- Digital Camera Resolution - A digital photo is composed of millions adjacent dots spaced so closely that you can’t distinguish individual dots. Imagine all this on a stretchy piece of paper. Now if you stretch the paper the dots are pulled apart. If you have a lot of dots to start out with you won’t notice much if any difference, but if you have to few you will start seeing the differences between adjacent dots. Where this becomes important is what your intent is with the photo.
- Image Quality Settings - All digital cameras have the option of saving photos in the jpeg format, pretty much the default for digital images. It’s popularity arises from the fact that it is a format allowing different levels of compression resulting in smaller file sizes. Understandably there are trade offs. More compression means lesser quality. It’s hard to understand why they even provide the option of normal, fine, or superfine. A ‘normal’ setting will result in a crappy quality picture even on a rather forgiving computer monitor. Always use superfine or whatever they choose to call it.
Taking Pictures Of Fireworks
Taking digital photos of fireworks can be a bit tricky. By using a few basic rules however you should be able to get at least a few good shots that will impress your friends and family, even if your a novice photographer.
Focus, Focus, Focus - Auto focus does not work very well with fireworks, at least on the cameras I have used. So I’ve always used manual focus, carefully set up before the fireworks start. The biggest danger is that you must not inadvertently bump or touch the focus ring of the lens if you’re zooming in or out. This happened to me a once, and I ended up with nearly all the pictures out of focus, big time! I’m almost thinking of using a small piece of masking tape to the hold the focusing ring into position. Set your focus on something a few hundred feet away. That with the proper f-stop will put everything in focus to infinity. Handy online calculator can be found at here.
ISO Setting - Use the lowest ISO setting, normally 100
F-stop - Somewhere between F/8 or F/11. If your f-stop is to open, you will end up blowing out large sections of the picture in the center of the firework burst.
Shutter speed - Anywhere from 1 to 4 seconds. Shorter exposures are better for star type bursts, longer ones to get the willow tree effect. Typically one would use what historically was called the ‘bulb’ setting along with a cable release. Digital cameras have the electronic version of that. A store specializing in camera accessories will likely have one for your camera. If your camera does not have a bulb setting you can use the remote (if it has one) with a preset shutter speed of a couple of seconds. Unfortunately changing shutter speeds for different effects will be a bit of a pain. Last resorts would be to use a built in timer, set to minimum, or actually (very gently) pushing shutter button as if taking a regular picture. Obviously you’ll also need a tripod.
Other Considerations - After taking a few shots you might want to review what you’ve got. Inspect a picture or two very carefully by zooming in and scrolling around, and making adjustments to your settings as needed. Fat trails mean either out of focus, or over exposure (close down f-stop). Also look at other objects in the picture, such as distant street lights to confirm focus. Also be sure to turn off review, or you will have to wait for the review screen to disappear before you can take the next picture.
Happy shooting.
Digital Camera Aspect Ratio and Photo Print Size
What You Saw Is Not What You Got - You take your brand new digital camera along for your European vacation, shoot hundreds of photos, and start printing them when you get back home. To your shock and dismay you discover that all of your photos, many of which you carefully composed to include nice backgrounds, are cropped, missing either portions of the top or bottom, or both. What happened?
History of Photo Sizes - Going back in time recall the widespread 35mm format film used in almost every camera. The actual size of the negative was 36mm wide x 24mm tall, resulting in an aspect ratio of 1.5 (36/24). Next you took your film to be developed and have photos printed, most likely 6 inch x 4 inch in size. Since 6/4=1.5 is the same ratio as the negative, the image on the negative would be enlarged untill it filled the size of the photo paper. Perfect match. If you had your photos printed at 7 inch x 5 inch (aspect ratio of 7/5=1.4), a bit of cropping would be done either manually or automatically, amounting to less than 1/4 inch on each side. You probably never noticed.
