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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Square Bokeh?

L

Luis de la Cerda

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I was watching "My Sister's Keeper" last night, which I found quite good btw, and a few takes seemed to have been shot with a square aperture lens of some kind. The film must have been shot with anamorphic glass, because of the characteristic oval bokeh, but the square bokeh was puzzling, not only because I found it unusual, but because I can't imagine why one would chose to mix footage from round aperture and square aperture lenses, since it sticks out like a sore thumb. DOP is Caleb Deschanel, whose work I have always enjoyed.

Btw, I had never seen anything like it. I've seen triangular, hexagonal, round, etc... but never square.
 
Yes, I couldn't help but notice this too. Don't think anyone will ever miss it unless they fall asleep, which is highly unlikely on such a great movie.

Wouldn't the hard matte have to happen at the iris? Could I just tape the front of the lens?

Cholo, I also thought it was quite a strong of a visual choice to make. I guess it might be motivated by the boy's dislexia which perhaps made him feel like he didn't fit in the "normal world". Likely also by not being able to find his place in his family's world who seemed to keep forgetting about him altogether.

Great movie!
 
I notice this alot at the long end of an angie or cooke zoom with the matte built in (which is what causes the "squareness")- makes square bokeh with slightly rounded edges. Might be exgerated with an rear anamorphic adapter as well.

lenses.JPG

image.php
 
There are two causes -- one is a hard matte in front of the lens, if it's too tight, it will cut into the bokeh. You see this all the time in movies (spherical or anamorphic), it may be cut on just the top, or on all the sides.

The other is that anamorphic zooms (with a few new exceptions) and telephotos are adapted spherical lenses -- instead of a big front anamorphic element designed into the lens, they have a tiny rear anamorphic element added on. The anamorphic lens element is cylindrical, so when viewed head-on, it is square in shape. When put in the back of the lens, on longer focal lengths, you see this square shape in the bokeh.
 
Flags vs. Matte

Flags vs. Matte

Rather than use a Matte in the mattebox that is too small for the lens I would try to put a flag between the light that is hitting the front element and the lens, if you get the flag half way between or so you have some control without "cut-in".

In general the hole in the matte should be wider than the stopped down size by half the width of the lens's front element, that is if you need an opening of 8" wide to not see your finger at the edge of the matte when the lens is stopped down, and your front element is 4" wide, then you need about 2" more on each side to be sure you are clear wide open, so the matte hole should be 12" wide not 8" wide.

If you are going to shoot with a 50mm at T/1.3 then you might use the matte for a 35mm lens to be sure you have clearance.
 
I used to drive my ACs a little nutty because I hated this artifact so much. No hard matte allowed in the mattebox and I usually made the grips try to keep the light off with flags. I made sure the ACs had a look at the onboard asistant's monitor to see what I was objecting to. So often they would just stick in the matte as an automatic thing. Much more of an LA thing than a NY thing, at least in my experience.
 
I use hard mattes whenever I feel there is a lot of soft edge lighting that might be flaring the lens -- I've been burned too many times by that. But I always use an oversized hard matte and I never use any tighter than the 50mm one, even for a 100mm lens. But it's maybe only once or twice a day that I have a shot where I tell the AC's to add a hard matte.
 
Holy crap, why did I never think of that? This would have been great back in the 80's!
 
First application of shaped out of focus highlights that I know of was ten or fifteen years ago with Frank DeMarco's LOGOSCOPE. He could put virtually any shape in the lens to act as an iris. There were some shots of the NY marathon that were stunning an also beautiful shots of cars on his reel. Frank shot HEDWIG and also some MAD MEN. Really talented guy.
 
Waterhouse stop

Waterhouse stop

Its called a "Waterhouse stop", if it goes in front of the lens its best to use a longer focal length like 75mm to 150mm, for inside you can modify any FL lens.

The iris in the lens should be wide open.

I have thought you could use a tall ellipse to simulate some of the anamorphic look while using spherical lenses.

Here is a link about "Waterhouse stops",

http://en.wikipedia.org/wiki/Waterhouse_stop
 
Wow, I learned a lot! Thanks everyone.

Now, who's gonna be the first to make a hip-hop video with dollar shaped bokeh ;)
 
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