Is a crop sensor or full frame sensor camera best for you?

The best sensor type depends on your individual needs, your budget and how much weight you want to carry around. If you’re looking to learn more about the differences to help you decide between a crop sensor vs. a full frame sensor then this is the perfect article for you.

The camera sensor – why is it important?

The camera sensor is a grid of tiny photosites which takes the light (photons) and converts it into electrons. These are then converted into voltage and then into pixels ready to be written onto the memory card. If all of that went way over your head, then don’t worry. Basically, your sensor is important! But how important depends on your needs…

There are typically two main characteristics that describe a sensor.

• Sensor size: Full frame, crop, Micro Four Thirds etc.
• Sensor resolution: This is the number of pixels which are packed within the sensor, usually reported in megapixels.

The size and resolution of the camera sensor can lead to differences in the dynamic range, noise and field of view (magnification difference due to crop sensor multiplier).

People often say larger sensors will “gather more light”. However, this isn’t strictly true. It’s because they enable the use of a larger lens for the same field of view.

As a larger lens is needed to cover a larger sensor size (full frame) when this is coupled with a larger aperture the “aperture diameter” (focal length divided by f/number) is larger. It’s this larger aperture diameter which gathers more light, not the sensor itself.

Crop sensor or full frame sensor?

Both crop and full frame sensor have their benefits which are described below.

Crop sensor benefits

• Generally housed by a cheaper camera body.
• Allows for cheaper, smaller & lighter lenses. As the camera lens needs to cover a smaller sensor area.
• Enables reduced-size camera body.
• Enables increased reach due to crop factor (e.g. 1.6-1.6x). A larger, heavier and more costly lens is needed to achieve the same focal length reach on a full-frame camera.
• Can be used with most full-frame compatible lenses. This is an important factor when compared to differences in camera body as the lens has far more impact.

Full frame sensor benefits

• The larger pixel size typical for larger sensor crop sensor cameras assists with providing an improved dynamic range for full frame vs. crop sensor.
• For the same resolution sensor, larger pixels on a full-frame camera tend to help reduce noise, especially in low-light situations.
• For the same resolution sensor, a full-frame camera sensor will have larger pixels when compared to a smaller crop sensor camera. This will typically allow for better quality images at high ISO in comparison to a crop sensor camera.

Full frame benefits on selected camera bodies

• A full frame sensor camera will typically come with more extensive features found in “professional” use camera bodies, not always found in crop-sensor cameras.
•  A larger sensor size facilitates higher sensor resolutions. This facilitates cropping without losing detail. This is only typical on the most recent flagship cameras such as the Nikon Z7/Z8, Canon R5 & Sony A7CII/A7Riii.

What about depth of field?

There is often a misunderstanding that the full frame sensor itself creates a more shallow depth of field.

When taking a photo of a subject at the same distance with equivalent focal length and aperture on a crop and full-frame camera, the depth of field will be the same. The difference is that the cropped sensor image will have a tighter crop. However, if the full-frame camera image is cropped to match the crop sensor image the depth of field will be equivalent.

The misinterpretation comes from the fact the full-frame camera would need to move closer to the subject or use a longer focal length to achieve the same field of view, therefore naturally giving a shallower depth of field. 

TOP TIP: To achieve a shallow depth of field (and the associated Bokeh/ background blur) ensure you consider the following aspects. 

• The lowest possible aperture
• Longest focal length
• Increase the distance between your subject and the background
• Reduce the distance between you and your subject

To summarise, full frame sensors do allow for a shallower depth of field, due to focal length or distance from your subject as opposed to the sensor itself. 

Megapixels?

Lower-megapixel cameras typically have lower noise, especially in low light conditions. However, higher-megapixel cameras have the advantage of increased resolution which can retain fine detail.

Both full-frame and crop sensors can come at different resolution sensors. However, the largest megapixel sensors will be found on the larger full-frame sensor camera bodies. Typically, unless you’re a professional, these flagship models may not be needed. 

DSLR vs. Mirrorless?

What is a DSLR: A Digital Single Lens Reflex camera has a mirror. This covers the sensor and directs the light across a pentaprism to the optical viewfinder. When taking a photo the mirror is raised which reveals the sensor for taking a photo.

What is a mirrorless camera? A mirrorless camera, as the name suggests doesn’t have a mirror. Instead, the sensor is directly in front of the lens, without the mechanical mirror assembly, only a shutter. Some are without a mechanic shutter and use an electronic shutter which reads the required information when taking an exposure.  Without a mirror, these cameras rely on an “EVF” an electronic viewfinder.

A crop sensor DSLR will typically be smaller and lighter than a full-frame DSLR. However, a full-frame mirrorless can be smaller than a crop sensor DSLR. 

