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Old Nov 25, 2010, 4:36 PM   #1
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Default Wild Bokeh

So saw a squirrel in the yard doing some odd my territory dance and grabbed the K2000 which had a 135mm mounted. My 2X (vivitar) was sitting there also, so I slapped that puppy on (have never matched those two up before) and went squirrel hunting. Now my Tamron has a really nice Bokeh typically. But with the 2X on it, it is wild, almost like an impressionist painting (or so I think, I am far from an art dude). Is it typical for a converter to effect the Bokeh that much? I would have shoot one without the doubler to show you the smooth blur vs. this, but it started to sprinkle and by the time I got in the house it was raining. i wasn't going to remove the lens in the sprinkle, you will ahve to take my word for it. I told the camera it was a 250mm because that was the closest I could come to 135 doubled. F 2.5 ISO 800.
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Old Nov 25, 2010, 10:09 PM   #2
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I like it!
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Old Nov 26, 2010, 10:49 AM   #3
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OK, it's daylight and it quit raining. So I took the 135mm without the 2X on it and using zoom (my feet) tried for the same picture. I had to move about 6 or 7 feet closer. You can see the Bokeh is smoother in the lens without the 2X. Focusing was much easier.
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Old Nov 26, 2010, 11:08 AM   #4
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More spectral highlights in the second one and less of a feeling of 3-D separation from the background. But that may just be my computer.
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Old Nov 26, 2010, 11:24 AM   #5
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Well some of it could be due to the recent rain, and morning vs afternoon, even though both were overcast. But there is not as much "choppyness" in the one without the doubler. I don't hardly ever use the doubler, so it was more a curiosity question because I would have thought the Bokeh would be set by the lens and no effect on it from the converter. One thing i do know, it is always a learning experience.
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Old Nov 27, 2010, 12:31 AM   #6
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Hi fofa,

I use TCs quite a bit, and have noticed that they can sometimes effect bokeh in this way, making it what I call "frantic". I've noticed this the most when the background is relatively close to the subject in distance, and the subject to camera distance is relatively close. I think it's pretty much dependent on the particular combination of lens and TC and the distance between the camera and subject and subject focusing plane and the background. I haven't taken the time to quantify the conditions where this occurs because I mostly shoot as opportunities arise, and have no control over these factors.

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Old Nov 27, 2010, 8:40 AM   #7
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I wouldn't be surprised to see the TC affect the bokeh - after all, there's glass in them and they would affect the optics. Both my macro lenses will show occasionally jittery bokeh like this, depending on the relative distances of subject to background (when shooting flowers and such). It seems to me it works much like what Scott things - it's most noticeable when the background is not much beyond the focus range of the lens/aperture choice. Pine needles and bare ground both cause problems.

It's often not that difficult to handle in pp - select the background and apply a little gaussian blur to the worst parts.
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