digital

What you need to know about blank DVD discs

Kevin

techdaisy-090403-0002What is the difference between DVD-R and DVD+R ?

The DVD-R standard (pronounced: DVD dash R) pre-dates DVD+R (pronounced: DVD plus R). Today, most DVD players can read both. A DVD burner may be specific to one or the other. Use discs that are compatible with your burner.

DVD+R has a few technical advantages; notably, DVD+R supports both single layer discs and dual layer discs.

DVD-R discs are typically the least expensive.

What about DVD-RW, DVD+RW, and DVD-RAM ?

Rewritable discs (RW) can be erased and re-written. These discs contain a phase-change metal alloy. R formats utilize an organic dye (non metalic); once it has been written, it cannot be erased.

RW discs typically take more time to write/burn. DVD-RW or DVD+RW discs are commonly rated either 2x or 4x speed, while DVD-R discs are commonly 16x.

DVD-RAM discs are relatively uncommon or obsolete. DVD-RAM is typically not compatible with the DVD player attached to your television.

What is 2x, 4x, 8x, etc. ?

This indicates the speed at which the disc can be written.
Time to write an entire single-layer disc
2x = 30 min
4× = 15 min
8× = 8 min
16× = 5.75 min

What is dual layer ?

Dual layer discs have an embedded second layer, so have twice the storage capacity of single-layer. Some DVD burners can write both single-layer discs and dual-layer discs. A standard DVD player attached to your television likely does support dual-layer, unless it is a particularly old machine. Many Hollywood movie DVDs are actually on dual-layer discs.

Which should I use for compatibility with most DVD players ?

Most DVD players can read any R or RW disc. The following list begins with the highest compatibility.

(1) DVD-R should be compatible with 95% of all DVD players.
(2) DVD+R should be compatible with 85% of all DVD players.
(3) DVD+RW
(4) DVD-RW

Once again, DVD-R is typically the least expensive.

What about Blu-Ray ?

While Blu-Ray discs are the same physical size (as DVDs), Blu-Ray is higher density (more storage capacity), and capable of much higher data rates. For HD 720p or HD 1080 video, you need Blu-Ray.

DVD players cannot play Blu-Ray discs. Many Blu-Ray disc players can play both Blu-Ray and DVDs, but this is not universally true.

Which disc should I use to save computer files ?

For use on a single computer, you can use any disc that it can write. For sharing with other computers, single-sided single layer discs are the most compatible.

4.7GB – single sided, single layer DVD
9.4GB – double sided, single layer DVD
8.5GB – single sided, dual layer DVD
17.1GB – double sided, dual layer DVD
25GB – single layer Blu-Ray disc (BD)
50GB – dual layer Blu-Ray disc (BD)

I want a custom image on the top of the disc; How do I do that ?

There are three methods.

Inkjet printable disc label

Adhesive disc labels are generally frowned upon. Adding a label can cause problems for some DVD players. If you do apply a label, always use a donut-style round label and be very careful to insure the label is centered on the disc. An off-center label can cause a disc to wobble at high speed.

Inkjet printable disc

Most printable discs are plain white on the top surface. Some inkjet printers include the ability to print on discs. Alternatively, specialized disc printers are capable of printing many copies very quickly.

If the blank printable area extends almost to the center of the disc, this is referred to as “hub printable”. On a regular printable disk (not hub printable), the printable area stops about 3/4-inch from the center hole.

LightScribe disc

A LightScribe disc includes a reactive dye (in the top surface) that allows imprinting using a LiteScribe-capable DVD burner. In my experience, the print always fades, even to the point of disappearing.
Lightscribe has apparently been discontinued; both discs and burners are increasingly difficult to find.

When saving video for a disc, what video bitrate should I use ?

The ability of a DVD player to sustain playback at a given bitrate is highly variable from across different models.
You can choose variable bitrate (VBR) or constant bitrate (CBR). If you use VBR, then the average bitrate should be comparable to CBR. Here are very vague guidelines.

Standard definition 480p : 10 MB/minute

High definition 720p : 20 MB/minute

High definition 1080p : 35 MB/minute

 

 

New cameras for HD, 2K, and 4K video

Kevin

In 2008, Vince Laforet shocked the film-making world with a short film called “Reverie” (http://vimeo.com/7151244).  He shot this in just two days using a borrowed Canon EOS 5D mk II (borrowed from Canon) before the camera was released.

Since then, the 5D mk II has become a serious tool for film-makers, particularly because it is much smaller than existing cameras (those specifically designed for cinematography) … and also because the cost is a small fraction of those cinematography cameras.
Recently, Canon announced a successor for 2012, the EOS 5D mk III.

The overwhelming success of the 5D mk II for video purposes was somewhat surprising to everyone, including Canon and Nikon.  Just a couple months prior to introduction of the 5Dm2, Nikon had introduced the first DSLR that supported 720 HD (not 1080).   By most accounts, Nikon trailed behind the success of the 5D2, but successfully “caught up” with cameras such as the D7000,  D4, and D800, all of which offer excellent 1080 HD video capture.  By some measures, the D800 trumps the Canon 5D mk III.

