Very long lenses could become redundant...........??

[FarQinell]

With high density sensors coming on stream at a fast rate image size on your computer screen increases in proportion to the square root of the Mp.
Thus when (not if!) the current 7D 18Mp is superceded with say a 24Mp sensor (the R3200 already has 24Mp but on a slightly bigger sensor) a 600mm lens becomes equivalent to a 693mm and so on.
Perhaps in say ten years time there will no longer be a need for huge focal length and Canon/Nikon will not make anything bigger than a 400/2.8 with a built in 1.4xTC!
Assuming of course they can do something about improving S/N ratio of those tiny pixels.

 

[prestonpalmer]

There will always be a need for large lenses.

 

[Random Orbits]

DOF increases for smaller sensor areas though...

 

[herbert]

A lens is basically capturing a cone of light from the object and focussing it back to a point. So the wider the cone you capture the more light you have to form the image. The need for this is very apparent when there is not much light, e.g. the Hubble space telescope has an aperture of 2.4 meters and focal length of 57.6 meters (a 57600mm F24).

Bigger lenses will make a better image with the same sensor with the same exposure time because they have more light.

On the other hand what you are stating is that a better sensor will make better images with the same lens because it more accurately captures the same amount of light.

(Note that the usual caveats about imperfections apply. If sensors/lenses are not perfect then comparisons between combinations are not straightforward.)

If you want the best image then you should use the best lenses and sensor. So the requirement at the top level for large lenses will remain.

However if you want images to a certain quality with a restricted budget then a better sensor is more economical than bigger lenses.

Also, as previously mentioned, depth-of-field is important in photography. Lens aperture effects depth of field but must always be considered in the context of equivalence (see http://www.josephjamesphotography.com/equivalence/). Bigger lenses may be the only way to get the desired image look.

 

[Aaron78]

400+1.4 extender? Heck, i would love for my 7D to autofocus to F/8 so i could get a 600 F/4 and a 2X to give me 1920mm.