G vs ZM lens size

[AlanS]

Can anyone explain why the new ZM lens are so much bigger and slower than the G lens? (21 & 28 focal lengths).
Regards,
Alan.

 

[sepiareverb]

The ZM28 is a bit longer than the G, but the 21/4 is only one of the 21's in the ZM line. The G21 is one of my favorite lenses, partly because of the compactness.

I wonder this too- the ZM25 looks to be similar in size to the ZM21/2.8, and the 25 is one long lens. Seems counter-intuitive to me that a wide angle lens would be so long, but then I'm surely no optical engineer. The ZM21/2.8 uses a much smaller filter (46 vs. 55 for the G21) so that may come into play?

 

[thebard37]

Retrofocus

Retrofocus

T

I wonder this too- the ZM25 looks to be similar in size to the ZM21/2.8, and the 25 is one long lens. Seems counter-intuitive to me that a wide angle lens would be so long, but then I'm surely no optical engineer.

I would imagine this is because the lens is a retrofocus design. Perhaps Zeiss had solid state imaging in mind when designing these WA lenses. Certainly the front elements seem to give those design cues awahy in my mind.

 

[ferider]

I would guess the size difference is due to retrofocal design
to share design and features between M mount and Nikon mount lenses.

Roland.

 

[Rayt]

The G lenses don't need a complicated helicoil set up because they are AF?

 

[jaap]

The G lenses are designed for a FILM range finder camera. So the rear element can get as much as nessecary inside the camera. The zm lenses had to b designed with a digital range finder in the future in mind so there had to be a curtain distance between sensor and rear element. That is why I prefer the G line over the Zm line !
So a lot of the elemennts of G-lens is actually inside the camera instead of outside the camera!

 

[sepiareverb]

Yes!- the G21 & the 28 both have a deep rear cap where the ZM do not.

 

[ferider]

The G lenses are designed for a FILM range finder camera. So the rear element can get as much as nessecary inside the camera. The zm lenses had to b designed with a digital range finder in the future in mind so there had to be a curtain distance between sensor and rear element. That is why I prefer the G line over the Zm line !
So a lot of the elemennts of G-lens is actually inside the camera instead of outside the camera!

I doubt that Zeiss will build a digital camera in the near future.

But the ZM lenses came out for Nikon SLRs first, and there is a mirror behind the lens ....

Roland.

 

[jaap]

I doubt that Zeiss will build a digital camera in the near future.

But the ZM lenses came out for Nikon SLRs first, and there is a mirror behind the lens ....

Roland.

The zeiss nikon are a different story the wide angels are retrofocus design