When preparing to buy a digital camera many people are faced with the tough decision of whether to buy a DSLR camera body with a full frame sensor or to get what is known as a crop sensor DSLR.

Unfortunately there are pros and cons of each type, but much of the decision should come down to what subjects you mainly photograph, whether weight and cost are an issue, and if you shoot mainly wide angle or telephoto photography.

In this short article I am going to try and cover some of the strengths and weaknesses of each sensor type to help guide you in your buying decision.

But first, let me just clarify the meaning of full frame and crop sensor in case you are still a bit unclear on the subject.

All 35mm DSLR cameras contain a digital imaging sensor with electrically charged receptor sites for capturing light as it comes through the lens, the camera body, and then into the sensor. The sensor in digital cameras is what replaces the old analog film technology from the past which used to capture light by exposing a piece of light sensitive emulsion with today’s electronic method of capturing light. But the physical size of these digital sensors vary on different models of digital cameras.

A full frame sensor simply means that the sensor is equivalent in physical size to a frame of 135mm film. A crop sensor, also known in technical terms as an Advanced Photo System type-C (APS-C) sensor, means that the physical size of the sensor has been cropped down from a full frame sensor size to something smaller. The actual size of APS-C sensors will vary a bit from camera to camera and brand to brand, but generally they are about 30% smaller in physical size than full frame sensors.

Canon 7D Mark II Crop Sensor

Now you might already be thinking; How can there be any advantage to having a crop sensor which is smaller in size than a full frame sensor?

Size Difference Between Crop Sensor And Full Frame Sensor

The truth is there are a number of advantages of a crop sensor, although they may not be so obvious at first. To understand these advantages though let’s first discuss something known as the crop factor and how camera bodies with APS-C sensors are affected by it.

Various Different Sensor Types And Sizes From The Smallest Up To Medium Format

The first major difference is that the crop factor increases the focal length of any lens when it is mounted to a crop sensor body. Normally this is by a factor of 1.5 or 1.6 of the actual focal length of the lens you are using. This means for example that a 200mm lens becomes a 300mm lens equivalent when placed onto a crop sensor DSLR body, but thankfully without all the extra weight of a true 300mm lens. This is particularly useful if you are shooting sports, birds, and other objects at a far distance away as it gives you more reach without more weight and cost of a bigger lens. It is a disadvantage though if you are trying to shoot wider angle subjects as it also causes you to lose the wider end of the focal length of a lens.

Crop sensor bodies also increase the depth of field on your photos. So shots taken at F/5.6 for example on a crop sensor body will have the appearance of about 1 more stop of depth of field and resemble more like a shot taken at F/8. Again, this can be good or bad depending upon the look you are aiming for. If sharpness and greater depth of field is your goal then a crop sensor DSLR could suit you better.

Now why are these two issues the case? Since a cropped sensor is about 30% smaller than a full frame sensor, it can only utilize the middle 2/3 of the lens’ glass area itself. This center area of the lens also results in a longer focal length and a sharper overall image because the loss of sharpness and area of shallower DOF normally occurs towards the edges of a lens and this is the area of the lens that the cropped sensor doesn’t utilize.

Also, crop sensor DSLR bodies are less costly for the manufacturer to produce. This makes the prices of crop sensor DSLR cameras generally lower than full frame DSLR bodies on average by 30%. In some cases a crop sensor also makes the camera body smaller and lighter in overall size and weight, which will be more advantageous to some photographers who prefer a lighter and more compact DSLR build.

The biggest advantage to a full frame sensor is though that it has more physical size and a larger image capturing area. So for one, it can usually capture more pixels than a cropped sensor camera can. You also don’t lose any focal length at the wide end of a lens with a full frame sensor. So it is usually more advantageous to use a full frame sensor DSLR camera when shooting landscapes and taking other types of wide angle shots.

Full Frame 35mm DSLR Sensor

For the most part, a full frame sensor is what most people desire since it is the same feeling as when you were shooting with 135mm film in the past. Also, the viewfinders are normally bigger and brighter to look through than those on a smaller crop sensor camera. This makes a full frame camera easier for most people to shoot with.

For me, I only want to shoot with a full frame body for the work I do. But if I were a sports or nature photographer, then I am sure I would welcome a crop sensor camera body because of the added reach on lenses and the lighter overall weight of the body.

If you feel there are other major advantages or disadvantages of full frame or crop sensor cameras that I failed to mention then please feel free to add your thoughts below. I hope you at least now have a better understanding of the subtle differences in sensor sizes and the pros and cons of each type.