You Didn't Believe Me
Thursday, December 3, 2009 at 1:05AM 
10 frames of a 7D resolution chart, shown here cropped 1:1, courtesy of Paul Lundahl of eMotion Studios (click the image to visit)
This article over at DVXuser caused quite a stir. Which is strange to me, because I’ve been telling you about this problem for a while now. Apparently a detailed, well-researched article with great visuals and clear explanations is more convincing than pithy quips and offhanded remarks. I’ll have to remember that.
The article by Barry Green is about the oft-reported “aliasing” artifacts in video from the Canon HDSLRs (5D Mark II, 7D, 1D Mark IV). Barry does a great job of backing up a few steps and defining the term aliasing.
Aliasing occurs when you observe, or sample, something infrequently enough that you create an impression of something that wasn’t there. Imagine a blinking light in a room with a door. You must open the door to check the status of the light. If you open the door often enough, you get a pretty good picture of the status of the light, maybe something like on, on on, off off off, on on on, etc. Your samples are frequent enough to accurately represent the light’s activity.
But imagine that you just happen to relax your light-checking to a frequency at which you see nothing but on. The light flashes once per second and you check on it once per second. As far as you know, the light is always on. Your infrequent samples give you a completely bogus picture of what the light is doing.
That’s temporal aliasing, because the insufficient sampling takes place over time. The classic cinematic example of this is the wagon wheel that seems to spin in reverse. Aliasing can also happen in spatial samples. For example, if you looked through venetian blinds at a zebra standing on his head, your partial sampling might reveal a white horse, or a black horse, depending on how the stripes lined up with the blinds.
So what does this have to do with Canon HDSLRs? The same thing it has to do with every digital camera. Every camera that uses photosites to create pixels has to deal with this venetian blind problem. There’s space between those photosites, and in that space you can miss out on important information about what was happening in front of the lens.
This is nothing new. We’ve long known that we shouldn’t wear detailed patterns or fine horizontal stripes when appearing on video. This despite the camera manufacturers’ inclusion of an Optical Low Pass Filter (OLPF), a very fancy term for a simple layer of diffusion atop the sensor designed to scatter the light a bit, so that the zebra stripe that might have slipped through the cracks will actually be spread to the pixels on either side of said crack. OLPFs work, but if they work too well the camera gets dinged by pixel-peepers as being too soft, so every camera company makes a judgment call about how much sharpness they’re willing to give up for less sizzling when a zebra does a headstand in a field of blowing grass.
The current crop of HDSLRs cheat in a big way to make video. Their sensors are not designed to blast an entire, full-resolution image out every 30th of a second. So Canon’s engineers (and Nikon’s and even Panasonics to some degree according to Barry) did what stills camera makers have always done with the “good enough” video modes on point-and-shoot cameras; they grab something less than every photosite. They look at the blinking light less often, and as a result they can pull off a whole picture at a rate speedy enough to make video.
But this picture is full of holes. And while the OLPF was designed to spread light between adjacent pixels, we’ve now dropped entire rows of pixels, so suddenly it’s insufficient by a huge margin.
What’s great about Barry’s article is that he shows you how this problem manifests itself on test charts (you know how I feel about those) and in practical use. But what’s even more shocking is that he reveals the actual resolution of these cameras. Thanks to the aliasing, it’s shockingly low. Yet the images appear crisp — and that’s Barry’s most artfully elucidated point: It’s precisely this infernal aliasing that makes the images seem sharp. If you fitted a 7D with an aggressive enough OLPF, the aliasing would disappear — along with any illusion that the 7D is a “full HD” video camera.
Some aliasing makes zebras appear stripeless. Some makes wagon wheels seem to spin in reverse. And some makes low-resolution images appear sharper than they really are.
So every HDSLR user needs to be aware of this and make a decision: Is that OK? Is the “fake detail,” as Barry repeatedly calls it, good enough for you?
