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Modifying cine lens to alter bokeh character?


Dominik Bauch

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Disclaimer: I have no idea about lens mechanics...

In theory if you have a set of lenses that have very smooth bokeh but you wanted a more painterly, 'harsh' bokeh, i.e. similar to a Panavision C series where the out of focus areas seem to have more texture than with other lenses. How would you go about achieving this, is this a simple tweak or an entire redesign? I'm not talking about introducing noise or chromatic aberration.

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Not really.

The shape of the iris appears in out-of-focus areas, being particularly visible around point lights. Naturally this will change depending on the aperture setting, especially if the lens has a small number of aperture blades which creates a recognisable shape. The general optical setup of the lens may affect the way in which this shape is rendered, whether it's evenly illuminated, whether it's distorted away from the centre of the image, and so on. I wouldn't consider this something that's really a practical target for modification, though.

Some people have had fun by shooting through carefully-shaped mattes cut into the shape of words, or other things. I've seen it done on the front or rear of lenses.

 

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A large part of the 'anamorfake' process that is popular with hobbyists on YouTube is altering the shape of out of focus highlights with oval mattes fitted into the rear of the lens with varying degrees of permanency.

Many of the other characteristics of bokeh are due to lens design, and therefore probably not that easy to modify. For instance, 'Bubble bokeh" is caused by over corrected spherical aberration, which I don't think is something you can replicate at home in DIY fashion

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18 hours ago, Dominik Bauch said:

Disclaimer: I have no idea about lens mechanics...

In theory if you have a set of lenses that have very smooth bokeh but you wanted a more painterly, 'harsh' bokeh, i.e. similar to a Panavision C series where the out of focus areas seem to have more texture than with other lenses. How would you go about achieving this, is this a simple tweak or an entire redesign? I'm not talking about introducing noise or chromatic aberration.


This is the sort of thing “detuning” accomplishes, which is something Panavision have been doing for a number of years now, and other large rental companies like Arri Rental are starting to get more into. Adjusting another lens to more closely match a C series for example is exactly what Panavision have spent those years trying to perfect.

You can alter all sorts of aspects of how a lens renders an image, including the bokeh, but it’s very much a lens by lens process. Panavision guard their many detuning recipes quite closely, so you won’t get any how-to guides from me, but some of the ways you can alter bokeh include adjusting element spacings and coatings, internal masking or filtration and adding or replacing elements. 

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2 hours ago, Dom Jaeger said:


This is the sort of thing “detuning” accomplishes, which is something Panavision have been doing for a number of years now, and other large rental companies like Arri Rental are starting to get more into. Adjusting another lens to more closely match a C series for example is exactly what Panavision have spent those years trying to perfect.

You can alter all sorts of aspects of how a lens renders an image, including the bokeh, but it’s very much a lens by lens process. Panavision guard their many detuning recipes quite closely, so you won’t get any how-to guides from me, but some of the ways you can alter bokeh include adjusting element spacings and coatings, internal masking or filtration and adding or replacing elements. 

Is this what Canon is doing with the Sumires? 

13 hours ago, Stuart Brereton said:

A large part of the 'anamorfake' process that is popular with hobbyists on YouTube is altering the shape of out of focus highlights with oval mattes fitted into the rear of the lens with varying degrees of permanency.

Many of the other characteristics of bokeh are due to lens design, and therefore probably not that easy to modify. For instance, 'Bubble bokeh" is caused by over corrected spherical aberration, which I don't think is something you can replicate at home in DIY fashion

I think the "bubble bokeh" helps sell the anamorphic look. But there are cheap options to get it imo.

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9 hours ago, M Joel W said:

I think the "bubble bokeh" helps sell the anamorphic look. But there are cheap options to get it imo.

I think you might be confusing the characteristic oval anamorphic bokeh with bubble bokeh.
 

Bubble bokeh looks like this:

0d91a5f7a9c7993572962298fad9bc01.jpg.315
 

You see it occasionally on older lenses. Meyer Görlitz are the famous example, but Pentacon and some Asahi Takumar also do it.

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20 hours ago, Dom Jaeger said:


This is the sort of thing “detuning” accomplishes, which is something Panavision have been doing for a number of years now, and other large rental companies like Arri Rental are starting to get more into. Adjusting another lens to more closely match a C series for example is exactly what Panavision have spent those years trying to perfect.

You can alter all sorts of aspects of how a lens renders an image, including the bokeh, but it’s very much a lens by lens process. Panavision guard their many detuning recipes quite closely, so you won’t get any how-to guides from me, but some of the ways you can alter bokeh include adjusting element spacings and coatings, internal masking or filtration and adding or replacing elements. 

