HDRx Tip

[Christoffer Glans]

I've been trying to figure out a way to get HDRx to work better for narrative work, removing the artifacts (sharp edges during movements) that so often screw up those kinds of shots. I was thinking about why they occur and it's obviously because of a frame in between the "actual" frame of the A-track. There are some strategies in removing those sharp "ghosts", but most of them has to do with smoothing out the X-track with motion blur without really removing the "ghost", it just becomes a blurry "ghost".

So I did a test where I've shot at 50 fps instead in order to decrease the distance between these two tracks exposure, making them blend a little more close to each other in the time between two frames. Now there are different ways to do this, either you shoot as is at a relative 180 shutter and apply motion blur to the final HDRx image in post or you can try and expose at a 360 degree shutter, but I think I've found the best way to blend the two tracks without any noticable artifacts showing. It takes a bit of work in post, blending the tracks, speeding up the track 200% and applying motion blur at 180 degress, but the end result is the best I've seen of it. Maybe this can help some shoot HDRx without the fear of those ghostly artifacts.

Password: HDR

5K 2:1
Shot at 50 fps variable frame rate.
T2.0
ISO 800
180 degree shutter
HDRx at 6 stops difference
Applied 200% speed in post with pixel motion blur

(windows are completely blown out in regular footage)

I imagine that shooting at even higher frame rates would make the final result even better, but there's both exposure and resolution to take into account when doing it. For narrative 24 or 25 fps work I think 50 fps is a sweet spot to make it look good (of course 48 fps for 24 fps).


EDIT: here's some recent footage

So I've finally gone out and shoot some better test footage. Now, this is filmed very "hand held" in order to show off the lack of motion artifacts. I'm gonna do some more shooting with this technique in a more traditional way when I have the time. But for now, enjoy the 50 to 25fps HDRx way of shooting 25 stops of DR

 

[Joey Balmforth]

Good tip. I'll have to try this out. Did you do all the tweaking in RCX?

 

[Christoffer Glans]

Good tip. I'll have to try this out. Did you do all the tweaking in RCX?

Nope, you can't add pixel motion blur there. For this I used Resolve to combine the tracks and AE for the pixel motion blur.

 

[Marc Wielage]

I still say it's possible to not use HDRx and still get good results if you expose for the highlights and fill for the blacks. We did this for decades with film and it worked fine. It just takes lighting skill and time.

 

[Christoffer Glans]

I still say it's possible to not use HDRx and still get good results if you expose for the highlights and fill for the blacks. We did this for decades with film and it worked fine. It just takes lighting skill and time.

Yes of course, but that doesn't mean you can't use these new tools. Especially for situations when you don't have fill lights, or not enough to get a decent exposure -maybe a larger interior location or to be able to get reading on a sunny sky without everything else being silhouettes (even if you have fill lights it might look too lit in such a situation.

I'm not saying this should be used for every shot on an entire film, it's a tool that as everything else with cinematography and filmmaking should be tested, tried etc. Just because something has been done for decades doesn't mean it should always be done that way, isn't that a bit of a narrow minded viewpoint overall? Using HDRx and getting a decent look with it might even get you a kind of look you won't get with just fill lights.

Experiment, master and know the tools at your disposal, that should be everyones mentality, otherwise what's the point with buying a camera that has all these possibilities? If all people do is shooting ISO800 180 degrees 24 fps at 3200K or 5600K and not doing anything else with the tools in the camera, that's kinda missing out on a lot of possibilities.

 

[Craig Parkes]

Have you tried ReVision's Reel Smart motion blur on the X track before comping? http://revisionfx.com/products/rsmb/

Or even on the finished footage. It's worked wonders on footage that we shot at 50 fps, but with a 1/500th shutter, that we were then doing twixtor to create super slow mo with but then ramped to real speed.

Imagine the same principle could apply here.

 

[Christoffer Glans]

Have you tried ReVision's Reel Smart motion blur on the X track before comping? http://revisionfx.com/products/rsmb/

Or even on the finished footage. It's worked wonders on footage that we shot at 50 fps, but with a 1/500th shutter, that we were then doing twixtor to create super slow mo with but then ramped to real speed.

