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Tiffen 4K Diffusion Filter Tests


Guest Stephen Murphy

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Guest Stephen Murphy

At the forthcoming BSC expo in London, Carey Duffy of Tiffen UK will screen the Tiffen 4K Diffusion tests I shot for them late last year. The tests consisted of a series of simple comparisons between every brand of Diffusion filter Tiffen currently offer and serve as an excellent reference.

Designed in conjunction with Steven Poster ASC the test is a simple, but very effective, starting point for a Cinematographer to compare the effect of Tiffens range of Diffusion filters before selecting specific filters to test under their own lighting conditions.

We wanted to keep as many of the parameters as simple and unbiased as possible. The light is soft but not too soft to allow us to see the effect of the filter. The half light allows us to judge contrast changes, the backlight and bare bulb allow us to see blooming. Similarly the Primo primes were chosen because I felt they were a). familiar to most Cinematographers worldwide and B). sat somewhere between Master Primes and Cooke S4's in terms of sharpnes and contrast and therefore would be a better lens to showcase the effect of the filter.

Shot on a Panavisied Sony F55 in 4K the tests will be presented in 4K at events around the world over the coming months. I believe the idea is that eventually Panavision and Technicolor, who co-sponsored the tests, will have copies of the 4K DCP as reference for projection in facilites around the world, so speak to your local Panavision/Technicolor rep for details, or contact Tiffen directly.

 

For my tastes the current generation of 4K+ cameras are just too sharp, especially when projected at 4K, so for me I cant see myself shooting without some form of filtration either infront of, or behind, the lens, especially if I think the project will be projecting in 4K. I also think a lot of the diffusion filters give the image some texture, something I find lacking in most digital images. It'll be interesting to see how many people feel the same way and perhaps we'll see a resurgence in the use of Diffusion over the coming years. Regardless, these tests should still be a very useful reference for us over the next few years so keep an eye out for them.

 

There's a few BTS images and brief video here along with a few other notes on the tests

http://stephenmurphydop.blogspot.co.uk/2014/01/notes-on-tiffen-4k-diffusion-tests.html

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For my tastes the current generation of 4K+ cameras are just too sharp, especially when projected at 4K, so for me I cant see myself shooting without some form of filtration either infront of, or behind, the lens, especially if I think the project will be projecting in 4K. I also think a lot of the diffusion filters give the image some texture, something I find lacking in most digital images. It'll be interesting to see how many people feel the same way and perhaps we'll see a resurgence in the use of Diffusion over the coming years. Regardless, these tests should still be a very useful reference for us over the next few years so keep an eye out for them.

 

I've actually been thinking about this a fair bit lately as I have a new project which is again likely to have a complicated optical path at least for some of it.

 

I've been wondering about the whole idea of 4K and diffusion. On the one hand being bothered about high resolution and diffusion seem at odds with one another. Having said that something like a black promist only affects parts of the image and lets the light through somewhat undisturbed as far as that is possible, and a net, probably even more so as there is no extra glass involved.

 

Also the extra resolution should help with effective colour representation which shouldn't be that affected by diffusion? So perhaps there would even be an advantage with something like a fog filter.

 

HOWEVER I'd love to know if there is an advantage to shooting 4K if you are, for example, shooting through an old coke bottle.

Obviously the coke bottle will affect what can be resolved but will a coke bottle lens resolve more in 4K than it would in 1080p or will it just act something like a bandpass filter and the overall resolution will only be as good as the weakest link in the chain. I suspect the latter but I honestly don't know. Is there an advantage to using ancient superspeeds for their softer look on a 6K or 8K camera or will it be just as good on a 4K camera.

 

How do these aspects interact, can anyone tell me?

 

Freya

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Obviously using diffusion on a 4K camera lowers the resolution effectively. You would use diffusion -- on camera or in post -- for the same reason you traditionally used diffusion, mainly for two reasons: (1) either for a visibly diffused look (halation around bright areas, glowing highlights, dreamlike or romantic quality) or (2) for cosmetic reasons, which generally means that only the closer shots are diffused and generally are not meant to look diffused, you just want some of the fine detail to be diminished because it is unattractive for the actor. It's what I call "visible" versus "invisible" diffusion. And either reason still applies to 4K productions.