For many, the answer is yes. As I have pointed out, the sex appeal of filmic DOF often wins out over technical shortcomings in shooters’ hearts, if not their minds.
Still, I have tried to warn you. I tweeted not long before Barry’s article that anyone pointing a 5D or 7D at a resolution chart is in for a nasty surprise. I also made mention of the Canon SLR’s low resolution in this post, which confused commenters, who responded that 1920x1080 was plenty. Of course it would be, but I was referring to the actual resolving power of the poorly-sampled images, which is much, much lower, as Barry empirically shows.
I even blogged this, over a year ago:
Let’s get something straight. The video from the Nikon D90 and the Canon 5D MkII is not of good quality. It’s over compressed, over-processed, over-sharpened, and lacks professional control. It skews and shears and shuts off in the middle of a take. It sucks.
I was really trying to warn you guys about this.
But you didn’t listen. It took Barry’s awesome article to drive the point home. Maybe it was his facts and figures. Maybe it was his patient explanations. Or maybe it was because he did not end his article with anything like what I usually say after decrying the downsides of these cameras. Stuff like:
What the D90 and 5D2 have done is show us that it’s no longer OK for video camera manufacturers, whether they be Sony or Canon or RED, to make a video camera that doesn’t excite us emotionally. Buttons and features and resolution charts just had their ass handed to them by sex appeal.
That Barry didn’t wrap up with something gushy like that led many readers to accuse him of anti HDSLR-bias, but I think those people are wrong. Barry is a 7D owner, and challenged one aspiring HDSLR-hater with this comment:
I’ve shot some (what I consider) really, really good looking stuff on a 7D. It’s capable of great results. And I’ve shot some trash on it too, and found it very frustrating for anything wide/deep focus. But it’s $1700! You’ve got to cut it a lot of slack for that!
All I’m doing is pointing out exactly how these things work. It’s up to you to decide whether your scenarios would work within their limitations. If you’re shooting faces, they can excel. The more that you can keep out of focus, the better they’ll do. The more that’s in sharp focus, the more potential for negative complications from aliasing.
They are not a magic bullet. They are not Red-killers. They’re not sharper than conventional video cameras. Keep that all in perspective, and use them for what they’re good for, and they can do astonishingly good things at an unprecedented low price point.
Nicely said Barry. All around.
For my part, I’ve focused on the positive aspects of the 5D Mark II and the 7D because I like where they are pushing things. But I do owe it to you guys to show you that I take this aliasing problem seriously. You need to understand it well to evaluate whether an HDSLR is right for you. And I would hate to give Canon the impression that we’re content with looking at the world through venetian blinds.
Reader Comments (61)
I read all of the aliasing articles. Very compelling stuff. Got me a little worried about the future of HDSLRs, but I guess it's not good to dwell on these things. I have faith that the community will push Canon to tackle these issues in the future.
For now, I'm using a 7D and don't think I've ever been this inspired to shoot video in my entire life, period.
Thanks for presenting this 7D information clearly. Alas, I'm keeping the Canon 7D as it's a sub-$2000 camera that allows you to swap pro lenses for the first time... ever. Glass is as important as body. The overheating is another drawback, making the 7D a horrible events camera. But if you're looking at it from a filmmaking angle, that you can swap lenses, and rent lenses at awesome weekly rates, that's worth $2,000. Lens selection was not a realistic creative choice for under $2,000 (you almost spent that much on adapters alone) ... (Edit this out if you want): If folks are on the fence with the 7D, rent it. Places like TheLensDepot.com rent for under $150/week+ shipping. Don't shoot charts, shoot people and your environment and review the footage on a HDTV. If it looks good enough, it's good enough. (HDV was good enough, but difficult as there is a bias against it as fake HD. Folks accept the 7D as "real hd." Use perception to your advantage.) The human eye forgives so much. The human ear? Less so. Our ears can detect crappy audio, and crappy dialogue, and crappy performances. HD can't correct that. It's up to you.
