Scarlet Killers – Attack of the HD DSLRs!

HD capability in new crop of DSLRs deserves a look

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Nikon is claiming its recent release of the D-90 is the first HD DSLR camera. Plus there’s the news of Canon’s entry into the HD DSLR race, the EOS 5D Mark II as well as the Sony DSLR-A900. The combined pressure of these seemed to sink the much anticipated release of the Scarlet.
 
So why are these SLR form-factor camera’s making a scene? Well, lately it’s been about the release of Vincent Laforet’s HD film “Reverie” on the Canon website. The images are stunning and the entire project was shot on a 72 hour deadline with a budget of $5,000. So many people downloaded the movie that it shut down Canon’s video webserver.

Out of the three cameras, Canon does seem to be the one to beat. It starts with a CMOS imaging sensor that is exactly 24 x 36mm and 21 Megapixels (5616×3744 pixels). That entire image (with the exception of the aspect ratio difference) is used as the basis for the HD video that the camera produces. Oddly the camera shoots at an HD frame rate of exactly 30fps. The frame size is also the most impressive of the competition at a full 1920x1080p. The cool thing is that the footage is created in native QuickTime using an MPEG-4, H-264 codec. The audio is a little skimpy, with a built in mono mic that must not be good for anything other than slating shots or maybe as an assist in syncing some dual system sound. There’s an optional stereo mic than can provide stereo sound through a 3.5mm stereo mini-plug, so I would think that dual system sound is the way to go. Audio is recorded uncompressed at 16bits, 44.1K, PCM.
 
I think that what makes the images in Laforet’s film amazing is that he shot with almost no additional lighting. Virtually everything was shot with available light, or available with a single, small additional source, like and LED light. The only way that that modus operandi is possible (have I been watching too many cop shows?) is that the still camera can be rated at an astonishing ISO of 25,600! That is an “extended” ISO, but the basic ISO is from 100 to 6,400! And most of the footage in Laforet’s movie was shot at about 1600 ISO with virtually no noise. This incredible low-light sensitivity is due in part to the size of the individual pixels on the chip. In HD mode, the sensitivity of the camera can go up to 12,800 ISO, but normally operates in the same standard range that the camera uses for stills.
 
Canon is mum about stating the dynamic range of this camera (which is expected to street by the end of November), but estimates based on other Canon cameras with similar sensors put it over 8 stops.
 
The images also benefit from the depth of field provided by the wide range of prime and zoom lenses available for the camera (using Canon’s EF lens mount) and the large, full-frame sensor size. The bigger the sensor, the shallower the depth of field when all other factors are considered.  Compare the 36mm chip of the Canon to most prosumer video cameras at 1/3 or 1/2 inch. For those without a metric calculater 36mm is more than 1.4 inches. I’m not sure how the HD manufacturers measure their tiny sensors, but if it’s diagonal then you have to have to compare that to a sensor size of 1.7 inches for this Canon!
 
The camera records to off-the-shelf, inexpensive UDMA CF cards. The QT files can be played directly off the cards. And HD video out is available via an HDMI-mini port or a standard def RCA jack, switchable between PAL and NTSC. CF cards have a maximum single file size of 4gigs. This has translated – depending on subject matter – to about a maximum shot length of 12 minutes at full 1920x1080p. Multiple 4gig files can of course be held on a single 8gig or 16gig CF card.
 
Some of the excitement about this HD capability is tempered by the fact that this is not SUPPOSED to be an HD camera, but rather a still camera with the ability to shoot HD, so certain features are definitely missing, like timecode. Also, the camera can only operate in essentially full auto exposure mode when shooting HD. (In still mode, the camera is capable of being fully automatic or fully manual.) The cool thing is that you can make adjustments using an exposure compensation control. You can also lock the exposure so that changes don’t occur in mid-shot. The camera’s “flowchart” for doing the auto-exposure is to first control the sensitivity or ISO of the camera, then adjust shutter speed, then f stop.  The shutter speed range in HD mode goes from 1/30th to 125th.
 
The camera can use auto-focus in HD mode, but Canon suggests sticking with manual focus for video. Remember, that the SLR viewfinder is inoperable in movie mode, so you have to monitor your image using the LCD on the back of the camera, or with an external monitor fed by the HDMI jack.
 
