Thom explains the novel design of this 400 rather well, I thought. Kudos to the engineers who perpetuate Nikon's prowess in engineering, going back decades.
We discussed the optics some weeks above - Page 4. And somewhere above I shared this interview, which should translate in Chrome, but I've appended it anyway. The engineers state they considered a PhaseFresnel design but opted for their no less novel solution to trim weight and length: exploiting Z mount architecture and Nikon's Super ED and their new SR glass
to quote the machine-translated text:
Interview with the developer of the NIKKOR Z 400mm f/4.5 VR S, which combines high optical performance and portability
Shamelessnikon
Liang Shuang 2022-07-22
"Next, the developer of the NIKKOR Z 400mm f/4.5 VR S introduced the development concept of this lens in detail. The NIKKOR Z 400mm f/4.5 VR S continues the design philosophy of the NIKKOR Z 800mm f/6.3 VR S lens to combine "lightweight, small size for handheld use" and "high optical performance". The lens adopts an f/4.5 aperture to better control the size and portability of the lens body. The weight of 1,160 grams can achieve high flexibility and reduce the fatigue of long-term handheld shooting. At the same time, the NIKKOR Z 400mm f/4.5 VR S has an excellent focusing speed comparable to that of the NIKKOR Z 100-400mm f/4.5-5.6 VR S, satisfying those who love airplanes, wild animals, birds, sports and other subjects The needs of photography enthusiasts to help them capture decisive moments.
After the introduction, there was a question-and-answer session between the media and developers about the product:
Question: Nikkor Z 400mm f/4.5 VR S is a F4.5 lens, why is it set to F4.5? In the past, such lenses were usually F4.0.
Answer: When we design this 400mm lens as F4, the size and weight will increase significantly, and the price will also increase. Considering the balance of the product, we set it as F4.5 to ensure its portability.
Question: How fast is the lens focusing?
Answer: Although the specific data cannot be disclosed here, the Nikkor Z 400mm f/4.5 VR S is comparable to the speed shooting of the Nikkor Z 100-400mm f/4.5-5.6 VR S.
Question: This lens and lenses such as 100-400mm have repeated focal lengths. How big is the actual difference for users?
Answer: The NIKKOR Z 400mm f/4.5 VR S combines the high resolution and soft bokeh typical of a bright fixed-focus super telephoto lens, and is suitable for enthusiasts who value the portability of the lens. The NIKKOR Z 100-400mm f/4.5-5.6 VR S is suitable for users who need a wider focal length range.
Question: Does the NIKKOR Z 400mm f/4.5 VR S use the development idea of the Z 800mm f/6.3 VR S?
Answer: Like the NIKKOR Z 800mm f/6.3 VR S, the design concept of this 400mm lens is also an ultra-telephoto lens that combines "lightweight, small size for handheld use" and "high optical performance". Regarding operability, the setting position of the operating parts is the same as that of other NIKKOR Z super telephoto prime lenses. Anti-slip rubber is placed on the left-hand grip for a more comfortable grip; the design of details such as its touch feel (such as small dents, etc.) is designed to assist operations without relying on vision.
Question: Nikkor Z 400mm f/4.5 VR S and Nikkor Z 400mm f/4.5 VR S are some of the differences between these traditional lenses. The advent of this Nikon product actually draws a brand new market, aimed at telephoto users who need light weight and relatively cost-effective Market, will it be a new market segment? Will there be more similar products to support?
Answer: In terms of product development concept, we pursue the portability and cost performance of this lens, which is the same concept as the Z 800mm lens. The idea of a 500mm lens for the NIKKOR F mount is also realized in the NIKKOR Z series, so it cannot be said to be a new market segment. While we can't reply to you with specifics about future plans, we hope to meet our users' expectations.
Question: If the PF lens is used, can this lens achieve F4.0?
Answer: In fact, during the research and development, we tried to use PF lenses, and carried out basic design research such as F4.0, but in order to realize the product concept of "small size, light weight, and easy to use", we finally chose the optimal lens. Solution of F4.5.