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

[ebiggs1]

"Black bills, you say? "

Yes, Crows have black bills. The second bird is still a Common Starling.  They have black bills in winter.  It turns yellow in the summer.  It is not uncommon for birds to change colors of some parts with the season.  Starlings can mimic other bird's call. too.  They are considered a nuisance bird by most people.

[Waddizzle]

---

@ebiggs1 wrote:

"Black bills, you say? "

Yes, Crows have black bills. The second bird is still a Common Starling.  They have black bills in winter.  It turns yellow in the summer.  It is not uncommon for birds to change colors of some parts with the season.  Starlings can mimic other bird's call. too.  They are considered a nuisance bird by most people.

---

Starlings, it is.  I had assumed they were younger crows.  Like I've said, they're kind of small for a crow, anyway.  I know adult crows are in the area, though.  I wonder if starlings can mimic another bird's call when the other bird isn't anywhere nearby?

[ebiggs1]

" I wonder if starlings can mimic another bird's call when the other bird isn't anywhere nearby?"

They have good vocal ability.  They remember songs they hear but I have never heard one do a Crow.  The males are more vocal then the females.  We have a lot of bob-whites and meadow larks, kill deer and cow birds and they do all of them.

[ebiggs1]

But the bokeh lines thing.  I think it is well known that the 100-400 doesn't do well with any filter.   My guess it is the filter or perhaps a combination of things.  Filter, exposure + editing, etc.

I have never seen it in my shots.

"It shows up in the 150-600 ..."  It hasn't in mine and I have both versions, or I mean all versions.  But I haven't tried to duplicate it.