Imagine the same principle could apply here.

Trick here is that the 50 fps is pushing together the different tracks closer in time, which makes the "ghosting" less apparent. In doing so, the shutter gets sharper and you need motion blur on both the A and X-track. I've not yet tried the reel smart motion blur, but it would be interesting to hear how much better it is compared to After Effects pixel motion blur or the Resolve motion blur.

 

[Christoffer Glans]

Here's another video of this way of shooting HDR. The room was pretty dark compared to the outside. HDRx is set to 6 stops with no visible ghosting.
The "hand camera" shakes are deliberate in order to get as much movement as possible. :tongue_smilie:

Password: HDR

 

[Dustin Hoye]

"HDRx at 6 stops difference"

Nice to see where 6 stops can come into play. 2-3 stops have been the trend in our shots, when comparing to non-HDRx shots.

"Applied 200% speed in post with pixel motion blur"

Very inventive. I like the reverse engineering of timing you did here to the project base. Thanks for sharing!

 

[Marc Wielage]

Here's another video of this way of shooting HDR. The room was pretty dark compared to the outside. HDRx is set to 6 stops with no visible ghosting.

I think the guy needs more fill on his face, but that's me. I don't see anything in this shot that you couldn't get conventionally.

I don't dispute that the "6 stops of difference" people talk about occurs at different ends of the spectrum. If you need mainly highlights at the expense of lowlights, or need lowlights at the expense of highlights, it can get problematic.

I have pulled highlight keys and dropped in HDRx material in shots before, but again the motion can be a problem. In the white room / black actor / hot windows example you use, my two lighting suggestions would be 1) add more fill light [even from a bounce board], and 2) ND gel the windows. If the latter is not possible, then just expose reasonably for the highlights and it should fall into place with modern cameras.

I have had projects where (without the DP in the room) I've struggled to keep some detail in the highlights while still having solid blacks and good contrast. What often happens is the director and DP come in at the end and say, "oh, we never wanted to see that stuff. Let the windows blow out -- we don't ever want to see the outside world." So sometimes, this becomes a creative issue more than a technical issue. And it's their decision (and always easy to let the windows blow if that's what they want).

 

[Christoffer Glans]

I think the guy needs more fill on his face, but that's me. I don't see anything in this shot that you couldn't get conventionally.

I don't dispute that the "6 stops of difference" people talk about occurs at different ends of the spectrum. If you need mainly highlights at the expense of lowlights, or need lowlights at the expense of highlights, it can get problematic.

I have pulled highlight keys and dropped in HDRx material in shots before, but again the motion can be a problem. In the white room / black actor / hot windows example you use, my two lighting suggestions would be 1) add more fill light [even from a bounce board], and 2) ND gel the windows. If the latter is not possible, then just expose reasonably for the highlights and it should fall into place with modern cameras.

I have had projects where (without the DP in the room) I've struggled to keep some detail in the highlights while still having solid blacks and good contrast. What often happens is the director and DP come in at the end and say, "oh, we never wanted to see that stuff. Let the windows blow out -- we don't ever want to see the outside world." So sometimes, this becomes a creative issue more than a technical issue. And it's their decision (and always easy to let the windows blow if that's what they want).

I put on a small curve, but everything in the shot is within range and without any noise gain if you want to get more coverage on him and the room. I would also say that if we were to watch such a clip with a HDR grade (as in HDR screens), it would probably look better. Thing here though, the key to what I think is good about this is that I shot this within 10 seconds. For anything where you absolutely need to get a shot and you don't have time to put up gels or light and just want everything in range and as a key light as well, doing this enables that.

A good example of a production that used a lot of these kind of shots is the Breaking Bad spinoff Better Call Saul. While they definitely used traditional lighting techniques, it would be possible to shoot those scenes with HDRx in this way and get coverage without anything other than natural light as the primary key for the rooms, actors and outside.

