Nokia 1020 A00013691 Manuale Utente

In addition to oversampling, the large sensor also allows 
for high resolution zoom. As you zoom there is no drop 
in the default 5MP resolution; in other words the high 
resolution zoom is lossless. The level of pixel oversam-
pling is highest when you’re not using the zoom. It grad-
ually decreases until you hit maximum zoom where the 
pixels start behaving in a more conventional way. The 
relationship between zoom level and oversampling is 
shown in Figure 5.

At  maximum  zoom,  the  Lumia  1020  system  behaves 
more like a traditional camera, but there are still some 
advantages: as only the center part of the optics is 
used, the optical and geometric distortions are minimal 
and vignetting is negligible.

The problem with traditional digital zoom is that the 
zoom level is extremely limited without clearly visible 
loss of image details. This happens because the system 
needs to zoom further than the required output resolu-
tion of the final image, and the camera needs to upscale 
the captured image to achieve that resolution. In prac-
tice this means that, for example, a 12MP device might 
capture only 4MP after zooming, and the 4MP image is 
then digitally up-scaled back to 12MP. This up-scaling 
has a significant impact on image sharpness. However 
with Nokia Lumia 1020 we never need to upscale the fi-
nal images, because the starting resolution is already so 
massive. In Full HD video mode the massive resolution 
means that the camera never zooms further than the 
required two megapixels, which ensures that the resolu-
tion stays excellent throughout the zoom range. 

The advanced PureView method of lossless zooming also 
provides multiple benefits over traditional optical zoom. 
Traditionally the aperture of optical zoom systems be-
comes significantly smaller towards the long end of the 
zoom range compared to the wide end. This has a big 
impact on low light performance and usable exposure 

times. Also with traditional zoom lenses the macro dis-
tance often changes while zooming, which means that 
the photographer needs to change the physical cam-
era-to-object distance while zooming for macro shots. 
In addition, most optical zoom lenses suffer from overall 
reduced sharpness towards the long end of the zoom 
range; this is because of optical design issues that of-
ten produce different distortions at the wide angle end 
compared to those at the telephoto end of the zoom 
range, which in the case of Full HD is up to 4X. See Fig-
ure 6 for a visual on the maximum high resolution zoom 
for 5MP (3X) and 720P video (6X) compared with the full 
resolution sensor in 16:9 and 4:3 aspect ratios.

However with Nokia Lumia 1020, the aperture stays at 
a constant f2.2 throughout the zoom range which is, 
in SLR terms, 25/27-69/74mm (16:9/4:3) for stills and 
25-100mm for Full HD video. These zoom range/aper-
ture combinations are rare, and expensive even in the 
SLR world.

Also  as  the  aperture  stays  the  same  throughout  the 
zoom range in the Lumia 1020, the macro distance of 
~15cm also stays the same. With Nokia Lumia 1020 
we are actually using the centre part of the lens where 
distortions, diffractions and lens shading are smallest, 
giving extremely high levels of resolved details and dis-
tortion-free images and videos throughout the zoom 
range.

Zoom Quality Comparison

Figure 5. Oversampling vs. high resolution zoom in the case of Lumia 1020 (blue) compared with conventional digital zoom 

 

(orange). High oversampling means high image quality.