Mirrorless cameras have come a long way in recent years, especially for full-frame cameras. The lens choice is also expanding rapidly, which was historically limited. However, mirrorless cameras still come at an increased cost when compared to DSLR cameras with similar features. 

Most camera manufacturers are now fully focused on their mirrorless camera lineup, with many models of DSLRs being discontinued. With a huge range of DSLR lenses available on the market DSLR cameras most certainly still have their space and can offer a cost-effective option to high-end cameras and lenses, with the drawback of the increased size and weight. Read more about lens options for crop and mirrorless cameras in this article on travel photography gear.

Additional aspects to consider for mirrorless cameras:

• Battery life is typically worse as the EVF uses power together with the sensor stabilisation. However, battery life is always improving and is getting close to what is expected for a DSLR. 
• Sensor cleaning may become something that’s required more often as most cameras have the sensor exposed during lens changes. It’s good practice to keep your camera body facing downwards while you change your lens to reduce the chance of dust entering your camera body. 
• Regarding image quality you’re unlikely to see any difference when comparing cameras with similar sensors. 
• Autofocus systems were initially problematic on some models, but now exceed the capabilities of most DLSR systems, especially with capacities such as eye tracking. 
• The speed of photo capture rate is incredible for mirrorless systems, with 20 fps+ achievable, even with raw files, with a buffer you’re unlikely to ever be limited by.
• For those used to an optical viewfinder an Electronic Viewfinder may take some getting used to, as the image isn’t as you would see it “live’ with your eyes, it’s how your camera would see it. Although limited by the frame rate and resolution, long term this has benefits for monitoring both exposure and focus while capturing images. It also works well for reviewing images in direct sunlight, which can be a challenge on the rear LCD screen.

Crop vs. full frame sensor: What is right for you?

Full frame 

• Indoor/ Low light situations: Inside or in low light situations tripods are not always appropriate, for example moving subjects. Therefore, the shutter speed is limited by the focal length of the lens (and any added sensor or lens stabilisation). To maintain this shutter speed an increased ISO is required, depending on the lighting conditions. The reduced noise capability of a full frame sensor can assist in these environments. There are also often bright lights indoors, which can create extreme dynamic range, typically better suited to full frame cameras.
• Night / Astrophotography: Where extended shutter speed is limited to avoid star trails and you’re at the lowest possible aperture, there is no other way than to significantly increase ISO. A full-frame sensor will allow good high iso performance while reducing noise. The wider field of view also enables both the foreground and sky / Milky Way to be captured reducing the need to stitch multiple images.
• Landscape: Many prefer full-frame cameras for landscape photography with their improved dynamic range and wider field of view. However, these do come with a cost, size and weight penalty. 

Crop sensor

• Travel: The size and lower weight of both the camera body and lenses are highly attractive for travel photography. The increased effective focal length due to the crop factor also helps achieve increased reach with smaller lenses.
• Street: A compact camera allows you to stay discrete, especially when paired with smaller lenses.
• Hiking/landscape: Often it’s preferred to hike with a variety of lenses as this helps to capture the scene. Smaller and lighter crop sensor cameras are preferred, especially for mountain landscape photography where you may be hiking up significant elevation. 
• Wildlife: Even some professional photographers use crop sensor cameras for wildlife as the smaller sensor and the associated crop sensor can enable longer focal lengths, key for this genre. For bird photography, this is very effective. Reaching long focal lengths on a full-frame camera will set you back £10k+ for a 500 or 600mm f/4 lens. Whereas shorter focal length lenses are far more reasonable, achieving similar reach due to the crop factor.
• Sports/Action: Sports in similar to wildlife with regard to the advantage of the crop factor. For sports, like wildlife a low aperture lens is preferred, and money can be saved by using a shorter focal length wide aperture lens and relying on the 1.5-1.6x crop factor to gain the reach.

Summary

In summary, both full-frame and crop sensor camera systems have their pros and cons for different genres of photography. 

If you’re a professional or you have the budget, a full-frame mirrorless camera and the associated lenses will be the preferred option. However, these come with a significant price tag, weight and size disadvantage.

Therefore, for travel photography, especially if you’re often using longer focal lengths, a mirrorless crop sensor camera system could be preferred. This setup will be lower cost, size and weight, with a slight reduction in dynamic range and low-light performance. 

If you’re just starting out you may be interested in our article on Travel photography gear for beginners.

To save on costs further, an older DSLR system is a great way to save on costs and make use of the extensive lens portfolio of both full-frame and crop-sensor cameras, while still achieving excellent images.

Read more about the D7200 camera I use and the best lenses for travel photography.  As many crop sensor cameras can use full-frame lenses, this is a great way to get started with purchasing a set of lenses for the long run (more important than the camera!) ahead of a more expensive full-frame camera.