If, while filming with your HDSLR, you happen to stumble upon a resolution chart (or tiled roof / herd of zebras) in your shot, make sure it's out of focus. :)
I remember talking to Graeme privately when the 5D2 first came out. He tried to warn me about the sampling and aliasing on the 5D2.
I didn't listen, and headed out into the wilds with my new camera. A month later, I came crawling back with my tail between my legs. A bunch of important and hard-to-get sunset shots (mostly with high-frequency waves in lakes and sea water) were totally ruined by aliasing. That's when I started to care about zone plates and charts.
I am definitely of the sentiment that it's the artist not the brush.
That being said: the artist needs to know a lot about their brush. Great post!
I used my 7D as a b-cam a few weeks ago for a promo shoot in a nice home for a singer/songwriter duo (who I also play bass for) and on some of the wider shots with venetian blinds in the background, the aliasing was pretty bad. Fortunately for the main wide shot (and proper audio) I used my HVX200. I kept the 7D tight on the talent most of the time, and did fun rack focus stuff, so it mostly turned out great for insert shots, which was my intention the whole time.
The 7D definitely has its limitations, but I'm still thrilled with my purchase, and will have it paid for as soon as a couple clients send the damn checks... I'm very happy to have another tool up my sleeve for my video work, and thrilled to have such a great still camera for my photography play...
Gee, I used to see that same effect (to my eyes) on my Betacam and later on the HVX200, so I strayed away from patterns and contrasty lines, yet I shot great video. MHO is that if I start deciphering the meaning of life on earth, I may go crazy.
Someone should start a new standard test chart that features nude male or female versions, something more interesting to look at and discern.
I'm guessing this problem is probably worse on HDSLR's but I think it is an inherent problem with all cmos chip cameras. Last year I was shooting a work out video with the Sony EX3 and the talent was doing jumping jacks. We completely lost his fore arms and hands. Fortunately I had a monitor on set because in the view finder it looked like it could just be because of the resolution of the view finder. That was a bit of an unnerving moment for me. I was able to get an acceptable shot but adjusting to a faster shutter speed.
I think it's sad that people are getting so hung up on the aliasing factor or the 'jell-o' factor with the 7D. The 7D has the ability to produce some amazing images.
Before I purchased my 7D, I was using my XH-A1. I still have the A1 and I still plan to use it. The 7D doesn't hold up very well in situations with deep focus, but you know what does the job nicely? The XH-A1. The 7D 'jell-o's' around when I pan quickly, but you know what doesn't? The XH-A1. The 7D has no XLR inputs, lacks zebra stripes, doesn't have auto focus while recording, and isn't easy to use for handheld. You know what does? The XH-A1.
Now I don't want this to sound like the XH-A1 is my preferred camera. The XH-A1 is not great in lowlight, it doesn't have the option to shoo 60fps for better slow motion, and it is difficult to get a nice shallow DOF shot from it. But you know what take care of all of that? My new Canon 7D.
People need to stop viewing these cameras as 'the thing you use' and more like tools for specific jobs. Everyone would call you crazy if you undertook a small job that involved nails and screws and you were trying to make the decision between a nice hammer or a nice screwdriver. Will cameras like the RED One take care of a lot of the shots that I need both the XH-A1 and the 7D for? Sure, but I save a lot of money by owning two cameras than getting one really nice one. And you know what else? Now I have two cameras to set up multi angle shots.
Both of my cameras have downsides, but together they are a force to be reckoned with. It's a great time to be a filmmaker.
P-Worm
Oh, boy. Another log on the fire. These cameras are either the greatest thing ever or deeply flawed. My sister, my daughter, my sister, my daughter. It bears repeating: these are, first and foremost, stills cameras. They excel at that capability (gnashing of teeth on DPReview notwithstanding). They also deliver HD video, but strictly as an afterthought. Can talented people make cool shit with them? I think Nocture demonstrates that they can. Is Panavision cutting their wrists? Probably not.
