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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 :)

Iris Rack?

Not sure if it's in keeping with topic but (same short)
and to maintain dreamy feel, we had set up a shot
to dolly past kid, standing still against the sky;
however, in the end I kept the camera still (tripod)
and put the kid on the dolly- he floats through
(head and shoulders) and the background stays put.
Not hugely noticeable on the take we used. Placing
something a little closer (than sky) in the background has a greater impact.
I think I should have put the farmhouse in the
background for that shot.
 
Anything, except water patterns from a rained on
window flowing over someone's face: In Cold Blood
is the beginning and end of that one.

One shot that still creeps me out is the scene
in Hour of the Wolf, where the ...man walks
up the wall and across the ceiling.
Still pretty effective.

And talking about Hitchcock, have you seen Scorsese's
short film spoof on the man? Very decent:
http://www.scorsesefilmfreixenet.com/video_eng.htm
 
Anyone ever tried a depth-of-field ramp (iris stops down/opens up while shutter compensates to keep exposure) - is there an example of this in a well known film?
 
If you practiced, you could use a variable ND filter and rack that at the same time as the iris. I think this could work over about a 5 stop range. If you could mount a gear on the filter you might even be able to use a couple digital microforce setups to match the movement of each ring to keep an even exposure.
 
I was kinda thinking that you could use a long lens, an MB-14 (6x6 mattebox with geared tray) and and attenuated ND grad. The long lens means you're using less of the attenuation, and you could pull the tray to match exposure for the iris pull.

Those situations take a bit of practice, but you could probably make it work, if you're willing to live with a slight bit of stop difference between the top and bottom of the image.
 
Tim Sutherland said:
I was kinda thinking that you could use a long lens, an MB-14 (6x6 mattebox with geared tray) and and attenuated ND grad. The long lens means you're using less of the attenuation, and you could pull the tray to match exposure for the iris pull.

Those situations take a bit of practice, but you could probably make it work, if you're willing to live with a slight bit of stop difference between the top and bottom of the image.
Click to expand...

I was starting to wonder about this option last night as I lay in bed thinking about this (how boring is that eh?). It could be easier and cheaper than a whole lighting setup fade. However, parts of the scene would be at different exposures at the same time. Though, if you used a custom filter that was much longer than normal, you could have a fairy decent smoothness of light blocking.

-J.A. Brown
 
One way: If you had a static subject you could shoot it in a series of stills, keeping the exposure "bang on" as you open up (or close down) and then import as an image sequence. Might even work on a face close up if the hero's head is clamped/supported. So a shallow depth of field close up could sweep over the face's terrain, adding or diffusing information without moving the subject or the camera. Might work well if motivated by the story context. Cameras with an aperture/exposure priority might help a bit labor and negate the need for touching the camera between adjustments. Just a thought. The RED wireless control, just announced in RECON: "Control" might help, not sure.
 
Has anyone thought of using a pinhole on their RED?
I've noodled around with it for my digital stills work.
Exposure times would be a big issue with 24P but
probably doable in direct sunlight. One of the fine
things about pinhole is that depth of field is unlimited-
there is no critical plain of focus.
From one inch to infinity is the same. So, if you
like the dreamy diffuse effect, consider trying it.
Drill a hole in a (extra) cap that is used on the body
when the lens is not mounted. Make a pinhole in a
piece of aluminum foil and tape this inside the cap,
making sure the hole is centered (and it will be centered
with the sensor, more or less. The rounder and less
ragged edged the hole is the better.
It might take a few tries with a needle and
magnifying glass (to inspect hole) to get there.
Placing and pricking the foil on a piece of
firm card stock will help.
Experiment with pinhole sizes- I usually aim for
about a 1/64th of an inch- but I'm not sure how
far the RED cap plane is from the sensor.
If it's 2 inches then your pinhole focal length will
be equal to a 50mm lens on a 35mm sensor if I'm not mistaken.
But your 1/64" pinhole effectively becomes f128!
The farther the pinhole is from the sensor, the greater
the effective pinhole/Fstop ratio.
Might still be worth a try outdoors- even with high
asa settings, it can be pretty dreamy.
Even in the harshest sunlight conditions the diffused
effect of the pinhole works very well, and the colors
are pretty damned nice.
 
