My computer, using Nikon’s own software, takes ages (about 10s) to convert from RAW to JPG, My camera, when set to do so, seems to do it immediately - occasionally it may delay by a second or two when I’ve taken a few photos in a row, but otherwise it’s pretty much instant. Why can’t the PC do it that quickly?
Your video card, probably. May not be up to snuff when it comes to larger files.
Also, and I’m not sure if this is true but it seems to be the case with some situations, if it has to display at full resolution on a monitor (1920px wide, for example), working through that process may interfere with the simultaneous resizing process, whereas on a camera your smaller res display screen eliminates a good chunk of that reserved processing power.
The PC based “development” programmes do a lot more work, and generate a much better result than the in-camera ones as a general rule. It is sobering to compare the two - a JPEG built in camera with the same image taken as a RAW file and processed on a PC.
That said, there is a silly difference in the processing power available - and a long lag in the process on a PC is likely more to do with poor and sloppy coding of the programme.
The entire circuit board of the camera is optimized for the task of reading out the imaging sensor, compressing it and writing it to the memory card. The processor chip itself is custom-designed for this task, and it probably does most of the JPEG compression in hardware. It’s much less efficient to do it all in software, using a general-purpose computer.
Big picture, mostly the above answer. Your camera’s hardware is an embedded system specifically designed & built for that purpose alone. A PC is general purpose hardware doing most everything via software.
For example, Nikon’s image processor chip is called Expeed, and is a variant of the Fujitsu Milbeaut. As you can see, it’s a custom chip (application specific integrated chip, or ASIC) which contains a CPU, DSP (digital signal processor), and hard-coded logic to perform many major tasks including compression.
Another point to note is that the camera *needs *to be faster; it has to be ready to take the next picture ASAFP, and therefore is optimized for speed. The PC, presumably, is not in the business of actually *taking *pictures, but only processing them after the fact, and therefore is optimized for quality.
The camera is just following a set pattern to convert between the separate colored pixels (RGBG) to combined colors. Your computer is using edging algorithms and such to get to get the best possible conversion.
Just in case you don’t know, on the camera, each pixel only captures one color. The data from the pixels around it is used to extrapolate the other two colors for that pixel. A fixed method is going to be faster than any algorithms.
And that’s all before the actual conversion to JPEG. Though it wouldn’t surprise me if the camera cheats and does both at once. There are some tricks it could do with color. (Color resolution in JPEGs is independent of luminance–kinda like adding color to a black and white image.) Of course, these tricks would make for a lower quality image.
Modern digital cameras do a lot more image processing than you seem to be suggesting. The image processors do demoasicing, tone mapping / gamma correction, noise reduction, sharpening, edge enhancement, etc. In fact, with some modern high-end cameras, the out-of-the-camera JPEG is better than a RAW file processed and converted to JPEG on a PC.
This.
I use Fujifilm cameras and there are many professionals using these cameras who take the JPEGs direct from camera, quite satisfied with the results. It sure saves on disk space.
In fact, it’s kind of disappointing to import shots into Lightroom and watch the rich beautiful photos turn flat and unappealing as Lightroom replaces the in-camera JPEG with a default rendition of the RAW. But then after hitting a few sliders the photo regains its beauty.
To the OP, don’t forget that the camera is not processing the photo in the time between shutter presses: the photos are in cache, processed at a slower rate. Most cameras can cache a dozen or so shots until the camera finally balks and tells you to wait until it is done. If you take several shots, turn off the camera, and yank out the SD card, there is a good chance you will lose the last few.