In previous tutorials, we discussed what the optimal shutter speed and aperture setting should be when we are shooting HDR photography. Now, we are going to discuss the optimal ISO setting. In HDR photography, we are combing multiple exposures to create one final HDR image. This process of combining exposures automatically creates certain challenges, one being the overall grain in the final HDR image. When you shoot at your camera’s lowest native ISO, you will still see a little bit of grain in your images. Because of this, always keep your ISO at the lowest native ISO on your camera whenever possible. For Canon users, the lowest native ISO is 100. For Nikon users, the lowest native ISO is around 160. In this article, we will discuss reasons why the optimal ISO setting in HDR photography is the lowest native ISO on your camera. In addition, we will also explain what native ISO means.