Bokeh has parallel lines with 100-400 f4.5-5.6 and slower autofocus

[mfostervt]

I recently upgraded from a prime 400 5.6 to the 100-400 4.5-5.6.   Many of my shots have a bokeh with parallel lines in it.  Trying to figure out why.  I have a UV filter on, not a polarizer, which was my first thought.  I have not tried without a filter yet, but will.  Thought maybe someone here might have an idea why I'm getting this.  The other thing I have noticed is that the autofocus is not as fast as with the prime and sometimes struggles to get to focus.  I'm a bird photographer, so sometimes my subject is quite small and in a bunch of branches, but my prime was faster.  I still like the final photo result of the new lens better, so I'm sticking with it.  I attached an example of the bokeh problem

[Waddizzle]

"I would have never guessed that the motors in the camera and lens could create harmonics, but it totally makes sense.  I have now taken a bunch of photos without the filter, and have yet to find an image with the same distortion." 

Don't take it as fact.  I guessed, too.  I can see those distortions both with or without a filter, but not always.  I need to investigate this further.

[mfostervt]

Thanks to you both.  I am trying the sharpening in Lightroom right now and it seems to work really well.  Seems there is always a trick that I don't know and something more to learn.  

Here is an image from today of a spotted sandpiper.  I did crop the original about 75% and tried the image sharpening sharpening trick from TT Martin.  A great trick and one that will become a part of my normal processing procedure.  I had to use a little luminence on this one to clean up some noise.  Thanks again to all for the great help.

[ebiggs1]

Great pictures are made in post, not in the camera.  Usually, that is.  You need to and if you don't learn PS and/or LR you can probably forget great bird photos.

Don't kid yourself, a lot or even most all great bird shots are cropped.

BTW, that servo motor harmonics thing, whatever, is more likely just a good theory.  Nothing more.  Ditch the filter and learn how to post edit.

[Waddizzle]

"BTW, that servo motor harmonics thing, whatever, is more likely just a good theory.  Nothing more.  Ditch the filter and learn how to post edit." 

"Good theory?"  That's a compliment.  I consider it to be a wild guess, just a blind shot in the dark. 

The use of a UV filter seems to make no difference.  I've seen it both with and without.  For me, it just seems to appear at certain shutter speeds in AI Servo mode.  It could also be the IS at work.  I haven't figured out a way to rule out the Image Stabilization, not short of turning it off, because there is nothing in the EXIF data that reports the state of the lens in that detail.

[ebiggs1]

Also forgot to mention, your sandpiper is real nice.  That's what you'er after.  Keep doing it.

[Waddizzle]

I give up.  I took a few hundred pictures the same day I shot the robin.  There seems to be no rhyme or reason as to why a handful of shots show the parallel line bokeh.  I can only speculate. 

Here's a shot with same shutter speed, and exposure.  EXIF says AI Servo was active, but the crow was motionless.

The only variable that is changing is AF mode, and whether or not AI Servo is actively tracking.  Remember, I'm using BBF.  In the above shot, the bird was grubbing for worms, so I grabbed a focus in AI Servo and kept it active.  Thanks, to the Show Focus Points plug-in for Lightroom, I can tell whether or not AI Servo is active or not.

When AI Servo is active, then the "red+black" focus point is displayed.  When I release the BBF button, then the "red+white" focus point is displayed.  This shot, and the robin shot, are both reported with a "red+black" focus point.  In DPP4 there is also a way to tell when AI Servo is active, too.   Curiously enough, when you look at the EXIF data of shots when the BBF button has been released, but after focus has been locked on something, then no AFMA data is recorded, which corresponds to the first scenario shown above, "red+white".

I cropped it as close to 1:1 as I could.  Clean bokeh, without any lines.  Same filter, lens, camera, photographer, exposure, BUT, it is a different bird.  I NEVER see the distortion when I've released the BBF button, which does not mean that I will always see it when AI Servo is active.  And, I never see the distortion when AI Servo seems to have nailed the focus, either.

That's all for now, folks.  I'll start a new thread on this, if I have anything conclusive to add.

[ebiggs1]

Not sure about your guesses as to what's wrong, but that bird is not a crow!  It is a common starling.

[Waddizzle]

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@ebiggs1 wrote:

Not sure about your guesses as to what's wrong, but that bird is not a crow!  It is a common starling.

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Crow?  That was another guess.  Too lazy to look it up, really.  It seemed to be too small to be a crow.

[ebiggs1]

Crows have black bills.

 Your investigation of the bokeh problem is interesting to say the least.  i don't think the IS is the culprit, however.  if it is, it must be unique to the 100-400.

[Waddizzle]

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@ebiggs1 wrote:

Crows have black bills.

 Your investigation of the bokeh problem is interesting to say the least.  i don't think the IS is the culprit, however.  if it is, it must be unique to the 100-400.

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Black bills, you say?  I have no idea what type of birds they are.  I know crows were in the area, because I could hear the distinctive "caw caw" of crows in the trees.  All I know for certain is that these birds are ugly and aggressive, but smallish.

I don't know what to think about the bokeh.  It shows up in the 150-600, too, but randomly scattered line segments, not parallel lines.  I;m not using sleep over it.  I'm gonna blame stray nuetrinos.  Case closed.