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best F-stop for super speeds with a black net


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#1 Dave Navarre

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Posted 18 February 2007 - 04:31 PM

Hi All,
I?m shooting a film on super-16 and I would like to use a black net on the back of the lens. I?ll be using Zeiss 35mm Super Speeds (18, 25, 50, 85) and a Zeiss 10-100. Unfortunately I won?t have the ability to test this and I?m concerned about seeing the net. Does anyone know what f-stop I should be working at so as to not see the net?

Thanks
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#2 Michael Nash

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Posted 18 February 2007 - 04:57 PM

What do you mean you won't have time to test it? You can see the effect through the viewfinder, and can test that the day you set up.

I would stay below an f-4. Personally I'd be more comfortable closer to f-2 or f-2.8. Also, the net will be more visible against against bright backgrounds, so you might get away with a higher f-stop in low key scenes than you would with bright scenery.

The focal length will also matter. On the 10mm end of the zoom, for example, you might want to stay wide open (f-2.2?); on the 100 end you can get away with a higher stop.
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#3 Dave Navarre

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Posted 18 February 2007 - 06:02 PM

Thanks Michael. I didn't realize it was something you could see in the viewfinder. I was scared that I would get the film back and suddenly see it.
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#4 Michael Nash

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Posted 20 February 2007 - 02:55 AM

Thanks Michael. I didn't realize it was something you could see in the viewfinder. I was scared that I would get the film back and suddenly see it.


Well, that's not unreasonable. Film can often reveal things we can't see or don't catch in the VF. Especially when blown up on a big screen!

Of course you're right that a proper film projection test would give proof. But in this case, a good viewfinder can give some guidance.
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#5 Thomas Cousin

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Posted 20 February 2007 - 11:27 AM

Of course you're right that a proper film projection test would give proof. But in this case, a good viewfinder can give some guidance.
[/quote]

hi,
the viewfinder may give you a more diffused image that it will be on the film,
due to the optical quality of the ground glass.
if it appears ok while you view it through the viewfinder, it may be less diffused on the negative.

just another question for eveybody, what are the different techniques used to stuck a net on the back of the lens ?

thomas
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#6 marc laliberte else

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Posted 20 February 2007 - 05:06 PM

I found through experience that netting the back of the lenses works much better on 35mm. 16mm is inherently grainier and if the net isn't stretched enough it really breaks down the image too much for my taste. Especially if you are using a higher speed stock and exposing at the toe end (usually nighttime shooting). If you do shoot it, make sure it is stretched tighter on the long lenses (just like you would when using front diffusion filters, heavier on wide lenses, lighter on long lenses), but because of that you will need to check the back after almost every good take to make sure the net hasn't come off the snot tape holding it in place. Some older lenses have screw in rings which are much easier to attach the stockings to but you give up even more sharpness.

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#7 Clark S. Splichal

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Posted 26 March 2007 - 09:17 PM

Hi All,
I?m shooting a film on super-16 and I would like to use a black net on the back of the lens. I?ll be using Zeiss 35mm Super Speeds (18, 25, 50, 85) and a Zeiss 10-100. Unfortunately I won?t have the ability to test this and I?m concerned about seeing the net. Does anyone know what f-stop I should be working at so as to not see the net?

Thanks


Classic softs or black nets? The eternal question...
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#8 Tony Brown

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Posted 26 March 2007 - 09:40 PM

Nail varnish was the best solution but you almost certainly will damage the matte black coating to someextent when you use the nail varnish remover. You have to be VERY careful. Never liked snot tape..... too unreliable

I love black nets (Dior 7 was great) but I'd avoid nets on 16mm personally...Why have you decided on nets as opposed to other diffusion out of interest?
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#9 Satsuki Murashige

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Posted 27 March 2007 - 12:00 AM

What do you mean you won't have time to test it? You can see the effect through the viewfinder, and can test that the day you set up.

I would stay below an f-4. Personally I'd be more comfortable closer to f-2 or f-2.8. Also, the net will be more visible against against bright backgrounds, so you might get away with a higher f-stop in low key scenes than you would with bright scenery.

The focal length will also matter. On the 10mm end of the zoom, for example, you might want to stay wide open (f-2.2?); on the 100 end you can get away with a higher stop.

And also, you can sometimes see the pattern of a rear-mounted net in the out-of-focus circles of the image if you're using a long lens. David Mullen posted some stills from Bob Richardson's work on "Bringing Out the Dead" a while back that had this artifact. I just looked through all 27 pages of posts in the DVD and TV section of the forum and came up with nothing, so you're on your own there!

Here's a thread I came across on how to net lenses.
http://www.cinematog...showtopic=13023

Hope this helps you out.
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#10 David Mullen ASC

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Posted 27 March 2007 - 12:18 AM

And also, you can sometimes see the pattern of a rear-mounted net in the out-of-focus circles of the image if you're using a long lens. David Mullen posted some stills from Bob Richardson's work on "Bringing Out the Dead" a while back that had this artifact.


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#11 Felipe Perez-Burchard

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Posted 27 March 2007 - 02:24 AM

However,
I recently heard Stephen Burum say that on "Snake Eyes" he shot with the net (pantyhose) in front of the lens, at an f/8, on a 40/50mm anamorphic... I was surprised & asked if he could see it at times, replied with a sturdy "no, never"... however I haven't seen the film recently and mean to re-visit it; The AC article didn't reveal anything pertaining to this.
Also, as I recall there was a lot of darkness in the frame, and the netting I bet was mostly used on shots of the actress...
So, all the more reasons for testing and seeing what you like, no?

Best,

-felipe.
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#12 K Borowski

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Posted 27 March 2007 - 10:43 PM

Just as a general rule having to due with depth of field (this phenomenon occurs on the front and rear elements of the lens), you want to shoot as wide-open as possible so that anything out of focus will have as much "confusion" or light scatter due to being unfocused as possible. If you're stopped down too far (say 3+ stops from wide open), the net starts to cast more focused light on the negative, rendering a more focused artifact.

I've never used nets, but had a bad experience, in still photography, with a matte in the matte box in front of the camera where the matte should have produced a soft, pleasing light falloff near the bottom of the frame, but, due to my 3 1/2 or 4 stop closure down from wide-open, produced a rather abrupt light falloff to black. Same principal was at work.

~Karl
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