Background Blur Sigma 18-50

[scott_mills]

I just got this lens a few weeks ago and I really like it. I just thought the BG blur in this photo looked odd,

more like a PS blur . To me it looks like I tried to add the blur post, it looks "fake" to me. What do you

think? Maybe I'm just not used to have big, smooth structures in the BG (usually leaves and such). Here's a

100% crop.<div></div>

[ben_quinn1]

I agree with you but perhaps the back ground is a little over exposed, do you hvae a shot with a lower exposure?

[JDMvW]

Is from a jpeg? It could be "post-processing" (at least, non-lens) in the settings on what kind of compression, sharpening, etc. you've got on the camera. Does it show up in a RAW image?

[scott_mills]

Ben - The BG is a little over as I was exposing for the backlit subject. I don't have any other exposures of the same shot.

JDM - It's the Rebel XTi's default settings which always seem fine to me, never got this look before. I shot this one jpg only and do not have a RAW for it. I did do some post on this but it looked the same right out of the camera. The only PS I did on this was a very minor levels adjustment (maybe moved the black slider 1/8 inch if that) and USM at 150%/1.0/2.

[JDMvW]

Well, I think that you may have run into the extreme difference at the edge between a really overexposed (clipped) sky and the dark of the shadowed wall and pipe. It was just too much, I'm betting, for the normal algorithm to work as usual.

[chrisjb]

Could it be the sharpening technique? I rarely use USM, (mainly it sharpens overall and don`t want flat tone areas sharper like sky) I use either high pass filter, or Smart sharpen as you are using CS3, generally have mine 140/1/0 using `lens blur, seems to work far better than USM, I believe rebels sharper in parameters for jpeg maybe drop it back and select sharpen in PS :)

[JDMvW]

In any case, I guess all I and the others are saying is that we don't think it is the lens per se, but rather what is happening in an extreme contrast situation in the settings, etc. for the jpg _in the camera_..