Image playback

Although all DSLR cameras provide similar basic playback functions to a sophisticated compact digicam, they also include some useful, more informative displays that provide a wider range of shooting data and other information photographers can use to improve their picture-taking. They may also provide better image management facilities and more options for fine-tuning camera settings. For example, when captured images are displayed on the camera’s monitor after a shot is taken, DSLR photographers can usually determine how long they wish the image to remain on the screen.

Digital SLR cameras normally provide a wider range of playback options that a typical compact digicam.  

However, the majority of cameras – both enthusiast and professional – also support the standard playback options, including:

1. Auto rotation of shots taken vertically so they display upright during playback, both on the camera’s LCD and when the images are downloaded to a computer. Manual rotation is also supported in most DSLRs.

   

   Rotating the picture displays vertical shots with the correct orientation.

2. Playback with magnification. This allows you to magnify part of a displayed image to check focusing and most cameras allow up to 10x magnification. A dedicated button is often devoted to this function and photographers can scroll around the image by using the arrow pad keys.

   

   Playback zoom allows you to magnify parts of a captured image to check focus and highlight and shadow detail. The white box in the lower right corner indicates the area of the image that has been magnified.

3. Image playback with shooting information. This usually includes the image quality and size settings, the image file number, the date and time the shot was taken, the shutter speed and lens aperture, the ISO and colour space settings, the metering and white balance modes and any corrections or adjustments to parameters like exposure, flash output or white balance. Many cameras also include a histogram in this mode.

4. Playback with histogram. (See Camera Functions.) Whereas the histograms on compact digicams tend to be too small to be really useful, most DSLRs display histograms that are large enough to read. Some also give separate graphs for the red, green and blue components of the image, making it easy to detect colour casts in the shot.

   

   Most DSLRs can display a thumbnail of the shot plus a histpgram and detailed shooting data. More sophisticated DSLRs give users the option of viewing a brightness histogram (top)

5. Playback with highlight/shadow alert. In this mode, any over-exposed areas in the subject will blink when highlight alert is selected, while underexposed areas can be made to blink by choosing shadow alert. The degree of over- or underexposure is not shown but photographers can use the EV adjustment control to change exposure settings and then re-take the shot and re-check highlights and shadows once more.
6. LCD brightness adjustment. Even entry-level DSLR allow the brightness of the LCD screen to be adjusted. This can make the screen easier to view in normal lighting but may not provide significant improvements in bright sunlight, where all LCDs become difficult to ‘read’.
7. Index displays allow four, nine or 16 shots to be viewed simultaneously on the LCD screen. This function is used for seeing the images already stored on a memory card or locating wanted shots among a large number of files. To display a single image at full screen size, you select the shot using the arrow pad and press the playback or magnify button.

8. Jump displays, which allow you to jump forward or backward by 10 or 100 images. This option is handy when you have to scroll through a large number of files on a memory card. Some cameras allow the jump function to be used with the magnified view, maintaining a pre-set magnification size and position throughout the jumps.

   

   Index playback shows thumbnails of the most recent shots taken.

9. Auto playback as a slide show. Many DSLRs include a slideshow setting that automatically plays back all the shots on a memory card in sequence. Each image is displayed for roughly three seconds.

   

   Jumps displays let you skip forward by a selectable number of images.

10. Image marking. Various systems have been developed for tagging images to allow automatic protection, downloading or printing. The most widely-found is the DPOF system that allows photographers to tag files for automatic printing. Details can be found below.

LCD Limitations
Although a lot can be done with the camera’s LCD screen, photographers should be cautious about placing too much reliance on assessing the quality of shots on the basis of what they see on the camera display. Small LCDs (including those with 3.0-inch diagonals) are not the ideal way to view digital images because they can be affected by the actual viewing conditions in which they are used. In bright sunlight, most LCDs are next to useless. In the dark, they can give an unrealistic estimate of the tonal range in the shot.

Many LCDs are direction-limited. In other words, displayed colours and intensities change with the viewer’s angle of view in respect to the display. For best results, always view the LCD straight-on. Even displays that claim wide viewing angles can introduce colour shifts when viewed from one side.

When checking focusing and colour reproduction, remember the resolution of your camera’s LCD is much lower than the resolution of your computer monitor. By the time you have enlarged images enough to see an adequate amount of detail, the dot structure of the display is large enough to interfere with the displayed image. The range of colours camera can display usually also lower than the gamut of computer monitors. In short, the camera LCD can display is a useful guide but your computer monitor will show you the colour and detail you have actually recorded.

In-camera File Management
All DSLRs include a variety of ways of tracking and organising image files and it’s important to understand how they work. We’ve already covered file numbering systems in Camera Adjustments. In this section we’ll look at systems for erasing and protecting image files and tagging shots for automatic printing.

The control that erases image files is usually identified by a ‘rubbish bin’ icon. In most cameras it’s a dedicated button, although you can also erase files through the menu system. Selecting a file for erasure usually calls up a warning screen that asks you whether you want to delete the file. The default setting on this screen is ‘Cancel’ so if you want to trash the file you must select ‘OK’. Many cameras allow you to delete all files on a memory card by providing an additional ‘delete all files’ option.

