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                   Friday, July 31, 2009 - 8:17PM

New upward lightning lens: 1300mm test!

By DAN ROBINSON
Editor/Photographer
25 Years of Storm Observing
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UPDATE 8/4: Success: Lightning at 1300mm at the WVAH tower!

My new 650-1300mm lens arrived today, and I immediately took it up to the tower site for a test run. I really didn't know what to expect from such a long and inexpensive lens, but overall I'm pleased with the results. The lens is very heavy, and my Bogen tripod was barely enough to keep it steady with the camera on it. I had to use the mirror lock-up feature on the camera to minimize softness. Here are a couple of shots of the lens (sans camera) framed for the WVAH tower tip:


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And the result:


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Here is a 100% crop of the above image (click the image for the full size crop). One thing I can see now is that the tower's lightning conductor is equipped with 'dissipation combs', fine points that are supposed to prevent strikes by draining a storm's charge. Obviously, these don't work, a fact that's been well-known in the scientific community for many years! Chromatic aberration is pronounced here - so it remains to be seen how an intense lightning channel will expose.


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I also tested the Raynox 2.2x teleconverter/300mm lens setup that I posted about earlier. Surprisingly, the results were not as bad as I had expected - a little softer than the 1300m lens, but not by much:


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And a 100% crop of the Raynox 2.2x300mm image (effective 660mm):


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For comparison, here is the 300mm shot that I've been shooting with up to this point:


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And just for good measure, a 55mm shot from the 18-55mm:


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Although this proof-of-concept test proves the 1300mm setup certainly works sufficiently (I'm more after the research aspect of this shot rather than getting something to frame on the wall), it is going to be very challenging to pull this off with actual lightning. Focusing was difficult, and getting the tower tip halfway centered in the image was a huge pain. Moving the lens by a fraction of a millimeter results in the tower tip moving significantly in the shot, meaning a slight bump could easily take the tip out of the frame altogether. Just tightening the tripod head clamp moves the lens enough to completely mess up the framing. Mirror lock-up was needed to get the sharpest image possible. A dual-tripod setup (one for the lens, another for the camera) may help, but will increase the setup time - a big factor in a storm situation.

So, all I need at this point is another storm up there. We'll see how it goes then!

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The following comments were posted before this site switched to a new comment system on August 27, 2016:

Why do I foresee a phone call or blog post saying that the wind knocked this camera over?
- Posted by Doug K from locked in your computer and partying
Cool lightning shots. What is the f/number of this lens?
- Posted by Darren Addy from Kearney, NE
Thanks Darren, the aperture is fixed and dependent on the zoom position - from F8 at 650mm to F16 at 1300mm. The exposure is controlled with shutter speed.
- Posted by Dan R. from Charleston, WV

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