85L and "chopped bokeh"

That is normal. It happens. In some cases it can make bokeh really ugly, and in some cases you can't even notice it.

Here is an example of the 85L in a bokeh fail situation. highlights cut off by mirror box and pronounced astigmatism

ugly 85L shot

So the 35L does it too, though much less noticeable.
Check the blue COC near the left border
And this shows that the cause can not be [just] the rear contacts of the 85L, since the 35L has no contacts over the last element.

The question remains, is the 1Ds mirror box any better than the one in our 5D2 ?

smorter wrote in post #8513169
35L:

85 L does not have a good bokeh. If you want a nice portrait lens with awesome bokeh get the old 135mm sonnar.

I guess I must not shoot many night speculars because I've been using my 85L a lot and never noticed this. But I use it mostly when photographing faces and absolutely love it for it's bokeh; that's why I bought it. Now it's married almost all the time to my MKIII. I've have to say it's got the prettiest bokeh I've ever seen. Also like the bokeh on the 135L as well.

I just went through my keeper files and looked at all my shots taken with the 85L, (542) most of them being at 1.2. Not a one had the specular variation because I guess I just don't shoot speculars. I don't even consider them bokeh but to me the bokeh is the way the lens turns the background into a velvety softness like a watercolor.

But if I were into little round hot spots (speculars) then it appears you probably want to stay away from the Canon cameras from what has been shown here for it appears to be a camera issue, not a lens issue. I do remember in school using specular highlights to create depth in a photo when we were using our 4x5's and medium format cameras and don't ever remember having this problem. I do remember weirdness with mirror telephotos though when put to this kind of work.

In the studio, and sometimes with tabletop we'd wad up a bunch of aluminum foil and place it in the out of focus background to create a specular, kind of fun to experiment with.

The 200 2L is spectacular also.

DocFrankenstein wrote in post #8522098
85 L does not have a good bokeh. If you want a nice portrait lens with awesome bokeh get the old 135mm sonnar.

bokeh is subjective, to me the bokeh from those older lenses look like a POS, but it's all subjective

The 85L II has nice bokeh for my usages (portraits), but isn't too great for this situation (though it's more a format limitation rather than a lens problem).

And by the way, we're only talking about wide open bokeh here. When you stop down to f/2.0 or so this issue dissipates

My 1ds2 does the same thing. It's normal and only we will notice. If you are really worried about it clone the missing part in.

does the 135L ever suffer from this phenomenon?

I happen to be watching Pulp Fiction right now. The scene where Vincent is driving Mia back home... I noticed chopped bokeh in the shot where the cam is mounted on the hood of the car.

Pop your DVD in and see for yourself. I never noticed before.

The narrower the angle of view, the less likely one will observe this effect on a fast lens shot wide open.

There are two effects to observe when the blur circles are not in fact true circles. First, OOF highlights that are off axis will never appear as true circles, because the entrance pupil does not appear circular when viewed off-axis. Just like when you look at a coin from an angle, it looks elliptical rather than circular. Therefore, the projection of the OOF highlight onto the focal plane will not be circular, even if there were no other obstacles to block the path of light.

The second "chopping" effect appears to be caused by the mirror box. When the aperture is very wide, we see that there may be some light rays that pass through the lens and would reach the sensor, but do not because it is recessed inside the mirror box.

A possible third effect may be due to the design of the 85/1.2L (as well as the 50/1.2L) in which the contacts are glued directly to the rear element. This is unlikely to be noticed, however, since light passing through the lens but blocked by the contacts would also be blocked by the body.

You will generally not see this effect on, say, lenses 200mm and longer, because the angle of view is sufficiently narrow.

This also raises a question as to why the rear element for the 85L is as large as it is. Surely they could have made it smaller since a lot of the area is blocked by the lens mount anyway :S

^ to combat vignetting?

The chopped bokeh away from the edges is a characteristic of the 85/1.2 and 50/1.0. All specular highlights are irregular at the edges.

smorter wrote in post #8524217
This also raises a question as to why the rear element for the 85L is as large as it is. Surely they could have made it smaller since a lot of the area is blocked by the lens mount anyway :S

Well, this is sort of true.

The amount of light blockage due to the mirror box and mount can be directly witnessed in the sample photographs in this thread. As you can see, even wide open, it isn't very much. The "chopped bokeh" is really just a fraction of the blur circle.

After all, the lens has to reach the corners of the sensor, too--and you can see that the corners go all the way to the edge of the mount.

smorter wrote in post #8523419
bokeh is subjective, to me the bokeh from those older lenses look like a POS, but it's all subjective

Bokeh is not subjective, there's a very easy way to describe and predict how a background looks based on how the COCs are rendered.

DocFrankenstein wrote in post #8525354
Bokeh is not subjective, there's a very easy way to describe and predict how a background looks based on how the COCs are rendered.

I disagree. Go visit the mflenses forum and watch all those guys swoon over the hideous swirly cateye bokeh of the Helios 40! There are also those that love the donut bokeh from mirrored lenses.

I think in the case of the 85L, though, someone is paying top dollar for buttery bokeh, and it looks like the lens is not delivering 100%