 

It's always easier to get rid of detail than to obtain detail that doesn't exist, so if you need to shoot through an old distorted lens for a look on a flashback or dream in a 4K production, then go ahead -- you'll still have scenes that will need more resolution.

 

Now if you are going to shoot everything top to bottom through a soft lens or heavy diffusion, then yes, another choice would be to use a sharper lens and less diffusion on a 2K or 3K camera. The advantage of 4K at that point may be more subtle, like having a bigger file that may handle noise reduction in post if needed, or can be resized in post easier.

 

It's a bit like asking "if I'm going to shoot in 35mm with an old lens and heavy diffusion, shouldn't I just shoot in Super-16 instead with normal lenses and no diffusion?" Well, maybe, maybe not -- old lenses and diffusion filters create unusual optical artifacts that would not occur by just using modern lenses on a lower resolution camera. I know it's not a perfect analogy because the grain size difference between Super-16 and 35mm is a bit more visible than the noise size difference between 2K and 4K (not to mention the depth of field difference between Super-16 and 35mm.)

 

Plus you may have a green screen shot or other element in your "soft" movie that needs to be higher in resolution for the post people, so it helps to be using a camera that can deliver more resolution just by pulling off the diffusion filter rather than being stuck at a lower resolution.

 

I'd think of it this way, 4K may just be the "standard" that everyone works creatively with and around, just like 35mm has been a standard for a century. There was no law generally that you had to shoot 35mm for maximum resolution.

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Thanks for the reply David.

 

My question is more about whether there is any advantage to having the extra resolution all else being equal.

It's not a case of having sharper lenses on a lower resolution format but more like the comparison of shooting through an old coke bottle on both formats. The optical path remains the same on each.

 

For example if you have soft lenses on say a 4K camera then there would be little advantage to making the jump to 6K or 8K?

 

It's more like if I'm going to shoot on 35mm with soft lenses and diffusion, wouldn't I be just as well off shooting on Super16 with the same lenses instead for the most part? If the lens just acts like a bandpass filter then it would make no difference what the resolution of the sensor was because it could only record the information it is given but if it's not working in that way... The fact you suggest sharper lenses would be needed to get similar results in Super16 would imply that the soft lens would resolve more detail in 6K or 8K than it would in say 4K and that is what I am wondering.

 

Freya

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If you put the same soft filter or lens on a 4K versus a 2K camera, you would be starting at different resolution levels and thus ending at same difference in resolution, i.e. the 4K camera would get you more resolution plus the diffusion look, if that's what you want. It's similar to me switching from 500T stock to 200T stock when I wanted to use a ProMist on the lens for a more fantasy look -- the degradation of the image would be compensated somewhat by starting out with a cleaner, sharper stock. It's one reason (among many) why fog and low-con filters dropped in popularity once high-speed stocks hit the market, it was not a good combination.

 

So I'd be less concerned about ending up with too much softness from using an old lens or heavy diffusion if I was starting out with a camera with more resolution.

 

I'm just saying that the resolution of the camera / recording / post / exhibition is one factor among many when picking the right cocktail of filtering and lenses, etc.

 

Even if you end up distributing in 2K, there are some advantages in oversampling information -- just as in digital still photography, you have a bit more flexibility with a camera that shoots 24MP as opposed to 8MP, let's say, as long as there wasn't a trade-off in other areas (due to cramming too many pixels onto a small sensor, for example, and then compressing the heck out of it -- which is why I'm a bit wary of these 1/3"-ish camcorders that offer 4K coming onto the market.)

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  • 2 months later...
Guest Stephen Murphy

If anyone is going to be at NAB this year please pop by the Tiffen booth and check out the new 4K Diffusion filter tests I shot with Carey Duffy and Nick Shaw last year, it's an excellent resource for all of us. Designed with Steven Poster ASC we shot a series of tests comparing every type of Diffusion filter Tiffen make. You can see a sample here:

 

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  • 1 month later...
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Terrific, thanks Stephen. I think I may have fallen head over heels for the 'Black Net 1' - but I can't find that specific filter listed anywhere on Tiffen's site. Is there a different name for it that I'm missing?

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