iZoom, FZ200, LX7, FastStone - a few thoughts

Started Apr 10, 2013 | Discussions thread
Detail Man
Detail Man Forum Pro • Posts: 16,789
Re: iZoom, FZ200, LX7, FastStone - a few thoughts

Mikedigi wrote:

Detail Man wrote:

(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.

Ill try that in FastStone.

I've now run a quick hand-held "rough test" at 400 ISO and the 48x looks pretty awful.

There is no absolute need for you to sharpen after up-sampling. I'd just sharpen as a last step in post-processing as I normally would (or would not), depending on how the final image looks.

Also, note that there may well not be any need to up-sample at all (as the pixel-size of your post-processed final image might not need to be larger than the cropped sensor pixel size).

I recall that the LX5 produces (just) a sensor-cropped RW2 file when LX5 i-zoom is used. The LX7 probably works the same way. Roger Nordin verified that Lightroom 3.x (and no doubt 4.x as well) allows the RAW processing of a sensor-cropped RW2 image-file (no i-Resolution BS):


So would any other RAW Processor, as well. You get the beloved "zoomed" preview (with very likely reduced CDAF performance due to the AF system using only 25% as many photosites to AF), and out comes a sensor-cropped RAW file from the camera, with no funky up-sampling or "i-Resolution" sharpening at all. Then, you work your magic with your RAW processor of choice. Much better.

(Maybe) your present Panasonic camera of choice operates the same way (if it records RW2s) ? (Maybe) it (and the LX7) can also record a RW2 image-file when Digital Zoom is used, as well ?

But "rough tests" are useless (especially hand-held at 48x) and when I have a spare half hour I'll do it properly.

Use mechanical stabilization of some sort and shoot something with a whole lot of fine details. I have seen "i-Resolution" sharpening look pretty gross. Better to do your own sharpening later.

I also want to see that if does at intermediate random magnifications between 24x and 48x, and understand better what it's doing.

That's just going to vary the amount of optical zoom, though ? You want to use an even 2x sensor-crop (the Bilinear up-sampling will have less artifacts in that case).

The Focal Length in the EXIF meta-data will tell you (only) the amount of optical zoom. With that data as well as the amount of Zoom Factor displayed (when it is set to maximum, anyway), you can deduce the amount of sensor-cropping taking place.

(However), at intermediate Zoom Factor displayed values, there is only 1-digit resolution, and the Zoom Factor displayed rounds-up half way between displayed digits. Thus, these things will be hard to figure out if not at maximum Zoom Factor.

And there was I saying that I have joined the Pixel Peepers Anonymous Therapy Group. How am I going to explain this to the Group?

Pixel Poopers have their own deep problems. Sometimes they degenerate mentally, wandering around mumbling "good'nuff" until that is the only thing that they can enunciate. So sad ...

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