Photojournalists are pumped about the camera because many outlets want them to shoot video as well, and this allows them to shoot with the same lenses without having to carry a video camera. The Canon is capable of switching between HD and stills almost instantaneously.
 
All of that is pretty impressive for a camera retailing for about $2,300.
 
The Nikon D-90 is also in the hunt in this competition. I have always been a Nikon shooter, since high school, but the specs on the D-90 are just not as impressive as the Canon and there are some seemingly fatal flaws. The D-90 has a 12.3 Megapixel image sensor (60% of the Canon). It has three different size modes when recording video, however, which is a feature not offered by the Canon. The sizes seem aimed at capturing video for the web however: 320×216, 640×424. and 1280×720. And for most people the fact that the native capture is in AVI with motion-JPEG compression could be a killer. Though for others, that could be a selling point.  The Nikon records to SD memory cards, and it approves models up to 32gigs. The small type on the Nikon site states that the auto-focus does not work while in video mode.
 
Sony’s entry – the DSLR-A900 – has a 24.6 Megapixel, full 35mm frame CMOS sensor, rated at ISO 200-3200.  HD was unveiled with an earlier version of the camera – the A700 – last year at this time, but the camera seems to only output HD via the HDMI-mini port, not actually record it.
 
As someone who shoots with SLRs, DSLRs and video cameras, I think the form factor of the HD DSLRs will be a problem for adoption as serious HD workhorses. The way the cameras can be held and moved will not be acceptable to many cinematographers and videographers looking for an HD option, But formany, the form factor will be a benefit. The lightness and compact size of the body will allow it to be mounted and held in ways that are impossible with even the smallest of camcorders.
 
The real benefit in image quality seems to be the size of the sensor which allows a beautiful depth of field and the impressive ISO ratings of the cameras which allow minimal lighting to deliver exceptional results.
 
(If you are interested in reading the full interview with Chuck Westfall, the Technical Advisor for Canon, about the Canon EOS 5D Mark II, check out the next page.


imageQ: Steve Hullfish
A: Chuck Westfall, Technical Advisor for Canon U.S.A., Inc:
 
Q: Tell me about the EOS 5D Mark II.
A: This is basically – as you can tell by the name – a second generation of the EOS 5D which is our high end advanced amateur Digital SLR. And one of the things that this particular product category has done is kind of establish the full-frame image sensor at an affordable price point in a relatively lightweight and compact camera body. If you go back to 2005 where we introduced the original 5D it came into the market at a time when the only full frame DSLRs were roughly in the $8000 price range and it came in at $3299. Now,  three years later the 5D Mark II is a far, far superior piece with the addition of the 21 Megapixel sensor and the HD movie mode for roughly $600 less at its introduction. So it’s kind of an exciting product now because it has updated the technology and at the same time has dropped the price even more.
 
The basic spec is 21 Megpixel full-frame CMOS. For still photos we can shoot up to 3.9 fps. And it has a full range of standard digital SLR features. The headline feature on this camera is the full HD movie support. That’s still relatively unique to have a 1080p 30fps movie capability.
 
Q: And why would you put that feature in this high-end consumer category?
 
A: Well, it’s a starting point for us and I’m sure that over time this technology will proliferate across the industry. We understood that the initial interest at least at the initial stage, was going to come from what I’ll call advanced amateur and even entry level and advanced professional photographers who wanted to try out the feature first without necessarily getting involved in a full-blown professional camera. And then the other reason is that being full-frame it really gives us a chance to show off the image quality that the sytem is capable of producing at a relatively affordable price point, so it spreads the appeal of this camera out to as wide of an audience as we could. If we’d gone considerably lower in the product line, like a Rebel-class camera first, I think we would have cut off a lot of the interest that the higher-end people had and vice versa. So this is enough of an upper-advanced type of camera that had enough of a foothold in both the amateur and professional market to be able to appeal to both.
 
Q: Tell me about the size of the sensor.
 
A: The size of the sensor is exactly 24 x 36 mm.
 
Q: How does the size of the sensor help with image quality and greater depth of field?
 
A: It helps quite a bit with depth of field because of the fact that it is large. For any given combination of subject distance, angle of view and lens aperture, you’re going to get less depth of field with the larger format, and that’s true with not just this microcosm of full HD on this camera, but it’s also true in general photography. If I had an old-style Hasselblad with 2 1/4″ film, and I was equalizing every single setting that I possibly could in terms of the subject distance and f stop and the focal length of the lens to get the angle of view to be the same, then I would have less depth of field in the larger format. The size of the format really does make a difference in how much depth of field control there is. And at the same time it also allows us to make each of the individual pixels relatively larger so that we’re able to increase the sensitivity to light and at the same time reduce the noise levels in low-light.
 
