Except where indicated, the information in this post was retrieved from Sensor Size Comparison: Find Your Best Camera Fit. You should read that post for greater detail.

There are many different ways to categorise cameras. For example, cameras can be categorised by media type; sensor size; single or interchangeable lens; viewfinder, electronic screen, or rangefinder; and so forth. In this post, I will attempt to classify, clarify, and cross-reference these categories. So let’s begin.

Sensor Types

Digital cameras use one of two sensor types: Charge Coupled Device (CCD) and Complementary Metal-Oxide-Semiconductor (CMOS). CCD sensors were used in cameras up until about 2005 or so, with CMOS sensors being used from the early 2000’s onwards.

CCD sensors have traditionally produced higher quality, lower noise images. CMOS sensors are more power efficient, and have advanced to be just about on par with CCD sensors in terms of quality and noise performance. For a detailed discussion of the differences between CCD and CMOS sensors, and how camera sensors work, see What is the Difference Between a CCD and CMOS Camera Sensor?. Since all sensors in modern still photography cameras are CMOS type, the differences are not germaine to this discussion.

Sensor Sizes

Sensor size (both physical dimensions and the number of pixels on the sensor) affects a number of characteristics, such as low light performance, depth of field, and out of focus quality (bokeh). For example, a 1/2.3 sensor has extremely poor low light performance, but larger depth of field (the amount of the image that appears in focus) and much less bokeh for the same lens aperture setting than any of the larger sensors.

Sensor size also affects the size of lenses required to cover the full area of the sensor. For each increase in sensor size, lenses must be larger in diameter and therefore are heavier in weight. Compare, for example, the lenses for the cameras in your smartphone to the lenses on a typical full frame camera.

*There are actually a number of different size designations ranging from 1/3 to 1/1.7 with corresponding physical size differences, but 1/2.3 is the most common, and therefore the only one listed here.

**Called 1 Inch for historical reasons.

***Canon’s APS-C sensors are 22.5mm x 15mm.

**Fujifilm GFX cameras have a sensor size of 43.8mm x 32.9mm.¹

Camera Types

DSLR

• interchangeable lenses
• sensor is fronted by a two screen shutter which is in turn fronted by a mirror that diverts the light entering the camera into a pentaprism and then out the viewfinder.
• some DSLRs also have a rear electronic screen which may display the same image as the viewfinder.
• any of large and medium format, full frame, APS-C, and Micro four Thirds
• When the shutter button is pressed, the screen flips up out of the way, first shutter screen opens, and at the end of the exposure, the second shutter screen closes. Mirrorless
• interchangeable lenses
• sensor may be fronted by a one or two screen shutter which remains open. The sensor is read continuously and the image is fed directly to an electronic viewfinder or electronic screen on the rear of the camera.
• Point and shoot
• automatic settings making it simple to use
• usually 1/2.3 sensor
• fixed lens with either a fixed focal length or small zoom range (1-3x is typical)
• poor low light performance Compact
• similar in size to point and shoot, but with advanced camera settings
• may have larger sensor than point and shoot. At least one has a full frame sensor.
• fixed lens with either a fixed focal length or small zoom range (1-3 types is typical)
• poor low light performance Bridge
• fixed lens with very large zoom range (1-24x up to 1-60x)
• usually 1/2.3 sensor size so poor low light performance Large and Medium format Smartphone Rangefinder

Sensor Sizes 1/3 to 1/1.7 1/2.3 is a typical size, about 6.17mm x 4.55mm budget point and shoot cameras older smartphones and entry level phones pocket zoom cameras poor low light performance

1 Inch 13.2mm x 8.8mm (actually 15.9mm diagonal, not 25.4mm which is 1 inch) newer smartphones poor low light performance, but better than 1/2.3

Micro Four Thirds 17.3mm x 13mm offers balance between compact camera and lens size, and performance better low light performance than 1 inch sensor, but poorer than APS-C

APS-C 22.5mm x 15mm (Canon) to 24mm x 16mm (Other manufacturers) good balance between image quality, low light performance, and cost

Full Frame 36mm x 24mm (same as 35mm film) very good image quality, low light performance, and superior depth of field control

Large Format 43.8mm x 32.9mm (Fujifilm GFX) up to 53.4mm x 40mm best image quality, incredible depth of field significantly more expensive than full frame bodies and lenses

Camera Type vs Lens Type

Camera Type vs Sensor Size

Questions to Ask Before Buying a Camera

What Am I Interested in Photographing?

You may have one or two photography ideas in mind, but you should consider other areas that you might be interested in. For example, here is a non-complete list of things to photograph. I have tried most of them at least once.

