Big or Small, the confusion of DX and FX formats

Hi All,

For this month in January, I am going to go over the issue many photographers face when buying a camera - Should I buy a DX or FX format camera (Nikon) or Full frame or APC sized Canon.

Why is this format stuff important?

Generally, most entry-level and mid-price DSLRs use an APS-C sized sensor, which has it's image sensor dimensions measuring 23.6 x 15.7mm (22.2 x 14.8mm on Canon DSLRs). 

Back in the film days, the rectangle that captured the image on a standard SLR (the film) was one size: 24mm x 36mm

"In digital SLR cameras, the camera's format refers to the size of its image sensor. Nikon makes a DX-formatsensor and an FX-format sensor. The DX-format is the smaller sensor at 24x16mm; the larger FX-formatsensor measures 36x24mm which is approximately the same size as 35mm film." -- Source www.nikonusa.com

So, Nikon has two different sensor sizes: full frame (FX) and 1.5x (DX) and Canon has three sensor sizes: full frame, 1.3x and 1.6x.

Generally speaking, cameras which sport a full-frame sensor, will have specific advantages and disadvantages: (below from quora.com)

Full Frame Advantages – Generally, a full frame sensor can provide a broader dynamic range and better low light/high ISO performance yielding a higher quality image than a crop sensor. Full frame sensors are also preferred when it comes to architectural photography due to having a wider angle which is useful with tilt/shift lenses.

Crop Sensor Advantages – On the other side, while a crop sensor DSLR doesn’t provide the same level of image quality as a full frame DSLR, it does offers major advantages when it comes to cost. It can also be very effective for telephoto photography for the extra reach gained from the crop sensor multiplier. For example, this can be very useful when shooting sports, wildlife, and other types of photojournalism. Just imagine that on a Canon crop frame body such as a Canon 7D; your Canon 70-200mm f/2.8 lens is effectively a 112-320mm lens! 

24mp D610 has 24mp, practically the same file dimensions as the 24mp D7100 camera, which, as you guessed, also has 24mp. If you wanted to print images from your camera, they would both be the same maximum size because the dimensions of your image in pixels between this full frame and cropped frame camera are the same.

Issues with lenses:

Using a 24-70mm lens is “equivalent”  to filming with a 36-105mm lens on a film body, or 50mm lens on a full frame camera is the equivalent of a 75mm on a cropped lens.

Basically, each format is double the dimensions of the next format, or four times the area. (square law) and  results in  a large difference. Using a 1.6x or DX vs. Nikon FX or Canon full-frame, the difference is only 1.5x on each axis,  and about double the usable area. One negative can be, full frame cameras and their lenses are heavier and  larger than their cropped counterparts. Cost is another huge issue with full frame cameras. See the list below - 

Here are some cameras that make the list for Full-Frame (keep and eye for the prices vs cropped cameras)

Canon EOS 5D Mark IV $3499.00

Nikon D810 $2475.00

Canon EOS 5DS $2523.49

Nikon D750 $1796

Nikon D5 $6496

Canon EOS-1D X Mark II $5999

Canon EOS 6D $1899

Here are some cameras that make the list for Cropped Sensors

Nikon D3300 $446

Canon EOS Rebel T6i / Canon EOS 750D $570

Nikon D5500 $720

Canon EOS Rebel T6s / Canon EOS 760D $650

Nikon D5300 $500

Canon EOS Rebel T5i / Canon EOS 700D $500

Nikon D3400 $350

Canon EOS Rebel SL1 / Canon EOS 100D $400

Mirrorless - Excellent choices!

Fuji X-T2 $1790

Sony Alpha A7R II $700

Olympus OM-D E-M10 II $650

What's my take?

IF $$$$ is a large consideration; you don't do weddings or pro photography for a living, stick to cropped sensor cameras. I used a D300 prior to my D750, and was happy with it. Years later, I find the newest Nikon 7100's are years ahead of the old prosumer level D300, and this is the main point. Mid level cameras like the 7100 are better than old tech! The difference between the D300 and D750 (full frame) is huge in my practice, and so I sold the D300. If I bought the D7100, would I be happy? Perhaps or not, but I had the money to buy more, so I went with the FF setup. I am just extatic with that camera, and have some great pics from it. I must say, I did doll photography before the D750, so I can directly compare. Now I do this professionally as I get paid to do this, but I have been doing this from the late 70's, but started using digital point and shoots and learned how digital filming works in the 90's - I still have my first 1mpx camera. I also have several old film cameras like Nikon FE2 and FG20 and 8mm films. So i would learn how film theory works, practice and learn the camera in and out. Learn how lenses work, DoF, Bokeh, F-Stop, shutter speeds, and focal length interplay.

Ok, that's all for this month, till next time!

Mishka