Deleting individual files is simple. Select the Delete setting from the Playback menu and use the arrow pad to select the displayed file or all files on the memory card. (This is not the same as formatting the card).

Another way to delete all files is to format the card. This is always done through the camera’s menu system. Details of how the process works can be found in Camera Functions.

Most cameras also allow images to be tagged to prevent them from being erased accidentally. This also protects the shots from erasure when the card is formatted. Protected files are identified by a key icon and can only be erased when the protection has been cancelled in the camera.

To ‘tag’ images for automatic printing, select Print Order from the Playback menu then press Order to key in how many prints you want from the shot.

The majority of cameras also allow users to tag files for automatic printing using DPOF (Digital Print Order Format) tags, which can be ‘read’ by most automatic printers (including photo labs). Note: only JPEG can be tagged for automatic printing.

The Print Order menu can also be used to order index prints and imprint the date and/or file number on prints. Note: The print settings are applied to all images tagged for printing so if you tag one image for date and/or file numbering, it will appear on all prints. The memory card must also be the card that was used to capture the shots; you can’t download a set of pictures to a spare card and print from them with this function.

Ordering prints via the DPOF function can be tricky as some printers and photofinishing equipment are not fully compatible with the DPOF metadata tagging. When this happens, the picture may be cropped incorrectly or the image may be distorted to fit on the paper. For these reasons, enthusiast photographers usually prefer to print with full manual control.

Direct Printing from DSLRs
Direct printing facilities have been added to a number of DSLR cameras since the establishment of the PictBridge system in 2004. When the camera is connected via USB cable to a compatible printer, PictBridge allows users to:

• Print one or more images selected from the camera’s monitor display;
• Automatically print images tagged using the DPOF specification
• Produce an index print of all images
• Print all images in the camera’s memory.

Although the system is convenient, only JPEG images are supported by both PictBridge and proprietary direct printing systems.

The main disadvantage of direct printing is that it limits the adjustments you can make to shots before printing. In addition, the only way of viewing the image you want to print is on the camera’s monitor. Consequently, this facility should be seen as more of a proofing option than a serious printing facility, although it may come in handy when you need snapshot prints on the spot (as long as a compatible printer and USB cable are at hand).

Downloading Image Files
Image files can be copied to a computer’s hard drive by either connecting the camera to the PC via the USB cable supplied with the camera or removing the memory card from the camera and inserting it in a card reader which, itself, is linked to the PC via USB cable. Both work equally well, although downloading via a cable-to-computer link draws power from the camera’s battery as the camera must be switched on.

Card readers are more convenient if you have several cameras with different types of memory cards or if there are two or more people in a household using the same computer. Turn the camera’s power off before removing the memory card.

Direct printing facilities are convenient for quick on-the-spot proofing of images.  

The speed of data transfer depends on the USB system supported by the camera and computer. This can be one of three types:

• USB 1.1, which has a transfer speed of 1.5 Mbits/second and was the original format;
• USB 2.0 Full Speed, which has a transfer rate of 12 Mbits/second, and
• USB 2.0 Hi-Speed, which has a transfer rate of 480 Mbits/second.

All USB connections support Full Speed transfer but both the camera and computer must be Hi-Speed compliant if the Hi-Speed data rate is to be achieved during file downloading. For high-resolution cameras (10-megapixels and over), USB 2.0 Hi-Speed is a definite plus.

The Photo Browser function in Adobe’s Photoshop Elements allows you to organise images as you download them.

Some professional DSLRs are supplied with FireWire connections, either instead of or in addition to USB. FireWire supports similar data transfer speeds to USB 2.0 Hi-Speed but the latter is considered technically superior and is cheaper to implement. Consequently, USB 2.0 Hi-Speed is rapidly replacing FireWire in a wide variety of devices.

The software supplied with many cameras includes automatic file management facilities that recognise image files and automatically organise them in folders, which are usually identified with the current date and time. (Adobe’s Photoshop Elements includes a similar facility that operates automatically when images are downloaded.) These automatic cataloguers can be convenient but they vary greatly in how well they work. While some are efficient, others can be downright frustrating to use and folders can sometimes be stored in parts of your computer that you may not normally access.

We advise readers to beware of relying too much on automated cataloguing systems. It’s very easy to set up new folders for files in your PC’s operating system and, when you have your own naming system and a dedicated place to store them (e.g. the My Pictures folder), wanted files are easy to locate.

TV Connection
Most DSLRs are supplied with video cables that allow them to be connected to a TV set so you can view the shots on the memory card. The cable plugs into the Video-In terminal on the TV set. Both camera and TV should be switched off when the cables are plugged in. The camera’s video format must be set to match the TV display standard (PAL for Australia).

Selection of shots for display and moving from one shot to the next is done with the camera’s controls, using the playback button and arrow pad. At the end of the show, switch both camera and TV off before disconnecting the video cable.

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