Of course there are films and productions where it's part of the look to burn out the windows, but then there are the others that don't want that. This technique can also be used to keep very hot highlights in situations with extreme sun or reflections.

But as said, I'm gonna make some better tests as soon as I receive my battery mount.

 

[DJ Kast]

This is extremely useful info, thanks for posting! One question I have is when combining A and X track it seems to just be increasing/decreasing opacity of the x track. Is there a more intelligent way to combine so you have more control IE: Camera Raw data. It would be useful to be able to grab highlights and bring them down without needing a power window in Resolve. The example of the hand in front of the window; did you just combine the two tracks in Red Cine-x and then increase footage speed/add blur? Is there more going on here? Thanks!

 

[Christoffer Glans]

This is extremely useful info, thanks for posting! One question I have is when combining A and X track it seems to just be increasing/decreasing opacity of the x track. Is there a more intelligent way to combine so you have more control IE: Camera Raw data. It would be useful to be able to grab highlights and bring them down without needing a power window in Resolve. The example of the hand in front of the window; did you just combine the two tracks in Red Cine-x and then increase footage speed/add blur? Is there more going on here? Thanks!

In this case it's just a normal blend of the HDRx within the normal R3D RAW settings, it's not even "magic motion", just the normal blend option, in order to reach as high DR as possible. But if you want more control, you can in Resolve, for example, divide the two tracks into two sources and mix them with a layer node. But I haven't tried it in Resolve yet so I'm not sure how the 50 to 25fps convert applies. However, it would be much faster to apply motion blur using Resolve than say After Effects that I used in this test.

Good luck

 

[Brendan H. Banks]

Yeah man, really incredible work here! Such great tests and things to think about when approaching HDRx. Seen tons of tutorials on how to use it for landscape, but these scenarios are exactly the ones I feel I'm up against a lot while working. Going to have to play around a bit on my own with some of this.

 

[Lee Kelly]

HDRx is an interesting one. When i have used it I found it a little too 'real' which actually became un-real. Also maybe its just me but I found the motion blur in your second video to be a bit distracting. I wonder how the non blurred footage actually looks and if that is a bit too staccato in comparison?
Still awesome that you shared your ideas and I agree that there are many situations where you might lose your day waiting to gel windows or carry enough light into your set and this is a pretty decent get out of jail, as long as you explain it to your producer and director with confidence that itll be good and their grader is all over the idea too.
Ha! often the post houses complain enough as it is about Red footage that giving them more work to do is not going to help that cause!

 

[Christoffer Glans]

HDRx is an interesting one. When i have used it I found it a little too 'real' which actually became un-real. Also maybe its just me but I found the motion blur in your second video to be a bit distracting. I wonder how the non blurred footage actually looks and if that is a bit too staccato in comparison?
Still awesome that you shared your ideas and I agree that there are many situations where you might lose your day waiting to gel windows or carry enough light into your set and this is a pretty decent get out of jail, as long as you explain it to your producer and director with confidence that itll be good and their grader is all over the idea too.
Ha! often the post houses complain enough as it is about Red footage that giving them more work to do is not going to help that cause!

Yeah, it's a bit of a process to do all of this, but I think that if you plan the shots even at location scouting and if you get together a strategy for how to deal with 50fps HDRx images in post and how to mark them as this so that they won't get mixed up with regular footage it's not more complex than handling VFX material. But as said, I've yet to try out doing it all within Resolve, with the GPU motion blur it might not be any bigger ordeal than regular footage if the computer is powerful enough.

As for the test footage, the motion blur is set at 180 degrees within AE. I'm not sure if Adobe made it perfectly accurate with real world 180 degree shutter, but it should look the same if shot normally at that degree. The original material looks like Saving Private Ryan so it would be quite distracting to watch if it intercuts with normal material.

I think this should be looked upon as giving you additional DR to work with. My test footage is just showing the DR capabilities, but you'd need an HDR screen and work on layers of different grades at different luma value intervalls in order to create "a look" that feels like a normal grade but with more DR. But for regular use, I can still see blown out highlights in episodic and feature work and this will erase that entirely, giving you the ability to do a really super soft highlight rolloff that no camera can really do, not even 35mm.

