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Optical Design value Analysis - NIKON NIKKOR 14-24mm F2.8 F vs Z -tele part[No.035]

2022-12-07

This article compares the performance of Nikon's large-aperture F2.8 super-wide-angle zoom lens, the F mount Nikkor 14-24F 2.8, and the Z mount Nikkor Z14-24F 2.8, at the telephoto end (24 mm).

You hardly understand the specific differences in how the lenses work and how their performance differs from each other, do you?

Even if you look it up in magazines or on the Internet, all you will find are similar "word-of-mouth recommendations" and articles like that.

In this blog, while researching the history of lenses and their historical background, we estimate lens design performance based on patent information and actual shooting examples, and analyze lens performance in detail from a technical viewpoint through simulations.

Professional lens designer Jin Takayama will carefully unravel optical characteristics such as optical path diagrams and aberrations, which are generally not visible, and explain the taste and descriptive performance of lenses in a deep and gentle manner.

Now, please enjoy the special information that you can read only on this blog in the world.

Overview

The old F-mount NIKKOR 14-24 lens is called "F14-24F 2.8" and the new Z-mount NIKKOR 14-24 lens is called "Z14-24F 2.8".

In the previous analysis

Comparison of new and old NIKKOR 14-24mm f/2.8 [Part 1: Wide-angle end]

This is a performance comparison article of the telephoto end of the 14-24F 2.8.

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NIKON NIKKOR Z 14-24mm F2.8 S

Notes!

The following design values have been selected and reproduced from the appropriate patent literature and do not correspond to the actual product. Naturally, the data is not guaranteed, and I am not responsible for any accidents or damages that may occur by using this data.

Analysis of Design Values

Optical Path Diagram

The left side (blue) of the above figure shows the optical path of the old lens F14-24F 2.8, and the right side (red) shows the optical path of the new lens Z14-24F 2.8 at the wide-angle end.

As I mentioned in the article on the wide-angle end, the new lens Z14-24F 2.8 has been miniaturized as a whole, but the huge and distorted large-aperture aspherical lens on the side closest to the subject attracts attention.

However, when looking at it in a room, it is a difficult problem because the first lens which is the shape of the projecting eyebrow of the old lens F14 - 24 F2.8 looks very mysterious and beautiful.

  • Note: This is not the correct way to use it.

Let's take a look at aberrations.

Longitudinal Aberration

The left lens (blue) is the old lens F14-24F 2.8, and the right lens (red) is the new lens Z14-24F 2.8.

Spherical Aberration, Field Curvature, Distortion

Spherical Aberration , Axial Chromatic Aberration

Both spherical aberrations seem to be well corrected.

In the old lens F14-24, the g-line (blue) is largely bent to mitigate the effect of axial chromatic aberration with higher-order aberrations. In the new lens, however, the aberration itself is reduced to a straight-line shape.

Field Curvature

With the new lens Z14-24F 2.8, the curvature of field changes gradually from the end to the tip, and the color components of the g-line (blue) and c-line (red) are also gentle, which indicates sufficient improvement.

Distortion

The distortion is different from the wide-angle side, but the plus side (winding shape) aberration remains, and the new lens Z14-24F 2.8 seems to have a larger value.

Even if it's big, it's only up to 2%, so it's not a noticeable amount, but it's probably because it's corrected by image processing, which is a blessing of the digital age, so it probably prioritized resolution improvement and miniaturization.

Lateral Chromatic Aberration

The left lens (blue) is the old lens F14-24F 2.8, and the right lens (red) is the new lens Z14-24F 2.8.

Looking at the chromatic aberration of magnification, the new lens Z14-24F 2.8 reduces the g-line (blue) by half while leaving some waviness, and the c-line (red) is corrected to nearly 0.

Transverse Aberrations

The left lens (blue) is the old lens F14-24F 2.8, and the right lens (red) is the new lens Z14-24F 2.8.

(Left)Tangential direction, (Right)Sagittal direction

The transverse aberration of the new lens Z14-24F 2.8 has been improved in both the tangential coma aberration and the halo component of the color.

Spot Diagram

The left lens (blue) is the old lens F14-24F 2.8, and the right lens (red) is the new lens Z14-24F 2.8.

Spot Scale 0.3 (Standard)

Now we are going to look at the optical simulation results, but at the spot diagram first.

The new Z14-24F 2.8 lens appears to have a slightly larger g-line (blue) at 6 mm in the center, but overall the spot size has been improved by half.

Spot Scale 0.1 (Detail)

This is the view of the spot with the scale changed and enlarged.

MTF

The left lens (blue) is the old lens F14-24F 2.8, and the right lens (red) is the new lens Z14-24F 2.8.

Maximum Aperture F2.8

Finally, let's review the results of the MTF simulation.

As with the optical path diagram, the upper line shows the old lens F14-24F 2.8, and the lower line shows the new lens Z14-24F 2.8 with the MTF opening F2.8.

For the new lens Z14-24F 2.8, the height from the center to about 12 mm in the middle is almost equal to the height of the peak of the ideal value level.

The halo (tilt) in the transverse aberration affects the position (focus) of the mountain from the circumference of 18 mm to the corner of 21 mm. However, the height of the remaining mountain is about the same as the old lens, so it does not mean that it is inferior.

Small Aperture F4.0

As with the optical path diagram, the upper line shows the old lens F14-24F 2.8, and the lower line shows the new lens Z14-24F 2.8 with the MTF opening F4.0.

The new whole, the new lens Z14-24F 2.8's original performance is too high for me to see the degree of improvement. This is a common luxury problem with good lenses.

In the middle of 18 mm where the performance degradation was observed, it was improved to almost the ideal level.

Conclusion

Since it is a wide-angle zoom lens, you may think that the telephoto end has a rough atmosphere, but you can see the degree of improvement.

In addition, it has been miniaturized and the weight has been reduced by nearly half.

This lens, which can be said to be "the true value of abandoning traditional optical finders and turning them into mirrorless lenses," can only be said to be "must-use."

Just on the eve of this article, Nikon announced two new cameras, the Z7II and Z6II, simultaneously.

I'm really looking forward to using it as a set.

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NIKON NIKKOR Z 14-24mm F2.8 S

Sample Picture

Example photos are in preparation.

If you are looking for analysis information on other lenses, please refer to the table of contents page here.

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