43 Rumors | Home. Questions arise about the financial results for Olympus. Thom Hogan, in a comment, notes that Olympus itself is fine – but the imaging division isn’t fine. And then there is Kodak … whose share price has fallen to $3.
Lacking consistent credible progress towards addressing their challenges, both companies have some huge issues to address to remain in their respective businesses. Who knows? I do not predict the future!
The 2011 National Association of Broadcasters convention (or just “NAB Show”) will be held April 9-14 in Las Vegas. The entire world of broadcasting, radio, television, film production, media, related software, transmitters, lighting, sound, cameras, DSLRs, video, online media production – you name – will be in Las Vegas.
NAB is huge. Mind blowingly huge.
You can receive a free, complimentary registration as follows:
We have a special registration code you can pass along to your readers, giving them FREE ACCESS to the exhibit floor, the Opening Keynote and State of the Industry Address, Info Sessions, Content Theater, Exhibits and PITS – a $150 value. Please pass this along and visit http://bit.ly/NABRegSM06 to redeem or register at http://nabshow.com/register with the code SM06.
More information on the NAB Show at http://blog.nabshow.com
There are many reviews online that say the Canon DLSRs, which are fantastic still cameras, are lacking in their video mode 1920x1080p resolution. Several web sites calim that the Canon DSLRs (not including the 5D) in 1080p mode are only a little better than 720p when tested on resolution charts. Online video examples show that the 1080p resolution is not the 1080p resolution of a true video camera.
And then there are the video resolution charts.
Why might this be going on?
How do they down sample a 5184 x 2192 (16:9) raw image (using the 60d specification here – the 5D has slightly larger numbers)?
Here is my technical explanation for a possible reason, if the online reviews are correct about the soft video images. (I do not own a Canon DSLR so cannot test this myself.) My explanation may very well be off in space but provides a plausible technical reason. But I can’t say this enough: my explanation may totally wrong! And keep in mind that most people do not even see a difference between 1080p and 720p video on their home HDTV. (And my explanation is wrong in the details – each “photo site” has 2 green, 1 blue and 1 red image sensor. Translating this into megapixel images is more complex than in my simplified explanation.)
The image sensor on the camera is much higher resolution than 1920×1080 used in video. The original image must be converted or downsized to 1920×1080.
They likely take every 2nd row and every 4th pixel across and throw away the extra rows and pixels. In 16:9 aspect ratio, the camera (60D) has a resolution of 5184 x 2192.
If this raster is simplified by pulling out every 4 pixel and every other row, this yields, for 1080p:
5184/4 = 2592 pixels wide (or alternatively, take every 2 of 3 for 1,728)
2192/2 = 1096 rows high
To convert this into 1920x1080p, they might do a simple weighted average of pixels horizontally across each row (the 2592 wide row or up size the 1728) to produce a 1920 row. This is going to soften the image horizontally but is an easy way to get to 1920. Dropping out rows, too, loses information and other processing adds information that wasn’t there (by averaging multiple elements) creating moire and aliasing. The result is an image that looks better than 720p but softer than true 1080p.
(There’s a reference in a comment here that the 5D samples every 3rd row and another comment saying it throws every 3rd row … take your pick!).
720p is much simpler:
5184/4 = 1296
2192/4 = 728
which is so close to 1280×720 that all they need do is throw out some pixels at top and bottom. This creates worse moire because even more rows are thrown away.
The Canon 720p should look fine except for moire. The Canon 1080p is going to look softer than true 1920x1080p and introduces aliasing artifacts.
With only one DIGIC 4 processor on board, they likely lack the processing capacity to do a clean conversion from 5184×2192 sensor down to 1920×1080, 30 times per second! Instead they take shortcuts to make it work.
My prediction: Starting this fall, the Mark III has a dual core processor and all cameras announced from then on will have dual core processors. Within 1 year, Canon will solve the moire problem.
Some of the cameras from competitors have dual core or even tri-core processors now.
DSLRs do enable photographers to shoot very narrow depth of field video, which would be harder to achieve on all but high end professional video cameras that are very expensive – or by using various schemes, like the Letus adapter, that project the image on to a screen.
DSLRs also generally have very good low light performance capabilities.
Ultimately, resolution is hardly the only criteria for shooting with a DSLR. Convenience, size, low light, depth of field, lens quality and that you just like how the image looks anyway may be more important.
vDSLRs are not smaller & lighter, nor cheaper. « I E B A Tech Thoughts.
The picture at the link says it all 🙂
The Powershot SX1 is an amazing camera. I bought mine factory re-furbished, at a tremendous discount.
But it has a two frustrating gotchas. Both are its poor low light capability due to its small image sensor and lack of good signal processing to clean up the noise.
Or so we thought. Today I discovered a trick to affect the video gain setting.
For those of you who are still photographers, the ISO setting of your digital camera is equivalent to a video camera’s video gain. The higher the ISO number, the more amplification is added to the signal to try and pull an image out of darker scenes. Amplification occurs to both the useful signal – and the noise on the image sensor – such that increasing the amplification results in worse noise.
Professional video cameras and higher end consumer video cameras have a video gain setting to select, typically, video gain of 0 db to +18 db (some go as high as +36 db gain). The greater the number, the more gain or amplification you are adding to the signal and the noisier the image. But this means on real video cameras, you can disable gain (and the ugly noise) if you don’t want to have that.
Now for the trick. I have CHDK installed on my SX1 so the screen might show something different if you do not have CHDK running.
I pointed the camera out the window to where the sun was shining. I pressed the video record button. I then pressed the photo exposure button half way until the white focusing rectangle turns green (or yellow if you pressed the +/- exposure compensation button first). Continue to hold the exposure button half way down. This shows the ISO setting the camera has selected – for video.
Pan the camera into the interior of the room while continuing to hold the exposure button half way depressed. The room will remain dark and the ISO setting stays at 160 (or whatever it was for you).
Now, with the video still running, let go of the exposure button. The auto exposure feature kicks in and the ISO jumps to 400 and the room brightens up.
Therefore, the trick is to start your video clip at a bright area or light. Press video record. Then half depress the photo exposure button until the green rectangle appears. This locks the exposure and ISO setting (gain). Now, pan the camera into the area you want to video without so much awful noise caused by jumping to a high ISO (gain) setting.
Pretty cool, huh?
For interior shots, the SX1’s auto-only exposure mode tries to go to ISO 400 for everything. The total ISO video range is from ISO 80 up to a displayed 400. The ISO 400 setting is what shows in the display but I think its pushing out to about ISO 3200 when it goes full open. It is way too noisy and way to bright for ISO 400.
I found the best images occur with the ISO set to anything below 250. ISO 80 to ISO 125 is best, but its okay to 250. The next setting level is 320 and that starts getting pretty noisy at that point.
I ran across this by accident. But it is a modified version of the exposure lock trick discovered on Canon’s HV20/HV30/HV40 camcorders. Same idea – point the camera at a brighter light and then invoke the exposure lock feature on the HV camera and you are good to go with video gain completely disabled. (On those cameras, you can also use the “Spotlight” mode, which disables video gain.)
Another trick that helps a little, and only a little, is the exposure compensation button in video mode. Start you video. Press the +/- button and it displays an exposure compensation setting bar (left to right) at lower left of viewer. Use the control wheel to reduce the exposure or increase the exposure. This affects the ISO but only a little.
Why didn’t Canon enable manual override of ISO, aperture and shutter speed? Certainly would have been possible. And might even be possible with CHDK if we can figure out what memory ports to poke with what values.