question about 1.5x Crop

[kisim]

Hi all,

Understand for FF lens, eg, Nikon 24-70 F2.8, when we use it on DX camera,
the actual zoon range will become 36-105mm.

How about, for those DX lens, eg. Nikon 12-24mm F4.0.
Do we really enjoy the wide angle 12mm (equivalent to 12mm at 35mm film?)?

 

[icebox]

No, apply the crop factor just like all lenses. All lenses have their focal lengths indicated for 35mm format.

The DX simply means that it is designed for 1.5x/1.6x sensor cameras, so the mounting, glasses and construction are different. Cannot use on full-frame cameras.

 

[kisim]

Thank you!!! solid quick reply.
So if I have 12-24mm, it make sense to get 24-70.
Though the latter is very expensive.

 

[icebox]

???

24-70 is precisely 20-70 on 35mm film. Or 36-105 on Nikon DSLRs (except D3).
12-24 is precisely 12-24 on 35mm film. Or 18-36 on Nikon DSLRs.

As in, just compare directly the focal length written on the lens name. Don't bother multiplying or what.

 

[lsisaxon]

Hi all,

Understand for FF lens, eg, Nikon 24-70 F2.8, when we use it on DX camera,
the actual zoon range will become 36-105mm.

How about, for those DX lens, eg. Nikon 12-24mm F4.0.
Do we really enjoy the wide angle 12mm (equivalent to 12mm at 35mm film?)?

This has been explained many many times... The focal length is just as indicated whether you use it on FX or DX.. except that on a DX, the angle of view is different because the sensing area is smaller.

A 24-70 on a DX will have angle of view like that of a 36-105 on a FF. Similarly, a 12-24 on a DX will have angle of view like a 18-36 on FF.

A DX designation on the DX lens only means that the image circle is only large enough to cover the DX area and will not be sufficient to cover the entire FF frame.

Here is an example of a 10.5mm DX fisheye when used on a FF body.