Yoshizen's Blog

Analog — Digital

Why such picture was heading the post “Analog — Digital”?    I guess most of the reader here has no idea what I meant, how this picture signify the Analog approach to stabilise the camera.  (To stop the vibration, instead to remove the cause, just forcibly gagging up, is quite an analog !)    The picture was a camera fitted with a modified chest-pod. (Because this mirrorless camera’s shutter shock was too much for their light-weight and small body, I needed to use such device to block the camera movement especially when I use almost weightless small Pentax 110 lens. —– that was the reason why Sony put the image stabilizer in the body for their new model.)

Till only a decade ago, there was many camera support / holder / bracket/ balancer to mount a cine camera which can eliminate / reduce the camera-shake.  All of them were using a clever design made with the counter balance / spring to stabilizing the camera when the cameraman was on the move.  So, when the camera was up and down, the counter balance or spring has to compensate the movement exactly the opposite direction = the camera’s weight / center of the gravity etc has to be carefully adjusted to the individual camera and its configuration. (when the lens was changed, the adjustment has to be done again from the start.)    But, when, the Gimbal came and took its position, it changed the whole story over night. 

The people are believing that the Gimbal was made with the Digital technology but they were not.  Gimbal was built while using the high-speed analog servo system.

Unlike popular misconception, digital system is slower than the analog system.  Any electronical system need to have the time to make it response.  Therefore, when the process has many stage, even the stage of just amplifying the signal, it takes certain time, which mean a delay.  And to drive high-power device, it need to drive them by higher current, and to do such drive, there needs to have several stage to increase the current though, with the development of high current semiconductor such as D-Mos, IGBT, etc, direct drive became possible without time delay.   Its mean, when the movement of the camera was detected downward, in the same moment, motor can move the camera upward.  Together with the development of such as a core less motor which can move instantly, the Gimbal was materialized.  And the same idea of  feedback control, the image stabilizer became very popular.

You might heard of the word “Digitizing depth of 12 bit or 16 bit” kind.  People might be thinking, 16 bit has 4 more bit data on top of 12 bit — was utterly wrong.  Say assuming the maximum output voltage from the image sensor was 1 volt. Then to measure 0.9999 Volt or 0.99991 volt in the detail of 1/16384 volt is by the 14 bit, 1/65535 volt is by the 16 bit depth. = The difference is how smaller its measurement would be divided. (imagine, the difference using inch or metric measure.)   In an A-D conversion, to measure in 16 bit, the reference voltage has to be increased 1/65535 volt each time and compared to the output voltage = count up to 65535 mean max 1 volt.  And to do this with its “Clock frequency” is all about digitizing process.  (Counting this to each three BGR (but actuary BGGR four) on 47 Mp is all about the imaging process.)   Yes in deed, it’s a lot of work !

So, in reality, Digital process is just a way to handle the electronic phenomena with counting measure — that’s all. (Save the additional implication / benefit etc)  Somewhat, the Stone-aged man handling the life, say I killed 200 kg deer with 2 kg axe, instead of saying I killed a big deer with my heavy axe.  —– how civilized our digitized mind is !  (The irony is, even if we could accurately measure, we still brandish an axe and kill = work is still the same. —– and even if the color was digitized into millions of individual color, our eyes can distinguish only 1000 colors = that was how jpg operates.)

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