Have You Ever Wished to Understand Digital Camera Basic Specification ?

Introduction

Digital camera specification is the major factor to decide on a digital camera.  It is easy to get confused on all the options described in the specification.  Most of the us usually decide on camera based on the mega pixel and brand name. In addition to the megapixel, there are other requirements contributed to quality of a camera.  The major requirement of a good camera are:

1. Types of camera
2. Mega Pixel
3. Sensor Size
4. Aperture (F/number)
5. Focal Length of the lens
6. Shutter
7. ISO
8. Features of the camera

Types of camera

First you have to decide what types of digital camera to buy i.e. Points and shot, or DSLR or mirrorless interchangeable lens camera.  I have already posted a blog about types of camera (Click here to read).  By and large, DSLR has better picture quality than a mirrorless digital camera and mirrorless digital camera is better than a compact digital camera. 

Compact Digital Camera

Mirrorless Interchangeable Digital Camera

DSLR digital Camera

 

Mega Pixel (MP)

A megapixel is equal to one million pixels. Digital pictures are formed by these tiny pixels in different color. Pictures taking with 10 mega pixels consist of 10 million pixels. Each pixel is like a tiny dot. Image quality depends partially on number of pixels of a sensor.  For printing a picture of 4x 6'', the camera should have at least 2 MP.  The minimum megapixels required for different size of pictures are stated as follows:

Print Size        Required Pixels

4 x 6″	2 megapixels
5 x 7″	3 megapixels
8 x1 0″	5 megapixels
11 x 14″	6 megapixels
16 x 20″	8 megapixels
16 x 24″	12 megapixels

Visualize the Tiny Pixel of Digital Camera

Image Sensor Size

The other factor which may affect image quality are sensor size.

Digital Camera Sensor

Sensor is an electronic device that records the picture and is light sensitive. The larger the size the better picture quality. The compact camera size is usually as small as the little finger.  The professional DSLR has a sensor as big as the size of 35mm (which is the same size of a 35mm film).  Entry level DSLR or some mirrorless interchangeable lens cameras usually has the second largest sensor (APS-C) and the third Micro 4/3 the third largest. APS-C sensor is about 64% size of a full frame sensor.  Micro 4/3 digital camera sensor is about 60% of a APS-C sensor.

Image sensor size comparison

If a small sensor compact camera has the same mega pixel of a large sensor size camera, the picture quality with a larger sensor should have better picture quality.  It is because the large sensor record more light than the small sensor. The small sensor is sort of over populated the tiny pixel in small size.

Aperture (F/number)

Amount of light absorbed by the sensor is measured by f/number. Aperture measure the quantity of light absorbed by the sensor.  Aperture is expressed in terms of  f/number for example f/2.8, f/4, f/5.6,f/8,f/22.  The smaller the number the larger the quantity of light.  For example  from f/2.8 to f/4 decrease the amount of light by 1/2  (1/(4*4/2.8*2.8)=1/2).  On the other hand, from f/4 to f/2.8 increase the amount of light by double (1/(2.8*2.8/4*4=2)

Digital Camera Aperture

Most of the lens has the best picture quality between f/5.6 to f/11.  The lower the f/number the lesser the picture quality.  The larger the aperture, the shallower of the depth of field.  Depth of field is the distance of clarity behind the main object of focus.

Focal Length

Focal length is the distance from the lens to the sensor of a digital camera. The longer the focal length and f/number the largest is the diameter of the lens.  Taking pictures of far distant object require a long focal lens and large aperture.That is why the long focal length (long Tele lens) that you saw on sport games is long and bulky.

Digital Camera Lens Focal Length

The higher the focal length, the shorter the depth of field. The shorter the depth of field, the less clearer of the background.  Depth of field is the distance of clarity behind the main object of focus.

Digital Camera Depth of Field

Shutter Speed

Shutter speed the amount of time that the digital sensor absorbing the light. Shutter speed is measured in seconds, i.e 1/30, 1/60, 1/100.  The bigger the denominator the faster the speed (ie 1/1000 is much faster than 1/30). The higher the shutter speed, the less time of absorbing the light.  Camera shake (that blurs the picture) is avoided with higher shutter speed.  If the time is too long, pictures become blurred due to camera shake.

ISO

ISO measures the sensitivity of image sensor.  The higher the number, the higher sensitive the digital camera is to light. In turns, the grainier (noise) the pictures shows and the less details of the pictures.

Features of the Camera

The camera features such as image stabilization, fully auto, automatic scene selection, intelligent contrasty adjustment all contributes to the pictures quality.

Relationship of the Aperture, Shutter and ISO that Have Impact on Depth of Field

1. The higher the focal length, the shorter the depth of field. The shorter the depth of field, the less clearer of the picture background. 
2. The smaller the F/number (i.e. larger aperture), the shorter the depth of field. Hence, the picture shows less clearer of the picture background.
3. The smaller the shutter speed, the smaller the F/number (larger aperture) is required.  Hence, the picture show less clearer of the picture background

Check List of Buying a Digital Camera

Before buying a camera, determine the following:

1. Budget
2. Purpose of the camera
3. Types of camera
4. Brand name of the camera
5. Minimum mega pixel of the sensor
6. Image sensor size
7. Minimum Lens aperture
8. Lens focal length
9. Minimum shutter speed
10. Minimum ISO of sensor
11. Features of the camera