely caused by the thermal cycling of air. It may be cool outside but dark surfaces are still being warmed by the sun. Those surfaces then cool off by dissipating that energy into the atmosphere which changes its density. The freshly warmed air rises, if even a little, before cooling and falling down. Totally normal.

The distortion you are seeing is what happens when you use telephoto lenses to zoom into something faraway.

**bkpix** · 04-27-2014, 04:31 PM

Yep, heat distortion. This is why astronomers don't use their telescopes from inside heated buildings to look out at the night sky -- the gradient between the warm room and the cool night air causes distortion where the light travels from denser (cool) to less-dense (warm) air, much the same way light bends when it hits the (dense) glass of a prism.

04-26-2014, 11:40 PM	#1
Tighelander Senior Member Join Date: Aug 2011 Location: San Diego Photos: Gallery \| Albums Posts: 228	Painterly like distortion in background I took this photo today, and the distortion is really noticeable in the background. What should be straight lines look like they've been dabbed on with a brush. This is from a Tamron SP 60-300 Adaptall 2 on a K5IIs set at f/14, 1/800 with ISO 800 The close-ups are full size parts of the whole.

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04-26-2014, 11:43 PM	#2
maltfalc Veteran Member Join Date: May 2010 Location: Winnipeg Photos: Albums Posts: 396	hot air rising from a bunch of cars and asphalt out in the sun.

04-27-2014, 12:15 AM	#3
Tighelander Senior Member Join Date: Aug 2011 Location: San Diego Photos: Gallery \| Albums Posts: 228 Original Poster	Even on the houses in the background? Is it a bit of bokeh causing it? The weather was cold, cloudy, and even rained a bit now and then. It rained quite a bit in the middle of the night.

04-27-2014, 01:14 AM	#4
geomez Site Supporter Join Date: Mar 2013 Location: Roanoke, Virginia, USA Photos: Gallery Posts: 1,760	That distortion looks a little high up for it to be hot air, espically given the described weather. I was just in Chula Vista a few days ago and the weather was jacket worthy. That said, I'm dumbfounded.

04-27-2014, 02:01 AM	#5
Giklab Veteran Member Join Date: Jan 2012 Location: Slovenia Photos: Gallery Posts: 2,182	Originally posted by Tighelander The weather was cold, cloudy, and even rained a bit now and then. It rained quite a bit in the middle of the night. Weird. Still, has to be atmospheric, there's nothing the camera or lens can do to produce anything like that, except maybe extreme noise reduction.

04-27-2014, 02:06 AM	#6
PJ1 Loyal Site Supporter Join Date: Jul 2012 Location: Toowoomba, Australia Photos: Gallery \| Albums Posts: 5,486	Looks like typical mirage effect to me. It is not really a matter of how hot it is but whether there are variations in air temperature. The light is refracted when it passes through air of different temperatures (that's why stars twinkle). The air rising off the car park is hotter but air movement means that it is not all the same temperature. Every little change in the temperature of the rising air cause a different amount of refraction so the image of things behind it to appear to swirl about.

04-27-2014, 05:55 AM	#7
Giklab Veteran Member Join Date: Jan 2012 Location: Slovenia Photos: Gallery Posts: 2,182	Originally posted by PJ1 Looks like typical mirage effect to me. It is not really a matter of how hot it is but whether there are variations in air temperature. The light is refracted when it passes through air of different temperatures (that's why stars twinkle). The air rising off the car park is hotter but air movement means that it is not all the same temperature. Every little change in the temperature of the rising air cause a different amount of refraction so the image of things behind it to appear to swirl about. Nailed it. Didn't think of this before but you were shooting across a parking lot. Cars can heat up a surprising amount when in broad daylight, even if the external temperature is low. And as PJ1 said, you only need a difference in temperature.

04-27-2014, 06:30 AM	#8
Oldbayrunner Pentaxian Join Date: Mar 2013 Posts: 1,665	Yep I agree, I got this in the background the other day when I was shooting some horses in a field with my DA 55-300 WR on both my K5 lls and K50 K5 lls K50 It's more noticable with the images larger.

04-27-2014, 06:41 AM	#9
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Some people photoshop their images to get that effect, you got it for free....but better lenses do change the nature of it.... in side by side shooting at distance, it was more pronounced with my Sigma 70-300 and a Sigma 120-400 I sent back than with our Tamron 90 or DA 18-135.

04-27-2014, 09:50 AM	#10
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by maltfalc hot air rising from a bunch of cars and asphalt out in the sun. What he said. Atmospheric disturbance is a concern and a fact of life with any longer telephoto. The subject is not the only thing that is magnified. Steve

04-27-2014, 10:42 AM	#11
Tighelander Senior Member Join Date: Aug 2011 Location: San Diego Photos: Gallery \| Albums Posts: 228 Original Poster	Oh, one other thing I wanted to note is that the SR was turned off, and I was at 300mm.

04-27-2014, 10:43 AM	#12
Oldbayrunner Pentaxian Join Date: Mar 2013 Posts: 1,665	Originally posted by Tighelander Oh, one other thing I wanted to note is that the SR was turned off. SR on or off wont matter.

04-27-2014, 12:30 PM	#13
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Tighelander Oh, one other thing I wanted to note is that the SR was turned off, and I was at 300mm. At 300mm on a sunny day with any distance in the equation, what you are seeing is expected. Steve

04-27-2014, 04:00 PM	#14
6BQ5 Veteran Member Join Date: Jun 2013 Location: Nevada, USA Photos: Albums Posts: 3,348	That distortion is definitely caused by the thermal cycling of air. It may be cool outside but dark surfaces are still being warmed by the sun. Those surfaces then cool off by dissipating that energy into the atmosphere which changes its density. The freshly warmed air rises, if even a little, before cooling and falling down. Totally normal. The distortion you are seeing is what happens when you use telephoto lenses to zoom into something faraway.

04-27-2014, 04:31 PM	#15
bkpix Site Supporter Join Date: Feb 2010 Location: Creswell, Oregon Photos: Albums Posts: 570	Yep, heat distortion. This is why astronomers don't use their telescopes from inside heated buildings to look out at the night sky -- the gradient between the warm room and the cool night air causes distortion where the light travels from denser (cool) to less-dense (warm) air, much the same way light bends when it hits the (dense) glass of a prism.