# Mirror box bokeh clipping haunts my dreams



## ahsanford (Dec 1, 2017)

Now that this blasted forum I love has told me what mirror box bokeh clipping is, I can't *not* see it in portraits.

https://petapixel.com/2017/12/01/shooting-portraits-christmas-lights-ordinary-bedroom/

IT'S EVERYWHERE! (85 f/1.2L II I believe for these shots)

- A


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## ahsanford (Dec 1, 2017)

So if you have a large aperture prime, a few questions come to mind:

1) Which Canon lenses demonstrate this phenomenon? Does the 135L as well? Does the Sigma Art 85 or 135 do this? Otus glass, perhaps?

2) How does one get round/soft/large bokeh balls from a large aperture lens? Just stop it down and forego the size/softness of the large aperture to eliminate the clipping? (Wouldn't that defeat the point of buying the fast lens?) 

- A


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## slclick (Dec 1, 2017)

ahsanford said:


> So if you have a large aperture prime, a few questions come to mind:
> 
> 1) Which Canon lenses demonstrate this phenomenon? Does the 135L as well? Does the Sigma Art 85 or 135 do this? Otus glass, perhaps?
> 
> ...



The 135L does not get clipped


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## ahsanford (Dec 1, 2017)

slclick said:


> The 135L does not get clipped



Phew. Some bokeh made it out alive.

- A


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## ahsanford (Dec 1, 2017)

85mm f/1.2 bokeh shots: http://www.shutterdial.com/#/search?s=bokeh&f=85&a=2
Mostly Canon shots, clipped, and one D800E shot with round bokeh on what is listed as an 80mm f/1.2 lens that I did not know existed.

85mm f/1.4 bokeh shots: http://www.shutterdial.com/#/search?s=bokeh&f=85&a=3
A fair amount of Nikon shots (on their 85 f/1.4) show round bokeh

135mm f/2 bokeh shots: http://www.shutterdial.com/#/search?s=bokeh&f=135&a=5
Some cat's eye but I'm not seeing any clipping.

- A


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## ethanz (Dec 1, 2017)

On those links you just sent, the 135 certainly has the cats eye but I don't see clipping.

What is wrong with the clipping, in your opinion?


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## ahsanford (Dec 1, 2017)

ethanz said:


> On those links you just sent, the 135 certainly has the cats eye but I don't see clipping.
> 
> What is wrong with the clipping, in your opinion?



Didn't even care about it until this bloody forum pointed it out to me, and now it's everywhere I look.

I don't know why I'm up in arms about this, if I'm honest. I just am. Maybe it's because I just rented an 85 f/1.4L IS. :

I appreciate the 85 on FF is (around) the shortest FL you don't get facial distortion from close shooting distances -- so it's gold for indoor portraiture -- but isn't this bokeh clipping thing kind of a big deal for a lens that is _renowned for generating bokeh?_ Shouldn't folks get 135 f/2 lenses instead?

In fairness, it seems to be a more glaringly noticeable phenomena for high contrast bokeh (i.e. background lights on a dark frame). It's far less noticeable as say greenery / trees / grass behind a subject.

- A


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## Ryananthony (Dec 1, 2017)

It has turned me off of a lens I was almost sure I would pick up. That's why I'm awaiting more sample images to see where and how define it is in a number of shots.


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## jd7 (Dec 2, 2017)

Just had a quick look in the Flickr group for the older Sigma 85 1.4 EX and there is some bokeh clipping but a perhaps a bit less than in the 85 1.2L shots??

These are the best examples (or should I say worst!) I found
https://www.flickr.com/photos/azproduction/33492603656/in/[email protected]/
https://www.flickr.com/photos/jf_paillie/34907120681/in/[email protected]/

Didn't find much for the Sigma 85 Art on a Canon body but ...
https://www.flickr.com/photos/[email protected]/23712057114/
https://www.flickr.com/photos/universal_creations/38189323536/


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## PCM-madison (Dec 2, 2017)

135L at F2.0


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## Ozarker (Dec 2, 2017)

ahsanford said:


> Now that this blasted forum I love has told me what mirror box bokeh clipping is, I can't *not* see it in portraits.
> 
> https://petapixel.com/2017/12/01/shooting-portraits-christmas-lights-ordinary-bedroom/
> 
> ...



