Since megapixels are often advertised as the measure of a camera’s image quality, one question that commonly comes up is whether a camera lens can add megapixels to your image.
Camera lenses can’t add megapixels to your camera. The camera’s megapixels are predetermined by the sensor, and there is no way to add any megapixels to the camera without changing the sensor itself. The lens is externally mounted on the camera and is a separate unit from the sensor, so it has no way to increase the megapixels.
Can a camera lens reduce effective megapixels?
Interestingly enough, there is a particular situation where the type of lens you use actually reduces the number of megapixels.
This happens when you use an APS-C lens with a full-frame camera. The APS-C lens has an opening that corresponds to the size of the APS-C sensor, which is smaller than a full-frame sensor.
When you mount an APS-C lens on a full-frame camera, light only falls on part of the sensor, and the camera can usually detect this, so you’ll end up with a cropped image.
That’s also one of the reasons APS-C sensors are called crop sensors.
Nowadays, most mirrorless cameras and dSLR cameras have APS-C sensors. APS-C sensors are of a decent size, and can do a great job for most photography needs. Full-frame sensors obviously can capture more light, and so they’ll be more sensitive in very low-light situations.
How are megapixels determined?
Now that we’ve answered the question of lenses and megapixels, let’s briefly look at how megapixels are determined to start with.
One megapixel is simply 1,000,000 pixels, much like one megabyte is 1,000,000 bytes.
A camera that has a resolution of 10 megapixels captures images with a maximum size of 10,000,000 pixels.
The sensor size determines how much information each pixel actually registers.
For example, a smartphone camera usually has a 1/2.55 inch sensor. If your smartphone can shoot 10 megapixel images, that means 10,000,000 pixels are crammed into a sensor of that size.
Compare that to a dSLR camera with an APS-C sensor that has the same resolution. In this situation, the 10,000,000 pixels are distributed in the much larger sensor. This means that each pixels is effectively “bigger”, resulting in better image quality.
Do higher megapixels mean better quality?
Higher megapixels don’t necessarily mean better quality. Image quality depends a lot more on the size and quality of the sensor rather than the raw megapixel count.
For example, a smartphone camera can take 20 megapixel images while a particular APS-C dSLR camera may take 16 megapixel images. The dSLR image will be of far better quality than the smartphone image.
The larger sensor can capture a lot more detail than the smaller sensor. In fact, even a 5 megapixel image captured by a dSLR will be far superior to a 20 megapixel image captured by a smartphone camera!
How do lenses affect image quality?
Just because the sensor is the main factor in determining the final quality of the image doesn’t mean the lens is not important. A good lens will do wonders. After all, it’s the lens that refracts the light and focuses it onto the sensor.
A poor quality lens may not refract light as well as a good lens. The quality of the glass and the mechanical parts may also not be up to par.
In most cases, though, lenses have a very high standard. Lenses made by camera manufacturers are always a good investment, as are third-party lenses from reputed manufacturers like Opteka and the like.
Do camera lenses have megapixels?
Camera lenses themselves don’t have any megapixel ratings, although certain lenses are designed to use with certain sensor sizes.
This is more apparent in cameras like dSLRs and mirrorless cameras, which have switchable lenses. When shopping for a lens, you need to make sure the lens is compatible with your particular sensor size.
Most camera manufacturers make a series of lenses for their cameras. For example, Canon makes a family of APS-C lenses for their APS-C cameras, just like they make a family of full-frame lenses for their full-frame cameras.
Frequently asked questions
How many pixels does a digital camera have if it has 10 megapixels?
A digital camera with 10 megapixels can capture images of 10,000,000 pixels. One megapixel is equal to 1,000,000 pixels.
Which factors of an image are affected by camera sensor size?
The camera sensor size affects the amount of light that is captured. A bigger sensor will lead to better low-light images, as well as being able to use lower ISO and larger aperture numbers.
So there you have it: camera lenses do not add megapixels, but they do affect the overall quality of the image. When shopping around for a camera, make sure the sensor size works for what you plan on using your camera for.