weird bokeh on 100-400 II

I shot some sports today and the bokeh seems weird/streaky.
Most noticeable in the leaves in #1 and the fence edges in #2

Taken with my recently acquired 100-400 II
The shot is cropped (about 70%)
Shot at 1/1600, f5.6 at 400 ISO

It was warm (about 26°C/79°F)

Not expecting bokeh like a 80mm prime, but wasnt expecting this. Due to humidity fluctuations in the air?

Anyone getting this?

The first question that needs to be asked is are you using a filter? Nothing in that image looks right not just the bokeh. I cheap UV filter would be the first thing I would suspect.

no filter here. Don't believe in cheap UV filters

Here is a link to the RAW file

https://www.dropbox.co​m …l86v6qb/IMG_028​6.cr2?dl=0

Just took another test pic (nothing special), almost same settings and almost same crop
Not evident here

I'll bet the grass was at least very damp, if not wet. The added water vapour content in that situation will make the mirage effects even more noticable. As well as photography I've been involved in competitive rifle shooting, as both a competitor and a coach for over 30 years, and mirage is one of the biggest issues we face, combined in with the wind.

One of the biggest issues is that the better the quality and resolution of the optical systems used, the easier it is to see the mirage. I remember one day using a very high end Zeiss spotting scope,about £5000 worth in total, and on an overcast spring day at less than 10C you could see mirage. No other scope on the range was showing anything.

So yes probably mirage effects, I'm on my phone at the moment so the images are hard to examin closely, but there is nothing you can do about it. Spending even more money for better optics will just show things up even more.

Alan

I see a very similar thing when using my 300/2.8 and 200/2 shooting field sports in hot weather (especially if the humidity is high).

Foliage on a sunny day in pretty close proximity can cause strange issues on many lenses. It might be the factor of high DR in the out of focus areas, with sunlight highlighting leaves, but other leaves and branches in very dark areas, with a bit of wind and convection current adding to the recipe.

Looking at the player's shorts, the more shaded side looks like the shadows were pushed quite a lot?

If so, it probably added to any atmospheric conditions.

I think it's just a busy background. I get the same thing with the 100-400v1 at times.

Left Handed Brisket wrote in post #18474610
Looking at the player's shorts, the more shaded side looks like the shadows were pushed quite a lot?

If so, it probably added to any atmospheric conditions.

That was my first thought, too. Plus a fair degree of oversharpening. Wrong on both counts. Raw is more or less properly exposed. The bokeh issue is present in the raw file.

EDIT:
I originally commented that my 100-400Lc does not do this. It does. Mostly with moderately distant foliage in the sun. The effect does vary.

Well having had a chance to view the image on my PC, I'm going to definitely go with mirage effects. One thing I didn't mention in my previous post is that the effect is actually far more noticeable against areas that are not in sharp focus. One of the reasons that mirage is such a pain for shooters is that it moves the location of the image in space. The big issue is that it tends to move the image in the same direction as the wind. So in conditions where mirage is forming it can act to double the effect of the wind. At competitions where the scoring is done electronically, and each shots location is shown to the shooter on a TV monitor, it is common to actually set the focus of the scope a few meters in front of the actual target to make the effects more obvious.

Although mirage will form at almost any temperature, it is usually limited to being observed relatively close to the ground, and will not form at all once the wind speed reaches around 12 mph. As such it is much more of a problem for photographers shooting subjects at ground level, rather than in the air. So sorry all you sports shooters, it's likely to be much worse for you compared to say those shooting BiF or for me aviation, where we are often shooting at angles in excess of 30 degrees.

Alan

I agree the above is most likely. However, as a quick check I would try taking some shots of a specular reflection or catch-light using a flash and check it doesn't have any weird CA or distortion (obviously under more controlled conditions)..

Thanks everyone, good to know that its not the lens
Checked my sharpening - was at 45in LR and heavily masked, so not too high

I will say I was sitting on the ground when taking photos so that would increase the mirage effects

The noise on his left pant leg is oddly high for ISO 250. Were the shadows pushed up? Wondering if the bokeh youre seeing is also just the same source of noise.