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01/22/2019 02:41:37 PM · #1 |
I have noticed it in a few photo's where you zoom in in PS, that I am having purple banding around white things. Not sure if calling it banding is the right word for it though.
Anyone know what this is from? Granted this is a very zoomed in shot, with 300 lens full out of a truck's load that fell off the mountain and I am on the other side of the mountain. But I just noticed it too when I zoomed in on a normal photo of a white car.
Could it be the card? camera? I just zoom in too much and over thinking it?
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01/22/2019 02:46:25 PM · #2 |
That’s chromatic aberration - common in many lenses and will be worse when shooting wide open. Lenses that have been designed to minimise that (APO lenses) can be very, very expensive.
It’s correctable in PS and indeed Aperture, there’s a slider for it - or in PS use the lens correction tool and dial in the lens and camera - then tweak if necessary.
I hope that helps
Paul |
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01/22/2019 02:59:59 PM · #3 |
Originally posted by Paul:
That’s chromatic aberration - common in many lenses and will be worse when shooting wide open. Lenses that have been designed to minimise that (APO lenses) can be very, very expensive.
It’s correctable in PS and indeed Aperture, there’s a slider for it - or in PS use the lens correction tool and dial in the lens and camera - then tweak if necessary.
I hope that helps
Paul |
That does help, a lot.
Also, helps to remind me that I am as thick as two planks, cus I know that and forgot it. Which is stupid as I was only talking about that two days ago with someone and how it is prevalent on Tamron len's.
I hang my head in photo shame =(
LOL
Thank you Paul x |
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01/22/2019 06:31:05 PM · #4 |
| I get that a lot with my 85 mm lens, I noticed it’s worse if you slightly miss focus. |
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01/22/2019 07:15:22 PM · #5 |
Originally posted by Neat:
I get that a lot with my 85 mm lens, I noticed it’s worse if you slightly miss focus. |
Yes indeed it is. That's because it is "longitudinal" CA; it leaves a magenta fringe on one side of focus, and a green fringe on the other. It can't be automatically compensated for as can lateral CA, however there are some tricks to remove it. |
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01/23/2019 11:57:05 AM · #6 |
I have to say, I am pretty damn impressed with this Tamron. The 1st pic is at 16, the 2nd is full out at 300, then the 3rd is where the purple comes into play and that is zoomed in at nearly 200% and cropped in PS. I can not see any green either, or I am green blind to it.
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01/23/2019 12:49:53 PM · #7 |
Originally posted by kirbic:
Originally posted by Neat:
I get that a lot with my 85 mm lens, I noticed it’s worse if you slightly miss focus. |
Yes indeed it is. That's because it is "longitudinal" CA; it leaves a magenta fringe on one side of focus, and a green fringe on the other. It can't be automatically compensated for as can lateral CA, however there are some tricks to remove it. |
Sometimes, I colour pick and then desaturate that colour - I often find it works better than the embedded tools. |
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01/23/2019 01:14:18 PM · #8 |
Originally posted by Paul:
Originally posted by kirbic:
Originally posted by Neat:
I get that a lot with my 85 mm lens, I noticed it’s worse if you slightly miss focus. |
Yes indeed it is. That's because it is "longitudinal" CA; it leaves a magenta fringe on one side of focus, and a green fringe on the other. It can't be automatically compensated for as can lateral CA, however there are some tricks to remove it. |
Sometimes, I colour pick and then desaturate that colour - I often find it works better than the embedded tools. |
Yep, usually works pretty well for the magenta. Can be tricky for the green. I have had success with the green fringe by limiting the desaturation to a selection of the general are where the problem lies. |
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01/23/2019 05:20:23 PM · #9 |
Good ol CA. That's the only problem with my Sigma lenses, they get the telltale purple fringing if I shoot contrasty subjects. Don't know if that's the same for other brands of third-party lenses or not.
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01/23/2019 06:04:42 PM · #10 |
Originally posted by snaffles:
Good ol CA. That's the only problem with my Sigma lenses, they get the telltale purple fringing if I shoot contrasty subjects. Don't know if that's the same for other brands of third-party lenses or not. |
To some degree you can expect it with even brand-name lenses if they are fast lenses, e.g. f/1.4 primes. When shot wide open, it's very uncommon not to see some evidence of longitudinal CA. |
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