I never imagined that choosing the “right” ISO for wildlife photography would be the most controversial subject that I would teach. If you ask many pros about which ISO you should use, the most frequent response you will get is: “Choose an ISO based on what you are shooting”. If you are shooting a portrait of a bird or animal, choose a low ISO and when shooting action, select a higher ISO. My philosophy is to start out with the highest ISO your camera can handle and shoot with it from the start no matter what subject you are shooting. Why? It is one less control you need to think about while you are photographing. You can focus all of your attention on the action to help maximize your opportunities when they arise. Notice I didn’t say to use auto ISO either. While it may work in certain situations it can also make unwanted choices and ruin an image. My philosophy follows the Boy Scout principle of “being prepared” and I will show you real world situations where following the high ISO philosophy works all the time!
Let’s use the image above as one of those real world situations when debating ISO. I chose ISO 1250 early that morning before we left camp because the light was very low/overcast and we were photographing action. I could have easily chosen a low ISO of 100 or 200 as the light was starting to get brighter and the cheetah wasn’t moving very fast. If I had chosen ISO 200, my shutter speed would have dropped to 1/500 sec. which would have been fine for the speed he was moving…….but something was up……the cheetah was visibly upset and turned to snarl at some unseen enemy. Suddenly like a ghost (image below), a hyena appeared from out of the tall grass. My shutter speed of 1/2500 sec. was fast enough to freeze any action and the f/stop of 7.1 gave me enough depth of field at 731mm to get both in focus if a clash occurred. Do you think you would have enough time to change your ISO and capture the action?
As it turned out, the cheetah simply ran away but at least I knew that given my settings, I would have captured any action if it did occur! Being prepared before the action starts is the key!!!
I can hear many of you screaming: “My camera gets too much noise at ISO 1250!” While that may be true on many low and mid range camera bodies the technology has improved to a point that almost every camera body on the market today can handle and ISO of 640-800 without the need for noise reduction! No noise reduction was used on any of the images in this article and the in camera noise reduction was off. I usually never go below ISO 640 when I head out the door to photography wildlife and the 2 images below, taken moments apart will illustrate why I choose to push my camera and the ISO settings. In the image below of the portrait of the Roseate Spoonbill, my settings on the Sigma 300-800mm f/5.6 were ISO 640, f/7.1, and a shutter speed of 1/2500 sec. and focal length of 687mm. If I had chosen ISO 100 because I was shooting a portrait, my shutter speed would drop to 1/800 sec. which was enough to freeze the action of the spoonbill preening.
So why would I automatically choose to head out with a high ISO? That’s easy! Part of being prepared as a wildlife photographer is knowing your environs and knowing to expect the unexpected. Wildlife is unpredictable!! I had seen Osprey fishing these waters by the spoonbills before. While I had not seen one that morning, I didn’t want to be surprised and have to change my ISO and shutter speed if that occurred. I don’t think anyone is fast enough to do that while the action is happening!!! Because I had pushed my ISO in the image above, a few moments later when the Osprey dove and caught a fish, I was able to zoom out and capture him with his prize as he gave us a close flyby! The only thing that I changed was to zoom out wider to 356mm……..all the other setting were enough to freeze the wing action and give me enough depth of field as I ripped off 20+ frames of the sequence with the one below being my favorite.
If you had used auto ISO on any of the 2 scenarios above, I don’t believe the camera would have choose the correct one for the action as the lighting conditions did not change. Given that I was shooting the portrait in plentiful light, there probably wouldn’t have been enough shutter speed to render the wings of the flying osprey sharp. It is a risk, I am unwilling to take.
I would like you to think about your ISO before you head out into the field and push your camera’s limits. No one makes you give back shutter speed or depth of field after you take the image. By choosing a high ISO you can decide to either increase the depth of field if needed or the shutter speed all while concentrating on the action without also having to fuss with changing the ISO in the heat of the battle. The image above from Tanzania of the wildebeest is just such an example. The sun was starting to go down and I set the ISO to 800. Wildebeest aren’t that fast but they were leaping into the Mara River during a crossing. I wanted a bit more depth of field to capture as many animals in focus as I could. I settled at f/8 because they were on the other side of the river about 300 feet away from us which would give me about 18 feet of depth of field at 687mm. I could have gone to f/11 which would have given me around 27 feet of depth of field but I wanted to keep the 1/1000 sec. shutter speed to freeze the leaping wildebeest mid air. These were changes I could easily and quickly make because I had pushed my ISO! Drop the ISO to 200 or 400……..and my shutter speed would drop to 1/250 sec. at ISO 200 or 1/500 sec. at ISO 400……neither of which may have frozen the leap of the wildebeest. Again, not a risk I am willing to take and no one has ever asked me to give back the extra shutter speed or depth of field!!!
I hope these few examples show you why you should choose a high ISO when photographing wildlife and you apply it on your next trip out in the field.