harryprayiv Posted May 16, 2004 Share Posted May 16, 2004 Hi all. I guess I could search this because it sounds like a fairly common subject, but I will just ask this question so it's out there in plain view for people like myself....inquisitive ones that is. Has HD improved video's exposure latitude at all? If so, how exactly has it improved and does it stand up to film? I recently saw 28 Days Later, which I heard was shot on some kind of HD 24p and was impressed with how it didn't blow out like I've seen. What I don't like about video in the way that I currently shoot (DV) is it's inability to handle extreme highlights. I have MANY other image complaints. I was having a discussion with someone about it and was wondering if anyone knew. Thanks in advance. Link to comment Share on other sites More sharing options...
Rachel Oliver Posted May 16, 2004 Share Posted May 16, 2004 I believe 28 Days was shot with many standard def XL1's! But some major post image work was done, I'm not that up with video but I would think a low contrast filter could help alot with blow out. Olly Link to comment Share on other sites More sharing options...
harryprayiv Posted May 16, 2004 Author Share Posted May 16, 2004 Wow...that's crazy that they shot that on XL-1's...granted I didn't see it in the theater and saw it on DVD, but it looked really nice. Thanks for that low contrast filter suggestion. I had no idea that those existed, actually. Anyone know about the latitude of HD, though? I need to know about this necessary evil that I have to deal with for low budget crap. Link to comment Share on other sites More sharing options...
Premium Member David Mullen ASC Posted May 16, 2004 Premium Member Share Posted May 16, 2004 I think HD does have a little more exposure latitude than standard def cameras but it's similar. The newer 4:4:4 HD cameras like the Viper have more exposure latitude. The difference though is that film has more overexposure latitude. Underexposure latitude is similar. This is because of the way film responds to light -- the gamma curve flattens at the high and low end. Video can simulate this but it requires even MORE latitude to work from to be able to compress the extreme ends down to retain more information. Link to comment Share on other sites More sharing options...
harryprayiv Posted May 17, 2004 Author Share Posted May 17, 2004 Thanks David. I was actually expecting you to reply. It must be nice to know so much about this stuff. On another note, I've been doing a lot of looking around and I saw the Kinetta web site. OH MY GOD, that camera looks too good to be true. However, I wonder, what excites you so much about it? Link to comment Share on other sites More sharing options...
Premium Member David Mullen ASC Posted May 17, 2004 Premium Member Share Posted May 17, 2004 I like the open-ended design that allows it to be upgraded over time. You don't have to worry about it being obsolete two years after you buy it. Link to comment Share on other sites More sharing options...
Premium Member Michael Nash Posted May 19, 2004 Premium Member Share Posted May 19, 2004 Most professional video cameras handle highlights better than consumer cameras. Digibeta and HD cameras like the Cinealta will always give you better chips and processing than a $600 consumer camera. Higher resolution (more pixels) and better signal processing allows you to recover detail in hot areas that cheaper cameras would simply blur into a white blob. But it's still not the same as film. As David mentioned the shadow response of video is actually pretty darn good and much like film, but the highlights clip like crazy. I figure about 1-1/2 stops of overexposure is all you really get (on average). The knee function will compress color info that's even hotter down into a recordable range, but it's essentially without detail and still looks blown out. I really wouldn't recommend low contrast filters for the purpose of increasing video exposure latitude. They can take some of the harshness off a high-contrast scene or be used create an interesting look in their own right. But they really don't change your ability keep highlights in check. Instead I'll adjust the camera's knee, black stretch and gamma while exposing for the highlights. But even that has to be done judiciously or else you flatten the gamma curve too much. The best control remains with the lighting. I carry an ND.3 grad in my kit for video shoots, which comes in handy for day exteriors where part of the frame is in full sun and part in the shade. Link to comment Share on other sites More sharing options...
Premium Member John Pytlak RIP Posted May 19, 2004 Premium Member Share Posted May 19, 2004 Color negative film has tremendous highlight latitude. Kodak image scientist Roger Morton has published several recent SMPTE papers comparing film and digital image qualities, including latitude. Link to comment Share on other sites More sharing options...
harryprayiv Posted May 19, 2004 Author Share Posted May 19, 2004 Is there any way that people have ever used for making a grad for a speciic shot that only affects the part of the image that is in highlight? What I am referring to is the possibility of somehow "painting" ND over specific areas of the frame to control their levels. I understand that this might somehow be less accurate than is really possible on set, but could you say, for example, get some ND gels and cutting them to specific sizes and then somehow adhere them to a clear filter in the matte box? Has anyone ever done this? What kinds of materials do yall think are needed for such an invention? I always get way in over my head in these weird inventions I crave! I just wish I had all of the tools to create my dreams. Link to comment Share on other sites More sharing options...
DanStewart Posted May 19, 2004 Share Posted May 19, 2004 If it's a locked off shot consider using a couple of exposures and compositing them in post. This won't work on moving shots or subjects but then niether will cutting out shapes in gel. Link to comment Share on other sites More sharing options...
harryprayiv Posted May 19, 2004 Author Share Posted May 19, 2004 well, if I had access to motion control, moving shots might even be feasible, but I DEFINITELY don't. Also, from what I hear, traveling mattes/garbage mattes don't generally work too well in practice. My friend does compositing in Flame, Smoke, and combustion and he says that even the motion controlled stuff is not perfect for this because of the various subject's changing the light around the area of the shot. Thanks for the suggestion too. Has anyone ever even tried something like this? or heard of the paintable ND I theorized on? Link to comment Share on other sites More sharing options...
harryprayiv Posted May 19, 2004 Author Share Posted May 19, 2004 well, if I had access to motion control, moving shots might even be feasible, but I DEFINITELY don't. Also, from what I hear, traveling mattes/garbage mattes don't generally work too well in practice. My friend does compositing in Flame, Smoke, and combustion and he says that even the motion controlled stuff is not perfect for this because of the various subject's changing the light around the area of the shot. Thanks for the suggestion too. Has anyone ever even tried something like this? or heard of the paintable ND I theorized on? Link to comment Share on other sites More sharing options...
