TEch Tuesday: FX Vs DX, Which is best?

Working for Nikon I have in my possession one of each camera we make, more than one of some.
I get to use all the different models and it is a great opportunity to learn about what works best for what situation. Some day I will retire and I will have to buy some camera bodies of my own. I’ve been giving that a lot of thought. Let me share some ideas with you for your future camera purchases. Do you have to decide between the two; FX or DX (by-the-way if you shoot another brand, they use different terminology, but the basic principles will apply as well). O.K., I highly recommend to any “serious” photographer that you own two camera bodies. If you are traveling
and something happens to your camera, you still have a back-up to be able to keep shooting.

In fact I plan to buy both an FX and a DX body when I retire. Since we don’t know what is coming in the future and every time I guess I get it wrong, let’s just deal with what you could do today. Since I use Nikons I will use that system for my examples.

First let’s state some of the major advantages of each type of sensor;

FX sensors are about the same size as a piece of 35mm film was 24cm X 36cm. The lenses that were made for film camera when used on an FX body will be the focal length they are marked.
For instance a 50mm lens will be a 50mm lens. The speed of the lens, widest aperture, will remain the same. So a 50mm f 1.4 lens will be a 50mm f 1.4 lens. All of the characteristics you remember from your film days will still be pretty much the same. Nikon’s three FX sensored cameras today are the D3s, D3x, and the D700. Both the D3s and D700 are 12 megapixel cameras. Both produce near state of the art images. Because their pixel size is larger they exhibit extremely low noise at High ISOs they are the obvious choice for people having to work in very low light. They both are also capable of frame rates between 6 and 9 frames per second, so they are also the ideal camera for anyone needing to keep shooting at very hight speeds, like sports photographers. The D3s is the newer camera and it has an even more advanced sensor and thus is the ultimate in overall image quality among our fast cameras. The D3x is a very high resolution camera with a 24 megapixel sensor, nothing beats it for resolution, but it is not as good at high ISOs in terms of noise and it is not near as fast as the D3s. Because it makes much larger files, it is slower to operate, but for studio and location shooters that would have shot 4X5 or medium format in the past, it provides exceptional resolution for the highest possible detail. The FX cameras also have larger viewfinders that are brighter and easier to see through. These three cameras are also very ruggedly built and made to stand up to the rigors of hard use, under less than ideal conditions of high moisture and dust. If the ultimate in image quality, low noise, speed, and rugged construction are your goals
you’re an FX guy or gal.

DX sensors are smaller than FX sensors, close to the size of APS film 23.6 cm X 15.6 cm. Since the sensor is smaller the individual pixels must also be smaller to fill an equal number on the sensor.
This, in effect, does two things, because they are smaller they need to be amplified to work at High ISOs and thus they are not quite as good in terms of low noise as the FX sensors are. Recent developments have improved them a lot, but they still fall well short of the High ISO performance of FX sensors. Where a D3s can very easily shoot at 6400 ISO with almost no noise, the D7000 a
16 megapixel DX camera will have some noise apparent at that high of an ISO setting. So FX wins the noise battle. However the offset is that the smaller DX sensor packs more pixels in a tighter pattern on the sensor and thus has very high resolution, appearing even sharper and more detailed than the same number of pixels spread across an FX sensor. So in terms of resolution
the D7000 holds an advantage over the FX cameras. It’s resolution compare very favorably with the $7,899. D3s! The D7000 cast around $1,200. Pretty amazing and there in lies one of the biggest advantages of the DX cameras, much lower cost for surprisingly good performance.
The D7000 is a very well made camera able to withstand hard use, but not up to the FX cameras
build quality. DX cameras, because they use a smaller sensor have a crop factor of 1.5. In simple terms this means that if you put a 50mm lens on a DX camera it will make and image that looks like it was shot with a 75mm lens. It is still a 50mm lens with all the characteristics of a 50mm lens it just will crop down to the portion of the image that a 75mm lens would have made. This is and important distinction because some lenses like the 85mm are know as portrait lenses because of the nice perspective they give of the human face. Some people think that since their 50mm will crop like a 75mm lens it will then be a good portrait lens, not true, it’s still a 50mm which for head and shoulders portraits does not give the same perspective, just the cropping. However in some kinds of photography like close-up work, the added cropping is a great advantage, since it gets you closer. Also because of the optical geometry of the smaller sensor the depth of field is also greater, especially in close-up work. Advantage DX. So, if the ultimate in apparent resolution, reasonably low noise, speed in the five frames per second range, and reasonably rugged construction are your goals, all at a bargain price, then you’re a DX guy or gal.

As you can see they both have their pluses and minuses. For me if I were buying today it would be the D3s for speed and low noise and a D7000 for a lighter, less expensive travel camera with still gang busters quality. If you can own only one, then it will come down to your budget and your most pressing needs.

Having said all of this, I have one last thing to share; “If you own any top notch camera made today and you’re not getting incredible results, it’s not the camera…….”

blessings,

the pilgrim

P.S. Starting O:Dark thirty in the morning I will be on the road for the next three weeks. First at San Diego for the International Symposium on Aviation Photography, the next week touring the Southwestern National Parks with the Bio Communications photographers and Scott Diussa. My lovely bride will also be with me for that week….Yeah!!! Finally the week after that at the Reno Air Races Pylon School. So for the next few weeks I hope to post lots of airplanes and nature and travel shots. I will post as often as I can, but the schedule will be hectic and I might miss a day somewhere in there. I promise to make the posts as entertaining as I can to make up for any dropped days. For the record, I’m taking the following on this trip; D3s and D7000, 12-24 AFs f 4 (DX), 16-35 AFs VR f4 (FX), 24-120 AFs VR f4 (FX), 70-300 AFs VR f 4.5-5.6 (FX), 85 Micro Nikkor DX f 3.5 a Lensbaby Composer (FX) with close-up lenses. Tripod and ball head and cable releases. A good chance to do some comparison tests of the D3s and D7000 face to face, I’ll share my thoughts…….

*Photo Note: F100, 17-35 f 2.8 Fuji Velvia.