Joshua Brown said:
H

Is this just pipe dreams or is this actually done. I guess I'm specifically talking about going from WFO to F16 or so.

-J.A.Brown
Click to expand...

Iris pulls are done all the time - to keep exposure. You want the change in exposure.

Best example is going from exterior to interior in a continuous shot.
 
They're talking about two different approaches Shawn,
one being a typical iris pull; the other (perhaps theory at this point)
an Iris pull with compensated exposure to negate overall
change in image values. ie.: altering the depth of field without
altering the light/mood. More of an effect than corrective
if I understand correctly.
 
Bill Anderson said:
They're talking about two different approaches Shawn,
one being a typical iris pull; the other (perhaps theory at this point)
an Iris pull with compensated exposure to negate overall
change in image values. ie.: altering the depth of field without
altering the light/mood. More of an effect than corrective
if I understand correctly.
Click to expand...

Correct, Bill. And it is just theory at this point (unless someone has a clip for me to see). I might try that stills idea though being as I don't have a proper motion camera here at the moment.

-J.A.Brown
 
Nick Gardner said:
This is technically impossible.

Nick
Click to expand...

No, it's semantically impossible. Big difference.

One of my teachers used to call me out on asking for a "pan up" in studio multicam classes - given the operator knew exactly what I meant I don't see the problem.

Technically, what is the difference between a pan and a tilt? I don't see the need to forcibly differentiate between two axes of motion on a tripod head.
 
Joshua Brown said:
I was starting to wonder about this option last night as I lay in bed thinking about this (how boring is that eh?). It could be easier and cheaper than a whole lighting setup fade. However, parts of the scene would be at different exposures at the same time. Though, if you used a custom filter that was much longer than normal, you could have a fairy decent smoothness of light blocking.

-J.A. Brown
Click to expand...

That's why I said to use an attenuated grad, which has a stop difference between the very top and bottom of the filter, and an even gradation between, not a short area of transition like a hard or soft edge grad filter. That way you have a longer area of even exposure to use.

http://www.tiffen.com/color_grad_filters_pics.htm
 
I've seen this effect done and it is incredible. That is to say I've seen the end result. I can only imagine it was pulled off like David Wyatt described. You do an iris pull as the shutter angle changes. So the depth of field changes from very crisp foreground and background to a crisp foreground but very soft background. I don't know where I saw it, but I remember thinking it would have to be computer controlled somehow to get the iris and the shutter in such perfect sync... because the exposure never shifted throughout the entire pull. I'm guessing David M. knows how this is done. Maybe he's been too busy with his series to read this thread yet.
 
Well here's my proof of concept. Could be a better example, but pretty much all the proper equipment is out of state right now. Haha. So this was shot on a Nikon d40 with kit lens using aperture priority mode to keep exposure relatively constant.

The iris was rolled from 5.6 to 36, and the video has been cropped to fit in a 720 HD clip.

It's Ok, could be done much better though:

http://vimeo.com/6845557


-J.A.Brown
 
Tyler Black said:
I've seen this effect done and it is incredible. That is to say I've seen the end result. I can only imagine it was pulled off like David Wyatt described. You do an iris pull as the shutter angle changes. So the depth of field changes from very crisp foreground and background to a crisp foreground but very soft background. I don't know where I saw it, but I remember thinking it would have to be computer controlled somehow to get the iris and the shutter in such perfect sync... because the exposure never shifted throughout the entire pull. I'm guessing David M. knows how this is done. Maybe he's been too busy with his series to read this thread yet.
Click to expand...

I think on film you'd need something like a Lens Control System and a camera with an electronic shutter like a 435 or Arricam ST? The electronic shutter reacts to the iris pull...never had a chance to give it a go myself but would love to see how it looks, used in the right context...
 
Any camera with an in-shot variable shutter like a 435, 535, ARRICAM, Panaflex, Sony F35 etc. etc. can all easily do a depth of field ramp.

I can't give references to particular films or ads off the top of my head, but it has been done many times before.
 
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