Canon EOS-1D X vs. the EOS 5D Mark III – ISO Comparison Test

Canon EOS-1D X vs. the EOS 5D Mark III – ISO Comparison Test

In this comparison of the Canon EOS-1D X (B&H) vs. the Canon EOS 5D Mark III (B&H), I will show you which camera gives you a cleaner image in a high ISO. However, I want to emphasize that when you’re shooting in a low-light situation, it is important to shoot with a higher ISO and expose the image correctly in-camera, instead of shooting with a lower ISO to prevent a noisy image and underexposing the image in-camera. Doing this will be more beneficial to your image results. Here’s why:

  1. You’ll have a better chance to capture the ambient light of the surroundings and avoid dark backgrounds in your photos.
  2. You’ll be able to use high shutter speeds, which will help you achieve sharper looking images and prevent bluriness, which can result from lower shutter speeds.
  3. You’ll be able to use a higher F-stop in case you need a greater depth of field.
  4. Your on-camera flash will need less power to achieve correctly exposed images, which indirectly saves you battery power and gives you a faster recycling speed.
  5. It will make it easier to shoot with the histogram weighted to the right because of the additional ISO and shutter-speed range.
  6. Correcting high ISO underexposed images in Lightroom will give you noisier results than you would get shooting with an even higher ISO that is properly exposed in-camera.

Let’s divide the image into 3 areas: highlights, midtones and shadows. When we look at the images from both cameras in the low ISO ranges, from ISO 100 through ISO 1600, both render almost identical, clean images. From ISO 1600, you start seeing a noise pattern in the midtones and shadows with both cameras, while the highlighted areas look almost identical up to ISO 6400 from both cameras.

From ISO 1600 to ISO 3200 the changes are gradual. But, starting at ISO 3200 you really see that the Canon EOS-1D X (B&H) excels with a much cleaner image and more pleasant noise pattern due to the sensor advantage in the midtones and shadows areas. At ISO 6400 and 12,800, especially at 12,800, we can see a definite advantage using the Canon EOS-1D X (B&H) in the highlights, midtones and shadow areas. It’s obvious that the EOS-1D X image is much cleaner at ISO 12,800. And, from 12,800 and above it’s a clear win for the Canon EOS-1D X (B&H).

If the lighting conditions you’re shooting in doesn’t require an ISO over 3200, both cameras will deliver almost identical quality images. However, if you need to shoot with an ISO 6400 and above (especially at 12,800 and above), the Canon EOS-1D X (B&H) will deliver a superior, cleaner image. This does not mean the Canon EOS 5D Mark III (B&H) cannot render deliverable images at ISO 12,800, it just means that the Canon EOS-1D X (B&H) controls the noise in the shadow area much better in a high ISO. See it for yourself in the images below.

The area in the yellow rectangle in the first image you see here is enlarged for the subsequent images to actual pixel size.

Below are the comparison shots between the Canon EOS 5D Mark III (B&H) and the Canon EOS-1D X (B&H) respectively.

You can reduce image noise In Lightroom 4.0 (B&H).  I find this to be the best noise reduction software on the market today.  This capability by itself is enough of a reason to purchase Adobe Lightroom 4.0 (B&H).

Below is the final image from the Canon EOS-1D X (B&H) at ISO 12,800, with the Noise Reduction adjustment applied in Adobe Lightroom 4.0 (B&H).




  1. This was an excellent blog posting. The graphic illustrations were fantastic.

  2. I believe your test have a problem. In every shot taken with the 1DX, the mannequin hair is in focus while on the 5D3 it is not. This seems to indicate that the focus on the 1DX was closer to the hair plane while the 5D3 focus was closer to the front of the mannequin’s face. That alone would explain why the noise is more evident on the 5D3 compared to the 1DX.

  3. Opps!, I would like to correct myself. Although I maintain my opinion regarding the back focus issue with the 1DX, on second thoughts, I realized that sensor noise has nothing to do with the surface being photographed. Noise is noise and will show up regardless the focus accuracy.

  4. I was weighing my options in upgrading my body. Either get into debt and put a loan to get the 1dX or borrowing a much much smaller amount and getting the 5D mark III. Based on all the reviews I read the advantage of me getting the 1DX is not worth the fuss for the amount of money problems I am going to get into if I buy one.

    I will go ahead and get a 5D Mark III which will be a good combo I think with my 200-400mm f4.

    I can use my existing 70D can go well with the wide angle 10-22mm.

    Thanks for the review.


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