what is Lossless Zoom ???

[Apoorvdec]

recently i was reading fourms and i came across a term Lossless Zoom on nokia lumia 920 . can any one tell me ???

 

[montsa007]

There are 2 kinds of zoom,

Optical & digital.

In digital zoom, you use the software to zoom into the picture, quality stays the same as original and you start getting grainy image once you start zooming, it gets worse as you go deep.

In optical zoom, you use the hardware to zoom, you do not loose quality.

There are phones that market themselves as 100x Digital zoom, trust me that is a bag of waste because the quality starts killing after like 2x zoom, a 4x optical zoom is much much better than a 100x digital zoom.

Unfortunately not many understand this concept and buy a phone with 100x digital rather than 4x optical zoom, and then regret

Imagine standing 5 feet away from a book that is kept open, you use a binoculars from the spot you are standing to see the contents of the book, of course it'll do the job but the things won't be that clear, its digital zoom. Now you keep aside the binoculars and take a few step towards the book and see it with your eyes, thats lossless zoom .

 

[anon5997296]

Well I think lossless zoom in 920 is that it uses the middle portion of the 8MP sensor when you zoom in.. I mean that camera is 8.7MP and full HD is merely about 2MP so it crops the central 2MP portion of the 8MP sensor when you zoom 1.8x lossless through pro cam. It's just my guess though, I don't know actually but I think it's correct.
And what montsa said is all correct too..

Sent from my ST25i using WPCentral Forums mobile app

 

[pantsaregood]

Optical zoom works by locally increasing the amount of information your lens picks up. Digital zoom increases the size of an image without additional information.

Look at the moon at night: you will be able to make out no surface features with your eyes. Take a picture of it and attempt to zoom in digitally - you'll see no additional detail. Now use an optical zoom - you'll be able to see much more detail because as you zoom in, you gain new information.

"Lossless" digital zoom isn't mathematically real, but it is a very good technique to avoid the need of an optical zoom. Rather than attach an optical zoom, the sensor merely takes in a surplus of information to begin with so zooming in leads to no apparent loss in quality.

 

[Moiz Mian]

Well I think lossless zoom in 920 is that it uses the middle portion of the 8MP sensor when you zoom in.. I mean that camera is 8.7MP and full HD is merely about 2MP so it crops the central 2MP portion of the 8MP sensor when you zoom 1.8x lossless through pro cam. It's just my guess though, I don't know actually but I think it's correct.
And what montsa said is all correct too..

Sent from my ST25i using WPCentral Forums mobile app

This is correct. Our Lumia 920's only have lossless video zoom of 1.8x. Since our camera's have 8mp and 1080p is 2mp, there is room to do digital zoom and still have 2mp video.

Lumia 1020 on the other hand oversamples 41mp images down to 5mp, but you can also zoom in to a 5mp crop which will still be 5mp. Hence lossless

 

[sdreamer]

Wondering if Nokia Pro Cam has any algorithms that make the digital zoom look better vs just cropping and zooming. From what I can tell default camera then use edit and crop turns out horrid, while Pro Cam comes out less horrid. Maybe a placebo affect.