Silverman wrote:
Please explain the difference between the DX and FX Cameras, I just bought a used Nikon D3300 with a Nikon DX 18-55 VRII and a DX 55-200 VRII Lens, I am a newbie to DSLR Photography, having only used Point & Shoot cameras prior to my newest purchase of the DSLR Nikon D3300.
The key difference is sensor size where an fx sensor is about the same size as 35mm film 36 x 24mm and a crop sensor is about 24mm by 16mm
These are both much bigger than the typical point and shoot.
when you view a photo at a particular size made with the fx sensor it is not magnified as much as with the dx sensor, and much less than with a point and shoot. If you take a photo with a particular lens focal length focused at the same point and magnify them both to the same extent you would see the image of the dx sensor would be exactly the same as the central area of the fx sensor. which is why the dx sensor is often referred to as a crop sensor. since if you cropped the image from the fx sensor to show the same view as the dx sensor the 2 images would be identical.
This leads on to something known as a field of view and the field of view is wider on the fx sensor for a given focal length. The longer the focal length the narrower the field of view you can calculate an equivalent field of view between the 2 sensor sizes using the crop factor which is about 1.5
so with a 50mm focal length lens, on a fx sensor it looks like 50mm. On a dx sensor it has the same field of view as a 75mm lens on the fx sensor.
As a general rule of thumb the longer the lens and the more light that it lets in the more expensive it is to buy and produce. With a lens designed to produce an image circle which covers the fx sensor the lenses have to be physically bigger than a lens designed to cover the dx sensor. With a point and shoot camera the sensor is really small and the crop factor can be much larger which makes for smaller lens elements and shorter focal length lenses which can give an equivalent field of view of that of a much longer focal length lens on an fx sensor size body.
right now you are probably thinking the smaller the sensor the better for me because i can use cheaper lighter smaller lenses compared with the fx sensor camera.
However there are drawbacks with these smaller sensors since the image has to be magnified so much more for a given image size and flaws are also magnified in both the lens used and the sensor. Lets keep it simple and just say image quality is better with the larger sensor size. If you only want small images this isn't really noticeable but with larger sizes it will be.
Depth of field also appears to change with smaller sensors appearing to give greater depth of field for a given aperture and focal length. Really it looks greater because of how much more you are enlarging the image. In practice photo's with the subject nice and sharp and a nice out of focus background is much harder to achieve with the smaller sensor size. There is also something called diffraction which comes into play with smaller apertures. Generally smaller apertures give greater depth of field and makes everything sharper but diffraction comes into play sooner with small sensors and starts to make the image fuzzy.
So really its down to image quality, control of depth of field, and low light performance, and noise which is where the fx sensor wins. With the drawback of heavier more expensive lenses and a more expensive sensor.
Dx Sensors makes photography more affordable and for long distance work as is often the case with birds the crop factor is quite useful. However you also need faster shutter speeds and or a good tripod. It's easy to become obsessed with long focal length lenses but really if you can get closer you will have better IQ.