It is cooling my desire for sure. I guess there is no way around it. Looks like the 1.2 and the 1.4 have the clipping. I don't think any of mine do that, but now I have to check. The only consolation for me is that few portraits I take have the bokeh balls to begin with. Still, it looks like hell.


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## aceflibble (Dec 2, 2017)

ahsanford said:


> 1) Which Canon lenses demonstrate this phenomenon? Does the 135L as well? Does the Sigma Art 85 or 135 do this? Otus glass, perhaps?
> 
> 
> > Off the top of my head (this is not a definitive list), the only Canon first-party lenses which do it are the 85mm f/1.2 and f/1.4, 200mm f/1.8, and the FD 50mm f/1.0. The 400mm f/2.8 does technically do it, too, but you'll never see it with that lens because of how strongly everything it flattened out. Rumour was back in the day a 135mm f/1.4 was prototyped and never moved forward specifically because the image circle was so cut up and shaped by the lens mount. (Remember, usually these things are caused by the lens mount, not the mirror box, so calling it "mirror box clipping" is, in most cases, inaccurate.)
> ...


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## neuroanatomist (Dec 2, 2017)

aceflibble said:


> (Remember, usually these things are caused by the lens mount, not the mirror box, so calling it "mirror box clipping" is, in most cases, inaccurate.)



Are you saying that the lens mount —which is round— is somehow causing a straight-edged clip of the bokeh highlights? How does that work, geometrically? Also, note that the rear element of the 85/1.2L is actually flush with / sits inside the lens mount, so again, how is the lens mount causing the clipping?




aceflibble said:


> Or, finally,
> - Ignore it and stop thinking about it, because nobody who looks at your images will care.



+1


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## BeenThere (Dec 2, 2017)

Could the mirror box be designed to eliminate this phenomenon? Rounded or tapered


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## Don Haines (Dec 2, 2017)

Personally, I have far better things to dream about


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## mb66energy (Dec 2, 2017)

BeenThere said:


> Could the mirror box be designed to eliminate this phenomenon? Rounded or tapered



Remove everything which is between the circular opening of the lens and the sensor. Or buy a mirrorless camera - it has not mirrorbox and hopefully nothing which interferes with the lens and the sensor. Would be great to see some images of FF mirrorless cameras with the EF 85 1.2 adapted ...

Definitely a strong drawback for ME because it looks very unnatural.


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## IglooEater (Dec 2, 2017)

Huh, thank you AH–this is very interesting. I personally don’t have any lenses that could generate that phenomenon, but I enjoy knowing about these things.


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## hne (Dec 2, 2017)

BeenThere said:


> Could the mirror box be designed to eliminate this phenomenon? Rounded or tapered



They were. Look at pretty much any film EOS camera and you'll see a cut out at the bottom.


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## 9VIII (Dec 2, 2017)

Don’t forget the Canon 85f1.2 has the electronic contacts on the rear element itself.
Bokeh on that lens will look a bit funky no matter what design the body has.


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## Sharlin (Dec 2, 2017)

I actually asked about this on Photo.StackExchange a few years ago, related to the old Sigma 30mm f/1.4 EX DC! Was a bit nonplussed when I saw the clipping for the first time. I'm not sure whether the new Art version exhibits the issue.


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## hne (Dec 3, 2017)

ahsanford said:


> So if you have a large aperture prime, a few questions come to mind:
> 
> 1) Which Canon lenses demonstrate this phenomenon? Does the 135L as well? Does the Sigma Art 85 or 135 do this? Otus glass, perhaps?
> 
> ...



1) As this is strictly geometric, with the same f number always having the same light cone angle from pixel to exit aperture, the placement of rear element makes no difference since it can't be larger than the rectangular hole of the mirror box. The mirror box intersects the light cones for some parts of the image starting at about f/1.8 at the extreme top for the 5DmkIV mirror box. The 5DmkII has a deeper cut out at the bottom but clips slightly more so is probably smaller. Haven't measured.

