LOG & Promist/Glimmerglass Filters - Frequently Misused?

[Zack Birlew]

Hi, everybody, I've been looking at test footage for various cameras recently and with almost every one I've seen, they all have some sort of weird bloom and light levels. The main suspected culprits I keep seeing are cases where LOG is used and the use of diffusion filters like Promist and Glimmerglass and it is getting to the point of being garish.

With LOG, I can't help but feel that it is being used incorrectly by many people and is seemingly replacing standard lighting and exposure practices that should be learned and utilized regardless of camera medium. In the case of increasing availability of RAW cameras, I don't see the point of LOG as you can stretch and pull your image in post production and you should already know how much you could push your footage around to the point that under and over exposure shouldn't be a problem. What I'm seeing now is that people are just using LOG for everything and ending up with milky, washed out or blooming images due to using soft wider open apertures when they ideally shouldn't. With the milky aspect of images coming through, that's just looking like incorrect color grading on top of everything and that's possibly the main problem that may be occurring when using LOG is that people may be using corrective LUTs as a crutch without actually "correcting" their LOG footage to begin with.

With diffusion filters, I've seen footage that is just too soft and muddy despite being full 4K, 6K, 8K, or even 12K and when the video cuts back to the Youtuber's studio/room/space, you can see the same blooming highlight softness in the "cinematic" example portion of their videos which makes it seem as if they always have the diffusion filter on no matter what. For someone trying to get an idea for what certain cameras can do, it's not very helpful when everything has a much too strong Promist filter thrown on top and making 4K+ material look like grainy HD.

I'm not saying that there's a problem with LOG or diffusion filters but it's seemingly becoming a widespread problem of overuse and perhaps miseducation for some. Oftentimes these videos are camera tests or "How To Be A Better Filmmaker"-type videos and it makes you wonder if these "experts" and "professionals" have even read an issue of American Cinematographer.

What do you think, am I just seeing stuff wrong or is there a case for toning down LOG and diffusion use? Are modern filmmakers/streamers/videomakers unknowingly misusing their equipment or taking on bad habits? Could it be the increased resolution difference of modern cameras pushing and conflicting with long held cinematic practices? Or could it simply be web video compression dorking up everybody's videos online?

 

[Phil Holland]

Sort of need to see examples, but you can certainly take diffusion too far, but we're also in an era of an occasionally plastic-like look being semi-common. Compression can also be a factor, but not really if you know what you're doing.

 

[Matt W.]

Can you provide an example?

In theory, a linear color space devotes as much data to the topmost stop as it does to everything below. That's fine for distribution but it falls apart quickly if you need to dig into the shadows during post production.

Log dedicates (in theory) equal bits to each stop. So that leaves a lot more room to grade before tonality falls apart in the shadows.

For raw stills, linear is fine, since that's how the camera's ADC outputs data. And generally you have 14 bits or 16 bits in raw correlating with about as many stops of dynamic range.

But ArriRAW and Canon Raw Lite I believe are log and better for it since they're only 12 bit but with a lot of DR. They have a lower data rate as a result but they also need to divide the data up more evenly to maintain tonality so 12 bit works.

Red and Sony raw (RedCode and OCN) I think are 16 bit linear and that's fine too.

That said I think I agree with some of what you've written, I notice that I light a lot better when I'm shooting with a t2i and my best photos are with film stocks that have very narrow DR.

On the other hand, I love vintage lenses. And I notice they render best at more aggressive contrast ratios, with natural high contrast light. Not so great when it's overcast. Whereas Ultra Primes, for instance, seem to like studio lighting.

Hmmm....

 

[Mark K.]

Hi, everybody, I've been looking at test footage for various cameras recently and with almost every one I've seen, they all have some sort of weird bloom and light levels. The main suspected culprits I keep seeing are cases where LOG is used and the use of diffusion filters like Promist and Glimmerglass and it is getting to the point of being garish.