In the end, these cameras prove the Chase Jarvis adage that the best camera is the one you have with you. If you get footage of an Airbus ditching in the Hudson River, no one's going to be pixel peeping it (well, some will, but that's besides the point). These cameras are two mints in one, and pretty damn tasty mints at that.
Damn, there goes my idea for "Test Chart - The Movie" shot on the 7D. ;-)
It's good to know the limits of any piece of gear one uses. I've yet to run into a situation that has shown a lot of aliasing, but I'm sure it's just a matter of time before I do. For MOST situations the bang vs buck of VDSLRs can't be matched. I don't regret my purchase for a second, especially when I see it can often hold its own against the Red: http://www.vimeo.com/7563238
This is the very first thing I shot with my 7D: http://vimeo.com/7214842 . Why?
I spent a lot of time in the DVX 7D forum and saw this test and article from Barry before buying my 7D (and I do remember all your posts about image quality issues). I had looked at a ton of footage but within hours of seeing Nocture, I pulled the trigger. I absolutely knew about the issues and found it easy (see my test clip) to figure out when the problem occurs. Shoot fine horizontal detail stopped way down with high shutter speed handheld - yowza.
However, after hours of shooting with my 7D, I've yet to see this again. Occasionally I see some mild aliasing.
But here's the most important thing to me - non-technical and technical people I've worked for years watching my Canon XL-1, DVX100a, HV30 and other footage respond "Wow" upon seeing 7D on a native 25" 1080p monitor.
I personally have not been this excited in a camera since I bought I top-of-the-line Chinon Super 8 camera in 1988. I love it - the camera excites me. People who watch the footage go "wow". It cost $1900 with a lens, ready to shoot 24p 1080p images with Super 35mm DOF with lovely low light and dynamic range. Yeah, it has a few technical issues. But who cares. I don't nor do the people watching.
I explained the same thing in my Vimeo Rant about the 7D and showed a short video clip of the problem.
The “Bloommers” crawled out from under rocks and went off on me as I am sure they will do to you also.
The sooner we can all agree that the Canon video enabled DSLR’s are one trick ponies (Shallow Depth of Field) and not a replacement for a camcorder, the sooner Canon will stop this nonsense and give us a big sensor camcorder with no line skipping.
Here are two small clips that I posted showing the unacceptable aliasing problem on the 7D:
http://www.vimeo.com/6885596
http://www.vimeo.com/7515562
-DR
(Comment removed at author's request)
I am a nerd. An editor usually. What's described here isn't a minor technical issue, it's a fundamental failing in the way the current crop of DSLR cameras capture video. Granted you can forgive a lot for the price, and reasonably so, but for many they see these cameras as some type of revelation and revolution.
Yup, they offer great opportunities for shallow depth-of-field and I'll probably shoot my next 48 Hour Film on a 5D, but they are not a Full HD camera and they are far from suitable to replace HD cameras in television or film production - yet.
That said, Canon is clearly aware of the interest they've created with their cameras, and they're also no doubt aware of the limitations. It's only a matter of time before they start to produce cameras that address a lot of these problems - cameras that borrow from this technology but aren't offering the video as a odd little after thought but as the core functionality.
Does it really matters since we watch all of our content these days online? Anything up close looks harsh. Shit, look at your girl in the AM. Let's put more energy into actually making content then fighting over pixels. Disclaimer: I'm not baggin' on Stu or Barry. Thanks a ton for researching these tools so we don't have to sell the farm to.
The fact that so many of us have or want 7D's shows that close enough must be good enough for the most part. Especially when seeing footage that looks THIS GOOD http://vimeo.com/7764570 it's easy to forgive any of the flaws the camera has. Pros>Cons
I was shooting a wedding recently and the groom and the groomsmen had all this very fine stripy suit that was causing aliasing quite bad and visible and guess what, I was using XHA1. So I guess it is not only DSLR.
