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Gear Talk => Lenses => Topic started by: jeffabbyben on November 30, 2012, 09:52:00 PM

Title: Is this the normal bokeh for an L series lens
Post by: jeffabbyben 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.
Title: Re: Is this the normal bokeh for an L series lens
Post by: PackLight 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?
Title: Re: Is this the normal bokeh for an L series lens
Post by: BlueMixWhite on November 30, 2012, 10:12:05 PM
Did u try without filter?
Title: Re: Is this the normal bokeh for an L series lens
Post by: jeffabbyben 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.
Title: Re: Is this the normal bokeh for an L series lens
Post by: PackLight 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.
Title: Re: Is this the normal bokeh for an L series lens
Post by: Promature 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.
Title: Re: Is this the normal bokeh for an L series lens
Post by: bluegreenturtle 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.
Title: Re: Is this the normal bokeh for an L series lens
Post by: PackLight 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.
Title: Re: Is this the normal bokeh for an L series lens
Post by: neuroanatomist 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).
Title: Re: Is this the normal bokeh for an L series lens
Post by: Promature on November 30, 2012, 11:05:59 PM
Just wondering, are these lights LED or incandescent? 
Title: Re: Is this the normal bokeh for an L series lens
Post by: hammy 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 (http://www.photozone.de/canon_eos_ff/773-canon2470f28mk2ff?start=1)
Title: Re: Is this the normal bokeh for an L series lens
Post by: jeffabbyben 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.
Title: Re: Is this the normal bokeh for an L series lens
Post by: PackLight 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.

Title: Re: Is this the normal bokeh for an L series lens
Post by: jeffabbyben 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 (http://lcap.tistory.com/entry/Sigma-35mm-f14-vs-Canon-35mm-f14-L)
Title: Re: Is this the normal bokeh for an L series lens
Post by: sanj on November 30, 2012, 11:45:56 PM
If this is normal, I am not impressed. Especially with the fringing..
Title: Re: Is this the normal bokeh for an L series lens
Post by: CharlieB on November 30, 2012, 11:47:05 PM
I seem to recall something about wide aspheric lenses (or lens elements rather) doing the "disk effect" or "target effect".  Something to do with internal reflections from the non spherical element... I just spent a while looking for that... can't find it... but I "think" it was on one of the Leica web sites that caters to very high end testing of lenses.
Title: Re: Is this the normal bokeh for an L series lens
Post by: PackLight on November 30, 2012, 11:50:43 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 (http://lcap.tistory.com/entry/Sigma-35mm-f14-vs-Canon-35mm-f14-L)

Blow up the picture the samples that say Bokeh Shape at f/1.4, you can see a few samples of it in that pic.
I just think it was the positioning of your tree and the exposure you used. I don't think you will notice this in 99% of the situations you shoot. But then I don't know what your subjects usually are.
Title: Re: Is this the normal bokeh for an L series lens
Post by: EOBeav on November 30, 2012, 11:57:20 PM
If this is normal, I am not impressed. Especially with the fringing..

You've got pretty high standards, then. I can just imagine the scenario: "Hey Mabel, will you come look at this? You can actually see the layers in the bokeh in our portraits! What was that photographer thinking when he bought that lens, anyway? Come here, look through this microscope, you can see it for yourself..."

Don't let this stuff get in the way of taking good photographs.
Title: Re: Is this the normal bokeh for an L series lens
Post by: Aglet on November 30, 2012, 11:58:25 PM
seems like aspherical correction elements, wide apertures and certain focal distances can make the onion highlites show up.  Many lenses will do this, tho not always at all settings.
YMMV

-
Title: Re: Is this the normal bokeh for an L series lens
Post by: dirtcastle on December 01, 2012, 01:34:04 AM
Ultimately, all lenses have limitations. And part of the challenge of photography is working around those limitations to get great shots. Big aperture lenses solve problems (low light, subject isolation), yes, but they also create new challenges (thin DOF, CA).

In this case, I'm sure we could come up with a dozen ways to avoid the undesirable effect. While I think we can all agree that it's frustrating to see those annoying effects. It's also a cool challenge. And occasionally, those shortcomings can be an unexpected benefit.

(http://farm8.staticflickr.com/7156/6805450549_27b6f02e17_z.jpg) (http://www.flickr.com/photos/75059479@N00/6805450549/)
new day's resolution (http://www.flickr.com/photos/75059479@N00/6805450549/#) by Eric Nord (http://www.flickr.com/people/75059479@N00/), on Flickr
Title: Re: Is this the normal bokeh for an L series lens
Post by: Rat on December 01, 2012, 03:11:14 AM
Great shot, dirtcastle. What I don't get is how the 'lemony' bokeh shape in the bottom come into being. Could anyone explain?
Title: Re: Is this the normal bokeh for an L series lens
Post by: Old Shooter on December 01, 2012, 03:28:12 AM
Great shot, dirtcastle. What I don't get is how the 'lemony' bokeh shape in the bottom come into being. Could anyone explain?

