Sunday, March 24, 2013

D800: 12 bit vs 14 bit raw images

I compared how well the Nikon D800's can take extreme adjustments and if there's difference between 12 bit and 14 bit raw files and when is it okay to use the lesser bit depth. Below you can observer how the shadows get abruptly clipped in 12 bit files when adjusting the by ten(!) stops in Raw Therapee since it does its magic in 32 bit float ensuring maximum image quality. In 14 bit raw files there's still some detail left although the image gets a tad noisy. However, if shooting above approx. ISO800, there's no discernible difference between the formats, the camera's noise floor rises so high that the clipped parts of the image are drowned in the noise.

D800: 14bit vs 12bit
(When measuring the dynamic range of digital sensors, this is it. The difference is almost always in the shadows since linear sensors such as CCD and CMOS always clip when the photon well of a sensel is full or ADC gets clipped.)

Northern lights with D800 and Samyang 35mm f1.4

Awesome show of northern lights, probably the best since the early 2000's when was the last solar maximum. According to Spaceweather.com the planetary Kp index peaked at six out of ten. All these images were shot with Samyang's 35mm f1.4, it's an awesomely sharp and contrasty lens, especially factoring in the price of just under 300 eur.

Samyang 35mm f1.4 northern lights

Sadly, the infinity stop wasn't properly calibrated as they usually aren't in these Korean miracles. Live view was used to focus instead of relying to the distance scale. At f1.4, less than half a millimetre of focusing ring movement is enough to ruin the sharpness of the image.

Samyang 35mm f1.4 and D800 shoots violet northern lights

It's a big lens, but so is the camera (Nikon D800) I'm using too. I also tried the lens on a older film camera (Nikon FM or somesuch) and the lens honestly felt just too big for that body. I couldn't get proper grip of the camera and the focusing was a pain in the shooting hand because of that.