I've been using the 5d in preference to the RED for a few things recently. I like the immediacy of it. I filled the first clip I did with it with fast motion to see wether or not the skew bothered me. It didn't at all, in fact I liked it. The cameras are what they are. A scene or shots impact will never stand or fall on lens resolution or aliasing. If it does, you've lost em.
Hi Stu.
Thanks for the interesting post (and a great blog!). I'm curious about this statement:
"If you fitted a 7D with an aggressive enough OLPF, the aliasing would disappear — along with any illusion that the 7D is a “full HD” video camera."
If you did find a way to fit an adequate OLPF to the camera, why would this not give "Full HD"?
Really well written article, I prefer posts to have some emotion!
As ever you have your techies and your visionaries. I agree what you have pointed out has to be a consideration but you must not forget who you shoot this stuff for, do they look at resolution charts? no they care what it looks like and how it makes them feel.
Resolution charts are very important if you plan to make a movie about resolution charts ! :)
Slowly, but slowly people are washing their heads :)
DSLRs are what they are: Foto Cameras that are capable of shooting still(s) good moving images though :D
I've never expected anything else and i'm still impressed about (Nikon, Canon, etc.) camera work from people around the globe.
Shitty Movie? Make good pictures.
Bad Pictures? Make a good movie.
In the end it's just about storytelling.
Any emotional galanty show can give you goosebumps.
Having just completed 3 weeks of shooting with 2 7D's on a feature film I'm glad we made the last minute decision to have the Production Designer ditch all the resolution charts from the sets. The 7D's were the perfect choice for our budget and filming style. We did steer clear of wardrobe that might cause moire but didn't worry about noise or aliasing and we have maybe one shot that we'll have to do a little mask to hide some noise.
We tested Red's, HPX 3000's and looked at all the low-end cam's and made the decision to go 7D and it was the right decision for us - small crew, use of natural light and practical's as much as possible and having lens and depth of field choices we wouldn't have with any of those other cameras.. The result is astounding, the entire cast and crew is blown away every night we review dailies in our hotel room. I think shooting rez charts and commenting about noise in shadows etc is just a waste of time. If you've got a good script and great cast it doesn't matter what you shoot with.
Lens choices were 16-35 2.8 L II, 24-70 2.8 L, my fav the 70-200 2.8 IS L, 100-400 4.5-5.6 IS L, 24mm 1.4 L and Zeiss 50 1.4 (great lens). So we used the best glass currently avail. - maybe that's why we have no tech issues worth mentioning - just insanely beautiful images? We are prepping 2 more features with bigger budgets and plan to shoot both with the 7D unless something better comes out soon. We will add the complete line of Zeiss primes for the next show.
Lance
I'm as fond as anyone of making the "so don't make a movie about test charts" joke. That's why I made specific mention of Barry's inclusion of real-world examples. Yes, you can work around these problems when they show up, but you need to know about the issue in order to do so. There are certain kinds of shots that you just won't be able to make with these cameras.
I agree Stu - I would not make an action film with these cams nor a film with a lot of driving unless you have Tyler mounts or something other than car suspension. Our lead character is a teen surfer who drives an old Volvo for pizza deliveries - we had to be careful where/how to mount the 7D to minimize or eliminate jello. We planned shots around the limitations of the camera but it suited our film perfectly and the results are really great.
Maybe it's because my "day-job" is in creating practicle effects. Or, it may be because I'm still somewhat new to actually controlling the camera, itself. But, I'm NOT impressed by DOF, "35mm lense-adapters", or whatever new "fetish-of-the-day" is the next new thing. I'm much more concerned with what happens in front of the camera. If you don't have something worth shooting, even the absolute best camera in the world won't save the day.
A good story, compelling characters, a PLOT, special effects that SERVE AND PROPEL THE STORY but NOT BEING a REPLACEMENT for the story, (good audio and lighting help a great deal, too), are what will set you apart. If all you're worried about is the 'technology' of the moment, then you will always be at a loss, because there will ALWAYS be a newer technology that offers "better" than what you already have.
