I was just in Denali NP camping this week and photographing everything I could find. This time of year the park has lots of animals near the road corridor grazing on the tender green shoots and plants. We found caribou, moose, lynx, ptarmigan and snowshoe hares on our trip. But what we didn’t expect to find was a calypso orchid. This is a rare flower, I’ve only seen them a few times in the woods, but we got lucky and found a beautiful patch of this orchid. We spent about an hour photographing the flowers trying soft focus, shallow depth of field at F2.8 and top down images. But the shot I liked the best rendered all the flowers tack sharp at a very close distance. And the only way to do that was focus stacking. The good news is most cameras automatically shoot a focus stack, you just have to set it up in the menu.
For Nikon shooters this is called Focus Shift Shooting. You can find this setting in the shooting menu.
You have a few choices to make. First, decide how many shots you want. For scenes that have a lot of depth, I choose 75-100 images. This way I know I will have enough shots to cover the entire plant. Next, choose the step width. I use five for wildflowers. If I am working on a large flower and at very close macro distances, then I might choose an interval of 2-3. In this menu I also set first-frame exposure lock so the exposure stays the same through the series. To start the sequence, just go to the start setting at the top of the menu and hit the OK button.
For the calypso orchid I shot 100 frames and my interval was 5. You start by focusing on the closest flower you want in focus, and then the camera will progressively focus back into the scene during the sequence. You can check how much of the scene was in focus by looking at your last frame in the sequence to see if you got enough. An important consideration is aperture. I like to use 5.6, the sharpest aperture on my 70-200mm lens. This gives me a little overlap with depth of field. You could choose F8 or even F11, but if you do enough frames you won’t need this much depth of field per shot, and smaller apertures start to introduce diffraction and won’t be as sharp.
I shot from a tripod so there was no movement during the shooting…you want your frames to perfectly match frame to frame. If the wind is blowing you may have to use a faster shutter speed to prevent moment. Happy shooting!