FZ30 raises the bar on Digital Zoom...

[John_Reed]

Here's a photo I shot at 8MP, full 12X (420mm) zoom of a beer bottle on my kitchen counter from ~15 feet (5m) distant, with my camera tripod-mounted:

http://John-Reed.smugmug.com/photos/36796166-M.jpg

I wanted to see how effective the "2X digital zoom" function is at retaining details, so I took a series of shots, all at ISO 80, 1/8 second, self-timer. I shot 8MP in 1X/2X; 3MP EZ in 1X/2X; and 2MP EZ in 1X/2X. Then I cropped part of the bottle label from each shot, and assembled them in one composite JPG image:

http://John-Reed.smugmug.com/photos/36795965-L.jpg

The legends should be pretty self-explanatory. The amazing thing to me was that in each case, the "enlarged" image preserved the details and sharpness of the original very well! I will say that the "fine print" turned out to be too small for the AF to work, so I used MF to freeze in the details.

I have always felt that DZ was OK for posting shots on-line, but would never hack it as a print quality image. But I have printed 8X10s from 2X DZ 2MP images, and they looked pretty sharp! This experiment of mine tells me that somehow Panasonic has been able to implement a magical DZ scheme that preserves sharpness. I don't know how they did it, could have something to do with the fact that they're only allowing 2X & 4X values, nothing in between, as before. Maybe there are better algorithms that apply in such cases.

[astro]

That looks pretty nice.
But have you tried doing DZ yourself in photoshop with RAW or TIFF, just as a "control" comparison? ;)

[propwash]

Nice work! You not only have good taste in cameras, but you have good taste in beer as well!

[John_Reed]

That looks pretty nice.
But have you tried doing DZ yourself in photoshop with RAW or TIFF, just as a "control" comparison? ;)Here's the comparison (made by a reader of this same info on dpreview). You can see the camera seems to do just as well?

[John_Reed]

Nice work! You not only have good taste in cameras, but you have good taste in beer as well!That it's an empty bottle, all by itself? ;)

[genece]

John I am not sure I am following you... is it really 1X and 2X or 12 and 24X?

[John_Reed]

John I am not sure I am following you... is it really 1X and 2X or 12 and 24X?If you remember the first post, the shots were ALL taken at 12X zoom. The digital zoom added 2X if used; the guy who did the PS work and posted the image above labeled them "1X" and "2X," I think. Maybe I didn't make that clear enough, but did you see my post on dpreview? I don't remember any comments you made there.

[genece]

Sorry John I missed it. Ok I understand now.

If you remember the first post, the shots were ALL taken at 12X zoom. The digital zoom added 2X if used; the guy who did the PS work and posted the image above labeled them "1X" and "2X," I think. Maybe I didn't make that clear enough, but did you see my post on dpreview? I don't remember any comments you made there.

[John_Reed]

When I said they were all taken at 12X zoom, I meant the full mechanical 12X zoom, 420mm on the zoom ring. Actually, the 3MP EZ mode, due to the sensor cropping scheme it uses, yields 19.1X zoom. As you can see from my composite photo, it really IS "just a crop," as it gives exactly the same size image as the 8MP 12X zoom shot. It's only useful for those of us who like to "crop in the field," to be able to get as close as possible, visually, to distant subjects.

[StanStan]

John I liked your presentation.

John, Gene: I am trying to 'get it'!

Using an aspect Ratio of 4:3

From reading the FZ30 manual:::>


Picture Size______ Maximum Zoom______Digital Zoom____ Maximum X
8m --------------------------12x------------------------- 2x -----------------24x
8m-------------------------- 12x -------------------------4x -----------------48x

5m-------------------------- 15.3x----------------------- 2x -----------------30.6x
5m --------------------------15.3x -----------------------4x -----------------61.2x

3m --------------------------19.1 x-----------------------2x----------------- 38.2x
3m --------------------------19.1 x-----------------------4x -----------------76.5x

But does all of this really mean a cropping of the image/chip?
IE If I took at picture at 12x and cropped it would I get the same result or is there some pixel interpolation going on here??

I still do not have a FZ30

TIA

Stan

[John_Reed]

John I liked your presentation.

John, Gene: I am trying to 'get it'!

Using an aspect Ratio of 4:3

From reading the FZ30 manual:::>


Picture Size______ Maximum Zoom______Digital Zoom____ Maximum X
8m --------------------------12x------------------------- 2x -----------------24x
8m-------------------------- 12x -------------------------4x -----------------48x

5m-------------------------- 15.3x----------------------- 2x -----------------30.6x
5m --------------------------15.3x -----------------------4x -----------------61.2x

3m --------------------------19.1 x-----------------------2x----------------- 38.2x
3m --------------------------19.1 x-----------------------4x -----------------76.5x

But does all of this really mean a cropping of the image/chip?
IE If I took at picture at 12x and cropped it would I get the same result or is there some pixel interpolation going on here??

I still do not have a FZ30

TIA

StanStan, yes, there is some cropping going on. Putting DZ aside for the moment, the 5MP EZ mode and 3MP EZ mode are implemented from a crop of the 8MP sensor. Taking advantage of this crop, Panasonic is able to say that the 12X zoom is "extended" to 15.3X in 5MP mode, and 19.1X in 3MP mode. And they make the low end 1X end of each of those ranges work by downsampling the 8MP sensor, because simply cropping wouldn't get them back to 1X. As you can see from my original post, the 3MP captures exactly the same pixels as the 8MP for the small segment (label) I showed. So yes, you could get the same info from the 8MP shot, you just wouldn't be able to see it as closely in the viewfinder.