Thanks, this is what I was thinking. Are there any good independent companies in LA experienced in modifying anamorphic lenses? 

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3 hours ago, Dominik Bauch said:

Thanks, this is what I was thinking. Are there any good independent companies in LA experienced in modifying anamorphic lenses? 

I don't know what they can or can't do, but Duclos lenses would be a good place to start. 

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9 hours ago, Stuart Brereton said:

I think you might be confusing the characteristic oval anamorphic bokeh with bubble bokeh.
 

Bubble bokeh looks like this:

0d91a5f7a9c7993572962298fad9bc01.jpg.315
 

You see it occasionally on older lenses. Meyer Görlitz are the famous example, but Pentacon and some Asahi Takumar also do it.

No, I know. I might have been unclear. Or I might be confused about what Dominik is after, I'm not sure what he's working with in the first place. Perhaps I'm just turning this question into one I have myself.

There's a discussion elsewhere about Iscoramas and taking lenses. Contemporaneous (or older) taking lenses seem to enhance the anamorphic look as their harsher bokeh and oval edges and fall off already look kind of anamor-fake. Here's some Iscorama footage that I find to have a stronger (imo better) look than most, not that it looks anything like Panavision. It just looks good for what it is imo:

That's using an old 50mm f2. So I guess what I'm getting at is the bubble bokeh complements an anamorphic system by enhancing the oval look where otherwise it might be less apparent...

Elsewhere, Panavision discusses the importance of the spherical system in defining the C-series look:

https://filmmakermagazine.com/107908-panavision-dan-sasaki-customizing-lenses-once-upon-a-time-in-hollywood/#.XhIyAC2ZN24

So I guess what I'm getting at is–if Dominik is using an anamorphic set up, the taking lens is probably what to focus on. And it's the less expensive part of the system. If he's using a spherical one, rather than detuning what you have, just buy (or rent) bubble bokeh lenses. They're cheap enough.

Am I the only one that finds certain Cooke Panchros (32, 50m 75) to have a bit of bubble bokeh? However they are not "cheap enough" I checked eBay. ?

Edit: maybe not "bubble bokeh" outright, but something close to it:

Isco-Gottingen Westromat 50mm f1.9

Isco-Göttingen Westromat 50mm f1.9

The combination of sharper edges (nisen bokeh? bubble bokeh?) and the sort of swirly look is what I think would complement an older anamorphic adapter well.

Edited by M Joel W
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I'm seeing swirly bokeh, edge softness, anamorphic and spherical flares, and very shallow DoF. Obviously these shots are designed to show off these artifacts, but it's all a bit distracting, frankly. It's an interesting look for a special effects lens, but I don't think I'd want to watch a narrative piece that looked like that.

Cooke Panchros do exhibit a little of the bubble bokeh. you can see it occasionally in 'Her", photographed by Hoyte van Hoytema

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13 minutes ago, Stuart Brereton said:

I'm seeing swirly bokeh, edge softness, anamorphic and spherical flares, and very shallow DoF. Obviously these shots are designed to show off these artifacts, but it's all a bit distracting, frankly. I don't think I'd want to watch a narrative piece that looked like that.

That's fair, but it's difficult to show what I mean unless I look for extreme examples. I wouldn't want everything to look like this either, but how else can I showcase what I mean? Cooke S2s still look like Cooke S2s at t4 or t5.6, they just don't have as much "character" as they do wide open so if I'm to pick a thumbnail that illustrates their look it would be when they're worse-behaved. Perhaps I should have searched a bit harder, but I think you know what I mean.

Regardless, I think rather than "detuning" an anamorphic system, the easier approach is complementing it with the appropriate taking lens. Which is what the Panavision article alludes to. But I don't know what Dominik is working with so, again, I might be coopting this into my own little thing where I'm looking for taking lenses with nisen bokeh.

Edited by M Joel W
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21 hours ago, M Joel W said:

Regardless, I think rather than "detuning" an anamorphic system, the easier approach is complementing it with the appropriate taking lens. Which is what the Panavision article alludes to. But I don't know what Dominik is working with so, again, I might be coopting this into my own little thing where I'm looking for taking lenses with nisen bokeh.

Replacing the taking lens in a composite anamorphic like a C series is not so easy! You have to completely disassemble everything, possibly re-machine the housing if the replacement is not the same size, reset the iris coupling and re-engrave the iris marks (on a new iris ring). Then you might find the focus marks that were hand-marked no longer exactly match and that has to be redone..

If it’s just an anamorphic front adapter like an Iscorama then sure, you can easily swap out the taking lens, but proper anamorphics are more integrated, and modern anamorphics are really just one lens.

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