How big would a Nikon 70-300mm f/2.8 lens be?

When you consider the size of a 70-200mm f/2.8 and a 28-300mm f/3.5.  THEN to add on just another 100mm to that 70-200mm, would it be THAT much bigger or just slightly if this lens actually existed?  

The bulk in length would not be the most spectacular
change but the weight and the front element diameter
would, reaching ~ 5 inches!

I wonder when technology in lenses will take the step forward where you can get something of this size into a lens the size of typical 50mm lens? 

How cool would that be! 

Neil Dulay wrote: I wonder when technology in lenses will take the step forward where you can get something of this size into a lens the size of typical 50mm lens? 

Technology can't change physics. As long as you have a large sensor and a large flange, the math dictates how big the far end of the lens has to be.

Have you seen a Nikon 300 f/2.8? It's quite large. If it could be smaller, I'm sure Nikon would have made it so. But it's not possible.

garyrhook wrote:

Neil Dulay wrote: I wonder when technology in lenses will take the step forward where you can get something of this size into a lens the size of typical 50mm lens? 

Technology can't change physics. As long as you have a large sensor and a large flange, the math dictates how big the far end of the lens has to be.

Have you seen a Nikon 300 f/2.8? It's quite large. If it could be smaller, I'm sure Nikon would have made it so. But it's not possible.

Sorry but I disagree, there a many things that historically were thought impossible, but technology and smart open minds prevailed and proved otherwise.   

And so I don’t offend anyone, I’m not discounting anyone’s intelligence here.  Just saying there are smart people, then there are stinking  SMART people.  

Sawyer wrote: Sorry but I disagree,

Disagree with what? That technology can't change physics? Yeah, good luck with that.

garyrhook wrote: Technology can't change physics.

Sawyer wrote: Sorry but I disagree, there a many things that historically were thought impossible, but technology and smart open minds prevailed and proved otherwise.

This is not quite right. I would suggest that your knowledge
of the history of sciences may have some holes.

True, there were false believes and misunderstood notions but
all these were re-written once they reached observational and
experimental consensus.

Things that were seen as impossible yesterday may well be the
norm tomorrow; technology, though will always operate within
the definitions and parameters of laws and principles discovered
over time through the scientific method.

G'day all

Okay fellas ... let's go back a bit into lens design

The early / original lenses of Leonardo's day were almost the same physical length as the optical length.  ie: a 500mm lens was about 500mm long [remembering that when the lens is focussed to infinity, the focal length is the distance from the front nodal point to the rear focal point ie: the film / sensor / eye].  

Without getting into the world of nodal points, you can see this via a magnifying glass versus a camera close-up lens.  Take each lens and focus the sun onto a piece of paper ... the magnifying glass with strong curvature of the glass has a short focal length, whereas the camera close-up lens has much less curvature and therfore a longer focal length

However, each of the above exhibits poor edge illumination and sharpness, leading lens designers to add extra elements to the lens design to improve performance - without altering the focal length.  So we end up with the multi-element lenses called Apochromatic or compound lens designs

During the 60's & 70s with better maths / computing and better machinery to make the optics, 'telephoto' lens designs became possible.  Now the physical length became much less than the optical length - where now a 500mm lens could become 350mm in physical size. However, when those same lens designers tried to shorten the telephoto design still further, they found that too many errors started to be seen - errors which we know as spherical &/or chromatic aberration; astigmatism, field curvature and distortion [and the list goes on]

Thus, there were limits to which a maker could produce a lens that we were prepared to buy

Hope this helps
Phil from the great land Downunder
www.flickr.com/photos/ozzie_traveller/sets/