Well, as pointed out enough times: what else is new? But Barry, being the (paid) shill he is, while eager pointing out flaws in the cameras that killed the Scarlet (that things never coming to live, ever) is not so eager pointing out glaring RED flaws: overheating? Nahh. Every friggin' RED I saw in action is surrounded with ice-packs! Timecode? Nahh, who needs that, you could play lottery with RED's timecode numbers? Audio? Right, that shit just isn't working, and why? Easy, you've got the wrong 'build' stupid, The old board, stupid, the what have you stupid! None of this is mentioned by Barry, Larry or Jim or whatever. Obsolescence obsolete? That's funny, because all REDs are actually obsolete by now.
Back to 'aliasing' flaws: of course there's a problem - shoot 16mm and you're working around problems, shoot 35mm - same, shoot RED, geez you work around a LOT of problems. Shoot SCARLET - yah right, no aliasing problems there ;-)
I can't afford a 7D or even a D90. What I can afford is a D5000 with a kit lens. There's no decent video camera in my price range either. And if I were to spend my available funds on a video camera I'd have no stills camera. So for someone like me I'm getting some video capability and I'll work on coming up with things I can do with the camera, rather than worrying too much about what I can't.
Barry spends a great deal of time talking about "fake detail". But you gotta ask yourself how big a problem this really is.
Do we care if a pebble on the ground is shifted by one pixel? If it is one pixel too big? No, we don't. Aliasing only becomes a problem when it's made visible through stair stepping and moire on some man-made structures. Tiled roofs are a problem, no doubt. But in most scenes the "fake detail" does the trick just fine. Those cameras never looked "barely better than SD" to me or anybody I showed footage to.
I believe that with an MTF50 pattern test we would be able to see the "fall off" curve to be longer for the 5D/7D rather than any cheap-ish camcorder, or even film. This article shows an example where resolution and MTF50 yield different results. The resolution tests are almost meaningless in the larger picture. In the real-world, MTF50 matches reality much better, and e.g. the 50/1.4 is much sharper at f/4 than at f/1.4. I'm not saying that the aliasing issues are nice, they aren't. But I don't believe this "fake detail" thing that it's been concluded by Barry. The right test would show that the 5D/7D do offer more real detail and sharpness than most camcorders.
Simple decimation of images can indeed produce seemingly "sharper" results than resampled scaling, as anyone who's seen footage scaled at After Effects' draft quality setting knows. An advantage of decimation is that sharp edges stay sharp, but with all the obvious disadvantages.
Barry Green's article exaggerates slightly when he says, "Aliasing is a cheat; it's not real detail, it's false detail." Even a stopped clock is right twice a day, and when decimated samples coincide with the real signal more or less, the results are good. For much natural imagery with lower-frequency texture, this actually works pretty well -- if it didn't, more people would be rejecting DSLR video out of hand. And the article says nothing about the actual decimation methods these cameras use -- are they doing any filtering of the image that comes off the sensor, before compression?
One wonders how soon it will become possible for relatively inexpensive cameras to do high-quality supersampled scaling of full-frame images at video framerates, with user control over the scaling method, sharpening, etc. How soon will DSLRs even be able to record full-frame images at 30fps, leaving any scaling to be done in post? Probably several years yet, but it seems inevitable.
Here is something I took yesterday. Is it the same issue ?
http://vimeo.com/7999113
what is the solution to avoid this?
Yes Ariel, that's exactly what we're talking about. The only solution is to not make that exact shot. Your example also shows how the problem doesn't go away when you scale the video down to web resolution.
In my day job I shoot commercial video, everything from trucks on the highway to people in retail stores, actors, real people, studio, chroma key, etc. I also do some documentary work. So far I've shot 4 projects with the 7D, no problems. Every video camera I've ever used, from $60K packages on down, has imperfections to work around. The 7D is an economical way to get great looking video. It's not the best thing out there, it's not a Red killer, it requires more expertise than using a "handycam" type traditional video camera. I like the look I get and it's better than with any 2/3" chip broadcast style camera I've used. I got it to be a backup camera, but I like it so well it's become my primary camera (although I still find my regular video camera more suitable for Steadicam work).
