A 100mm macro lens gives you more distance from your subject at the same magnification, while an 85mm macro is a little wider and often doubles as a portrait lens. Choose 100mm for skittish insects and cleaner lighting room; choose 85mm for a compact kit that mixes close-ups with people.
What Each Focal Length Is For
- 85mm macro: a short telephoto that suits portraits, product shots and close-up work. Models vary, so some reach full life-size magnification and some do not.
- 100mm macro: a classic macro length. Many lenses at this focal length reach 1:1 magnification, which means the subject appears life-size on the sensor.
Always check the maker’s page for the maximum magnification and minimum focus distance of the specific lens, as these differ between models.
Working Distance
Working distance is the space between the front of the lens and the subject. At the same magnification, a longer focal length gives more of it. That extra room helps with:
- Insects and small animals that move away when you get close.
- Lighting, since you can place a flash or reflector without blocking it.
- Avoiding your own shadow on the subject.
Key Differences
| Trait | 85mm | 100mm |
|---|---|---|
| Working distance | Shorter | Longer |
| Portrait use | Very natural | Works, tighter framing |
| Size and weight | Often lighter | Often a bit larger |
| Wild subjects | Harder | Easier |
How to Decide
- List your subjects. Flowers, jewelry and food do not mind a short distance; insects often do.
- Decide if portraits matter. An 85mm macro doubles as a flattering portrait focal length.
- Check the true magnification. Some 85mm lenses reach only half life-size.
- Think about stabilization and handheld use. Stabilization can help at close range.
- Consider your mount. Choices differ by brand, so see what your system offers.
Technique Tips for Close Work
Depth of field becomes extremely thin at close range, so even a small movement can shift what is sharp. Use a tripod or a firm rest when you can, and consider focus stacking for still subjects such as flowers and small objects. Narrow apertures give more depth but can soften fine detail through diffraction, so a middle aperture often balances the two. Natural light from a window with a simple reflector is a low-cost way to add shape to your close-ups.
FAQ
Is 100mm better for macro?
For distance and subject comfort, usually yes. For a lens that serves several roles, an 85mm can be the more practical option.
Can I use a macro lens for normal photos?
Yes. Most macro lenses focus to infinity and work well for portraits, products and general shooting.
The Short Version
Choose 100mm if you shoot small, wary subjects and want space for lighting. Choose 85mm if you want a lighter lens that also works for portraits. Confirm magnification and focus distance for the exact model.
