{"id":94551,"date":"2021-02-04T06:15:00","date_gmt":"2021-02-04T13:15:00","guid":{"rendered":"https:\/\/www.featheredphotography.com\/blog\/?p=94551"},"modified":"2021-02-04T11:12:34","modified_gmt":"2021-02-04T18:12:34","slug":"an-american-kestrel-and-investigations-into-the-cause-of-my-recent-soft-images","status":"publish","type":"post","link":"https:\/\/featheredphotography.com\/blog\/2021\/02\/04\/an-american-kestrel-and-investigations-into-the-cause-of-my-recent-soft-images\/","title":{"rendered":"An American Kestrel And Investigations Into The Cause Of My Recent Soft Images"},"content":{"rendered":"

I may have discovered the culprit.<\/p>\n

The last few times I’ve been out photographing birds I’ve been having a significant problem with soft images. I nearly always photograph in the early morning when it’s quite cold this time of year and I shoot from inside my pickup, using it as a mobile blind. Shooting with a warm lens in cold air is a known cause of sharpness issues but many other things could be responsible too including a malfunctioning camera, lens and\/or teleconverter and electrical contacts that need cleaning.<\/p>\n

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This photo of a Rough-legged Hawk taken five days ago is a typical example of the soft shots I’ve been getting. If I can’t get photos sharper than this one I might as well sell all my camera gear and start looking for the Loch Ness Monster or Sasquatch where I’d probably have a better chance of success and fulfillment.<\/p>\n

My 500 f\/4 prime lens has a huge lens hood mounted in front of it so there’s a large volume of air trapped inside the hood between my warm lens and the cold outside air. I wondered if turbulence in that trapped air caused by the extreme temperature gradient could be the cause of my soft images so two days ago on an early morning trip to Antelope Island I decided to perform a little experiment.<\/p>\n

I removed my lens hood and kept it off for the entire morning.<\/p>\n

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I photographed this female American Kestrel in deep shade only minutes after sunrise when it was still very cold. With my hood removed every photo I took of her was sharp, just like this one.<\/p>\n

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When she flew off to hunt from this ugly perch I took more photos of her just to test for sharpness. She was far away but once again they were all sharp (this photo has been cropped significantly)..<\/p>\n

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A couple of hours later when I was on my way home I found what was probably the same kestrel in the same general area. She wasn’t close but I took some more test shots and they were plenty sharp. The other photos I took that morning without the hood attached to my lens, including the Horned Lark I posted photos of yesterday, were also sharp.<\/p>\n

Was I on to something? Is air turbulence within my hood on cold mornings the cause of my sharpness issues? If so the solution seems obvious and easy – just leave the hood off.<\/p>\n

But leaving it off has its own issues.<\/p>\n

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Here’s my camera and lens with the hood attached (yes, my Lens Coat is old, worn and dirty and in need of replacement).<\/p>\n

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And here’s the entire setup with the hood removed. The hood is huge in both volume and length and adds almost 7″ to the total length of my lens.<\/p>\n

As every bird photographer with a long lens knows, aiming the lens quickly and accurately in the field is a critical skill that’s extremely difficult to learn well – especially when you’re trying to photograph birds in flight. It can take years to develop that skill to a high degree. When I first started photographing birds I can’t tell you how many hours I spent practicing on gulls and other common birds in flight. Once it’s learned the muscle memory becomes automatic and accurate – as long as you’re using the same lens!<\/em><\/span><\/p>\n

But if you remove the hood you might as well be using a different lens. Both its length and its diameter change dramatically so your muscle memory is now worse than worthless. Aiming the lens quickly and accurately becomes damn near impossible. Even with the stationary kestrel in the second photo above I had a hell of a time even finding the bird in my viewfinder. It’s no exaggeration to say that I felt l like a rookie bird photographer again.<\/p>\n

And when you remove the hood there’s another potential problem that I knew could be such a major disaster just the thought of it that morning on the island had me in a paranoid sweat.<\/p>\n

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With the hood removed the front element of my lens has lost any protection against scratches. That front element is a very large and very expensive piece of glass and I really don’t want to have to replace it. Lenses like mine will not accept front mounted UV filters to protect the front element so with the hood removed I’m playing a dangerous game.<\/p>\n

How much would it cost me to have the front element replaced if it became scratched? I don’t know but if I had to replace my lens hood, which is nothing more than a hollow tube with a tightening knob, it would cost me $640 so replacing the front element couldn’t be cheap. That’s a row I really don’t want to hoe.<\/p>\n

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So am I now convinced that my soft images when shooting in cold weather are caused by turbulent air trapped inside my lens hood? No, not quite. Becoming convinced will take more testing. Which means more time shooting with my lens hood off and more slow and inaccurate aiming of my lens.<\/p>\n

And more paranoia over a potentially scratched front element.<\/p>\n

Ron<\/p>\n

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Notes:<\/em><\/p>\n