I have been teaching photography for nine years, and the most common question I receive from my students is, “What kind of camera should I buy?” That is a loaded question, so I’ve decided to break up the blog into five different posts to address this question. This is Part 3 in the series on purchasing a new camera. To read Part I and Part 2, please view the previous two blog posts.
Below are the five criteria you should consider:
- What is my budget?
- Should I buy a DSLR or a mirrorless camera?
- Should I buy a full-frame camera or one with a cropped sensor?
- Should I buy a used or a new camera?
- What type of photography am I interested in?
This blog post will cover the 3rd criteria: Should I buy a full-frame camera or one with a cropped sensor?
DSLR and mirrorless cameras have three sensor sizes (sensor size is measured from corner to corner):
- Full frame – 43mm, aka crop factor 1
- APS- 28 or 27mm, aka crop factor of 1.5 or 1.6
- Four-thirds – 22mm, aka crop factor of 2
Understanding a camera’s sensor size will lead you to make a more educated decision on the purchase of a new camera.
First of all, what is a sensor? A camera sensor in a digital camera is the rectangular plate that is behind the mirror of a DSLR camera. In a mirrorless camera, there is no mirror to cover the sensor, so it can be found when you remove the lens. The sensor captures light and converts it into electrical signals, which make up an image. Sensors are the most expensive part to manufacture in a camera, so smaller sensors are found in many prosumer cameras. These are known as APS and four-thirds sensors. A full-frame sensor, which is the same size as a piece of 35mm film, is more expensive to manufacture, hence it is found on more expensive cameras.
Learning how cameras are labeled by sensor size will help educate you further.
Cameras with a full frame sensor are also known as full frame cameras. Cameras with smaller sensors are known as cropped sensor cameras. Full frame cameras include some Nikon, Sony, Canon, Leica and Pentax models. Cropped sensor cameras with a APS 28mm sensor size include some Nikon, Pentax, Sony, Leica and Fuji models The APS 27mm cropped sensor camera includes some Canon models. The smallest sensor size of 22mm includes Panasonic and Olympus models. All the above cameras will produce an acceptable image, so how do you know which sensor size you should consider?
The sensor size affects the lens focal length and the quality of the image. A sensor that is smaller than a full frame sensor has a crop factor. The crop factor is the ratio of the full frame sensor size and the smaller sensor size. For example, if you are using a Canon APS camera, the sensor size can be calculated by the following equation:
43mm/27mm = 1.6
The crop factor of 1.6 magnifies the focal length of a lens. A 35 mm lens on a Canon 6ti (APS sensor) would result in a true focal length of 56mm.
35mm x 1.6 = 56mm
There are advantages and disadvantages to a cropped sensor camera.
A 300-mm lens on a Canon 6ti camera would be 480 mm. This could be an advantage; however, on the other end, if you wanted to use a wide-angle lens of 15mm, the true focal length would be 24mm. Finally, a full frame sensor can provide a broader dynamic range and better low light/high ISO performance yielding a higher quality image than a cropped sensor. Cameras with full frame sensors are more expensive than cameras with cropped sensors. It all goes back to the question in Part 1: “What is your budget?”
The following image illustrates the different sensor sizes and the crop factors.
As always, I recommend you learn more about sensors by doing research. Below are some of my favorite articles and videos on this subject: