Why 1.5x magnification on most DSLRs ?

[megaweb]

hope this link can help

http://www.photo.net/learn/optics/dofdigital/

 

[Jed]

Originally posted by StreetShooter
Ah, but there would be no 1.5X crop factor any more. A lens built for this sensor (eg 80-200/2.0) would accomodate the entire sensor area into the optical frame. There would be no cropping effect.

You are right. As YS has said, there wouldn't be a cropping effect any longer. But what you would get is a narrower angle of view.

Good idea, but it will be like turning the Titanic around. Can be done, but with much effort and much time, and risking alienating 90% of the photographic community.

I think the problem is that it's sad that 90% of the photographic community don't examine the issue closely to decide for themselves, rather than just adopting the comfortable, old is good feel for wanting FF sensors (sorry if I've inadvertantly included present company).

Nikon are trying to turn the Titanic around. Of course these days Canon seems to have 90% of the photographic market so you might well be right.

 

[Jed]

Originally posted by reflecx
OK, one clarification question - are you talking about using a new set of lenses specially designed to fix DX sensor? Or using the current crop of 35mm lenses? Or using the best of both worlds?

Using the best of both worlds, and eventually to wean towards a complete DX system.

Nikon has addressed the main immediate problem of the 1.5x FLM; that of the inability to reach ultra wide angles. With that taken care of, the main issue is settled. It requires purchasing a new lens, yes. But buying your full frame 1Ds requires purchasing a notably more expensive camera. And as future generations multiply, ceteris paribus, each new FF sensor camera should cost more than a DX sensor. At least the imaging chip will.

As they keep the DX sensor and introduce more and more DX lenses, you can then upgrade at your own pace, or just continue using your existing set of lenses. In theory Nikon could price similar DX lenses very affordably, or they could choose to enrich the feature set; a 300/2 would be fairly inexpensive to manufacture compared to a full frame 300/2. And no, they are not new lenses to buy; there's nothing to stop you using your existing set of lenses.

 

[StreetShooter]

I think that what Nikon is trying to do with the DX lens series is commendable.

Would anyone knowledgeable know if it is possible to design a lens for a smaller sensor (say 1.6X crop factor) on the existing Canon EF mount? Or is it a physical impossibility? Not that Canon would do this, of course, but never say never.

 

[reflecx]

Originally posted by Jed
Using the best of both worlds, and eventually to wean towards a complete DX system.

I see where you're coming from now. I was coming from the angle of using the current crop of 35mm lenses on DX sensor cameras.

Originally posted by szekiat
look at it this way, the saving on the telephoto end definitely outweigh the expense on the wide end eg:

300 f2.8=7000 (N-AFS)
400 f2.8=14000(N-AFS)
As compared:
20mm f2.8=600 (N-AFd)
14mm f2.8=3000 (N-AFd)

Why do such comparisons if you're going to talk about using new lenses?

 

[Jed]

Originally posted by StreetShooter
Would anyone knowledgeable know if it is possible to design a lens for a smaller sensor (say 1.6X crop factor) on the existing Canon EF mount? Or is it a physical impossibility? Not that Canon would do this, of course, but never say never.

Heh. I guess that rules me out!

Yes it's possible to design a lens for a smaller sensor on the EF mount, I see no reason why not. Nikon are doing exactly the same thing, with DX lenses on the existing F mount.