The Difference between Optical Zoom and Digital Zoom

In recent times, photography has become one of the popular professions and passions. Here, in this article, we are going to throw some light on, one of the vital features in photography, zoom. Zooming lets the user manipulate the picture to keep the desired subject in the frame at a perfect angle. Everyone must have seen or at least heard of Optical Zoom and Digital Zoom terms. Let’s have a look at Optical Zoom vs Digital Zoom.

Optical zoom

Optical zoom is the conventional method of zooming used in photography. In this method, camera lenses, aligned in a particular series manner, are moved physically to alter the focal length to achieve the zooming effect. There is no involvement of software here and hence it is called the true zoom.

The quality of zoomed-in pictures is the best as the whole scene, to be captured, is magnified via manipulating the focal length. However, one thing that can hinder the quality of the image is the material of the lens/glass used in the camera as it can have some limitations of magnification. This method produces lossless images. Hence, clear and crisp photos can be taken with the optical zoom method.

Nowadays, smartphone cameras also have optical zooming features. However, the traditional optical zooming method cannot be applied to slim smartphones as there is no room for lens elements to move around to achieve the zooming effect. One solution that smartphone makers have invented is to utilize a periscope lens camera setup to achieve the optical zoom effect. In this setup, a mirror is used to reflect the incoming light by 90 degrees allowing it to penetrate through multiple lens elements before captured by the camera sensors. This way smartphone makers can still design slim devices whilst providing lossless zooming features.

Highlights

• Achieved by moving physical lens elements
• True zoom
• Lossless
• Sharp and crisp images

Digital zoom

In contrast to optical zoom, there is no involvement of the physical manoeuvre of any component. Digital zoom is achieved by manipulating the image via software. In this, the original image is cropped in such a way that it produces a zooming effect.

Firstly, the image is cropped keeping the subject at the centre. After that, the cropped image is enlarged by intelligent software. To enlarge the image back to its original size, the software needs to fill some of the pixels. This filling process is done by an algorithm. The algorithm performs certain calculations to find suitable colours to be filled. Finally, the zoomed-in image is produced. The image quality is reduced in this method as the software has to fill the pixels. Though there are many intelligent algorithms available nowadays to keep up image quality, it is still not as sharp and crisp as the original picture. The optical zoom method is better than this one.

The digital zooming method is widely used in smartphones as they cannot afford to have optical zooming. On a lower budget or mid-range phones, the zooming effect is achieved by simply just cropping the image and filling the pixels, not so accurately as they lack a powerful processor to compute complex calculations. On the other hand, in high-end smartphones, multiple cameras are used to take pictures simultaneously and then performing digital zooming by computing the information received by those samples to maintain the image quality as high as possible.

Highlights

• Achieved by software
• Widely used in smartphones
• Lower image quality

Bonus: Hybrid Zoom

With the evolution of technology, a new method of zooming has been invented called Hybrid Zoom. This method is majorly used in smartphones nowadays. As the name suggests, it’s an amalgam of optical and digital zoom. Hybrid zoom is achieved using the software. Phones’ different sensors and focal lengths are used to capture more details by having pictures clicked from multiple cameras simultaneously. This information is then used by intelligent software to produce a better-quality zoomed image. The picture quality is not as sharp as optical zoom but better than the digital zoom.

Conclusion

To conclude, it is evident that the optical zooming method is the most reliable over others in any case as the quality of an image can be maintained as high as possible. So, if you are concerned about the image quality, consider optical zoom providing cameras without second thoughts.

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By: Kunj ‘SomeN’ Patel