Lightning shots all mess up. What went wrong?

I have been looking forward to shooting lightning for awhile and last nights conditions were perfect. The storm was slow moving and from my location, no rain! So I was able to setup my camera on tripod, focused manually and turned off image stabilizer.

I had the camera in Bulb mode and I was controlling the camera via wifi using EOS remote to NOT get eaten alive by mosquito's.

My camera: 70D with 18-135mm STM lens.
ISO was either 500 or 650 and Av between 9 and 14 at times.
Time taken CST around 11pm

As you can see, I held open the shutter for a variable length of time, once the lighting hit, I would release. From the camera view, these looked good.

I loaded them up into DPP, where I noticed the odd halo/banding and was very disappointed!

What should I have done differently?

IMAGE LINK: http://i302.photobucke​t.com …_6808_01a_zpsuv​5a2hj5.jpg

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I would have set the aperture open more. 9 to 14 is way too tight.

Halo/banding? I guess I'm not seeing what you're seeing.

kezug wrote in post #17635437
What should I have done differently?

At that distance, you should have been shooting wide open.

There's also no benefit to using Av when you're not actually exposing any foreground object(s). It's not a show stopper, but you would have been just as well off shooting manual 10-15" continuously.

Shoot in manual, do a test exposure to nail the level of ambient you want. Unlesss you want boring isolated lightning bursts you need ambient light for context. Try 15 seconds at 5.6 to see what you get, adjust the time if you need more exposure for the surroundings. After the first strike adjust the aperture to brighten or darken the strike. Just like using flash, you have to balance two exposure values.

Thank you all for replying....I take it, that my Av needed to be as wide open as possible..perhaps then also allowing for lower ISO overall.

I cant wait till the next storm!

i disagree with the above, I think your lens had condensation on it, there are very low thick clouds diffusing the lightning, and your iso is too high. Expose longer at a lower iso so you don't pick up the clouds as much.

Your aperture doesnt need to be wide open, it really depends on how close the lightning is. In your shots the lightning was distant and behind clouds so you get the dual damage of not bright and not crisp