Digital Zoooooom!!! Another experiment!;-)

[nahau]

Hi why,

Very interesting photos you have here. I have a few questions. I will assume you resampled before cropping. I am puzzled at how the 0x capture can come out so much cleaner than the 2x or the 4x. I can understand that the 2x could be dirtier than the 4x, due to first being interpolated in camera, then being interpolated again in software, but I can't see the 0x really being so clean compared to both since it had to be interpolated to four times it's size just to get there. Every photo I ever resampled turned out with the enlargement showing less resolution than the digital counterparts. Did you simply use Image resize/resample to get these results...or did you use other PS techniques? Also, the 0x being a crop of the full image, what might be the full file size of the upsampled photo before cropping. I would think it would run in the order of around 36 megs if you shot the original in 1024x768 (medium). It seems I must be doing something wrong in PS, as I cannot get the results you show here.
nahau

G1 4x digizoom, 135x120 crop:
http://www.fototime.com/ {996C28CE-B137-4AAB-B09E-0E9D8C08C2E0} picture.JPG

G1 2x digizoom, PS5 2x bicubic upsampling:
http://www.fototime.com/ {E86CC4CB-A57E-4D7C-BB18-56CE36837146} picture.JPG

G1 0x digizoom, PS5 4x bicubic upsampling:
http://www.fototime.com/ {058EE274-AD21-49F9-BF0E-D4E0E11EF4A8} picture.JPG

 

[WH Yi]

Hi why,
Very interesting photos you have here. I have a few questions. I
will assume you resampled before cropping.

Yes, in PS5: Image > Image Size > enter new width val (2x/4x original width), Constrain Proportions, Resample Image/Bicubic; then Crop Tool to 135x120, Copy, File > New, Paste, save copy as JPG, Quality 10, Baseline.

I am puzzled at how the 0x capture can come out so much
cleaner than the 2x or the 4x. I
can understand that the 2x could be dirtier than the 4x, due to
first being interpolated in camera, then being interpolated again
in software,

Thanks for explaining this - I was mystified. Double interpolation seriously degrades quality.

but I can't see the 0x really being so clean compared
to both since it had to be interpolated to four times it's size
just to get there. Every photo I ever resampled turned out with
the enlargement showing less resolution than the digital
counterparts. Did you simply use Image resize/resample to get
these results...or did you use other PS techniques? Also, the 0x
being a crop of the full image, what might be the full file size of
the upsampled photo before cropping. I would think it would run in
the order of around 36 megs if you shot the original in 1024x768
(medium). It seems I must be doing something wrong in PS, as I
cannot get the results you show here.

I shot in 2048x1536 Superfine, resulting in a 2MB file for 0x, uncompressed to 9MB in PS, growing to 144MB when PS resized it to 8192x6144 - it took a couple of minutes to resize. I did not save it to disk, but I imagine the saved JPG would be about 32MB.

I think the difference in quality comes from the difference in compression ratios used for the original files: Superfine's 5:1 vs. Fine's 8:1. SuperFine gives PS more to work with. All in all, I'd say that G1's internal upsampling process is pretty good on its' own - it can beat post-processing for Fine JPG's and come pretty close for SuperFine ones.

nahau

G1 4x digizoom, 135x120 crop:
http://www.fototime.com/ {996C28CE-B137-4AAB-B09E-0E9D8C08C2E0} picture.JPG

G1 2x digizoom, PS5 2x bicubic upsampling:
http://www.fototime.com/ {E86CC4CB-A57E-4D7C-BB18-56CE36837146} picture.JPG

G1 0x digizoom, PS5 4x bicubic upsampling:
http://www.fototime.com/ {058EE274-AD21-49F9-BF0E-D4E0E11EF4A8} picture.JPG

 

[spejic]

Spejic, are you sure about this? Maybe I don't understand RAW
then. I thought RAW was basically what the camera sees, i.e. the
"raw" image from the cam. In any case, I wouldn't go so far as to
say digital zoom will "always" be better. I gotta think the best
digital zoom algorithm(s) have yet to be discovered / invented

RAW is not what the camera sees - a RAW image has a full color range for every pixel. However, in a digital cameras the sensors for each pixel only detect red or blue or green (there are CYM detectors too, but the idea is the same). The camera then interpolates what color each pixel is from information from the neighboring pixels. It also uses information from the brightness of the pixels, and a number of tricks to get the final image that you see as "RAW".

No zooming algorithm can replace lost information. If cameras apply more information to zooming than is available in a RAW image, then it is impossible to match it by zooming the RAW image.

 

[Hubert Tse]

Spejic,

For a digicam, it can only process information that it can "see" (i.e. the light information from the image sensor). It performs the digital zooming on the digitised image (from the image sensor). Unless the RAW does not reflect truely the output from the image sensor, I cannot see the fiference between in-camera and out-of-camera zooming if the algorithm used is the same.

Regards,

K Tse

Spejic, are you sure about this? Maybe I don't understand RAW
then. I thought RAW was basically what the camera sees, i.e. the
"raw" image from the cam. In any case, I wouldn't go so far as to
say digital zoom will "always" be better. I gotta think the best
digital zoom algorithm(s) have yet to be discovered / invented

RAW is not what the camera sees - a RAW image has a full color
range for every pixel. However, in a digital cameras the sensors
for each pixel only detect red or blue or green (there are CYM
detectors too, but the idea is the same). The camera then
interpolates what color each pixel is from information from the
neighboring pixels. It also uses information from the brightness
of the pixels, and a number of tricks to get the final image that
you see as "RAW".

No zooming algorithm can replace lost information. If cameras
apply more information to zooming than is available in a RAW image,
then it is impossible to match it by zooming the RAW image.

 

[joe_dejesus]

nahau wrote:
In combination with the B300 and 2X digital, the G1 becomes
a 10X camera.

I have a Pro90 and sometimes use 2x digital for those FAR FAR shots...
I need to be very very steady at this zoom to get nice printable pics...

Pro90+B300+digital zoom = an impressive 68X reach??
No hand holding IS at this zoom

Joe

 

[Arif <:-)]

Hi Nahau:

I guessed the photos wrong. Well, I know it won't be easy especially aftr you down-sized the digitally zoomed photos. When you scale down, you enhance resolution.

I've always been complaining about the useless digital zoom feature on G1. This is true when you need the photo as large as possible. I usually confine my subject to about 60% of the photo. By using digital zoom even after slight scale down to 80%, I still see the digital defects.

So the digital zoom doesn't work for me or anyone unless you only wish to present your photo aftr 40% down-size.

Arif

My e-gallery ..... http://www.webmeridian.com/gallery