I was just thinking the same thing!  :P
Title: Re: Is this the normal bokeh for an L series lens
Post by: eddiemrg on December 01, 2012, 03:58:38 AM
Great shot, dirtcastle. What I don't get is how the 'lemony' bokeh shape in the bottom come into being. Could anyone explain?

I was just thinking the same thing!  :P

Probably becouse the surface reflect an "oval" beam of light!
Title: Re: Is this the normal bokeh for an L series lens
Post by: gmrza on December 01, 2012, 04:14:58 AM
Here is another example that shows some of the aberrations that show up in the OOF blur, this time with the 100mm f/2.8L IS USM macro.
Title: Re: Is this the normal bokeh for an L series lens
Post by: Rat on December 01, 2012, 04:48:12 AM
Probably becouse the surface reflect an "oval" beam of light!
I don't think so. Some googling led me to this (very interesting) page (http://jtra.cz/stuff/essays/bokeh/index.html), which says:
Quote
Sometimes what would be a circular out of focus highlight in the center of the image has a lemon shape outside of center, gradually more near borders and edges. This is caused by mechanical vignetting because the optical path in the lens is too narrow. Resulting shape is often a intersection of two non-concentric circles, often described as "lemon shape" or "cat eye".
But that immediately raises the question why even a classy lens like the 135L (which was used for this shot, according to the exif data) shows such 'defects'. I'm assuming this is a consequence of shooting wide open (tho I'm not sure), is it something to do with the ratio between distance and aperture? Anyone?
Title: Re: Is this the normal bokeh for an L series lens
Post by: Viggo on December 01, 2012, 06:11:31 AM
Yes, it's normal! And yes the 35 has a CA issue. You're going to use it for portraits? Well... You really need to understand optics, the sooner you learn how crappy all lenses are, the better pictures you take ::) the 35 L is one of the absolutely greatest, I love it for the focal and that awesome AF, very sharp wide open. What makes me get the mk2 is primarily weather sealing, better corners and less ca.
Title: Re: Is this the normal bokeh for an L series lens
Post by: jeffabbyben on December 01, 2012, 09:56:40 AM
Viggo-thanks.  I realize that no lens is perfect and expected some CA as my 85mm also has this.  I am going to try some more shots in different situations but right now it looks like the bokeh would really bother me.  The central target  appearance in the center of the OOF light looks like eyes staring at me or a thousand nipples pointing at me :P
Title: Re: Is this the normal bokeh for an L series lens
Post by: robbymack on December 01, 2012, 10:13:03 AM
yes totally normal when shot wide open with a lot of contrast.  I find the need to look at bokeh at 100% pretty funny, only because no normal person does this, just the gear head.  Just about every lens will show these "onion rings" in various situations due to modern design including several elements of different sizes and shapes.  Essentially all you are seeing is the reflection of one piece of glass against the other.  That being said if you are unhappy with it return it and get another one.  I don't think that will totally solve the issue, but if it gives you more peace of mind so be it. 
Title: Re: Is this the normal bokeh for an L series lens
Post by: sanj on December 01, 2012, 10:47:21 AM
If this is normal, I am not impressed. Especially with the fringing..

You've got pretty high standards, then. I can just imagine the scenario: "Hey Mabel, will you come look at this? You can actually see the layers in the bokeh in our portraits! What was that photographer thinking when he bought that lens, anyway? Come here, look through this microscope, you can see it for yourself..."

Don't let this stuff get in the way of taking good photographs.

Naaaa. I won't. I promise!
Title: Re: Is this the normal bokeh for an L series lens
Post by: jeffabbyben on December 01, 2012, 11:20:30 AM
RobbyMack-I do get your point about looking for bokeh at 100% but many times I print some of my images.  They're not works of art per se but I find I enjoy them more hanging on my wall for a few months at a time.  Sometimes I even print pretty large.  I also don't want to keep sending lenses back with unrealistic expectations.  Unfortunately where I live their is not a camera shop for 250 miles so I can't go try different copies or compare the new sigma.

Title: Re: Is this the normal bokeh for an L series lens
Post by: eddiemrg on December 01, 2012, 01:06:06 PM
This is one of my fav shots...
Any comments?

@RAT: I have a "lemon effect" too!!

(the subject went out of the frame... her joke->good pic at all!)