With LOG, I can't help but feel that it is being used incorrectly by many people and is seemingly replacing standard lighting and exposure practices that should be learned and utilized regardless of camera medium. In the case of increasing availability of RAW cameras, I don't see the point of LOG as you can stretch and pull your image in post production and you should already know how much you could push your footage around to the point that under and over exposure shouldn't be a problem. What I'm seeing now is that people are just using LOG for everything and ending up with milky, washed out or blooming images due to using soft wider open apertures when they ideally shouldn't. With the milky aspect of images coming through, that's just looking like incorrect color grading on top of everything and that's possibly the main problem that may be occurring when using LOG is that people may be using corrective LUTs as a crutch without actually "correcting" their LOG footage to begin with.

With diffusion filters, I've seen footage that is just too soft and muddy despite being full 4K, 6K, 8K, or even 12K and when the video cuts back to the Youtuber's studio/room/space, you can see the same blooming highlight softness in the "cinematic" example portion of their videos which makes it seem as if they always have the diffusion filter on no matter what. For someone trying to get an idea for what certain cameras can do, it's not very helpful when everything has a much too strong Promist filter thrown on top and making 4K+ material look like grainy HD.

I'm not saying that there's a problem with LOG or diffusion filters but it's seemingly becoming a widespread problem of overuse and perhaps miseducation for some. Oftentimes these videos are camera tests or "How To Be A Better Filmmaker"-type videos and it makes you wonder if these "experts" and "professionals" have even read an issue of American Cinematographer.

What do you think, am I just seeing stuff wrong or is there a case for toning down LOG and diffusion use? Are modern filmmakers/streamers/videomakers unknowingly misusing their equipment or taking on bad habits? Could it be the increased resolution difference of modern cameras pushing and conflicting with long held cinematic practices? Or could it simply be web video compression dorking up everybody's videos online?

Without any specific examples to respond to - my take is that they're pictures. There's no "right" or "wrong", just personal taste.

Personally I have a really visceral reaction to people taking all this beautiful anamorphic glass, and then shooting everything wide-open with it (where the optics are complete mush). We all have different tastes, and those tastes are what we get hired for.

 

[Zack Birlew]

Without any specific examples to respond to - my take is that they're pictures. There's no "right" or "wrong", just personal taste.

Personally I have a really visceral reaction to people taking all this beautiful anamorphic glass, and then shooting everything wide-open with it (where the optics are complete mush). We all have different tastes, and those tastes are what we get hired for.

Oh my gosh, yes! So many people try to use wide open anamorphic footage all the time these days and, again, if you look at ASC magazine over the years, it’s always F4 as the strict maximum with F5.6 or F8 being the normal aperture rating for mostly everything. It’s as if they don’t realize how all the “classic movies” they reference for their anamorphic examples actually did things to get the “classic anamorphic” look that they think they’re getting simply by using an anamorphic lens. I don’t know if I want to specifically list anybody, don’t want to seem like picking on anyone, but I did recently look at a comparison video between Promist filters and Moment Cinebloom filters and while that obviously shows diffused footage, the filmmaker even states that they always use one or the other for their preference but when you look at it, it’s just too much.

 

[Ignacio Aguilar]

Oh my gosh, yes! So many people try to use wide open anamorphic footage all the time these days and, again, if you look at ASC magazine over the years, it’s always F4 as the strict maximum with F5.6 or F8 being the normal aperture rating for mostly everything. It’s as if they don’t realize how all the “classic movies” they reference for their anamorphic examples actually did things to get the “classic anamorphic” look that they think they’re getting simply by using an anamorphic lens. I don’t know if I want to specifically list anybody, don’t want to seem like picking on anyone, but I did recently look at a comparison video between Promist filters and Moment Cinebloom filters and while that obviously shows diffused footage, the filmmaker even states that they always use one or the other for their preference but when you look at it, it’s just too much.

I agree with you (anamorphic lenses tend to perform better at T4 or T5.6), but don't forget either that classic anamorphic was used together with 35mm 4-Perf film in order to achieve a widescreen look. Over the years it's true that some films used the format and its special optical characteristics (distortion, flares, bokeh, out of focus compression, minimal depth of field) not only to go widescreen, but also to show these anamorphic artifacts ("Alien" or "Die Hard" are often referenced for this). But they were a minority. Some "A List" DPs of the 70 and 80's (Fred Koenekamp, Bill Butler and Vilmos Zsigmond come to mind) even shot most of their anamorphic features on rear converted zoom lenses, which don't have any of the characteristics of the anamorphic prime lenses, and only switched to them when they needed to open the lenses more than a T4 for low-light scenes.

