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]

"Taken today with the 7D Mk II and EF 100-400 L IS II @ 400mm with the B+W CLEAR MRC-Nano." 

Nice.  I don't know how you guys get so close, but nice job.  I do note the fact that you have photographed the bird at a feeding location, which takes good scouting and planning.  Good shots like those do not happen by accident, and require planning.

[ebiggs1]

"...shots like those do not happen by accident, and require planning."

And luck!

[Waddizzle]

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@ebiggs1 wrote:

"...shots like those do not happen by accident, and require planning."

And luck!

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Consistent luck is more properly described as skill.

[ebiggs1]

"Consistent luck is more properly described as skill."

Still a beginner!, Huh?

[Waddizzle]

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@mfostervt wrote:

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

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I'm not sure if this issue has been fully diagnosed, but I can reproduce it at will.

Too much crop.  Too much sharpening, at too large a radius brings out the distortion, which is already present in the photograph.  I shot this photo in AI Servo mode.  In One Shot mode, it seems to go away. 

It is not always visible in AI Servo mode.  It seems to show up at certain shutter speeds.  I'm placing my bet on the shutter speed being a harmonic of the update frequency of AI Servo, or possibly combined with IS.

[EDIT]  I haven't been clear.  In One Shot mode, it is less apparent, although it still seems to be apparent.  I shot this in IS Mode 1, and focusing mode 3m to infinity.  Distance was roughly 20 meters.

Also, what I meant when I said the shutter could be a harmonic of the update frequency of the AI Servo, I was referring to the frequency of the pulses being sent to the motor, not how often it updates the tracking.

[mfostervt]

Well that is really interesting and not something I would have considered.  I never use any sharpening in post processing, but I will use the clarity function in Lightroom.  I think that works mostly like a contrast, but not quite sure.  The camera could have easily been set on AI servo.  I switch between that and one shot pretty often, but sometimes forget if I'm not trying for BIF shots.   Cropping is also probably a big culprit.  I'll have to look at the original to see how much I cropped this pic.  

I know I shouldn't crop, but I do so that I can see the bird.  I often do this just so I can ID the bird.  400 just never seems to be enough to fill the viewfinder with a bird.  Sometimes I get lucky and have a bird close enough for that, but usually not.  It gives me a real appreciation for the fantastic photos of those who can get a bird to fill the image.  

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.  I may have to try to intentionally create it like you did just to get a good understanding of the whole thing.  Thank you for your help.  I can only improve.

[TTMartin]

I seldom use more than 10 Clarity, but, will often use 100 Sharpening in conjunction with very heavy Masking typically 75.

Apply a heavy sharpening mask in Lightroom so you don't sharpen even areas.

By pressing and holding the 'ALT' key, while moving the Masking slider you can see what is being masked. Black areas will not be sharpened.

Sharpening Amount set at 100 and Masking set at 70

Smooth unsharpened bokeh.

[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.

[Waddizzle]

"By pressing and holding the 'ALT' key, while moving the Masking slider you can see what is being masked. Black areas will not be sharpened."  

Slick trick!

YOU cleaned up the shot of the robin.

[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.