All these cameras are built around CMOS image sensors that are far larger than what you find inside video camcorders.  When combined with a system of interchangable lenses, film-makers can create effects and quality not possible with consumer or prosumer video camcorders.

Since the success of the 5D mk II, Canon has been on a mission to create new cameras specifically for cinematography (movies & television).  Enter … the new EOS C300, EOS C500, and EOS 1D C  (“c” is for cinema).  Both the C500 and EOS 1D C can capture at digital resolutions higher than 1080 HD.  While the EOS 1D C is an SLR that can shoot still images and video, the C300 and C500 are pure video machines that will capture 12-bit 4:4:4 color, compared to 8-bit 4:2.2 color in any DSLR.

While the EOS 1D C is the same size as the EOS 1D and 1Dx, it can capture 4K video at 24 fps or 1080 video at 60 fps.  That’s a data output somewhere around 500 Megabytes/sec. 
Canon recruited film-maker Shane Hurlbut to test out the new camera.  He created a short film, entitled “The Ticket“.
http://www.hurlbutvisuals.com/blog/2012/04/looking-inside-the-canon1dc-dslr-4k-capture-project-the-ticket/

Canon’s new cinematography play is priced well for serious indie film-makers, but not for consumers.  So, another interesting camera for 2012, is the new Blackmagic Cinema Camera, which shoots 2.5K video and costs less than $3K.

 

720 HD  = 1280 x 720  (16:9)
1080 HD = 1920 x 1080 (16:9)  Panavision Genesis, Sony CineAlta, Canon C300
           and DSLRs: Canon 5D mk II, Canon 5D mk III, Canon 1Dx, 
                               Nikon D7000, Nikon D800, Nikon D4

2K   = 2048 x 1080 (17:9)   Ari Alexa, Silicon Imaging SI-2K, Canon C500
2.5K = 2432 x 1366 (16:9)   Blackmagic Cinema camera
4K   = 4096 × 2160 (17:9)   RED One, Red Scarlet, Canon C500, Canon 1D C

 

Camera Upgrade – Panasonic G3

Kevin

Across two decades, I have owned/used three film cameras, two digital cameras, and one video camcorder.  Recently, I acquired a new camera to replace my old digital compact.  The new camera is a Panasonic Lumix G3. 

The G3 is a relatively compact camera with interchangeable lenses.  It is half the size of my Canon DSLR.  The G3 is a Micro Four-Thirds camera.   Because Four-Thirds and Micro Four-Thirds are both open standards (jointly developed by Olympus and Panasonic), the camera can accept lenses from different vendors, such as Olympus, Panasonic, and Leica.

The biggest reason I replaced the old compact camera is poor low-light performance.  The old camera had a maximum ISO of 400 and was prone to a good deal of chromatic noise.  The new G3 has a maximum ISO of 6400 and the noise is far less than the old camera at ISO 400.  

The ability to record images in low-light is largely a matter of the image sensor.  Most small cameras employ small image sensors, which perform poorly in low light.  In recent years, some small-to-medium size cameras have been employing larger image sensors.  The G3 features a Four-Thirds sensor, which is about six times larger than the sensor in the old C-5060 and is half the size of the image sensor in my DSLR.  G3 has three times more pixels than the C5060, while the image sensor size is six times larger. So the individual pixels are larger; and, theoretically, larger pixels can take in more light.   But this is theory; the proof is the actual image quality.

 

Essential Guide to Memory Cards

Kevin



The two most common types of memory cards are Compact Flash (CF) and Secure Digital (SD).  Compact Flash was first introduced 15 years ago and is still used in many new cameras.  SD format is physically smaller and is more suitable to smaller cameras.  For larger cameras that can accomodate CF, some people find that the larger size of CF cards is easier to manage. Many SD cards today will actually be SDHC (Secure Digital High Capacity).  If you have an older camera, be careful to read the camera specifications to understand if you can use SDHC cards. 

From a technical perspective, both CF and SD/SDHC have evolved to offer increasing speed and storage capacity. In general, CF supports a maximum storage capacity 128 gigabytes. (The newest revisions can support far more.)  The original SD supports up to 4 gigabytes. SDHC supports up to 32 gigabytes. SDXC supports up to 2 terabytes (1TB = 1000GB).

The photo attached here shows three memory cards: xD, micro SD, and SDHC.  Micro SD cards are commonly used in mobile phones and come with an SD adapter, which is essential if you need to insert the card into a card reader. xD has been used by some Olympus and FujiFilm cameras, but both these vendors seem to be phasing out the xD cards in 2010 (see: http://en.wikipedia.org/wiki/XD-Picture_Card).  The xD card in this photo was taken from an 4-year-old Olympus camera that accepts both xD and SD cards.