Nowadays, with digital sensors provinding a sharper image, I don't think it's as mandatory to use anamorphics at their optical sweet spot. You can also tweak quite easily some loss of contrast or sharpness if it's not very obvious. You no longer need anamorphics either for 2.40:1 widescreen, as you can crop a digital sensor and the loss of quality (if any) won't be as bad as what happened when you shot Super 35 and put everything through an optical printing before the advent of DIs in the early 2000's. I have shot two feature films in anamorphic at a T3.2 base stop, and tend to like it because stopped down, in my opinion, you tend to lose some of the anamorphic artifacts and "look" that make anamorphic appealing with an Alexa or RED camera. On the other hand, any time I can, I like to shoot close-ups at deeper stops than the rest of the footage, so the talent and the camera can move while everything stays properly focused.

 

[Blair S. Paulsen]

Would be curious to see the uncompressed imagery side by side with the web versions. I agree with Phil that modern compression used properly should not significantly reduce sharpness and contrast. That said, there is a lot of footage - even from well known entities - that has been over compressed into oblivion.

Additionally, it seems like a lot of the new wave of content producers are less intentional in how they manufacture their images. As an example; last night I watched Black Swan with my family and my kid immediately asked why it looked a bit "soft". I explained that Aronofsky and DP Matthew Libatique chose to shoot on 16mm film as one way to show the gritty reality behind the scenes of a ballet company. I think it fits the stark, often dark reality of the dancers lives. Obviously others did as well, with Matthew Libatique nominated for an Oscar.

What I see all too often, is techniques like shallow DoF and anamorphic lensing used to create a patina of high art. Sure is easier than making more compelling content...

Cheers - #19

 

[Aaron Lochert]

Diffusion is the new shallow DoF. Change my mind.

 

[Marc Wielage]

Hi, everybody, I've been looking at test footage for various cameras recently and with almost every one I've seen, they all have some sort of weird bloom and light levels. The main suspected culprits I keep seeing are cases where LOG is used and the use of diffusion filters like Promist and Glimmerglass and it is getting to the point of being garish.

I would have to see what you're talking about. Remember that filmmakers used Promist and GlimmerGlass diffusion filters for many decades with film, and that was inherently a Log medium. Even in those days, we could see immediately in color-correction that diffusion was being used, so we purposely would avoid trying to crush the blacks, since it was inherently a low-contrast scene.

I always say, when in doubt: shoot tests, and shoot charts when possible, and experiment with different things. I usually tell people to go with a 1/8th ProMist or something like that, but I recently did a Red project where they shot the whole thing with a 1/4 ProMist and I thought it all looked fine. Great lighting helped a lot.

BTW, there is value in looking at applying diffusion in post. Video Village's Scatter is an amazing tool and I've been using it more and more when I need to add a bit of glow to an image without losing too much detail:

https://videovillage.co/scatter/

The Glow OFX filter in Resolve has recently been improved in 17.3, and it has some new features that allow interesting effects with a lot more control than you can get on set. The advantage of using digital filters in post is you can selectively set limits on how much diffusion is being introduced depending on the nature of the shot; the advantage with using glass filters in production is you see it instantly, so there's no doubt what the effect will be. But the disadvantages of using filters on the lens is that you're stuck with it forever; but the disadvantages of using the effect in post is it's not quite as real and "organic" as an actual glass filter, plus it takes time to do.

 

[Matt W.]

Diffusion is the new shallow DoF. Change my mind.

Is it new though? The 90s were full of Kaminski-lensed pictures with Classic Softs and Dior nets. Richardson and ProMist.

70s were full of diffusion, too. Even more so. Might be a trend that's getting popular again – but it's been popular before.

