iZoom, FZ200, LX7, FastStone - a few thoughts

Started Apr 10, 2013 | Discussions thread
Detail Man
Detail Man Forum Pro • Posts: 16,688
Re: iZoom, FZ200, LX7, FastStone - a few thoughts

Rodger1943 wrote:

Thanks for all that info Mike. I use izoom all the time. The enlarged image you get from it is pretty good until you try and enlarge that image and then you start to see it breaking up a bit. One of the great advantages of izoom is that it gives you a better view of your subject and therefore makes it easier to see if its in focus. It is also easier to control than digital zoom, as its limited, whereas digital zoom will skyrocket very quickly into very high zoom settings.

One thing I noticed from your shots was that magnifying the 24x up to 48x gives exactly the same result whether you do it in camera (izoom) or on a computer. I have done this comparison myself and got the same results, there's really no difference. I have also done comparisons between digital zoom ad izoom and can't see any difference there either, contrary to what Mr Panasonic has to say about this. When I had my FZ150 I did the same comparison between the two zooms and in fact the digital zoom gave a better result than the izoom. You can see the result here on my Flickr page


Poked around a bit looking for Panny Intelligent Zoom information. Here's a recent blog post:


Looks like one of those features that Panasonic believes "less is more" where it comes to disclosure:


In general, these cameras (I believe) all use the Bilinear re-sampling algorithm to re-sample images (which uses a 2x2 array for computations), as Bicubics, Lanczos, and other larger array algorithms would very likely be too computationally-intensive for the in-camera hardware.

Bilinear does well with up (or down) sampling ratios of exactly 2 - but not so well otherwise ...

Using "i-Zoom" with 2x sensor-crop, up-sampling by a factor of 2 sounds like the best way to use it.

(Likely) the only thing that differentiates it from using 2x digital zoom is the use of "i-resolution" functionality to post-sharpen the result. You (may) find that using 2x digital zoom and your own chosen controllable sharpening processes in post-processing gives as good (or prefereable) results.

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