Do you ever do anything but complain and criticize. Reading this site its like nothing is good enough. But, what happened to your (now lost) spirit of making with what you have.
The last time I remember you having a positive focused post was a while back when you featured someone who had shot a short video. In that post you mentioned how this person just went and shot, and did not focus on getting the best equipment but made use of what he had.
Maybe a bit more focus on how to use what we might have and be able to afford (GH1, 7D etc.) and how to make the most if it would be in order. I thought this blog was supposed to be about making. How about techniques to take that so so video from a 5D do stuff with it etc.
But, posts that say everything from a 5D, to a RED, to a D21 just somehow does not cut it (even though all of these are used on Features); how does that inspire or help advance actual work?
Well Richard, I complained and criticized about the 5D Mark II not having manual control and 24p, and we have the former already with the latter on the way, and of course the 7D shipped with both.
But you obviously believe in the power of complaining and criticizing, because here you are doing it yourself! Keep it up, it works!
We just shot a couple of short films with a friend's 5D Mk 2. It is certainly not the camera to end all cameras, it is a very compromised shooting setup. Although it will get better with 25 fps, Canon really needs to add zebra and VU bars, for example- we missed sound entirely for one sequence because the external mic plug got partially dislodged and we had no feedback. On the plus side we caught that really quickly because we were checking the rushes card by card as we went!
I think the nicest thing about it is that the 5D Mk 2 scores very highly on the areas which we found most difficult on the HVX200's we also shoot on... and vice versa. If the 5D Mk2 or 7D just did what the HVX200 does a little better, there wouldn't be any fuss about them. Sure, there are a hell of a lot of compromises shooting with them, and sure, they are no magic bullet to kiss your shoot with and end up with perfect footage. But they are a hugely enjoyable and interesting thing to complement- rather than replace- our HVX200's. I'll be buying a 7D as soon as the budget allows (rather than a 5D Mk2, because I want slowmo 50 fps and my final output is 720p 25 fps).
Kudos to Stu, Vincent Laforet et al. for grabbing hold of these new interesting tools and dragging them by the throat through some film-making, and letting the rest of us know how it went. Frankly, without them, we'd just written off the video mode on the 5D Mk2 as a gimmick.
I am post guy mainly, so what I recommend for people shooting with either 5D or 7D is to shoot mainly static shots and always grab a stills frame of your shot. Later on you can use this to fix and enhance your shot with the full frame and also have ability to create some nice zoom in post.
I mean if its a stills camera, why not use it?
I enter into my future purchase with the full understanding of all of the drawbacks and limitations. Viva La revolution. Something new has evolved. I want to evolve with it. My craft, my artistry loves the challenge posed by crappy resolution, rolling shutter, line skipping, aiasing, lack of pro controls,
This stuff pushes me. If you want the perfect camera, then your in for a long wait!
If you want the tools.. well they are all out there from HDSLRs, 35mm adapters, to pocket sized hd, to pro rigs and high-end gear. Choose what tools you need. Charts are good, knowledge is always growth.
Every time there is a product shift or change in the industry the resolution charts come out. I read them, do my own tests, rent, borrow the new technologies. But they are tools. Neither is worse that the other. A F35 or RED is better to shoot a feature on given the appropriate resources, but you wouldn't shoot a wedding with one.
I read the word problem so many times in the article above it was problematic more me. These HDSLRs represent a new wave of tools. To me they are solutions. I ain't giving up my EX 1 over it. But I do have some niche customers I can offer budgets to, who wont go running to the hills. The jobs I have done already. NO customer has complained. I have had my projects shot on a 5D get to national TV in Sweden.
Tools not problems.
Resolve issues of Resolution.
Relax.
Its a great world with these new puppies.
