Re: Why was the larger Z mount necessary, exactly?
Steve Spencer wrote:
I don't think we actually disagree. I said Nikon provides smaller S lenses by making them with a smaller max aperture but not that they don't offer smaller lenses at all. That said even the f/1.8 primes while smaller are a little bigger than at least their Sony competitors. I will just report weights to keep it simple, but size differences are similar:
In the case of the f/1.8 primes I would argue that the differences in weight are small and there are probably few photographers who find the f/1.8 primes so heavy that they can't use them because of the weight. Without doubt the smaller bayonet (of Sony and others who use a small diameter mount) allows and makes it practical to make lenses that are physically smaller and lighter. But the small lens mount also tempts Sony to make very small camera bodies and when a large-diameter lens is mounted on such a camera the gap between grip and lens outer barrel is sometimes so narrow that some users cannot comfortably hold them, myself included.
It is a different situation with longer lenses where many traditional lenses are too heavy to comfortably hand-hold. And with lenses such as the 400/4.5 and 800/6.3 Nikon does offer very lightweight options that are high quality for the weight, focal length and maximum aperture (especially the 400/4.5) and I would argue that weight reduction is more important in long lenses than in the f/1.8 primes. In my opinion these lenses show that Nikon does care about the weight of their professional lenses where it really matters, but they don't use weight as the sole optimization criteria.
If the objective is to make a camera and lens that are as small as possible then obviously Sony has the edge here. But is that the objective? For me it is important that the camera and lens form a combination that is as easy to handle as possible and has enough space for sufficient controls to achieve the tasks that the photographer has in an efficient and practical way. Most camera bodies are too small and have too few physical controls for efficient use, in my opinion and practical experience. This is true of many Nikon bodies as well, those that are smaller than the Z8 tend to have way too few physical controls, necessitating frequent menu dives when changing between different types of subjects.
So where Nikon and Sony do make similar lenses the Sony lenses are a bit smaller.
Examples of Nikon lenses which are similar in specs to Sony lenses and the Nikon lens is a bit lighter:
Nikon 180-600 1955 g without tripod mount
Sony 200-600 2115 g without tripod mount
Nikon 100-400 1355 g without tripod mount
Sony 100-400 1395 g without tripod mount
Of course if one just picks pairs of lenses one can support a variety of arguments.
For their pro lenses it seems that Nikon has prioritized excellence in optics over reducing size and weight or at least it looks that way when comparing with similar Sony lenses.
In the case of shorter focal length lenses (<= 200mm) Sony lenses tend to be smaller and lighter weight, yes, but not at longer focal lengths of comparable specs. But this doesn't mean Nikon doesn't consider weight important. The design criteria are dependent on the specific case and can vary, depending on what they are trying to accomplish. But I doubt that in any situation do they increase weight without trying to achieve something that they wanted by making those choices.
Whether one lens is cheaper, smaller, lighter, sharper, has more even image quality, richer colour, less flare etc. all those things are in the control of the designers and any one pair of lenses cannot be used to prove something about the superiority of a lens mount over another. The lens mount is just one part of camera system design that the engineers make and it comes with advantages and disadvantages. Those decisions are made with expected lifetime of a system of several decades in mind (in the case of the F mount, about 70 years and counting). While the Z mount can limit the smallest size of the camera and the smallest size of lenses possible, I would argue that making the smallest lenses even smaller is not really an important objective except in very specific cases (such as mounting a camera on a gimbal stabilizer, pocketability of a camera (which is IMO a lost cause as even the smallest ILCs are too thick for comfortable placement in a pocket with most clothes, and probably it can also damage the gear if forced), mounting a camera in a concealed location for remote use etc.) and in most cases the smallest and lightest Z gear is small and light enough. Where weight has been a significant limitation to real-world use cases is long focal length lenses and there has been huge weight reductions accomplished by Canon, Sony and Nikon in this area over the past two-three decades. Some might also say the f/2.8 zooms are too heavy and all the big three manufacturers have accomplished weight reductions in those lenses compared to their own previous offerings. It's more a trend that the newest lenses are probably among the lightest as well, subject to differences in priorities such as focus breathing (which ironically enough Nikon seem to have placed highest priority while Sony attempt to address such issues in software correction which crops into the image to maintain angle of view when focus is changed). For Sony and Canon this may not have been a priority in their photography lenses because they also make cinema lenses and want to keep that market to some extent separate from the photo lenses. Nikon doesn't make a separate cinema lens line and tries to address video needs in their main line of Z lenses. I think this is a smart long-term play and users will be grateful for it over time, for the money saved not having to "upgrade" cameras or lenses to get minimized focus breathing.
Back to the original topic:
1. Lower CA
2. Easier to illuminate corners of the image
3. Less pressure on the mount when using heavy lenses
4. More freedom in optical design and other engineering
5. Can potentially make the camera thinner
6. Space for the sensor to move (IBIS moves the sensor making problem 2 above worse)
7. More freedom for lens movements (when the Z PC Nikkors arrive)
Personally I consider the lens mount an internal decision the manufacturer makes to best achieve their objectives in the camera system design and it's not really something users should be concerned about. As users we are mostly concerned about the performance of the system in our applications and the lens mount is just one small piece of design which can affect performance in the background but it's not really something that we need to evaluate. How well the system works for us is determined by applying it to practice, and not so much theorizing about whether some aspect of the system design is smart or not. That's not really our business, it's something the engineers decide internally in each company to achieve their aims. It's really up to them, not us.
Sep 02, 2023 at 10:05 AM
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