Q: And how is the camera sensor used in HD mode? How is the HD being generated?
 
A: What we’re doing is basically having the sensor do progressive scan. For all intents and purposes, it’s throwing off a full sensor’s worth of image data at 30fps. The reason I make the distinction is that there is a slight difference in aspect ratio of the actual sensor, which is a 2:3 aspect ratio via the HD format which is 16:9. That’s another factor where the fact that it’s a CMOS sensor comes into it because we’re able to basically not read out the thin strips at the top and the bottom of the frame, because that wouldn’t get used because of the difference in aspect ratio. Within the range that we are reading out we’re essentially just doing a progressive scan. We’re getting a full amount of data out of that, then downsampling, then compressing it and writing it to a file.
 
Q: Are there choices in the camera about file types, compression or frame rate?
 
A: There are no such choices really. The file type is always .MOV. The compression is always MPEG-4, AVC with H.264 codec. And that again is fairly efficient and also a fairly well known one. And the frame rate is fixed at 30fps.
 
Q: Is that a true 30fps or 29.97?
A: It is a true 30fps.
 
Q: And in still mode?
A: It’s 21 Megapixel. 5616 x 3744 pixels.
 
Q: And what is the lens mount type?
A: We call it the Canon EF lens mount.
 
Q: Tell me a little about the on-camear sound capability?
A: There is a built in monaural mic. And there’s also a speaker. But in addition to those two components there’s also a 3.5mm mini-plug jack that’s designed for use with an external stereo microphone. The basic specs are PCM encoding with no compression, 16 bit sampling at 44.1kHz for each channel. The in-camera settings for audio levels and wind-filter settings are all automatically controlled. There is no manual override in the camera for those two things.
 
Q: What about timecode?
A: Not on this generation.
 
Q: What about the form factor?
A: Well, for us, the 5D Mark II is primarily a still camera and the form factor reflects that priority. The HD movie function does break new ground in the areas we’ve discussed like depth of field control, low light performance and the access to a wide range of lenses, but we recognize that the camera does not have the same levels of functionality in terms of auto-focus, exposure adjustment and audio control as most HD video cameras. Certainly from the ergonomics there’s some issues to overccome.


Q: What is useable in HD mode as opposed to still mode?
A: There is a limited degree of auto-focus capability present even when you’re recording a movie there is an ability to press a button on the camera to cause the focusing system to operate and we’re not recommending it, but it’s something that can be done. The reason that we’re not recommending it is – there are several actually – one is that the auto-focus system that we use for movies is actually the same one that we use for the “live view” function of the camera, which is actually a way of being able to take still pictures when you’re looking at the preview on the back of the camera and the net result of this is that it may take a couple of seconds before the focus actually locks in. Another issue is that if you were to be using the built in microphone, it’s so sensitive that it would pick up audible noise of the focusing mode moving itself into position. There’s also the possibility in some bright lighting conditions that when you push that auto-focus button, there may be a brief change in the brightness level of the scene because sometimes the aperture setting of the lens does change. So we’re recommending manual focus as the primary focus method because you have more control over the speed and timing of it.

One of the things that is retained is a fully automatic exposure control. The camera sets its own ISO or sensitivity. It sets its own aperture and it sets its own shutter speed. There are controls on the camera for exposure compensation and auto exposure lock. But there are no manual overrides to be able to set those exposure settings individually in HD. In stills mode everything can be adjusted manually.

Q: And the primary monitoring is through the SLR viewfinder?

A: At all times you’re in movie mode you either have to work off of the LCD on the back of the camera or a connected monitor.
What we’ve seen some people do already is to put together a – one of our guys called it a Frankencamera – with the fluid head tripod mount and a matte box in front of the lens and platform to be able to hook a 7″ LCD monitor in the HDMI port.

Q: What about shutter speeds? They’re all automatic?
A: The range is set between 1/30th and 1/125th of a second.