Digital Camera Aspect Ratio - Fast forward to digital cameras. Initially manufacturers assumed photos taken with digital cameras would be primarily used for display on computer monitors. Many monitors have resolutions of 800 x 600, 1024 x 768, 1280 x 960, and so on. The common factor among all these is the aspect ratio of around 1.3 (800/600 for example). Looking at resolutions for typical consumer digital cameras such as Nikon Coolpix or Canon Powershot, you’ll find that these cameras have resolutions similar to the ones listed above. This means that they’re a good match for displaying your digital photos on computer monitors, but not so good for printing, in which case they should have an aspect ratio of 1.5 to transfer the complete image to a 6 x 4 photos. Note that DSLRs (digital single lens reflex, i.e. cameras with the flip up mirror) don’t suffer from this problem. Being essentially digital versions of the SLRs, their image sensors have the same ratio as 35 mm cameras.
Digital Image vs Printed Photo Proportions - This image shows an 800 x 600 digital image frame overlayed on a 6 x 4 print. As you can see a portion of the original image needs to be trimmed to match the size of the underlying 6 x 4 paper size. It may be equal amounts on the top and the bottom, or less on the top and more on the bottom, as long as the total pixel rows trimmed add up to 140. Automated processing will trim equal amounts from top and bottom of photo. If a human is assisting this process they may ‘move’ the photo up or down so as to capture what they believe are the important portions of the picture, but there is no guarantee. Most photo processing places now have the option of 6 x 4-1/2 prints, in which case the image and the paper are a near perfect match. The cost per print however is about double of a ’standard’ sized photo.
Composing Your Photo - So what to do? When you compose your pictures in the viewfinder or preview screen, be sure to leave a little extra space above and below the subject of interest, such as a person’s head. That way you won’t end up with the top of the photo annoyingly close to the head.
Optimal Digital Camera Resolution Settings
Digital Camera Resolution and Image Quality Settings - Almost all digital cameras have two types of resolution related settings: Actual resolution, and normal, fine, and superfine settings for each resolution (also known as quality settings). The two are only indirectly related. Whereas resolution determines the number of pixels in your photo, the quality setting determines the compression level of the file, which typically is a jpeg file.
Why It Matters - As camera sensor technology advances and memory chips get cheaper and more compact, digital camera manufacturers are one upping each other with resolution. This is great for those who really need it, but it also creates unnecessarily large files for many users’ needs. Though hard disk space is abundant and cheap, standing at a photo kiosk waiting for your 2 or 3 dozen of 7 meg photos to load can be painfully slow, not including any time spent cropping you may want to do. This article will give you some background on choosing camera settings in line with your needs.
Displaying Digital Photos on Computer Monitors - Most computer monitors have a resolution of about 72 dpi (dots per inch), regardless of size (such as 800×600, 1024×768, etc). Larger monitors don’t have anymore resolution than smaller monitors, they just have more dots because they’re larger in size. So if you intend your photos to be displayed on computer monitors only, than you really don’t need more than 72 dpi. This means that if you have for example a typical 14 x 10 inch monitor (advertised as a ‘17 inch’ (diagonal) monitor), of which about 2 inches are occupied by taskbars, headers, etc., you would need about an 800 x 600 photo (approximately (14-2)*72 x (10-2)*2 for those who like math). And in fact if you check image sizes on web pages you will find that they pretty much stick to this resolution of 72 dpi. Anything higher is just a waste of bandwidth.
Printing Digital Photos - The target resolution for photos to be printed should be 300 pixels per inch. This is not to be confused with home printer dpi. For more on printer dpi stay tuned for future articles. Most people have their photos printed at either 6 x 4 or 7 x 5 inch. This means that if you want maximum quality, your camera setting should be 6*300 x 4*300 = 1800×1200 for 6 x 4 prints, or 7*300 x 5*300 = 2100 x 1500 for 7 x 5 prints. The exact numbers vary between cameras.
Starting Points For Camera Resolution Settings:
| Usage | Pixels |
|---|---|
| 6 x 4 Print | 1800 x 1200 |
| 7 x 5 Print | 2100 x 1500 |
| Medium Computer Display | 800 x 600 |
| Large Computer Display | 1200 x 750 |
Note that your camera probably does not have the exact resolutions as listed above, and may even only list the first number (1800 as in 1800 wide). Just use something close. And remember, always use the highest quality setting (superfine).