(https://dl.dropbox.com/u/14904170/Andalucia%202012%20-%20%282638%29.jpg)
Title: Re: Is this the normal bokeh for an L series lens
Post by: Krob78 on December 01, 2012, 01:28:42 PM
I may be wrong, it seems to me though that I've seen this "onion skin" effect show more readily when the blown highlights are stopped down in post, such as using the highlight brush in LR... No?
Title: Re: Is this the normal bokeh for an L series lens
Post by: eddiemrg on December 01, 2012, 01:33:54 PM
nope... just noise reduction...
Title: Re: Is this the normal bokeh for an L series lens
Post by: distant.star on December 01, 2012, 01:56:28 PM

.
Coincidentally, I noticed exactly this phenom using the ef24mm f/1.4L ii last weekend. The room was decorated for Christmas with those icicle lights hanging from the ceiling.

After reading this thread, I wonder if it is not the lens at all, but a different issue of light. When you look directly at any light bulb, it has some light source element inside and an outer casing (glass or plastic). Light passing directly from the source to your eye (or lens) passes through a minimal amount of the casing. Light at the sides or border is passing through substantially more casing material and is greatly diffused.

Anyway, just a thought; could be completely looney. But if there is some "fault" in optics, I want to lean toward the maker of the cheap light bulb rather than a team of optics engineers who designed and built a very expensive camera lens.
Title: Re: Is this the normal bokeh for an L series lens
Post by: Daniel Flather on December 01, 2012, 02:24:33 PM
My 50L will do this if your close to the MFD and the BG is far. 
Title: Re: Is this the normal bokeh for an L series lens
Post by: Krob78 on December 01, 2012, 02:35:45 PM
This is one of my fav shots...
Any comments?

@RAT: I have a "lemon effect" too!!

(the subject went out of the frame... her joke->good pic at all!)

(https://dl.dropbox.com/u/14904170/Andalucia%202012%20-%20%282638%29.jpg)
I like it!
Title: Re: Is this the normal bokeh for an L series lens
Post by: jeffabbyben on December 01, 2012, 03:17:10 PM
Krob97-my photo with the onion effect was not adjusted in photoshop or lightroom either.  I don't mind the lemon effect as my 85mm has some of this as well.  It is more that central target in the middle of the onion that I will have to decide if I can accept or not.  My onion effect looks much more prominent than the other pictures I have seen.  Other than this the lens looks great with only some mild softness at the edges till close to 2.8.  Since I will be using it wide open much of the time that does not bother me. 
Title: Re: Is this the normal bokeh for an L series lens
Post by: Krob78 on December 06, 2012, 10:28:52 PM
Krob97-my photo with the onion effect was not adjusted in photoshop or lightroom either.  I don't mind the lemon effect as my 85mm has some of this as well.  It is more that central target in the middle of the onion that I will have to decide if I can accept or not.  My onion effect looks much more prominent than the other pictures I have seen.  Other than this the lens looks great with only some mild softness at the edges till close to 2.8.  Since I will be using it wide open much of the time that does not bother me.
Gotcha!  I don't mind the lemon effect either... all in all, there's nothing terrible here.  Most folks looking at our images never seem to notice any of the slight defects that we the photogs seem to pick up instantaneously..

Seems like we can fret and fret over little abnormalities and oddities in our images and they can walk up behind you and say; "oh that's awesome!", "I love that shot".  It's kind of crazy!  My customers often seem to most like the photos that I like the least! :o
Title: Re: Is this the normal bokeh for an L series lens
Post by: Aglet on December 07, 2012, 08:50:26 PM
..  My customers often seem to most like the photos that I like the least! :o

I wish I knew why that was in my experience too.
Would be a lot cheaper for me if I didn't buy gear to make images that satisfied ME. :)
Title: Re: Is this the normal bokeh for an L series lens
Post by: Zv on December 07, 2012, 11:10:31 PM
I thought we agreed to call this problem "BROKEh"!!   ;)
Title: Re: Is this the normal bokeh for an L series lens
Post by: jeffabbyben on December 07, 2012, 11:28:59 PM
..  My customers often seem to most like the photos that I like the least! :o

I wish I knew why that was in my experience too.
Would be a lot cheaper for me if I didn't buy gear to make images that satisfied ME. :)

+1
Title: Re: Is this the normal bokeh for an L series lens
Post by: Krob78 on December 30, 2012, 12:56:27 AM
..  My customers often seem to most like the photos that I like the least! :o

I wish I knew why that was in my experience too.
Would be a lot cheaper for me if I didn't buy gear to make images that satisfied ME. :)

+1

Ain't it the truth!! 
Title: Re: Is this the normal bokeh for an L series lens
Post by: skitron on December 31, 2012, 09:38:07 PM
It's more prominent with smaller light sources when the focus distance is close and the light sources are also close, but still OOF. 

True, and I inadventently had a nice 'test lab' this year since our tree had both clear miniature lights and the larger old skool solid color c4 lights. The mini - which as far as light sources goes is both the visible filament and the reflection of the filament in the clear glass - has some onion effect while the larger uniform light source c4 bulbs are perfectly smooth. Moral to the story is string your tree with c4 bulbs next year for premium quality bokeh, lol.