Manual White balance
This feature is present in most high end or “semiprofessional” cameras.
What it does?
Actually you can see it by yourself. Just take a white page and look at it in different lighting. When it is under sunlight it will appear white; Under low light it will appear gray; Under fluorescent lighting – purple … etc.
When digital camera is taking pictures all colors will be shifted and it will be really hard to obtain right colors. Manual white balance comes in help – when you use it point to something that you need to be white and camera will do the corrections for you.
In most of the cameras you have some preset values, but in real live this may not be enough.
Beginner photographs can ignore this feature.
Battery run time
One of important characteristics is how much time camera works on given set of batteries? Does it accept rechargeable batteries or already incorporates an integrated accumulator?
In later case you will need some additional information as:
- can you charge it in car or you will need to buy optional car charger? – If no you may need to consider buying DC to AC adapter.
- How much take for the accumulator to charge?
- What is the life of integrated accumulators? – usually measured in discharge/charge times
Tip: If you need to increase run time consider turning off LCD display. Of course you will need an optical viewer to see what you photograph. Unfortunately most of low cost cameras either do not have one or it “lies” – does not show correct picture area.
Attention: For some of the cameras out on the market the specifications show the time with optional high capacity accumulator and LCD turned off – read the fine-print.
One of important features is what type of storage is used into camera? What is maximum capacity? The recording speed?
Currently several technologies are used in digital cameras:
- CF – compact flash
- Micro-drive – miniature hard drive in CF format
- SD/MMC – secure digital/multimedia card
- MS – memory stick
- SM – smart media
- xD – picture card
They vary in sizes, speed and capacity and are often incompatible. So if your camera uses one you cannot put another format. Some of professional grade cameras are equipped with multiple slots supporting more than one type of card.
After determining the type you can shop for card prices and capacity. Verify camera documentation for maximum supported capacity.
Attention: Some cameras have small amount of integrated memory often impossible to expand.
Every camera has internal memory with capacity enough to store one picture and after you toke the picture the camera cannot take another one until the previous one is stored in storage media. So you need to verify the time need and how many pictures your camera can take before internal memory is filled.
To be continued
Now more about “other” specifications for a Digital Camera.
Angle of view
When photographing a group of people sometimes you need to take them closer together or step back to put all of them in a photo. This is called angle of view it depends on the ratio between the focal length and the film size.
As 35 mm cameras were professional standard, lenses are often described in terms of their “35 mm equivalent” fields of view. This is the difference between a normal lens (e.g. 50 mm), wide-angle lens (e.g. 24 mm), and telephoto lens (e.g. 500 mm). And is particularly common for digital cameras.
Mean values are 30-90mm for 3x zoom cameras.
The noise in the picture is one of most important parameters, but usually the one than is often omitted in characteristics of the camera.
Probably you’ve already seen that on some solid color areas you have dots or lines with different color just like when watching bad videotape on old VCR. This is called “noise”.
Theoretically if camera matrix is bigger there is less noise, but the size is not the only factor, the others like technology, thermal processes even electricity consumption are in play. So the best way of seeing the quality is to make test pictures. As a guide you can use camera sensitivity – usually measured in ISO. Camera with 50 ISO will be not so good as one with 800 ISO. In addition some professional cameras have noise reduction system.
The optic is one of the most important components for a camera. Low quality optic is usually seen when you take pictures with contrasting areas at the edge you could see colorful areas.
The only way to verify is to take test pictures.
Autofocus precision and speed
The precision and speed of autofocus differ from old 35mm cameras. On new digital cameras autofocus could take a second which could be crucial if you are going to take a picture of moving object, but is OK when taking static pictures. In addition autofocus could work properly when you have good lighting(such as taking picture outside), but poorly in low light (like taking picture at home).
Some cameras have low light indication and that is very useful, because in those conditions shutter is in 1/30 s and you need to keep camera steady – not a problem when light is good and shutter is 1/100 s.
to be continued…
Summer come and is time for vacation. One of the tools you will use to store those wonderful moments is Digital camera. But the question is how to choose one(in case that you still do not have one)?
This guide is not intended to replace other published guides, but to stress on “forgotten” parameters often crucial for the resulting image.
- Number of matrix pixels
- Manual white balance
- Storage type
- Interface type
- Time to run on batteries
Number of matrix pixels
This is one of the most advertised part of Digital camera specifications. Image resolution and from there quality depend on it.
But what is needed matrix size? It usually depends for what the acquired image will be used. In most cases this image will be printed.
“Standard” quality printing is 300 dpi (dots per inch). Standard photo is 10×15 cm (4×6 in) from there (with simplification) we can calculate 4×300=1200 pixels and 6×300=1800 so for ordinary photo you will need image 1200×1800=2.2 Mpixels (approximately).
If we do the same calculation for 20×25 cm(8×10 in) the result is: 7.2 Mpix. And following this procedure you could calculate the needed resolution for desired resulting print size.
NOTE: Probably best will be to have spare pixels if you need to crop the image. More you have – better.
WARNING: Some Digital cameras use interpolated resolution in their specifications, so you need ro read carefully.
ATTENTION: There is no linear dependency between matrix resolution and image quality.
Very useful function included in almost all Digital cameras allowing you to Zoom on the object without the need to change the distance between the camera and the object.
In addition this function will allow to crop from initial image everything that is not needed.
Zoom could be “optical” and “digital”.
Optical zoom is “the old school” zoom used in classical 35mm cameras. It uses optical lens to bring the object closer.
Digital zoom is not zoom in definition – instead it enlarges portion of the image using numerical algorithm or if matrix has more pixels than resulting image image is cropped(not common).
Typical numbers for digital cameras are from 3x to 10x for optical zoom and 3x-30x for digital one. Often the two are multiplied (when advertised) resulting 10x-300x zoom.
Quality wise optical zoom is much better than digital. Don’t wonder why your photos are not as sharp when using digital zoom – just use low resolution image for your desktop wallpaper and stretch it to full screen to see the results.
To be continued…