Digital Lenses: What's the Point?

[carney2]

Nikon designates their "digital lenses" with a "DX." Other manufactureres do something similar. Why? What does a "digital lens" do that the "old" AF's," etc. don't?

[ajuk]

Apart from the ones designed for APS sized sensors, the only difference isthe two letter on the lens ;)

[payn817]

Digital lenses are optimized to work with Dslrs. If you use a non-digital lens, you get a 1.5 multiple effect (due to sensor size) so, a 28-100mm non digital, acts as a 56-200 on a digital.

[Michael Fanelli]

Nikon designates their "digital lenses" with a "DX." Other manufactureres do something similar. Why? What does a "digital lens" do that the "old" AF's," etc. don't?

The digital designation almost always means that the lens projects a much smaller image circle. The circle covers the small APS sensor but will not work with film cameras or full-frame sensors.

[mjs1973]

If you use a non-digital lens, you get a 1.5 multiple effect (due to sensor size) so, a 28-100mm non digital, acts as a 56-200 on a digital.

I think digital only lenses still use the same focal lengths as 35mm lenses so you still have to account for the crop factor with the smaller APS sensor, just as you would with a "standard" lens.

[another view]

The digital designation almost always means that the lens projects a much smaller image circle. The circle covers the small APS sensor but will not work with film cameras or full-frame sensors.

Yup - try one on a film body and you'll see it.

[Mig]

An exception is Sigma's DG line - they all work with full frame. Their DC line does not. The DG lenses are supposed to have coatings to optimize their performance - ie reduce reflection from the digital sensor.

And mjs is correct - a focal length is a focal length.

Danielle