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Image Size / File Quality Options

The D30 offers a five different image / resolution combinations. You can shoot at either 2160 x 1440 or 1440 x 960 at two JPEG qualities or in RAW (lossless) format at 2160 x 1440. This may seem overly simplistic, however it's more than sufficient for a camera such as this, the majority of people will use JPEG FINE which (thankfully) uses a relatively low JPEG compression. Purists will no doubt shoot RAW files, however the killer for me is the amount of time it takes to acquire each RAW image (over 30 seconds).

Camera settings: ISO 100, Aperture Priority set at F8, shutter speed 1/3 sec (-0.3 EV compensation), Parameters: Default. Lens used was 28 - 70 mm F2.8 L.


Standard Test Scene

To give an impression of what each combination of image size and quality produces the table below is a cross reference of image size against quality. Original images are available for all but the RAW format (simply because you can't read the RAW files without the D30 TWAIN module), instead we've re-saved the RAW as both TIFF and super high quality JPEG.

Crops below are of the same 240 x 120 area of each image (magnified by 200%).


 
2160 x 1440
RAW
RAW: 3,234 KB. As 8-bit TIFF: 4,795 KB. As SHQ JPEG: 1,776 KB
JPEG
FINE

1,382 KB
JPEG
NORM

684 KB
 

 
1440 x 960
JPEG
FINE

696 KB
JPEG
NORM

356 KB

A more than adequate selection of resolutions, JPEG FINE files are small enough to be able to get plenty on a storage card yet not over compressed, no visible JPEG artifacts. Often there's very little difference in quality between RAW and JPEG FINE, however remember that RAW is recorded with full 12-bit data and can be acquired with different sharpness, saturation, contrast and white balance settings (can also be acquired as a linear - untouched data file).


ISO (Sensitivity) Adjustment

The D30 has five ISO sensitivities: 100, 200, 400, 800 and 1600. It exhibits the smoothest, noise free ("grain free") images we've ever seen out of a digital camera, at ISO 100 and 200 they're almost completely noise free. Above this we found that generally speaking images suffered very little up to ISO 800, however there was noticeable noise at ISO 1600 (not bad for a "consumer grade digital SLR"). Although I haven't made an extensive analysis of the high ISO noise it does appear to be random with no discernible "pattern" (easier to clean later).

ISO 100, 1/4s, F8
ISO 200, 1/8s, F8
ISO 400, 1/15s, F8
ISO 800, 1/30s, F8
ISO 1600, 1/60s, F8

The next set of samples were taken of a blue sky (something seldom seen in the UK in October) at ISO 100, 200, 400 and 800. Many people complain of "blue sky noise" (actually noise in the red channel), so I thought this would be an interesting test of the abilities of the D30. The samples below are 120 x 120 crops from the sky in each image broken down into their red, green and blue channel components.

ISO 100, 1/500s, F8
ISO 200, 1/1000s, F8
ISO 400, 1/1600s, F8
ISO 800, 1/3200s, F8

As you can see, red channel noise does increase (along with a little in the green channel), but the good news is it's not visible to the human eye, even at ISO 800... Very impressive.

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