Mitch Gross Posted May 19, 2004 Share Posted May 19, 2004 Has anyone ever even tried something like this? or heard of the paintable ND I theorized on? Yes. John Seale did this for many shots in "Rain Man" and other films. The problem is that the shot must be locked out or very limited in movement, the lens fairly wide angle and the filters VERY large. He would do things like cut out the "V" shape of the roadway going through the desert to the horizon line by placing some ND gel onto an optical flat in the mattebox and using the videotap as a guide for where to cut. This way he could keep the desert sand from blowing out while still keeping detail in the black roadway. I believe he talked about it in American Cinematographer at the time or ICG. I've also done this with diffusion. I'll take an optical flat, cover part of it with a piece of paper, spray some areosol hair spray into the air and wave the filter through it gently. Remove the paper and I have a selective diffusion filter. This takes a lot of practice & time and puts severe limitations on shots and camera movement. But the results can be quite effective. Link to comment Share on other sites More sharing options...
harryprayiv Posted May 20, 2004 Author Share Posted May 20, 2004 Wow. I am really happy to read this. I am definitely going to try this when I get the proper tools to do it. I like it when I think I've come up with something and someone else has already done it! Link to comment Share on other sites More sharing options...
Premium Member Michael Nash Posted May 20, 2004 Premium Member Share Posted May 20, 2004 If you've really got the $$, filter companies will make custom grads for you in any shape you like. Obviously this takes a bit of lead time. For more impromptu filter manufacturing, I've held a small piece of ND gel against the lens and tried to disguise the hard edge against a natural line in the background. As mentioned you could cut this to any shape you want, in the field. Sometimes you can use 2 ND grads to create a more compound shape. I've often felt it would be advantageous to have grads that have a curved edge instead of straight, allowing you to "window" objects in the frame more selectively. Maybe a set of four filters; a large and small convex curve and a large and small concave curve. Maybe large and small center-spot filters; one set positive and one set negative to selectively dodge or burn part of the frame (these filters would have to be large to allow for a larger area of positioning). Link to comment Share on other sites More sharing options...
Premium Member Phil Rhodes Posted May 20, 2004 Premium Member Share Posted May 20, 2004 Hi, How about an LCD filter? It wouldn't have to be that out of focus to hide the pixels. It'd inevitably cost you at least a stop and a bit, or about two stops if you wanted colour, but you'd have a grad of infinite flexibility. Paint your grads in Photoshop! Excuse me, I'm just off down the patent office.... Phil Link to comment Share on other sites More sharing options...
Premium Member Luke Prendergast Posted May 20, 2004 Premium Member Share Posted May 20, 2004 Thought of this ages ago, but didn't bother because of the polarising issues, darn it. Would be very cool. Link to comment Share on other sites More sharing options...
harryprayiv Posted May 21, 2004 Author Share Posted May 21, 2004 Yeah, Phil that's a really good suggestion. How would I find an LCD filter that lets light through unaffected in some areas and stops stops it down in others? Do they sell these? Anyway, thanks for all of these suggestions. I am loving the way that cinematography makes the wheels in my mind spin.... and I've only been doing film for like a year or two. Thanks for all of this, again, everyone. I love this forum! Link to comment Share on other sites More sharing options...
Premium Member John Pytlak RIP Posted May 21, 2004 Premium Member Share Posted May 21, 2004 Just announced yesterday, Kodak may have the answer for your variable filter! :D http://www.kodak.com/US/en/corp/pressRelea...040519-31.shtml Link to comment Share on other sites More sharing options...
Mitch Gross Posted May 21, 2004 Share Posted May 21, 2004 Fascinating. I'm especially interested in the fact that polas are not involved so off-angle viewing is greatly improved. I'd be interested to know the relative brightness and if daylight viewing is feasible. Would the NITS measurement be germane to this technology? Link to comment Share on other sites More sharing options...
harryprayiv Posted May 21, 2004 Author Share Posted May 21, 2004 Did they say anywhere whether the screen could be made translucent? I am under the impression that there would be at least a small amount of distortion of an image when you are attempting to get the image to pass through it. Maybe I missed something though. My initial idea came from learning about a new camoflauge (sp?) At MIT, the government is funding the development of chameleon-lke camoflauge with for a soldier's clothing that actually records color information from the surrounding area and then mimics it on the surface of the material. Link to comment Share on other sites More sharing options...
Premium Member Phil Rhodes Posted May 22, 2004 Premium Member Share Posted May 22, 2004 Hi, Seems to me that this Kodak technology describes a display which would be transreflective only, that is, require external light to be visible. Therefore it wouldn't inherently have a NITS rating, but it could probably score better than an equivalent LCD if it was translucent enough to backlight since it wouldn't have the 3:1 losses in the colour filters and then the 50% loss in the polariser. Phil Link to comment Share on other sites More sharing options...
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