This week we’re talking about two different high definition recording formats and pitting HD and HDV head to head.
HD and HDV are both high definition video formats. Instead of playback formats, HD and HDV are recording formats. HD describes an image that is 1920×1080 or 1280×720 pixel images. HDV describes an image that uses rectangular pixels at a size of 1440×1080 that displays the same size as a 1920×1080 square pixel image (The pixels are 1.33 times wider than an HD pixel).
Bit rates vary between the two also, HDV has a bit rate of as high as half and as low as a quarter of an HD bit rate. Both formats use compression, but HDV uses interpolation and groups of pictures (gops) to create the necessary compression. HD also uses compression, but you have an option as to what kind of CoDec you want to use.
We’re finishing up our basics of photography with ISO, or film speed. This builds on our previous episodes on the pinhole camera, shutter speed and aperture.
ISO applies to film, but it translates to the digital world. ISO stands for the International Organization of Standardization. The word order is French. The standard for color negative film is ISO 1500:1987, for black and white, it’s ISO 6:1983. You won’t see those listed on film canisters, but these are the standards document references. The ISO numbers that we are used to are the arithmetic scale. ISO is also available on a logarithmic scale, but it less common.
High speed films (higher numbers) allow more light, but also have the potential for more grain in analog photography or grain in digital photography. Lower speeds (lower numbers) are less sensitive to light. On the digital side of things, ISO refers to the sensitivity of the image sensor to light.
Nikon Coolpix P6000 with SB-400 High Shutter Speed by littcool
Today our topic of conversation is shutter speed, continuing our media science series about photography.
Shutter speed refers to how long the shutter of a camera is open for. Shutter speed is closely tied to aperture. When talking about fast lenses, the shutter speed is what really makes a lens “fast”. As more light comes in from a wide aperture, the shutter speed can be shorter and shorter to accommodate capturing an extremely quick moment like a baseball being thrown or a hummingbird’s wings.
Shutter speed and aperture go hand in hand. When camera standards were decided upon, changing the shutter and aperture inversely would maintain the same amount of light in an image. This has changed a bit with digital cameras, but originally shutter speed options were in multiples (like 1/30, 1/60, etc.), so multiple properly exposed images could be created using different settings.
Here is an Flickr set as an example of photos of the same subject (fountains) at different shutter speeds: Shutter Speed Tests.
This week, we continue our media science conversation about cameras and talk about aperture.
Aperture is measuring using f-stops in a ratio or fraction. It measures the opening of the iris of the camera. In remembering our pinhole camera example, the aperture is how wide the pinhole is made. The f:aperture number means that the larger the numbers get, the smaller the hole is. The f stands for the focal length of the camera.
Playing with your aperture settings can produce some fun images. One example is bokeh images. For some great bokeh images, take a look at the bokeh Wednesday pool on Flickr. If you see anything that jumps out at you, leave the url in the comments.
09/06/2007 - Art Center College of Design by amayzun
This week, we begin our series on photography. We’re starting the series with the most basic camera, the pinhole camera.
A pinhole camera is a lightproof container with a hole on one side and a film plane on the other side. Together, the aperture, the shutter and the plane create a camera. Building a pinhole camera is a simple weekend project and instructions are readily available online. Kodak has directions on creating a pinhole camera on their website and so does Instructibles. The Instructibles directions are embedded below. To create the aperture, you can use this pinhole camera design calculator to get your proper dimensions.
So, what camera should you buy? This week, Rob and Chris set out to answer a question that Chris gets asked on a regular basis.
Video cameras can range from a hundred dollars to hundreds of thousands of dollars. The components vary in quality and price. Chris brings up four questions that you should ask yourself when you are thinking about buying a camera.
Note: We reference some topics discussed in episode nine How Video Cameras Work, but it’s not necessary to listen in order to understand this week’s show.
Review recommendations CNET Reviews is always a good starting place Photo.net is one of the best sites for anything photo related. camcorderinfo.comhas some good reviews & comparisons
This week we discuss video compression. “What is Video Compression” continues our Media Science series. It’s not about BBQ sauce, but you’ll understand why we’re using that image after you listen to the file.
Video compression is different from file compression because it is a “lossy” compression, meaning you can not get the original video back once it’s compressed.
There are many factors that go into how a video is compressed, some factors are video resolution, frame rate, bit rate, codec and file format. This doesn’t include how the video is shot, just the hard decisions that come with shooting video. On the image acquisition side of things, lighting, camera movement and framing can all have an effect on file size and compression.
This week we discuss the basics of video editing. “Video Editing Basics” is the next part of our Media Science series.
Once you’ve recorded your video, the next step is editing. There are two ways to edit. the first is called linear ot tape to tape editing. This is the analog way of editing where you are physically handling strips of tape. Often, this kind of editing happens with an EDL or edit decision list.
The digital way of editing is called non-linear editing. Some applications that edit in a non-linear fashion is Final Cut Pro, Avid, Adobe Premiere and Vegas. Non-linear allows you to be more experimental and flexible in your edits.
An analogy would be creating a mixtape vs. creating a playlist. In order to create a mixtape, you have to commit the songs you want in the order you want as you record them. When you create a playlist, you have the option to test out the order of songs to hear how they sound before calling it finished.
This week we discuss how video cameras work. “Video Cameras” is the next part of our Media Science series. How they work is part one of four.
Discussed is the three basic parts to video cameras and how they function. The lens, the imager chip (CCD or otherwise), the A/D converter and the recording mechanism. The recording mechanism could be recording onto analog or digital, but for this conversation, we’re talking about a digital medium.
Also discussed is how light and color really work. For instance, what color is a red ball? The answer might not be as simple as it might seem.
Our theme music is “Understood by Your Dad” by Brad Sucks
This is the present and future of all media - old and new. CCD is a podcast for creators, consumers, and “deleters” of all kinds of media. Blogs, podcasts, video, television, film - even books & magazines! Hosts Chris Cavs and Rob Blatt hold a regular discussion on the issues that affect content creators and consumers, and help them to become better at what they do. Tips and tricks, how-tos, Q&As, professional discussions…they’re all part of the CCD experience. create/consume/delete is a podcast about how media is created, consumed and deleted.
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