Just walked in the door from an incredible trip to Patagonia, one of my favorite places to travel and photograph. We had an amazing group, wild and crazy conditions, and some photo opportunities I have never had in over 20 years visiting this area. We have been working with gauchos at various ranches in Patagonia over the years, and have some special friends there. How special? Our gaucho friends offered to run horses through turquoise Lago Argentina for us for a photo app. This is an incredible picture by itself, but this year something special happened.
As the horses were being driven by the gauchos through the lake, a small group of flamingos took off and flew perfectly through the photo at just the right moment. Literally pure luck, a shot I will never repeat, and one of my favorite Patagonia images of all time. Others in our group also captured this special moment, but an important question came up. If you were focused on the horses, your flamingos might be blurry. If you were focused on the flamingos, the horses might be blurry. Nikon wide area large with people eye detect was set on my camera. Luckily the flamingos and horses crossed a narrow window where both could be sharp with focus on the horse rider. But how would you know just how much depth of field you had? That depends on lens (zoom) length and your aperture.
I knew at 400mm, even at F8, depth of field would be minimal at that distance…may 4-6 feet. But I also knew if I came back to 300mm or wider this would improve my amount of depth field for this image. I quickly backed off to under 300mm, improving my chances of getting both birds and horses in focus. Thankfully the birds and horses/rider intersected and the shot of a lifetime came together.
The take away here is look up a few of your favorite focal lengths and apertures on depth of field charts (lots online) and get a sense of how much depth of field you are working with. Shooting my 600mm F4 at a bird 20 feet away at F4 only gives me a few inches to work with. Shooting my 400mm at 400mm at F8 gives me a few feet when the subject is 70 feet away. Look up wide angle lenses too. Knowing these figures will help you quickly gauge how to set up your shot!