Schierer Space

A camera doesn’t really make any sense unless you plan to do something with the images. Depending on whether you plan to show them on a website or print out poster size color glossys will have some impact on what the camera needs to have and what short-falls you can get away with. Of course your choice of printer (or online print house) also comes into play… but that’s another post.

Here’s a summary table for those of you in a hurry:

Want some details? Read on MacDuff!

• Most casual snappers want to share their images with friends and family via email. Email is a universal medium which, contrary to our modern WYSIWYG perception, is a completely text based medium*. Unfortunately, this means that any non-text item in your email (like that picture of your new cat) must be encoded into text. As you can imagine, this is a rather inefficient process which results in an expansion in size of at lest 25% (there’s some overhead too, but lets just agree that it’s bigger). Of course this means what is 500 kB on your hard drive is 625 kB in your email. THat may not sound like much if you’re reading this on broadband, but to those with slower connections (e.g. old school dial-up or new school wireless PDAs) this can make a big difference.
  Oh wait, we’re talking about cameras. Right… so pretty much any modern digital camera (and quite a few phones and PDAs) will take an image that’s too big to be sent conveniently via email. Be kind… please resize.
• The next category, “The Web” covers a lot of ground. I guess I’m thinking mostly casual viewing and browsing on your computer screen. A 17″ monitor will support a screen resolution in excess of 1000 pixels depending on the display and the visual comfort level of the user. This translates to an image just over 1 Mp (the monitor I’m sitting in front of is set to 1280×960 or 1.2 Mp). So anything bigger than this will require the user to scroll around to see the whole image. This is ok if your user is patient, or you’re posting the image for photographic review, but generally this will get annoying. I post all the images on our gallery at 640px maximum, with a “high res” image at 1800 px (about 1.5 screens tall and 1.5 wide).
  The nice thing about these smaller images is that lower quality optics in RM and N cameras are not generally perceptible. Also, high noise ISO settings are much less of an issue. When you resize the image from its native resolution the noise and blurriness gets smoothed out. With appropriate tools, the image will look sharper and crisper at lower resolution (viewed at the same PPI). Also, this is your opportunity to “digital zoom”. Did you really want to be closer to that animal in the zoo? Crop off the part of the image that doesn’t look like the zebra and you have a 1Mp image of just the zebra. Sweet.
• Prints are the holy grail of photography. Every aspiring amateur wants to see their images gracing the halls of some public building in glowing 8×10 (or bigger!) color glossys. At least I do. Resolution is key here. Remember the discussion about DPI and printing. For decent photo quality, you need an image at 300 ppi (yes ppi not dpi). You will then print it with a printer with HIGHER DPI so that the interlaced little dots of colored ink can form the much higher color depth of your camera (Wikipedia has a fairly nice example image of this phenomenon). Obviously more dots is better, and more pixels is better. So an 8×10″ print at 300 ppi is a 7.2 Mp image! FOr a more typical 4×5″ print, a resolution of 2 Mp is enough, but more is better. Obviously, the RM and N cameras with limited sensitivity and optical quality will start to reach their limits sooner. Primarily due to graininess in higher ISO images and due to lack of sharpness in the optics.
• Finally two non-photographic topics: Movies and audio. I’m not going to talk about digital camcorders since I don’t own one, but some cameras provide a movie mode. Generally this is not available in SLRs due to the way the lenses and viewfinder work, but generally IS available in compact digital cameras. For movies, resolution and frame rate define the quality of the video. Frame rate (in frames per second, fps) is the number of still images captured by the camera per second that are played in sequence to generate the ‘moving picture’. If this feature is important to you, make sure to check out whether the camera automatically adjusts lighting and focus while the movie is recording. If it doesn’t, a shot that begins in daylight will look like very little after you drive into that tunnel. Also be sure to investigate the maximum length of a clip. Some cameras (and media) can’t write the data out fast enough, and once the internal camera memory is full it will stop recording. This is often a function of the movie quality selected to to the amount of data per second being recorded. Most cameras with movie features have a small microphone/speaker for recording and playing back sound during the video. Don’t spend extra for a stereo microphone. How much stereo separation can you really get from a 4″ camera?
  An interesting feature that has been available for a while, but is appearing more and more on digital cameras is an audio note feature. This would allow you to record a small audio file which would be associated with the image you just shot. This replaces the photographers notebook that all of us were told to keep next to our cameras (yeah right) to help us remember what we were shooting.

This entry was posted on Sunday, October 21st, 2007 at 9:12 pm and is filed under Advice, Photography. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.