I'm still fairly new to DSLR, but so far I've gotten excellent results with my D3200. I just have the 18-55mm lens that came with the camera and recently picked up a AF-S DX VR 55-200mm G ED lens. Two types of photography I've always loved - macro and high speed / stop motion. However, I don't understand why my shutter speed is restricted to a max of 1/200 when using the built in flash, and apparently using an external flash unit will make no difference.
Here is my attempt to explain the issue, in a different manner than I've noticed anyone else trying to do.
Like nearly all SLRs, the D3200 uses a
focal plane shutter. As the name implies, this shutter is located just in front of the focal plane—in front of the film (or in this case, the image sensor)—rather than in or near the lens as is usual in non-SLR cameras.
The shutter consists of two curtains. With the shutter set to 1/x of a second, the first curtain begins moving across the film/sensor, uncovering it, and 1/x of a second later, the second curtain follows, covering the film/sensor.
These curtains move at a finite speed. In the case of the D3200, it takes 1/200 of a second for the curtain to move across the sensor. This means that at any speed faster than 1/200 of a second, the second curtain will begin covering the sensor before the first has finished uncovering it; and the sensor will not, at any time, be fully-uncovered. By 1/400 of a second, only half of the sensor is uncovered at any time. At 1/800, only a quarter is uncovered at any time. By the time you get up to the top speed of 1/4000 of a second, only 1/20 of the sensor is uncovered at any given time.
You can think of the action of the shutter, at this high speed, as simply being a slit that is 1/20 of the size of the whole sensor, moving across the sensor at such a speed that it takes 1/200 of a second to complete the trip.
Xenon-tube electronic flash units have a very short duration—typically 1/500 to 1/2000 of a second. This is why they are useful for stopping very fast motion. But since this duration is shorter than the time it takes the shutter curtains to cross the film plane, at any shutter speed where the film plane is not fully-uncovered while the flash fires, those parts that are covered at that time will not be exposed by the flash.
This has always been an issue with focal plane shutters and xenon-based flash units; and it probably always will be. Be glad that your D3200 can use these flash units at 1/200 of a second. My forty-year-old F2 (Nikon's top-of-the-line when it was built in the early 1970s) can only do so up to 1/80, and that is slightly better than the 1/60 that was typical of most SLRs of its period.
In bright enough sunlight, you can use the shutter itself to stop motion, without depending on the flash. In theory, this ought to be even better, since the shutter can go up to 1/4000 of a second. I don't know what the duration is of the D3200's built-in flash, but as I said before, 1/500 to 1/2000 is typical of such units. However, at high speed, focal plane shutters are subject to some other distortion issues related to
rolling shutter effects.
In any event, this is an issue that you will always have with any camera that uses a focal plane shutter, which includes nearly all SLRs. If you want to get away from this issue, and still have a DSLR, then I think your only options are some offerings from
Hasselblad, but if you were someone who could afford a Hasselblad, then I doubt if you would have started with Nikon's “entry-level” model.
A water splash stopped using the built-in flash.
And outdoors, using the shutter.