2) if you want perfectly round bokeh balls, you need to buy slower lenses than f/1.8 (with humongous front elements to avoid cat's eye bokeh), stop down to at least f/2 or use only the centre part of the frame.


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## ahsanford (Dec 4, 2017)

hne said:


> 2) if you want perfectly round bokeh balls, you need to buy slower lenses than f/1.8 (with humongous front elements to avoid cat's eye bokeh), stop down to at least f/2 or use only the centre part of the frame.



I'm not convinced that's true. Here's an 85mm f/1.4 lens on a FF sensored SLR, in this case a Nikon D810 -- I don't see any clipping.

https://www.youtube.com/watch?v=E4RXQNAeCeo

So either Nikon has a much larger mirror box (for the same size sensor?), or there might be a lens design component to this.

I tried to find some background lighting bokeh balls for other fast 85s (including Dustin Abbott's site) and struck out. If someone has 3rd party lens 85 1.4 samples on a Canon FF rig, please share. 

- A


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## jd7 (Dec 4, 2017)

ahsanford said:


> hne said:
> 
> 
> > 2) if you want perfectly round bokeh balls, you need to buy slower lenses than f/1.8 (with humongous front elements to avoid cat's eye bokeh), stop down to at least f/2 or use only the centre part of the frame.
> ...



Any of these any good to you?

https://www.flickr.com/photos/wefwef/5198757019/in/dateposted/
https://www.flickr.com/photos/wefwef/5182085737/in/dateposted/
https://www.flickr.com/photos/wefwef/5150349093/in/dateposted/
https://www.flickr.com/photos/wefwef/5205019328/in/dateposted/
https://www.flickr.com/photos/wefwef/5218131465/in/dateposted/


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## arthurbikemad (Dec 4, 2017)

Check out the 35/1.4II. Has perfect Bokeh imo.


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## hne (Dec 4, 2017)

jd7 said:


> ahsanford said:
> 
> 
> > hne said:
> ...



They all show clipped OOF balls.


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## hne (Dec 4, 2017)

ahsanford said:


> hne said:
> 
> 
> > 2) if you want perfectly round bokeh balls, you need to buy slower lenses than f/1.8 (with humongous front elements to avoid cat's eye bokeh), stop down to at least f/2 or use only the centre part of the frame.
> ...



hen you record a video in 16:9 aspect ratio, you cut off 5% top and bottom which likely hides rather efficiently also on your Canon DSLR.
The Nikon F mount has a 2.5mm longer flange focal distance and as such ought to be more susceptible to this. It could very well be the case that Nikon is using a wider opening on its mirror boxes than Canon does.

That said, the phenomenon is there on the...
D700: https://www.flickr.com/photos/geoff_sills/11939255546/
D750: https://www.flickr.com/photos/stephanrudolph/31296328703/
D800: https://www.flickr.com/photos/hishnessmahal/21399122753/
D800E: https://www.flickr.com/photos/charliemcmahon/26360753869/
D810: https://www.flickr.com/photos/[email protected]/15574134554/


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## bholliman (Dec 4, 2017)

hne said:


> 2) if you want perfectly round bokeh balls, you need to buy slower lenses than f/1.8 (with humongous front elements to avoid cat's eye bokeh), stop down to at least f/2 or use only the centre part of the frame.



My understanding is that the Sigma Art 85mm f/1.4 has perfectly round bokeh balls wide open, with no mirror box clipping. If that is true, is it due to the large front element (86mm)?


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## neuroanatomist (Dec 4, 2017)

bholliman said:


> My understanding is that the Sigma Art 85mm f/1.4 has perfectly round bokeh balls wide open, with no mirror box clipping. If that is true, is it due to the large front element (86mm)?



Your understanding is incorrect. For example, see the set of Flickr images posted by jd7, which are with the Sigma 85A. A couple of images from that set are highlighted below.