Conventionally, DZ modes are implemented as follows: Suppose you shot a photo at 8MP density, 2X digital zoom. Internally, the camera's computer would crop your 8MP down by a factor of 2 in each dimension, in this case then, you'd be left with a 2MP crop, and that's what you'd see in the viewfinder while composing the image. When you shoot, the camera converts the captured 2MP image back to an 8MP image via pixel interpolation. Obviously, since 3 out of every 4 pixels in the output file are "manufactured" by guesswork, detail must be lost, though depending on the situation, I've seen many excellent photos taken at this level, just not sure how large they could be printed!

Frankly, I can't explain how Panasonic implemented the DZ in the FZ30, because it seems better than it should be! I took a 2MP DZ 2X photo of my cat:
http://John-Reed.smugmug.com/photos/34437911-M.jpg
I printed this thing at 8X10, and it still looks sharp on the paper. Knowing what I know now I'd have shot it at 3MP DZ to get it even sharper. As far as your multiples go, I think they're all correct.

I hope that helps?

[StanStan]

John: I just love the picture of your cat. I am impressed that the cat prints as well. I will look at the EXIF. Did you use a tripod?

I have been looking into up-sampling. I see some posters have written routines to up-sample 10% at a time to get the final image size they wanted for printing.

John: "But I have printed 8X10s from 2X DZ 2MP images, and they looked pretty sharp"

Had to go back to the FZ30 booklet. I now see now that at 4/3 the options for PS are 3m, 2m, and 1m at 19.1x max. Why would anyone shoot at 1m or 2m when 3m is available? Maybe the 2m and 1m are superfluous. With 2x; 38.2x and with 4x; 76.4x Looking further the digital zoom is fixed at 2x and 4x now. Also for 2x DZ the min WA is 2x with max T at 24x and for the 4x DZ the min WA is 4x max T is 48x Which means the table is missing at lot of settings available for the FZ30!

Thanks to all

Stan

I guess I will have to get the FZ30 to make sense of all of this.

[John_Reed]

Stan, the first time tripod ever met my FZ30 camera was to take those beer bottle shots in my kitchen the other night. That kitty shot was handheld, at a distance of about 10 to 12 feet from my furry subject. You will marvel at the flexibility of the FZ30, the tremendous range of things it can do, without attachments! Here's (http://forums.dpreview.com/forums/read.asp?forum=1033&message=15090003) a link to a series of photos I gathered on a little Sunday outing this week, all taken without benefit of macro lenses, teleconverters, etc. Just my trusty (already) FZ30. All shot at 3MP EZ, some of the photos used 2X DZ, more didn't. But can you tell which is which?

[StanStan]

Stan, the first time tripod ever met my FZ30 camera was to take those beer bottle shots in my kitchen the other night. That kitty shot was handheld, at a distance of about 10 to 12 feet from my furry subject. You will marvel at the flexibility of the FZ30, the tremendous range of things it can do, without attachments! Here's (http://forums.dpreview.com/forums/read.asp?forum=1033&message=15090003) a link to a series of photos I gathered on a little Sunday outing this week, all taken without benefit of macro lenses, teleconverters, etc. Just my trusty (already) FZ30. All shot at 3MP EZ, some of the photos used 2X DZ, more didn't. But can you tell which is which?
John:
Now I am uptight with you. Those pictures are so perfect I will have to go and thin down my wallet again!!

I did not find the EXIF but that is so unimportant compared to the quality of your images . I know the FZ30 helps but there must be a photographer behind the EVF.

Thanks

Stan

Spent some time on EBAY, no luck, Google and Froogle as well as a few others. Found the FZ30 is quite available at about the same minimum price. Got to get one now. I trust your ears are red! I have been on the fence due to all the buzz about noise.

[John_Reed]

Sorry that you're uptight with me, but I can't help it, I love my FZ30! I've been getting beaten about the head and ears over on dpreview for my advocacy of digital zoom as it's implemented on this camera. Today I left a meeting with some lawyers and decided to go out and breathe some fresh air on the local baylands. Here's a 2X DZ shot of a red-tailed hawk I shot:
http://John-Reed.smugmug.com/photos/37015836-M.jpg
I dunno, maybe it would have been sharper if I'd used a 2X optical extender? But I didn't have one with me, so I was pretty happy with what the DZ allowed.
I'm glad you enjoyed my photos. I had a lot of fun taking and chronicling them!

[StanStan]

I was just pulling your leg. I was going to trim your photo out of this but it is so good I am leaving it in. I do have a TCON 17 that fits a FZ30 and understand it works better on the '30 than on the '20. I guess I'll have to go to dpreview to see what is happening there.

Stan

Sorry that you're uptight with me, but I can't help it, I love my FZ30! I've been getting beaten about the head and ears over on dpreview for my advocacy of digital zoom as it's implemented on this camera. Today I left a meeting with some lawyers and decided to go out and breathe some fresh air on the local baylands. Here's a 2X DZ shot of a red-tailed hawk I shot:
http://john-reed.smugmug.com/photos/37015836-M.jpg
I dunno, maybe it would have been sharper if I'd used a 2X optical extender? But I didn't have one with me, so I was pretty happy with what the DZ allowed.
I'm glad you enjoyed my photos. I had a lot of fun taking and chronicling them!