*clutches Classic Soft filters*

Also, can anyone provide examples? The last show I worked on that had heavy diffusion was network TV and certainly not "high art." Since I've seen a lot of vintage lenses maybe and even shallow focus but not a lot of diffusion.

 

[Les Hillis]

I think the OP is mainly referencing Youtube 'how to' and gear-review/new camera and lens-test type video's. I've seen more diffusion mentioned and used in those kind of video's than ever before, to the point where some of those same content creators themselves have mentioned it's being overdone.

Seems like the low-con LOG look, diffusion filters, shallow DOF, anamorphic, slow-motion, creative LUTs and gimbal/slider variations are a permanent part of the 'aspiring film-maker' landscape now, coming and going in popularity as new products arrive and get reviewed, or as they're used successfully by the content creators that some people are aspiring to be.

Not seeing the same trends with TV or cinema content, which usually seems to be more focused on using all those same tools to achieve a particular content-related end rather than as a stylistic end in themselves.

The modern digital 'LOG' look reminds me of what used to be seen when shooting expired film or skimping on the colour grade (and usually on the lighting and every other aspect of production too).

Not saying it can't be used creatively to enhance the story, but it often isn't/wasn't.

The increased use of diffusion makes more sense now in a way, now that digital sensors and camera lenses can give a ridiculously sharp and contrasty (and in that way more film-like) image by default.

I don't think diffusion has the same effect now as it did back in the 70's & 80's though, culturally or aesthetically.

The diffused film image and the diffused digital image aren't the same, and neither are the audiences watching them or the creators using them.

Have to say too, talking more generally, if anyone does want to use diffusion, none of the stuff I've seen online will show or tell you as much as what you can find out by doing your own testing and seeing for yourself what you want/need to use.

 

[Matt W.]

I think the OP is mainly referencing Youtube 'how to' and gear-review/new camera and lens-test type video's. I've seen more diffusion mentioned and used in those kind of video's than ever before, to the point where some of those same content creators themselves have mentioned it's being overdone.

Seems like the low-con LOG look, diffusion filters, shallow DOF, anamorphic, slow-motion, creative LUTs and gimbal/slider variations are a permanent part of the 'aspiring film-maker' landscape now, coming and going in popularity as new products arrive and get reviewed, or as they're used successfully by the content creators that some people are aspiring to be.

Not seeing the same trends with TV or cinema content, which usually seems to be more focused on using all those same tools to achieve a particular content-related end rather than as a stylistic end in themselves.

The modern digital 'LOG' look reminds me of what used to be seen when shooting expired film or skimping on the colour grade (and usually on the lighting and every other aspect of production too).

Not saying it can't be used creatively to enhance the story, but it often isn't/wasn't.

The increased use of diffusion makes more sense now in a way, now that digital sensors and camera lenses can give a ridiculously sharp and contrasty (and in that way more film-like) image by default.

I don't think diffusion has the same effect now as it did back in the 70's & 80's though, culturally or aesthetically.

The diffused film image and the diffused digital image aren't the same, and neither are the audiences watching them or the creators using them.

Have to say too, talking more generally, if anyone does want to use diffusion, none of the stuff I've seen online will show or tell you as much as what you can find out by doing your own testing and seeing for yourself what you want/need to use.

That makes sense and to be fair I think on an ad or something you want a more stylized look. So if all you're going for is style it makes sense.

 

[Aaron Lochert]

Is it new though?

I just mean it's the new trendy thing that is being overused. Not that it's new tech or anything.

I think it's a feedback loop of youtubers and youtube viewers that are promoting whatever the new "it" thing is. It was widescreen. It was lifted black levels. It was teal and orange. It was shallow DoF. It was drone shots. It was 4:3. It was high frame rate. It was LUTs. It was gimbals. All can have their place in this artistic medium. But many times they were slapped onto a project without any motivation behind that choice. I mostly see these things pushed to me via Instagram and Facebook and far less abuse/overuse in actual cinema. So it is ironic to see these shooters go too far with their "cinematic" (their word, not mine) choices and surpass what actual cinema is even doing.

I was going to expand more on this but I think Les did a beautiful job explaining exactly what I would have said.