Category Archives: Photography

5D mark II drops frames when recording video

I’ve been meaning to write about the 5D mark II (which I’ve had for about 1.5 months now) for a while but given the amount of information in the web already, it’s seemed somewhat pointless. However I have to rant a bit now, given the video mode on the camera was detected to have yet another fault. It drops frames, resulting in jerky movement.

Here’s how the video mode in 5DmII works: the camera is in full auto mode while shooting video. The user can compensate the exposure to under- or overexpose, but you can’t change the frame exposure time, aperture or sensitivity. (You can sort of work around this by fiddling the exposure compensation and pointing the camera here and there + locking exposure, but that workaround is not a real solution.) For some reason, the camera seems to sometimes make rational choices on the exposure, and sometimes prefer to use extremely high sensitivities even in bright light, resulting in noise.

Now, I noticed the video from the camera occasionally jerks a bit, but assumed it was my computer occasionally dropping frames due to the fact the 1080P footage from the camera is extremely CPU intensive to decompress. Turns out this is not a playback problem, but a fault in the camera. What’s happening is, whenever you’re recording video, if the camera changes the aperture, it skips 2-3 frames, and replaces those skipped frames in video stream with copies of the last frame recorded.

Reproducing this is very simple. If you have a variable aperture zoom lens, just change zoom in and out during capture of a moving subject, and check the footage frame by frame. For constant aperture lenses, find a spot that has dark and brightly lit spots that are bright enough that the camera has to change aperture when shooting (hint, point the camera out the window, then back in), record a clip while alternating pointing the camera to these spots, and check the footage. You can see the aperture being used during the video capture by depressing the shutter button halfway down. On my footage, I’m consistently getting four duplicated frames in a row when the aperture changes, making these clips useless.

The workaround is to always remember to lock the exposure with the * button prior to starting to record video.

With this issue in mind, I have a couple questions in mind. What’s the point of having the camera work in forced full auto mode by default, if that mode produces jerky video footage? Why on earth can’t I select the aperture manually, especially if the manual selection would prevent this from happening? Can a camera even be marketed to record video, if the camera regularly drops frames?

The most infuriating part about this that Canon still uses an old world communication policy, whereby they effectively don’t talk to their customers. The web is chock full of angry commentary about all the issues and lack of features on the video capture, and there’s no word whatsoever from Canon on whether anything related to the video will actually be changed.

Until this issue is fixed and the manual controls on the video are released as a software upgrade to the camera, I have to recommend anyone considering to use the camera to record video forgets about it. Sad, really.

Europe lives in 50Hz and US in 60Hz, or, why the 5D 30 fps video is an issue in Europe

So, if you read the comments to my previous post on the 5D video issues, people are saying supporting just 30 frames per second video capture in Europe is not a problem, since HDTV sets can display a number of frame rates, some of which are some multiplication of 30 fps (such as 60i or 60p – there are no 30p sets). Now, this is true, but this claim ignores the fact that European HDTV penetration is currently at somewhere close to 20%, and just 1% of the HD sets are actually hooked to a HD source (source).

This effectively means that if you want to share any clips shot at 30p, more than 99% of Europeans can only display your footage in a format native to Europe, which happens to be 50i. This in turn means your signal quality will reduce significantly. Oh, and, all European HD channels apparently broadcast using 50i or 50p.

But this isn’t the real problem, and I was dumb not to state this in the previous post.

The 30fps support causes issues in thee respects: capturing the footage, editing the footage, and displaying the footage. The displaying is pretty much covered above, so let’s continue with the two others below. The part where you especially need to play attention to is the capture part, as that will affect even the users planning to shoot cat videos to display on their own brand spanking HD set.

European electric current is distributed as alternating current (AC), with 50 hertz frequency on the waveform. Simplified, this causes the native operating frequency of any electric device connected to AC to be 50 hertz, unless the device explicitly overrides this by changing the current. Unfortunately, lighting is such a simple form of electronics that vast majority of indoor lighting oscillates at 50 Hz, or a multiplication thereof, such as 100 Hz.

The relevance of this fact comes in when you start to shoot video with artificial lighting. If you shoot at a frame rate which is an even multiplication of the current used for the lighting, you’re fine since each frame will get the same amount of light as it’ll be in synch with the lightbulb oscillation. However, if you shoot with a camera that uses a frame rate other than the light oscillation rate, each frame will be exposed with a different amount of light. With video cameras, this causes the exposure electronics to start compensating the lighting difference with each frame, causing funky image quality issues.

This is such a problem that apparently TV studios not only synchronize (lock) the frame timings of each camera in the studio to each other, but use the incoming electric current’s wave as the synch reference to time the frame exposure perfectly to the light oscillation.

So, in case of 5D with 30 fps which doesn’t play nice with European indoor lighting, if you want good quality footage, you can’t shoot any video in locations lit by artificial light. No sports videography, no indoor shots.

The Canon pro video department knows this, so it makes me think if they’ve intentionally sabotaged 5D by not letting the Canon camera department know.

The editing issue is less severe. The problem is also quite simple to understand. If you want to edit a set of footage, there’s no magic way to support multiple frame rates in one video clip rendered out as a result of the editing. Hence if you have some footage in 30p and some in 25p or 50i, some of the footage will have to be converted into the frame rate you want to use in the resulting video. This in turn means that if you have any existing footage you want to use with shots created with 5D, the chances are that stuff is in an incompatible frame rate, and something has to be converted, resulting in one of jerky motion, slowed motion, sped up motion, or ghosting. For home users this might be acceptable, but don’t expect to be able to ever sell your footage you shot with your 2500

The problem with Canon EOS 5D Mark II video

Update: before commenting, jump to the second post in this series.

