If you adjust the f stop and it turns to red, the camera thinks the exposure is incorrect and you will have to increase or decrease until it turns blue. This is where technology lends a hand or provides a guideline when it comes to exposure.
On the Samsung NX300, Aperture Priority is shown as A on the shooting modes dial.
Right: number of shots available, battery, Dynamic Range, photo size (20M), Drive, Flash, Metering, AF mode, Focus Area, OIS, RAW format, Fn menu
Left: Aperture Priority, Autoshare, AF options, Menu, Histogram (the graph)
Menu and Fn options are much the same as Program Mode, so once you are familiar with P Mode then the other Creative/Advanced modes are easy enough to understand.
ISO: 100, Aperture: f/5, Shutter speed: 1/640
The plane photo above was taken in the midday sun while the orange and silver Harvard at the back was moving. The photo was edited with levels, curves and Topaz Adjust.
ISO: 100, Aperture: f5.6, Shutter Speed: 1/100
The photo of the bubble above was cropped quite a bit. In fact, I cropped out about 2/3's of the photo because it contained people. I was at the Walter Sisulu National Botanical Gardens where a man was using a stick and rope to create beautiful bubbles. The sun was starting to set, the bubbles were moving with the wind and yet the Samsung NX300 captured a clear, sharp photo. As you can see that even cropped the NX300 handled noise and low light extremely well.
The photo was also taken with an 18-55mm lens. If I had taken the photo with my Canon's 18-55mm IS II lens and cropped in this close, there would have been obvious fringing. There also would have been some visible noise with the Canon 650D. I won't load the original photo as people don't always like having their photos taken by strangers and loaded all over the internet.
ISO: 100, Aperture: f/5.6, Shutter Speed: 1/25
The slow shutter speed for the photo above gave the water a slightly misty look. It was taken near a waterfall where the sun was blocked by the surrounding mountain as the sun started to set. The duck was moving about so I used the Tracking feature of NX300, which allowed me to keep the duck in focus even if he/she moved. Notice the detail in the grass and on the rock.
Keep in mind that a slow shutter speed without a tripod will give you blurry shots unless you are able to steady the camera enough to fire off a few shots and get at at least one sharp photo. The Samsung NX300 was fast enough to do exactly that as I didn't bring a tripod or monopod with me and didn't have anything to steady the camera on.
ISO: 400, Aperture: f/9, Shutter Speed: 1/500
Taken at the Bird Garden at Monte Casino, South Africa. The parrots are very vocal and love the attention from visitors. This particular parrot posed upside down when I lifted the Samsung NX300 up to take a photo. Edited in PSE 10 with levels, curves and Topaz Adjust + Topaz Clarity.
Again, this was taken in low light and to keep the shutter speed fast enough I had to increase the ISO to prevent blurring. I always seem to get to places a little late in the afternoon. The parrots were extremely active and moved about continuously, which tested the NX300's ability to accurately follow. The Samsung NX300's buffer filled up quickly and took a few seconds after a number of continuous shots before I could shoot again. I would suggest a fast memory card like Sandisk's Ultra or Extreme.
The camera's buffer is like a computer's RAM and is the speed with which photos are written to the memory card. Bursts of photos can cause a few seconds delay. With JPEG format the delay occurs after about a burst of 10-12 photos and with RAW at about 6-7 photos. It takes 4 or so seconds to write, which is why a fast memory card is important for bursts of photos.
It's tempting to hold down the shutter button for a length of time but this can cause you to lose photo opportunities while the photos are being written to the memory card. I tend to stick to 4-5 bursts with the highest being what the camera is capable of. In this case the Samsung NX300 can handle up to 8 frames per second but anything higher for actions shots would be a waste due to the buffer. Still photos with bursts over 8 are fine although there isn't a reason to go higher.
Shutter Priority is next and with this shooting mode you decide on the shutter speed while the camera adjusts the aperture.