| Joined: | Thu Apr 19th, 2012 |
| Location: | United Kingdom |
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Your term "Lens Cropping" I believe is misleading. I assume the optical zoom image and the sensor/processor zoom images are both the same pixel dimensions ie. not cropped in camera.
I have never owned such a camera but my expectation is that the image processing directly from the sensor will be interpolating the image file at RAW level to the desired crop, then processing it into a full size JPEG or TIFF image for output to the SD card.
Am I right in expecting the sensor/processor zoom only functions at set ratios? Is not infinitely variable? Like X2, X4, X6 etc.
If that is the case and it might even be infinitely variable, using clever algorithms, then the sensors image processor is sharing the digitally cropped image among the entire available pixel map.
Given this is taking place at RAW data level, prior to being formatted as JPEG or TIFF, I am not surprised the quality is acceptable, also, I assume the bridge camera is relatively high resolution, it wouldn't work well with a D1 2.4Mp image!!! Although, it was common practice to 'stretch' low res image to make them acceptable to publishers who seemed obsessed with high resolution images, that was usually done in certain set ratios which worked well with the original image mapping.
Forgot to mention, a lot happens to the image data in the image processor beyond simply being formatted into the final data format, JPEG etc.
If the pixel interpolation takes place first, in the image processor, then the other processes follow, they can even out the image and correct for stretching and re-sizing. Thus making the enlargement less obvious, smoother than it would be if done during post processing in a computer.
Sorry for misleading you Roberto.
I haven't tried this myself yet so am posting before fully thinking it through
The digital zoom is merely an extension of the normal zoom range. On Mikes camera the optical range ends at 400mm...with a flick of a switch, this continues upto 800mm seamlessly.
As JK says, it's probably just interpolation but the resultant files are identical size. But cropping the 400mm version to 800mm shows more noise than the out of the camera 800mm.
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Eric