• Nature
  • landscapes
  • flowers and leaves
  • birds and other wildlife
  • insects
  • tree bark
  • sand and rocks
• People
  • your friends and family in informal settings
  • your children playing
  • portraits
  • weddings
• Professional and amateur sports
  • baseball
  • basketball
  • hockey (ice, field, etc.)
  • football (soccer, rugby, American, Canadian, Aussie Rules, etc.)
  • tennis
  • track and field
  • bicycle races
  • canoe and kayak races
  • dragonboat races
  • car, drag, motorcycle races
  • horse races
  • highland games
• Street photography
  • people interacting with others or their environment
  • street portraits
  • indoor and outdoor events
    • fall fairs
    • street festivals
      • giant garage sales
      • ethnic festivals
      • pride parades and festivals
      • national holidays
  • buildings and architecture
  • cityscapes
• Closeup and Macro
  • flowers
  • insects
  • fungus and lichens
  • watches
  • jewellery
  • kitchen gadgets
• Other
  • air shows
  • car shows
  • carnivals
  • fireworks
  • food
  • still life
  • ICM (Intentional Camera Movement)
  • multiple exposures

And those are just a few photography subjects and ideas off the top of my head.

What Will I Do With My Photos?

The obvious answer is ‘you will display them’. But how? Here are the most frequent ways:

• On social media (Instagram, Facebook, flickr, Vero Social, etc.)
• In albums on my phone, tablet, or computer
• As slide shows on my computer and smart TV
• As screen saver images on my tablet or computer
• Printed and placed in photo albums and portfolios
• Printed and hung on a wall
• In printed books and zines
• Printed as post and other cards (Christmas, birthday, etc.)

Now What?

So, you have made a start at answering the questions above. What camera should you buy? If you own a smart phone, that is an iPhone or a phone that runs Android, then you already have a camera. Well, in most cases, more than one. Every smart phone has at least two, and probably three or four lenses and sensors, with one on the front for selfies, and one or more on the back. The ones on the back each come with a lens of different focal length, and each sensor may have a different pixel density. More on that in an upcoming post.

So, if you have a smart phone, start with that. You will be able to determine what your interests are, and what the limitations of that device is. Only then will you be ready to consider a new camera and its required capabilities.

But that is for a different post.

You may own several thousand dollars worth of camera equipment, but that equipment is worthless if you do not carry it with you. Your mobile phone works in a pinch, or even exclusively. Get to know it for when you do not have your camera with you.

1. Keeping stuff on their computing devices safe, whatever safe means.
2. Confidentiality: keeping other people away from information like passwords, banking information, and so forth.

Those people are only partly correct. Let me explain.

First of all, information security has three tenets;

1. Confidentiality, which almost everyone thinks of.
2. Integrity. Making sure that your information is, and remains unaltered when it shouldn’t be.
3. Availability. Making sure that your information is not lost, either accidentally or through malicious acts by others.

But I Don’t Have Anything on My Phone/Computer That is Worth Stealing

** Danger Notice** Boy, are you wrong there! Please read on.

To gain access to your computer/phone/tablet, you must log in using a password, PIN¹, or some biometric input (facial recognition, finger print, and so forth). If I can gain access to your device for even a very short period of time, I may be able to determine what that password or PIN is. I then have the same access as you to your device. I won’t discuss how at the moment since there are many different ways; just know that I won’t need physical access.

Once I have access to your computer or other device, I can then take all the time I need to determine your other passwords. I would be able to access your emails and any websites that you save passwords for. Think your banks, social media sites, and so forth. For all intents and purposes, I am you (confidentiality). I can then change each password so that you lose access (availability). This can result in anything from minor inconvenience if you catch it soon enough to outright disaster depending on what I have time to do.

I may not even be after your personal information and finances. I may encrypt all of your information and then attempt to extort money from you to give you back access to it. (availability)

Or, I may use your internet or data connection to attack others. This is far more common than you think!

Maybe I will modify your files (integrity) or delete them (availability) just to screw with you.

What About Those Old Income Tax Returns and Bank Records You Threw Out

Information security is not just computer security. It is also what you did with that piece of paper, with personal infomation on it, that you disposed of.

If I can gain access to your bank, income tax, and other financial records, even old ones, I have more information about you that I could use to impersonate you. Once I have enough information, I would be able to access to your bank accounts, take out loans in your name, and so forth. It will take you years to undo the damage I could wreak.

My Computer Crashed and Now I Can’t Access My Data

You probably didn’t think that this falls under information security, but it does. Remember that information security involves keeping your data safe. It is not safe if you can’t access it.

Summary

So, information security involves keeping your data available and correct, not just away from others.

Information security is not just computer security; it involves many things including how you disposed of that sheet of paper with personal information on it.

Where Do We Go From Here?

Future posts will cover many aspects of information security, including steps you can take to improve the confidentiality, integrity, and availability of your information.