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Chromatic Aberration?

PostPosted: Sun Oct 14, 2007 6:34 am
by scottvd
Bueno! (That's Californian for "hello!")

I just got in my 85/1.8 and was playing around outside - took a photo of a drippy faucet - when I opened it up in PS I saw an ugly glow on the edges. I think this is "chromatic aberration" - am I right?

See photos here: http://tinyurl.com/2mzfk4

But then I read where this guy: http://tinyurl.com/ek3k2 said I didn't need to waste money on ED glass because:
"Extra-low Dispersion glass." Nikon started using this only in their super speed super teles in the late 1960s. These lenses say "ED" on and have a gold band around the barrel. All ED lenses say so.

Since only the most expensive lenses used or needed this glass it acquired a cachet. Therefore Nikon started using the moniker on cheaper lenses, and today it seems everything says ED on it. Short and normal lenses have no need of this glass; it's benefit is reducing secondary chromatic aberration, which is green/magenta color fringes that used to plague lenses of 300mm and up."

So if that statement is true, and my lens is only 85mm and what I'm seeing is chromatic aberration - what gives? Thanks pros for the tips.

`S

PostPosted: Sun Oct 14, 2007 9:34 am
by digitor
Nicely caught drip coming out of the tap!

I notice this shot is taken wide open - it's not unususal to see this effect in an out-of-focus area against a bright background like this (it's more pronounced on the side of the nut opposite your arrows, you have both a green and a magenta fringe there). Try stopping down a bit and see what happens, the effect will probably disappear.

Oh, and probably not a good idea to take Ken Rockwell too seriously! :lol: :lol:

Cheers

PostPosted: Sun Oct 14, 2007 9:54 am
by big pix
that is an easy fix in photoshop........

PostPosted: Sun Oct 14, 2007 10:04 am
by iluxa
AFAIR, Nikkor 85/1.8 doesn't have ED glass.
And that is definitely chromatic aberration.

But the good thing is you can easily fix it in Photoshop (Filter->Distort->Lens Correction), in PTLens or during RAW conversion.

PostPosted: Sun Oct 14, 2007 10:56 pm
by Matt. K
What you are seeing is perfectly normal for the out of focus part of an image shot against the light (contra jour). Close down a couple of stops and it will disappear. Stop fussing about the blurry parts and start thinking about your subject choice and technique.

PostPosted: Mon Oct 15, 2007 3:44 am
by scottvd
Nicely caught drip coming out of the tap!

Thanks! (:

Oh, and probably not a good idea to take Ken Rockwell too seriously!
Yeah, I'm learning that!

AFAIR, Nikkor 85/1.8 doesn't have ED glass.
And that is definitely chromatic aberration.

You're right, no ED glass, and that's for the confirmation on what I'm seeing - I was expecting to hear it was actually something else..

Close down a couple of stops and it will disappear. Stop fussing about the blurry parts and start thinking about your subject choice and technique.
I'll try going a few stops down - I've also played with PS to see if I can remove some of it - thanks everyone for all the tips - mucho appreciate it.

Take care,
`S