Several years ago I added my first Nikon FX format sensor (Nikon D700) to my camera bag (today I own Nikon D5100 DX / D3200 DX bodies - and - Nikon D700 FX / Df FX bodies). As a photographer, the sensor is the most important component of my digital cameras, because it is directly processing images I capture and will be converting to digital images for client delivery. As we know, when a camera has 12 megapixels, it means that the camera sensor contains 12 million pixels for the purpose of gathering light. I like to think of those pixels as buckets that capture light particles. Therefore, the larger the bucket, the more light particles it can store in a given amount of time.

The pixel size (bucket size) plays a big role in sensor sensitivity and it'‚s ability to accurately gather light. Bigger buckets are always better than smaller ones (i.e., each of the 12 million pixels in a Full Frame (or FX) sensor will be bigger than 12 million pixels in an APS-c (or DX) sensor. With an FX sensor more light particles can be stored, without getting over-filled, which correlates to a good flow of information about light particles being passed on to the camera processor, which assembles a digital image. While larger pixels (or bigger buckets) are good, they are expensive to manufacture. To combat this problem, manufacturerst have been cramming more and more pixels into smaller sensors - while attempting to simultaneously increase the efficiency each pixel. This has resulted in a 'megapixel race' among the manufacturers - we are seeing more and more pixels in the modern sensors, despite the fact that the size of the APS-c and Full Frame sensors remains the same. In my experience, the difference between DX and FX sensors is clear when it comes to overall image quality. I have found the current sensor size and pixels within in my FX camera bodies more robust - for my photography needs - than sensors in my DX camera bodies, in terms of noise and dynamic range for instance.

In addition, I have been sarcastically asked - if I find my FX cameras so much better than my DX cameras - will I be getting rid of the DX cameras I own? I answer that question with an emphatic no! When I place my Nikkor 28-300mm FX format lens on my D5100 or D3200 DX camera bodies, because of the APS-c sensor 1.5x crop in the DX bodies, I get a reach of 450mm with the lens. This provides a good option when shooting sporting events. I have attached a couple images where I used the Nikkor 28-300mm FX format lens at 300mm (in effect 450mm) on a DX body. Also because the Nikkor 28-300mm FX format lens cover the entire DX sensor with the sweet spot center of the glass the close in captures at on a DX body are exquisite - there are a couple images attached that display captures at this close in rage using FX glass on a DX body. Have also included an image that describes the difference between the FX and DX format - and correlating lens sizes. I found this application of FX format lenses a favorable option for use with the DX format camera bodies I own. Just a heads up, the converse does not work. DX format glass will have an image circle that is smaller than the length of the diagonal of the image sensor - which generally results in severe vignetting. However, you can use this effect as an advantage to get an in camera vignette effect - as opposed to a software generated vignette.
Hope you found this share helpful - keep shooting and have fun!

Greg.