What the hell is that ??!!!

[drogos]

Mark III with newly acquired 35 1.4 at 1.4 i wanted to tuned in AF a little bit but than again what's this "rainbow" all about?

[PetKal]

Looks like an extreme case of CA, purple and green fringing.
Never seen anything like it.

[drogos]

does 1.4 justify behaviour like that? ..in a L lens ?

[PetKal]

My 35L, 24L and 85L all develop a traditional CA pattern along the high contrast transitions, when wide open. That behaviour largely disappears by f/2.
However, again, I have not seen your kinda CA before. I am not even sure if the new MkIII sensor might have anything to do with it.

[oldsquawk]

Yup, it's Chromatic Aberrations. L-lens or consumer grade, lenses with large maximum apertures are more prone to CA when used wide open. Stop the lens down a couple of stops and the CA will be much less noticeable. Also, the shorter the focal length primes and zoom lenses exhibit a greater probability of CA, to some extent or another, when used wide open. My 17-40L has moderate amounts of CA when using 17mm @ f 4. My 500mm f4L IS lens has zero CA wide open. CA is an aberration that is tough to correct in zooms and shorter focal length lenses.

[smirchfa]

My 24 1.4L does that to an extent as well, but maybe not quite that much. Then again, I rarely use it below 1.8. I only notice it when it is white against black, such as table setting cards at weddings out in the daylight, like this sample taken at f2.8:

[airfrogusmc]

Heres a couple I just shot with my 35 1.4L
http://i4.photobucket.com/albums/y118/airfrogusmc/IMG_4564-1.jpg
Cropped tight
http://i4.photobucket.com/albums/y118/airfrogusmc/IMG_45642.jpg
And with a red grease pencil and green pen.
http://i4.photobucket.com/albums/y118/airfrogusmc/IMG_4558.jpg
If you notice the Ds a little red and the L is a little green.

[drogos]

ok so i guess it is pretty typical ...still i will try to find a better copy out there

[Lightstream]

My 35L, 24L and 85L all develop a traditional CA pattern along the high contrast transitions, when wide open. That behaviour largely disappears by f/2.
However, again, I have not seen your kinda CA before. I am not even sure if the new MkIII sensor might have anything to do with it.


Any sample shots that you have? Just help me shoot a lens box or something. I want to correlate some of my own observations. Thanks :)

[Adcuz]

That lens seems pretty nice!

[farrukh]

I wish Sigma make a full frame 35 1.4 lens as my 30mm 1.4 was flawless wide open.

[PetKal]

Any sample shots that you have? Just help me shoot a lens box or something. I want to correlate some of my own observations. Thanks :)

Any shots with a very pronounced CA I generally don't keep.
However, here is one mild case of red fringing with the 35L wide open.

[Adcuz]

The great thing about my partial color blindness fringing is invisible!

[Lightstream]

Any shots with a very pronounced CA I generally don't keep.
However, here is one mild case of red fringing with the 35L wide open.


OK, do me a favor and shoot me one with the 50/1.4 at 1.4 :)

I have always complained about the 50 having lots of green and red - I want to see if this is normal.

[airfrogusmc]

I wish Sigma make a full frame 35 1.4 lens as my 30mm 1.4 was flawless wide open.

Lets see....

[PetKal]

OK, do me a favor and shoot me one with the 50/1.4 at 1.4 :)

I have always complained about the 50 having lots of green and red - I want to see if this is normal.

I do not have the 50 f/1.4 any more. However, if I remember right, it will fringe on strong highlights and high contrast borders.

[Lightstream]

Oh well. I ain't buying the 50/1.4 anyway - I bought the 50 Compact Macro and I am quite happy with that.

Ain't a 1.4, but my preferred low light blaster is a 28/1.8. Makes a really nice 36/1.8 USM on a 1.3x too.

[airfrogusmc]

These kinds of aberrations will be in all lenses when shooting wide open. Aspherical elements address spherical aberration
http://en.wikipedia.org/wiki/Spherical_aberration (http://en.wikipedia.org/wiki/Spherical_aberration)
http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/aber.html (http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/aber.html)
An aspherical element is used to correct this problem in Canons 35 1.4L lens. They also have special UD glass to help chromatic aberration. Every lens has these optical problems. Its simple physics. All glass has refraction. Look at the degree of magnification on the book shot I did and the first image of the bar code though the first one looks to be worse.
Every time you add another element to a lens design you add more refraction and thus more chances for optical problems because of refraction.
http://en.wikipedia.org/wiki/Chromatic_aberration (http://en.wikipedia.org/wiki/Chromatic_aberration)
http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/aber2.html (http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/aber2.html)
On Canons 300 2.8 they use a flourite element to correct chromatic aberration which can be a real problem in long lenses.

[baybud]

My 35L, 24L and 85L all develop a traditional CA pattern along the high contrast transitions, when wide open. That behaviour largely disappears by f/2.
However, again, I have not seen your kinda CA before. I am not even sure if the new MkIII sensor might have anything to do with it.

I can cetainly second what others have said with it being related to shooting wide aperture lenses wide open.
I had the exact same thing with my first 85L MK1, my 35mm 1.4, 24mm 1.4 and my new 85L MK2.
And they all looked IDENTICAL to yours.