For example the Nikon Z 50mm f1.2 is 1090 grams, 150mm long, and has a 82mm filter size. The Canon RF 50mm f1.2 is 108mm long, but the other dimensions are similar.
Compare that to a Leica Noctilux 50mm f1.2 with a Techart, Megadap or similar adapter (available for Z and E mounts) for autofocus abilities: 405g lens +150g adapter = 655 grams, 52mm lens + ~11mm adapter = 63mm long and 49mm filter size. A little more than half the numbers in all dimensions.
This link approximately shows the size differece (the M to L mount is indeed smaller than the M to Z or M to E autofocus adapters, but the difference is small)
All of these have the same focal length (50mm), max aperture (1.2), and autofocus. So why do these newer mirrorless lens designs have to be so much bigger and heavier than using an old manual lens with an autofocus adapter? Sure the autofocus speed may not be as fast with an adapter but why can’t they design a native autofocus large aperture lens that is tiny like the Leica M lenses. Clearly it is possible to do so.
The Leica has 8 elements vs the Nikons 17 (!). Plus Nikon has an AF that moves two groups of elements.
I’m not a lens engineer but I think the modern “big three” primes are just totally over-engineered for crazy edge-to-edge sharpness with very low chromatic aberration, which means LOTS of lens elements. Throw in a silent AF motor and potentially image stabilization too, and you have a Quaker Oatmeal can sized lens.
Carlinwasright has your answer!
Another example: The Nikon F 50mm /1.4 AF-D has 7 lenses in 6 groups. Thats 10 lenses less than the Nikon Z. BUT: Even in old times the step from 1.4 to 1.2 was relativily huge, the 1.4 weighs around 260g, the 1.2 around 380g…thats nearly a 50% increase
The modern prime lenses for digital have - in the lab! - much better optical qualities than the old primes like Leica or Zeiss that are around for literly decades. If anybody can see this differences in real life is a complete different discussion.
One major aspect is autofocus and the motor systems needed to shift the large f-stop pieces of glass within the same housing whilst also offering silent motors, weather sealing, electronic control/communication and overall durability.
Historically and technically, primes are very simple designs, but, earlier designs could cut corners due to the formats they were designed for. I.e. b&w, 35mm, etc. These formats were nowhere near as detailed as digital images and so new elements are needed to refine the quality.
They also have a lot of patents taken up. The Leica and Zeiss patents for Summilux and Plannar, etc are very old. So rival designs often needed to take the long route to the same result.
But it all together and you have that behemoth of a Nikkor!
If what you’re saying about patents is true, that’s such garbage. Consumers being punished arbitrarily
That’s just how patents work. And not just for lenses. Any invention can be patented in this way and any rival will need to have a variation in the design, otherwise, they’re infringing on that patent.
Sorry, you misunderstood. I know how patents work! I more meant it’s garbage if it’s true that patents are the reason why they can’t be smaller.
The overall effect of patents is difficult to assess but there’s arguments in both directions.
Patents mean that small niche companies can bring items onto the market safe in the knowledge that larger players won’t just copy them and drive them out of the market
The same goes to companies which just make copycat products (see Amazon today if you want to know what such a world looks like) in countries with cheap manufacturing and labor costs.
Patents mean others are incentived to become creative themselves, thus adding to the total level of innovation present in a market
Don’t forget that patents only last for 20y max, and you can license patents too.
I also have some vintage 50mm 1.4 the size of a shot glass which are tiny compared to modern 50mm 1.4 lenses which resemble the size of a Saturn V.
I guess the modern glass is correcting for much more optical errors people in the 70s and 80s were accepting but won’t any more today. After all there wasn’t 60 megapixel resolution on 35mm film (no, don’t even start!).
Maybe manufacturers could have corrected these already in the 70s and 80s but the lens would have been ridiculously expensive, or big, or heavy. Or all three.
this is a very good question.
i imagine that the physics of lenses and light play a part in this…
i wonder how much of this is a business decision?
i wanted to compare two of my better lenses… the tiny EF-M 32 mm f/1.4 and the very big and very heavy EF 85 mm f/1.2
i put the camera on f/4 and positioned the cameras so that they had approximately the same field of view of this $100 bill. I focused in the middle of Ben Franklin’s face.
i adapted the EF lens onto the M6 MkII: I wanted the same camera capturing the images. the angles of view may be slightly different. Contrast and sharpness? They look awful darn close to me.
The EF-M lens cost me a few hundred. the EF 85 cost me one or two thousand.
https://www.flickr.com/photos/73760670@N04/albums/72177720313024348/with/53362824792/
More optical groups for correcting optical aberrations.
Zeiss otus 55mm is massive for a 1.4 lens