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Author Topic: Is this the normal bokeh for an L series lens  (Read 8941 times)

jeffabbyben

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Is this the normal bokeh for an L series lens
« on: November 30, 2012, 09:52:00 PM »
Just got my Canon 35L 1.4 and was surprised to see all this "onion skin" in the bokeh.  I have tried a quick web search but can't find out what causes this.  Is this amount of onion skin normal for a 35 mm L lens?  Will all lenses do this wide open.  This is from the central area of the image.  Thanks.
« Last Edit: November 30, 2012, 10:04:02 PM by jeffabbyben »

PackLight

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Re: Is this the normal bokeh for an L series lens
« Reply #1 on: November 30, 2012, 10:02:46 PM »
Onion Skin? I am not sure I have heard it refereed to that way. I see nothing abnormal except a Christmas Tree in the background.

Is this your first real fast lens?

BlueMixWhite

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Re: Is this the normal bokeh for an L series lens
« Reply #2 on: November 30, 2012, 10:12:05 PM »
Did u try without filter?

jeffabbyben

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Re: Is this the normal bokeh for an L series lens
« Reply #3 on: November 30, 2012, 10:12:59 PM »
Packlight-Thanks for the reply.  No I have the 85mm 1.2.  I am referring to the target like appearance of the christmas lights.  You can see it really well on the close up image.  The other image has it but you have to click on the jpg to enlarge it (sorry this is my first post with attachment).  I have seen a few people call this onion skin but I admit I don't know what the technical term is.  My 85mm I haven't noticed this artifact very much but I have seen it before.

Bluemix-no filter was used.

PackLight

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Re: Is this the normal bokeh for an L series lens
« Reply #4 on: November 30, 2012, 10:18:36 PM »
Someone else may have a different idea or actually have know the answer  ;D
But I am going to put out the guess that it is the make up of the christmas light itself making this effect.

Promature

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Re: Is this the normal bokeh for an L series lens
« Reply #5 on: November 30, 2012, 10:30:19 PM »
I've never noticed this before, but generally, with lots of lights in the background, one usually kicks it up to f16 to get nice stars.  Almost looks like localized lens flare.
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bluegreenturtle

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Re: Is this the normal bokeh for an L series lens
« Reply #6 on: November 30, 2012, 10:46:57 PM »
So in one of the recent comparisons between the Canon 24-70, Nikon 24-70 and the new Tamron 24-70 (which is supposed to be really good, even superior to the Canon, there was note that the Tamron tossed off this "onion skin" as well in it's bokeh.  It seems to be something with the construction of the elements - perhaps that is true of this lens as well.

PackLight

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Re: Is this the normal bokeh for an L series lens
« Reply #7 on: November 30, 2012, 11:01:07 PM »
I just took a few pictures to see if my 35mm f/1.4L would do this with the neighbors Christmas lights outside. Couldn't replicate it. I am still speculating it is the style of light you have on the tree and possibly the distance from the tree.

neuroanatomist

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Re: Is this the normal bokeh for an L series lens
« Reply #8 on: November 30, 2012, 11:05:33 PM »
Both of the aberrations you're seeing are normal for the 35L, yes.  The green edge of the light blur discs is longitudinal chromatic aberration (LoCA, aka bokeh fringing) - pretty much all fast primes have it, your 85L will too on specular highlights (it's magenta or green, depending on whether the OOF highlight is in front or in back of the focal plane). 

The onion skin occurs in some lens designs, usually mild in typical lens designs, more noticeable and even stopped down in the 70-300 DO lens. Many times, people don't notice it because the OOF point light sources are overexposed.  First shot below is an example from my 35L @ f/1.4 (on a 5DII), a 100% crop from the center of the image.  Focus was on my daughter, she's off center and ~3 feet in front of the tree, and exposure was correct for her face in the fairly dim room, meaning the Xmas tree lights in the background are mostly blown like the one on the left, but the one on the right was dimmer because it was partially obscured by branches, and you can clearly see the onion skin pattern. 

It's more prominent with smaller light sources when the focus distance is close and the light sources are also close, but still OOF.  Second shot is another example 100% crop, where the OOF lights were further away (3rd shot shows a wider framing of the same shot for reference).
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Promature

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Re: Is this the normal bokeh for an L series lens
« Reply #9 on: November 30, 2012, 11:05:59 PM »
Just wondering, are these lights LED or incandescent? 
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hammy

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Re: Is this the normal bokeh for an L series lens
« Reply #10 on: November 30, 2012, 11:09:48 PM »
You can find the onion ring like bokeh here
http://www.photozone.de/canon_eos_ff/773-canon2470f28mk2ff?start=1

jeffabbyben

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Re: Is this the normal bokeh for an L series lens
« Reply #11 on: November 30, 2012, 11:24:50 PM »
I want to use this lens mostly for portraits but the pattern seems like it would be quite distracting.  Should I expect that a different copy of the canon or even the new sigma lens would respond the same way (to the same degree) under these test conditions?  I certainly don't expect to be shooting that close to lights on a regular basis but then again it wouldn't be unheard of when shooting indoors with low lighting. 

Promature-They are not LED lights.

PackLight

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Re: Is this the normal bokeh for an L series lens
« Reply #12 on: November 30, 2012, 11:31:35 PM »
I want to use this lens mostly for portraits but the pattern seems like it would be quite distracting.  Should I expect that a different copy of the canon or even the new sigma lens would respond the same way (to the same degree) under these test conditions?  I certainly don't expect to be shooting that close to lights on a regular basis but then again it wouldn't be unheard of when shooting indoors with low lighting. 

Promature-They are not LED lights.

Neuro has it right. I just took the pics I just made and decreased the exposure to see at what point it would replicate.

I think you have a good copy of the 35mm L and wouldn't change. I have been using mine as the walk around lens on my camera for almost four years. I have never had a problem with this, mainly because it never presents itself. Like Neuro mentioned most people will never notice because lights are usually over exposed. Also you have to be a pixel peeper to notice this, and you have to do your pixel peeping in the bokeh area.


jeffabbyben

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Re: Is this the normal bokeh for an L series lens
« Reply #13 on: November 30, 2012, 11:44:55 PM »
Thanks Packlight.  I just took the same image with my 85mm at 1.2 and the "onion skin" is present but to much less degree and not nearly as prominent.  It seems like the 35mm has this prominent target in the center of the onion that the 85mm does not have.  I am not sure if that is a lens characteristic or related to focal length or whatever else may be involved.  It is interesting that in another thread in the third party section titled "Sigma 35 f/1.4 DG HSM First Impressions" comparing the canon 35mm to the new sigma lens neither lens showed this characteristic (actually canon did a little) in the images shown.  Although it is only a small portion of the image shown 

http://lcap.tistory.com/entry/Sigma-35mm-f14-vs-Canon-35mm-f14-L
« Last Edit: November 30, 2012, 11:47:10 PM by jeffabbyben »

sanj

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Re: Is this the normal bokeh for an L series lens
« Reply #14 on: November 30, 2012, 11:45:56 PM »
If this is normal, I am not impressed. Especially with the fringing..