 

[Lee Kelly]

I love that Saving Private Ryan is the term used for that overcranked shutter, almost as a rule as what not to do, however that film, if you watch it again will still blow your mind. Its not even that horrible to watch, as many might lead you to believe and was praised at the time for this effect. I guess that is what it was, a stylised effect but it sure did work well in that film and i think we all get quite caught up in avoiding that at all cost. I kind of feel that fast motion can be almost as distracting when its too blurred (180deg) as it might be when its too sharp. Its the jumping between that might stick out like dogs balls but I wonder if you presented an edit with a 90deg or 45deg shutter if it would really stick out as ugly? Maybe with older character lenses to take some more edge off it, the sharp video feel, it might disguise a little better, i dont know.

 

[Christoffer Glans]

I love that Saving Private Ryan is the term used for that overcranked shutter, almost as a rule as what not to do, however that film, if you watch it again will still blow your mind. Its not even that horrible to watch, as many might lead you to believe and was praised at the time for this effect. I guess that is what it was, a stylised effect but it sure did work well in that film and i think we all get quite caught up in avoiding that at all cost. I kind of feel that fast motion can be almost as distracting when its too blurred (180deg) as it might be when its too sharp. Its the jumping between that might stick out like dogs balls but I wonder if you presented an edit with a 90deg or 45deg shutter if it would really stick out as ugly? Maybe with older character lenses to take some more edge off it, the sharp video feel, it might disguise a little better, i dont know.

180 degrees is the norm of filmmaking, almost every film and episodic narrative work uses it so I'm not sure it's distracting. Saving Private Ryan had it's style from a feel of documentary footage combined with the sharpness of each image enhancing details and dirt more. The reason it worked was because of the material and story so I wouldn't use it for things that doesn't justify it's presence. However I usually shoot a bit lower than 180 degrees in order for the image to get a bit sharper, just as you mention, it can get a bit blurry some times. Mostly it's a decision that comes down to how much light you have and what type of light, but I seem to end up around 140-150 degrees instead of 180. But if you're doing low light work, like the dinner scene in House of Cards season 3, which were lit by practicals entirely, you'd probably need to go up over 180 degrees. As long as it's just a conversation scene it's working without being distracting, same goes for high shutter work. The problem with HDRx however has always been motion, which shooting at 50fps and converting will fix, so you could use the footage at high shutter, but the motion blur hides the blended tracks better.

 

[Marc Wielage]

Its the jumping between that might stick out like dogs balls but I wonder if you presented an edit with a 90deg or 45deg shutter if it would really stick out as ugly? Maybe with older character lenses to take some more edge off it, the sharp video feel, it might disguise a little better, i dont know.

No, the lenses won't make a difference, but you can introduce artificial motion blur if you really had to. But I think you should only go with a 45° shutter in cases where you've shot tests and are committed to going with that look. Don't shoot that look and then say, "ooooo, we've gone too far!" It's become a cliche in many TV shows and films when they go to action sequences... to the point where when I see the high-speed shutter kick in, I immediately say, "ah, here comes the fight scene!"

But if you're doing low light work, like the dinner scene in House of Cards season 3, which were lit by practicals entirely, you'd probably need to go up over 180 degrees.

I think the problem with shooting that slow is you wind up with a weird "electronic" look that starts to look way, way too much like video. I get that if you're out of light and there's no other way, it's one of the few remaining compromises you can go with. But I don't like that look.

I have to say, though, I was blown away by the 5000 ISO look of the Panasonic Varicam LT at NAB. That was an amazing-looking camera, especially for under $20,000. And they assured us that what we were watching (in 4K) had zero noise reduction, which blew my little mind.

 

[Christoffer Glans]

So I've finally gone out and shoot some better test footage. Now, this is filmed very "hand held" in order to show off the lack of motion artifacts. I'm gonna do some more shooting with this technique in a more traditional way when I have the time. But for now, enjoy the 50 to 25fps HDRx way of shooting 25 stops of DR