Canon EOS 5D mark II supports HD video recording, and as can be seen in Vincent Laforet’s sample short filmed with the camera, the picture quality is stunning.

There’s just one problem. The camera only supports shooting 30 frames per second. This means the camera is effectively useless for Europe, since our TV uses 25 frames (or mostly, 50 fields) per second. You can convert between the formats, but it means you have to degrade the image by either dropping frames, which results in jerky movement or frame blending, which results in image ghosting.

Ghosting is hard to explain, so I created two movies that demonstrate the problem. The first one is the 30 fps movie of a bouncing 5D, and the second one is the same movie, converted to 25 fps using frame blending. If you stop the movement of the 25fps movie, you can see the horrible blur caused by the conversion. Below is a stop-frame from the resulting ghosting:

Now, if you shoot with 5D and post-convert to 30 fps, this issue will only be a problem in some shots. If you shoot mostly static subjects, people won’t really notice the difference, except your picture will appear a bit blurrier in movement. However, when you get hit by this with a moving subject on a right kind of a background, it will make your shot impossible.

Given this problem, I think there’s only one explanation as to why the camera only shoots at 30 fps: Canon intentionally crippled it. I refuse to believe the designers and executives who made the camera feature calls could be so ignorant that they didn’t realize Europe lives in a 25/50 fps world (vs Japan and US, who use 30/60). Hence the call was probably made by whomever controls Canon products in Europe, who didn’t want to see his video camera sales suffer.

The option to Canon users with this issue is that we either pressure Canon to implement 25 (and maybe 24 fps) support, or we help our friends at CHDK to hack the camera to support other frame rates. As can be seen by the Rob Galbraith EOS 1D debacle, Canon can be pressured to fix their products.

Canon – the hacking will happen if you don’t support the other frame rates, so I recommend you add the support. You can only lose by angering your clientele, and making them jump ship with hacking your products.

Canon EOS 5D mark II

So, the Canon EOS 5D mark II is now out and official. It’s a freaking cool camera and I had to put it on pre-order immediately, meaning I’ll probably sell the old 40D and the Samsung video camera soon. Which I’m not looking forwards to – I hate selling used equipment, probably because I feel I have too much responsibility if the stuff breaks after the sale.

For those uninitiated in digital SLR photography, the big difference between 40D and 5D is the size of the imaging sensor. 40D uses a smaller APS-C film size sensor while 5D has a full 35mm film size sensor. This changes the behavior of lenses when changed between the bodies – the 40D captures a cropped image from the middle of the lens while 5D captures the whole picture.

This means that on 40D, the captured image shows up as if it was shot with a lens that has a focal length that’s 1.6 times longer than what the lens really is, meaning wide angle shots require very, very wide lenses to produce. This also means the smaller sensor utilizes the center of the lens which probably has less optical problems with the projection.

Hence, migrating to the full frame sensor camera means every piece of glass I have a home changes quite radically, probably to the point where I’ll need to respec the lens arsenal to some extent as well… Bloody hell this is going to be expensive in the long run! :D

Another interesting new Canon product is the Powershot G10 compact camera. I have the G9 and it’s a very good compact, to the extent that you can call digital point and shoot’s good cameras. G10 looks like a serious improvement over the G9, so I’m tempted to do a switch there, too. If you’re looking at getting a compact, I recommend checking that one.

News from the DSLR-land

I’m a digital camera junkie. I’ve had 6 (3 point and shoots and 3 DSLRs), and am always looking to upgrade. However, the reasons for upgrading aren’t primarily more features, but convenience. The biggest shift that’s happened with digital cameras over the past six years that I’ve been on board, has been the current products have more of the good stuff from the film cameras than the early digicams, while also embracing the digital capabilities better. In concrete terms, my current DSLR body (EOS 40D) operates extremely fast (like film did) but also gives me very high sensitivity at good image quality (which film never delivered, at least at decent cost per frame). Compared to film cameras, cheaper DSLRs still mostly have inferior viewfinders and the autofocus systems are pretty sad compared to what affordable film cameras used to have.

Every digital camera I’ve bought has been a Canon and I have a considerable arsenal of lenses for the Canon EOS system, which would make switching expensive. This obviously results in myself being more interested in what Canon is releasing, than what competing companies do. There’s new product out now from Nikon, however, that makes me wish I’d gone the Nikon route. The Nikon D90 shoots HD video at 720P resolution. This is massive news. For the uninitiated, digital video solutions with similar imaging sensors and ability to swap lenses have have previously a hell of a lot more, and now you can get that “for free” as part of an awesome DSLR.

Chase Jarvis seemed to like the product a lot:

Not all is lost, however. Canon Rumors, and some other sites, are reporting the upcoming EOS 5D mark II also shoots HD, and maybe even at the 1080P resolution. The site has been slapped with cease and desists, which adds to the credibility of the rumor. If this is true, I’m going to fork out for the camera immediately, even if I have to sell something to get it. Video is cool, and having proper control over the depth of field when shooting would be awesome.

Joi's Leica is IR sensitive

I used to own a Canon G3 camera which was pretty sensitive to infrared light. You can shoot pretty amazing shots with an IR sensitive camera and an IR filter that only lets the infrared spectrum through.

Joi Ito blogged about his Leica M8 being IR sensitive and a bit jokingly he’s created an Leica M8 Magenta Madness group in Flickr. I’d suggest Joi go even further and get an IR filter and try to use the IR sensitivity as a feature.

Even with the little IR photography that I did, a whole new world was opened to me. I suddenly had a new type of vision which was pretty cool. Coming to think of it I guess I’ll go and try if my 30D is capably of any IR shots. I recall Canon’s new IR filters are pretty aggressive but there’s hoping.