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Over the weekend I went over to a photography shop, and they let me bolt various lenses to my SLR, including some seriously expensive ones. I took a few pictures, and was impressed. But when I got home and reviewed them at full resolution... wait, is that... chromatic aberration?!

enter image description here

Notice how the bottom letters are fringed in blue, and the top ones are fringed in green. I've never seen this effect with the cheap kit lens, so I'm a little alarmed to see it from an extremely expensive macro lens.

Is this actually CA? Or is it some effect of the lighting in the shop? (It's lit by "white" LEDs.)

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  • \$\begingroup\$ What lens are you talking about? \$\endgroup\$
    – null
    Feb 24, 2016 at 20:12
  • \$\begingroup\$ @null The kit lens is the 18-55mm. I tried several macro lenses, which all had some degree of colour issue; the one pictured is the annihilatingly expensive 105mm NIKKOR Micro. \$\endgroup\$
    – MathematicalOrchid
    Feb 24, 2016 at 20:16
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    \$\begingroup\$ "annihilatingly expensive" This is a high resolving, full frame, 4-stops stabilised macro lens. The canon equivalent has roughly the same price. Compare to the manual focus, unstabilised, extends-length-when-focusing APO-Lanthar 125mm from Voigtländer that sells for anything north of 2500$ used, but only if you are lucky enough to find one. \$\endgroup\$
    – null
    Feb 24, 2016 at 20:59
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    \$\begingroup\$ I never said it was expensive for no reason ;-) \$\endgroup\$
    – MathematicalOrchid
    Feb 24, 2016 at 22:05
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    \$\begingroup\$ I think null is saying it isn't really that expensive. Less than $1,000 for any pro level lens is actually fairly budget friendly. \$\endgroup\$
    – Michael C
    Feb 25, 2016 at 17:01

2 Answers 2

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That is normal "Axial" or "longitudinal" chromatic aberration and it is very common with fast lenses when used at wide open apertures. It is sometimes called "Bokeh Fringing" and yes, even expensive ones have this problem.

Cheap lenses have "transverse" or "lateral" chromatic aberration which can occur at any aperture.

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  • \$\begingroup\$ Is an f/2.8 lens stopped down to f/4 considered "wide open"? \$\endgroup\$
    – MathematicalOrchid
    Feb 24, 2016 at 22:07
  • \$\begingroup\$ @mathematicalOrchid no, "wide open" usually means using it for what you paid for. When it comes to macro lenses in their natural habitat, you don't want "wide open" for lack of depth of field anyway and even if you do (when doing focus stacking for example, with wide open aperture for whatever reason), CA can relatively easily be corrected in post. \$\endgroup\$
    – null
    Feb 24, 2016 at 22:27
  • \$\begingroup\$ It's not the f/4 aperture that causes the CA, it is the narrow depth of field caused by the close focusing distance. Look at it this way: At the closest focusing distance of your non-macro kit lens the DoF at f/3.5 is a lot deeper than demonstrated here by the macro lens at f/4 focused so close that the near edge of the lens cap is practically bumping up against the front of your lens. Notice the CA gets worse as the focus gets softer. \$\endgroup\$
    – Michael C
    Feb 25, 2016 at 16:56
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That's tiny, nothing to worry about. A lens that I used to have (the Nikon 35mm f/1.8 AF-S DX) had problems like that maybe 10x worse. If it really bothers you, get software like Adobe Lightroom to correct it. I think it actually looks natural in some situations!

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