Stopping down to a smaller aperture gives you more depth of field in a single frame, but it also introduces diffraction that softens fine detail. Focus stacking blends several frames, each focused at a different distance, to build a sharp image at a wider aperture. For still macro subjects, stacking usually gives crisper results, while a smaller aperture is faster and works with moving subjects.
The Problem with Macro Depth of Field
At close range, depth of field is extremely thin, sometimes a few millimeters. A small subject such as a flower or insect may have its front sharp and its back soft even at a fairly narrow aperture. That is why macro shooters need a plan beyond simply choosing a bigger number.
Option One: Smaller Aperture
- Set roughly f/8 to f/16 for more depth of field.
- Works in one shot, so it suits insects, breezy flowers and handheld work.
- Diffraction increases as you close the aperture, which reduces fine detail beyond a certain point.
- A narrow aperture needs more light, a longer shutter time or higher ISO.
Option Two: Focus Stacking
- You shoot a series of frames while moving the focus point from front to back.
- Software blends the sharpest parts into one image.
- You can stay near the lens’s sharpest aperture, often around f/4 to f/8.
- It needs a still subject and a steady camera, and the process takes more time.
How to Stack Focus
- Mount the camera on a tripod and set manual focus.
- Use a mid aperture, roughly f/5.6 to f/8, and a low ISO.
- Focus on the nearest part of the subject and take the first frame.
- Move focus a small amount farther, using a focusing rail or the focus ring, and shoot again.
- Repeat until you pass the farthest part of the subject, with each frame overlapping the last.
- Blend the frames in stacking software or a photo editor’s auto-blend tool, then check the edges.
Many modern cameras offer a built-in focus bracketing mode that automates the steps. Check your camera’s menu for it.
Quick Comparison
| Trait | Smaller aperture | Focus stacking |
|---|---|---|
| Shots needed | One | Many |
| Fine detail | Softened by diffraction | Stronger |
| Moving subjects | Workable | Difficult |
| Gear | Any | Tripod, software |
FAQ
How many frames do I need?
It depends on the subject depth and step size. A small object may need five to ten frames, while a deep subject may need dozens.
Can I combine both methods?
Yes. Many macro shooters stop down a little and also stack, which cuts the number of frames needed.
Practical Tips
- Use a remote release or a short timer to avoid shake during each frame.
- Keep lighting steady across the series so brightness matches.
- Shoot a few extra frames at each end of the subject.
The Short Version
Choose a smaller aperture for quick shots and moving subjects, and accept some softness. Choose focus stacking for still subjects when you want maximum detail across the frame.
