digital

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)

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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.