Sigma 30 1.4 questions

I haven't had much chance to use this lens yet, but I am liking it a lot. I was messing around with my cats and noticed that I'm getting so pretty noticeable "glow" around them sometimes - especially when the background is a very bright colour.

I'm wondering if this is the lens, settings, colour of the background itself, combination of things?

Here's the black (when he hasn't been rolling in the red dirt) cat with a hot pink & bright white blanket behind his head on the right as you look at the photo - aperture was 1.6. His ears have very pink lines around them...

Did I put this in the wrong area? If so, please move it as I'd really like some input from others on this

It's just CA - although the effect in the blue picture seems different...

Hi kja, not getting much of a response are you?

The reason for the apparent haloes is simply that the edges of your cats are out of focus, so they are mingled with the colour of the background at those edges. The difference here is that the backgrounds are overexposed, so lose some colour information except where they only just shine through the cats' fur. This leaves a stronger colour image of the background right at the edges of the cat image. If the backgrounds were not so bright, the effect wouldn't show.

So it's not a lens problem, just a physics limitation, and everyone knows "ye cannae change the laws o' physics Cap'n!"

Madweasel wrote in post #4220864
Hi kja, not getting much of a response are you?

The reason for the apparent haloes is simply that the edges of your cats are out of focus, so they are mingled with the colour of the background at those edges. The difference here is that the backgrounds are overexposed, so lose some colour information except where they only just shine through the cats' fur. This leaves a stronger colour image of the background right at the edges of the cat image. If the backgrounds were not so bright, the effect wouldn't show.

So it's not a lens problem, just a physics limitation, and everyone knows "ye cannae change the laws o' physics Cap'n!"

Hmmmm....I think you may have nailed it. Didn't look like chromatic aberration to me.

That's perfect, exactly what I needed to know!

I thought that was the case in the pink one, but wasn't 100% sure on the blue one. The maddening thing about the blue one is that the background isn't overexposed according to the histogram, it's well away from the right edge. Guess I'll just have to move it down even more next time I have something that brilliant behind!

Appreciate the help!

Regardless, those pics look great to me.

I REALLY want that lens.