Well, the detractors of the aforementioned Canons will be happy (or sad) to know that Mr Bloom (Philip) had a showing of some footage at the Skywalker ranch theater and apparently the quality of the cameras blew them away, them, includes Quentin Tarantino and Mr Lucas itself. Great news.
This is Mr Phillip Tweet:
"Any doubt I had of 7d/5d for filmmaking gone after seeing my work of 40ft screen a Stag theatre at Skywalker ranch"
and
"@GarethEEvans once you see it on one of the best screens in the world you know it's a winner. I was shocked and how amazing it looked."
I have some doubts about the explanations provided in the article. This explanation of DSLR video’s aliasing doesn’t seem to hold up.
The HD-sized images from these cameras are being downsized from a vastly larger frame; any aliasing due to the chip and its OLPFs would occur at the native resolution of the chip. Resizing it down to HD resolution would reduce (if not totally obliterate) this extremely fine aliasing. Barry says the same thing:
“...since web video is frequently scaled down in size (and scaling down helps to reduce aliasing artifacts) they released the 5D Mk II as-is...”
Scaling an image larger than 5000 x 3000 down to 1920 x 1080 should not result in more aliasing than a full-sized still. And 1280 x 720 should look smoother still. But in fact we don’t see that at all; most people think the 720 footage looks MORE aliased (although that’s probably because they’re blowing it up to the same size as the 1080 for viewing).
The aliasing in DSLR video almost certainly comes from one thing: a fast and crappy resizing algorithm. What happens if you resize an image with no resampling? Try it in your favorite image-editing program. The result: wretched aliasing.
To achieve the necessary processing throughput to deliver “HD” video, these cameras are taking shortcuts. They’re not downsampling the images well, and the result is aliasing galore. They may even be doing some abbreviated deBayering to speed things up. It almost certainly has nothing to do with optical low-pass filters, guys. The idea that somehow the image acquisition is somehow flawed because "it's not optimized for video" is silly. The limitation here is computing power and data throughput. As we all know, these are likely to improve over time.
@ Martin Briley: yes, you nailed it, the problem is "a fast and crappy resizing algorithm", so crappy that it is in fact just line skipping.
Whether processing power (better resizing algorithms) or storage space and speed (store RAW data, and do the resizing in post, if at all) will be our white knight, we shall know soon enough.
oh, and I forgot: in the meantime, we have some really inspiring tools, good enough in many situations, and at times much better than anything I could aspire to
Martin, the problem is not (primarily) the resizing, the problem is that the camera does not pull a complete image off the sensor. It skips entire lines. The article is correct. However, the results can look quite similar to "a fast and crappy resizing algorithm."
I've only notices this alias issue with the 7D when shooting slow motion 60fps 720p . I've shot a hell of a lot of footage on my 5D's and haven't noticed any aliasing problem.
Is it posible that it is something only present in 720p as a result of down scaling?
Scott
It's just a little worse at 60. More lines skipped.
The 7D should not be viewed as an HD camcorder replacement. Although useful to have and with slightly more shooting options as compared with the version currently offered in the 5DMkII, video capture in the 7D still suffers from lack of continuous AF. Unfortunately, the jello phenomenon (from rolling shutter) and monoaural sound (external stereo mic input is available, though) make for a less than harmonious package.
cartucho r4i
Thanks Stu. I do agree that aliasing does matter...especially when it is creating a loss of color information. We need to be mindful of this constantly when making films with these DSLRs.
Now if the definition of "aliasing" is that the sample rate of the camera is skewing reality, take a moment and consider the way your eye sees things. In a way, though your eye or brain may not exactly be sampling an image, it does at times "alias" things by definition. Take the example of the rubber pencil. When you move a pencil fast between two fingers it is blurring and it looks like it bends. In reality the pencil is not blurring nor is it bending, right? My point is, don't let any camera, pros or cons, stop you from producing some great videos...even if it's just to get your portfolio for the web boosted up until someone hires you so you can use a better camera.