The Sigma 24-70mm f/2.8 and the Sony FE 24-105mm f/4 G are both standard zooms for full-frame E-mount cameras, but they chase different goals. The Sigma gives you a brighter aperture, while the Sony covers a longer range. Choose f/2.8 for low light and background blur, or 24-105mm for flexibility with a single lens.
What each lens is for
A 24-70mm f/2.8 is the classic working zoom for weddings, events, portraits and general documentary work. It is bright enough for dim venues and gives clear subject separation.
A 24-105mm f/4 covers more ground, from wide scenes to a short telephoto. It suits travel, hiking, family trips and video, where you want to avoid changing lenses. The Sony is a G-series lens from the camera maker; the Sigma is a third-party lens, usually from the Art line for this focal range.
Key differences
| Trait | Sigma 24-70mm f/2.8 | Sony 24-105mm f/4 G |
|---|---|---|
| Maximum aperture | f/2.8 | f/4 |
| Longest focal length | 70mm | 105mm |
| Light advantage | About one stop brighter | Less light, more range |
| Typical use | Events, portraits | Travel, video, general use |
Confirm weight, size, stabilization and which Sigma version you mean on the maker’s page.
What one stop means
A stop is a doubling of light. With f/2.8 you can use a shutter speed twice as fast, or half the ISO, compared with f/4 at the same exposure. In a dim hall that can separate a sharp image from a blurry one.
Both lenses can give a pleasing portrait look, but f/2.8 delivers a stronger background blur at 70mm, especially when the subject is far from the background.
How to decide
- If you shoot indoors, at night or at events, choose the f/2.8 lens.
- If you travel light or shoot landscapes and street scenes in daylight, the extra reach of 105mm is useful.
- Look at size and weight, since many people prefer the lens that stays on the camera.
- If you shoot video, consider whether in-body stabilization on your camera is enough.
If you cannot decide, think about which mistake you can live with. Missing a shot because the room was too dark is common with f/4, while missing a shot because you could not zoom in far enough is common with 70mm. Some photographers solve this by owning the f/2.8 zoom and adding a small prime for evenings.
FAQ
Is f/4 enough for portraits?
Yes. Many portraits are made at f/4, and a longer focal length such as 105mm adds background compression.
Do I lose autofocus features with a third-party lens?
Third-party E-mount lenses are designed to work with the system, but feature support varies by camera. Check the maker’s compatibility notes.
The Short Version
Choose the Sigma if low light and background blur matter most. Choose the Sony if you want a flexible range from wide to short telephoto on one lens. Confirm details on each maker’s page.