Q: Is that range working at some fine granular detail or is it just 30th, 60th, 125th?
A: It’s pretty variable. The autoexposure on the camera technically lets it be set within an eighth of a stop. So there’s a lot of range to be able to adjust it. But what we’re noticing is that because it has the three different things to control, it does have a priority that the first thing it will usually do is work on ISO (sensitivity), then shutter and the last would be aperture.

Q: So even though there’s not a true aperture priority that’s kind of the way the camera’s flowchart of processing goes?
A: It has to be that way to be as silent as possible. Keeping the aperture adjustment to the last is one way of doing that.

Q: When you’re in HD mode does the camera stick to a certain ISO range or does it operate in the entire extended ISO range up to 25,000.?
A: If you leave everything on the camera set to its default it’s going to peak out at 6400 ISO at the top end, but there is an option to set it up to an ISO expansion range and at that point it can go up to 12,800. It will go up that high in movie mode. In still camera mode you can go up to 25,600.

Q: Where do you find the top of the ISO range for where you start seeing noise in HD mode?
A: It’s not really an easy question to answer. It’s so dependent on the subject matter and the lighting conditions. What I’ll say is this, the higher key the situation – in other words if you’ve got a fairly evenly lit subject matter and a lot of mid-tones to bright, into the white part of the tonal range, you don’t really see that much noise even into 6400. But if you start going for the real low-key, dark night time stuff, then you might start seeing it a little bit sooner than that, but not much. It’s phenomenal how good it is in terms of low noise even in the higher ISOs.

Q: Let’s talk about storage capacity.
A: One of the specs of this camera is that the maximum length of an individual clip is limited to 4gigs. And according to cameras tests in the lab in Tokyo with an average amount of detail and a fairly reasonable normal type of a scene we’re estimating that to come out to roughly 12 minutes of full HD. So if you had a 16gig card, you could shoot 4 12 minute clips on one card. There’s no issue as far as the camera heating up. The only reason that there’s a 4gig limit is basically because that’s as large of a file as you can put at one time onto Compact Flash.

Q: What’s coming out of the HDMI spigot?
A: If you are talking about playing back a movie that’s already been captured you get both audio and video. But if you are monitoring the live signal, then the audio is cut off and the video is the only thing that comes through. The RCA video jack can output PAL or NTSC.

Q: What is the mirror doing while shooting HD?
A: Well, the whole concept of this camera for movie mode is that the mirror is already up at the outset. To be able to even start a movie you have to flip the mirror up so that the shutter and the sensor can be totally exposed. So the mirror is really not involved.

Q: What about Canon lenses compared to HD video or film lenses?
A: The range of focal lengths that we offer is outstanding. Everything from 14mm or 15mm fisheye all the way up to 800mm lenses plus extenders. F-stop range, we’ve got a number of very fast lenses that get as wide open as 1.2. We have special purpose lenses such as tilt shift lenses and Vincent showed some of the effects of those to create some very interesting special effects. There’s macro lenses. But within this whole big range of lenses, Canon is pretty much an acknowledged world leader in the sharpness and the contrast and the color balance and alot of that has to do the the technology that we’ve developed around multi-coating also the type of glass that we use and the cuts of glass that we use, like various aspherical elements and even some crystal. We use flourite in some of our lenses. This is the same type of flourite that ends up getting used in some of the broadcast optic lenses.

Q: Is there a contrast ratio for the sensor from brightest to darkest?
A: Not that we quote yet. But based on passed experience with a camera that uses a very, very similar sensor to this, I’m expecting the actual dynamic range that translates out to still pictures to be over 8 stops.

dpreview.com has a review up on the EOS 1DS Mark III that uses an earlier generation of this sensor and they rate that at over and a half stops.

Q: When is the camera shipping?

A: We’re anticipating the end of November.


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Steve Hullfish

Steve Hullfish

Steve Hullfish has been producing and editing award-winning television since the mid-1980s. He has written five books, and edited two theatrical feature films (both Number One New Movies in the US). He has lectured at NAB, DVExpo and the Master Editor seminars. He has edited on Avid since 1992 and was named to Avid’s first group of Master Editors. His client list includes: Universal Studios, Sony Pictures, NBC, PBS, Turner Networks, The Oprah Winfrey Show, “Investigative Reports” and “Cold Cases” with Bill Kurtis for A&E, Jim Henson Home Entertainment, Major League Soccer, The Chicago Cubs, Wilson Sporting Goods and Exxon/Mobil.