Comparison of Zoom Lens and Fixed Focus Lens

As a Lens Manufacturing Company, share with you.

In the debate between zoom lens and fixed focus lens, the most fundamental issue is the dispute over optical quality. The basis of the dispute is the MTF curve. Many zoom lenses have very high MTF curves, so it can be concluded that some zoom lenses have a high MTF curve. The optical quality is comparable to that of a prime lens. There are exceptions to everything. A few individual zoom lenses show excellent performance on the MTF curve, but MTF does not represent the entire optical quality.

Fixed Focal Length Lense

Five major aberrations of the optical system:

⒈Spherical aberration: This is usually manifested in wide-angle/ultra-wide-angle lenses, and can be mostly eliminated by using aspherical lenses;

⒉Commatic aberration: This contraction of the aperture can partially compensate for it;

⒊Astigmatism: usually appear in telephoto lenses, this can be partially compensated by using fluorite, ED, APO, abnormal dispersion, LD and other lenses;

⒋Curved field: only shrink the aperture to compensate;

⒌Distortion: Unless the original lens is very large, only a small part in the middle is used for imaging.

The intuitive indicators for evaluating the optical quality of the lens are:

A. Resolution: the ability to express details;

B. Color reduction: the ability to reproduce reality;

C. Glare control: the ability to deal with stray light.

In the zoom/fixed focus lens, the design of the aberration solution is the same, in the aberration 1, 2, 3, zoom and fixed focus can be done. However, if you shoot at the same aperture, the cul-de-sac of the zoom lens will appear: field curvature and distortion are not the opponents of the fixed focus lens. Of course, in most cases, the difference is not visible to the naked eye. For example, when not shooting macro, the performance of field curvature is not very strong. The shortest focusing distance can reach 0.38m, such as TAMRON28-300XR, this lens is at the 300mm end, it can also focus at 0.49m, and can shoot macro. At this time, the curvature of the field is manifested.

Among the intuitive indicators for evaluating lenses, the resolution of some zoom lenses can be comparable to that of fixed-focus lenses. How about color reproduction? It has a relatively large relationship with the coating of the lens, so it is easy to be comparable to a prime lens. But what about glare control? Due to the large number of lenses in a zoom lens, it is difficult to compete with a fixed focus lens with a small number of lenses. From this point of view, the weaknesses of the zoom lens are: field curvature, distortion and glare control. So if you want to say it easily: zoom can be comparable to fixed focus. I am afraid it will take time.

In fact, the biggest culprit of a zoom lens is its maximum aperture. At present, the maximum aperture of the zoom lens is only f/2.8, and the longest focal length that can be extended to only 300, such as SIGMA's 120-300/2.8. But for fixed focus, there are more than f/2.8 everywhere.

There is a spinning theory that supports the view that a zoom lens is better than a fixed focus lens: the results of theoretical tests are difficult to achieve in actual shooting, so the advantages of a fixed focus lens may not be able to fully play, and it is finally equivalent to a zoom lens. This theory is unreasonable. If the fixed focus is 98 minutes and the zoom is 95 minutes, if in actual shooting, the fixed focus only exerts a 50% advantage, then for the same user, he can use the zoom as well. Can play 50%, fixed focus is still better than zoom.

Our company also has Fixed Focal Length Lense on sale, welcome to contact us.