Historically, Sony cameras have exclusively used a proprietary card type called Memory Stick.  This decision by Sony (to ignore standard card types such as CF and SD) has been a nuisance to camera buyers for a decade.  In a very significant and obvious change, new Sony camera models introduced in 2010 support both Memory Stick and industry standard SD/SDHC cards.

Not all cards are created equal.  Some memory cards will read or write faster than others.  The write speed can affect how fast your camera can save an image to the card.  Furthermore, if your card is too slow, it may not be compatible with some newer high-resolution cameras, that require high-speed cards in order to save fat megapixel images.  Before buying a memory card, I highly recommend that you check Rob Galbraith’s memory card database (www.robgalbraith.com/bins/multi_page.asp?cid=6007). 

To copy photos from your camera, you have four options. Most cameras can connect to a computer via a USB cable. Doing so, the camera appears to the computer as a simple external storage device, just like a flash drive or external disk drive.  Altneratively, you can remove the card from the camera and use a card reader, connected to your computer.  If your camera is built-in to a cell phone or tablet, you may be able to send your images via email (possibly incurring fees for large amounts of data). Finally, some cameras support a wireless connection, such as BlueTooth.  For some cameras, wireless connectivity may be available via a camera accessory that must be purchased separately.

Not all memory card readers are equal.  In the photo shown here, both card readers connect to a computer via USB.  Both accept a variety of different cards.  The big difference between the two is speed.  One supports Ultra DMA and the other does not.  Be careful to read the fine print before purchasing a card reader.  Using a slow card reader can be frustrating, particularly if reading 8GB or more.

Lastly, a particular note regarding video cameras.  With the advent of newer memory cards offering both fast write speed and high storage capacity, video cameras have quickly moved away from magnetic tape storage in favor of memory cards.  Some cameras allow you to record for indefinite periods of time by providing two card slots and automatically switching when the current card becomes full.

Pixels (part 2)

Kevin

With the information in my blog post entitled Pixels (part 1) [how-many-pixels-part-1], you may conclude that 8×10 inch prints call for a 5 megapixel camera. That’s generally true, but not entirely. It is possible to use computer software to artificially increase the number of pixels. Different software programs may perform differently. The general rule of thumb is you can double the number of pixels. So, you might print very good 8×10 prints though your camera only records 3 megapixels.

Maybe you just bought a new DSLR that records images up to 15 megapixels. Those 15 megapixel images may require three times more storage than 5 megapixel images. If you shoot
some pictures on Tuesday, intended for 11×14 prints, set your camera to record large size. If you shoot some pictures on Wedensday, intended for computer screens only, set your camera to record small size.

Pixels get a little weird when you move to television display. Pixels on a computer are square. A digital image that is 400×400 pixels will display square on your computer monitor. Not so on a television screen. Television pixels (defined by either NTSC or PAL standards) are not square.

Consider an picture aspect ratio of 4:3, meaning the picture is 25% wider than it is tall. Standard television (not HD) has a 4:3 picture aspect ratio. Yet the resolution is 720×480 pixels, which numerically seems to be 50% wider than it is tall. But rest assured it is 4:3 because each television pixel is taller than it is wide. (Take a very close look at a television and you can see this is so. It is more difficult to see on a HD television.) While pixels in a computer or in your camera are equally wide as they are tall (often called square pixels), pixels in television are taller than they are wide.

Pixels (part 1)

admin

Perhaps the most common question regarding digital photography is … how many megapixels do I need? The answer depends upon how you intend to use the photo. You need to answer two questions: how large will the photo appear (inches or centimeters) and how many dots per inch (or centimeter).

If you want to share it on a computer screen, one megapixel is more than enough. Why? Computer displays typically have either 72 pixels per inch or 96 dots per inch. So, for example, to display a photo at a size of 6 by 9 inches, you need (6 x 96) x (9 x 96) = 497,664 pixels = 0.497 megapixels.

Computer screen: 72 – 96 dots (pixels) per inch
Photo print: 240 – 300 dots per inch
Magazine: 100 – 200 dots per inch
Poster or banner: 100 – 150 dots per inch
Billboard: 10 – 20 dots per inch

Magazines print fewer dots per inch. If you look real close, you may see the individual dots, but maybe not. It depends upon the exact printing equipment and the tendency of ink dots to blend together. Billboards, viewed from far way, use very low resolution simply because it is not apparent from far away.

So, here is another example. For a photo print 6 x 9 inches, you need (6 x 240) x (9 x 240) = 3,110,400 pixels = 3 megapixels. More pixels in your camera means that you can get larger prints without sacrificing quality. Using the same math, you can easily see that a 20 x 24 inch print needs 27 megapixels.

You may ask: 240 dots per inch? My printer supports 1000 dots per inch.
OK, here is the bottom line. If you print at the higher resolution, can you see a difference in the final print? You might see a tiny difference, but 240 dpi usually provides excellent quality and sharpness. If you are using a photo lab to make your prints, consult their guidelines, but 240dpi or 250 dpi is very common.