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## hne (Dec 4, 2017)

bholliman said:


> hne said:
> 
> 
> > 2) if you want perfectly round bokeh balls, you need to buy slower lenses than f/1.8 (with humongous front elements to avoid cat's eye bokeh), stop down to at least f/2 or use only the centre part of the frame.
> ...



Then your understanding is incorrect: https://www.lensrentals.com/blog/wp-content/gallery/nicks-wedding-photography-sigma-85mm-f1-4-examples/Sigma-85mm-Art-Series-Example-Photo-3.jpg


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## stevelee (Dec 4, 2017)

In the examples, I would find the out of focus balls distracting even if they were all perfectly round.


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## bereninga (Dec 4, 2017)

ahsanford said:


> Now that this blasted forum I love has told me what mirror box bokeh clipping is, I can't *not* see it in portraits.
> 
> https://petapixel.com/2017/12/01/shooting-portraits-christmas-lights-ordinary-bedroom/
> 
> ...



LMAO! Seriously. I kind of wish I can unread the thread that mentioned the bokeh ball clipping concept.


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## jd7 (Dec 5, 2017)

neuroanatomist said:


> bholliman said:
> 
> 
> > My understanding is that the Sigma Art 85mm f/1.4 has perfectly round bokeh balls wide open, with no mirror box clipping. If that is true, is it due to the large front element (86mm)?
> ...



I think all of those images were actually taken with the older Sigma 85 1.4 EX rather than the Art ... although I do not expect there would be much difference in terms of bokeh clipping.

bholliman - perhaps the comments you have seen about round bokeh balls are about the ability of the lens to produce "perfectly" round bokeh balls if located near the centre of the frame? I would expect all of the higher end 85s (at least) to be able to do that. I believe the clipping occurs as you get closer to the edge of the frame. See the images Neuro posted in this thread http://www.canonrumors.com/forum/index.php?topic=33939.0


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## ahsanford (Dec 5, 2017)

jd7 said:


> bholliman - perhaps the comments you have seen about round bokeh balls are about the ability of the lens to produce "perfectly" round bokeh balls if located near the centre of the frame? I would expect all of the higher end 85s (at least) to be able to do that. I believe the clipping occurs as you get closer to the edge of the frame. See the images Neuro posted in this thread http://www.canonrumors.com/forum/index.php?topic=33939.0



I guess both 85L lenses aren't 'higher end' then:

http://www.canonrumors.com/forum/index.php?topic=33869.msg696463#msg696463

Lovely shot, btw, but the clipping is clearly present. And as best I can tell, it's not a corner or central issue, but somewhere in between. That shot shows cat eye bokeh up top (fine by me) and some lovely central circles, but the sides in particular have the bokeh clipped pretty hard. The bokeh sadly becomes a distraction when this happens. No knock on the photographer in this case -- it's a great shot that the lens couldn't fully realize, I guess.

- A


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## bholliman (Dec 5, 2017)

neuroanatomist said:


> bholliman said:
> 
> 
> > My understanding is that the Sigma Art 85mm f/1.4 has perfectly round bokeh balls wide open, with no mirror box clipping. If that is true, is it due to the large front element (86mm)?
> ...



Thanks for setting the record straight. That's what I get for speed reading the 85mm f/1.4 IS threads.


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## jd7 (Dec 5, 2017)

ahsanford said:


> jd7 said:
> 
> 
> > bholliman - perhaps the comments you have seen about round bokeh balls are about the ability of the lens to produce "perfectly" round bokeh balls if located near the centre of the frame? I would expect all of the higher end 85s (at least) to be able to do that. I believe the clipping occurs as you get closer to the edge of the frame. See the images Neuro posted in this thread http://www.canonrumors.com/forum/index.php?topic=33939.0
> ...



I take your point, although it does seem the bokeh circles which are very close to the centre are round ... it's just that you don't have to get very far at all from the centre before you see significant clipping. It seems to me that compared to the Canon 85Ls, the older Sigma 85 EX (and the newer Art?) is showing clipping in a smaller area of the frame, primarily near the top ... or am I imagining it? Anyway, I don't mean to suggest the Canon 85Ls are not high end, regardless of bokeh clipping!


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