Both lenses begin at a useful wide angle of 24mm, but the 24-105mm reaches much further on the long end. The 24-70mm designs are often built with a wider constant aperture, while 24-105mm designs favour range and carry-everywhere convenience. Which suits you depends on how often you wish you had more reach.
What the Numbers Mean
The two figures are the shortest and longest focal lengths. A 24mm view is wide enough for landscapes, interiors and group shots. At 70mm you get a natural portrait view, and at 105mm you get a tighter, more compressed look useful for head and shoulders or distant details.
The zoom ratio also differs. The 24-105mm covers more than four times the range, while the 24-70mm covers under three times. A larger ratio often means design compromises, though maker designs differ widely.
Where They Typically Differ
| Trait | 24-70mm | 24-105mm |
|---|---|---|
| Reach | Moderate | Longer |
| Maximum aperture | Often f/2.8 on professional models | Often f/4 on common models |
| Size and weight | Varies, often larger with f/2.8 | Varies, often lighter with f/4 |
| Low light | Gathers more light at f/2.8 | Needs higher ISO or slower shutter |
These are common patterns, not rules. Some makers offer a 24-70mm at f/4 and some offer a 24-105mm at f/2.8, so check the specific model’s guide.
Choosing by Use Case
- Events and weddings in dim venues: the wider aperture of an f/2.8 24-70mm helps.
- Travel and walking around: the extra reach of a 24-105mm means fewer lens swaps.
- Landscapes: both cover wide views; the longer lens helps isolate distant scenes.
- Video: consider the aperture, stabilization and how the lens handles focus changes.
Questions to Ask Yourself
- How often do I crop heavily because I could not zoom in enough?
- Do I shoot in dim rooms where a wider aperture matters?
- Will I carry this lens all day?
- Does my camera body have stabilization that can offset a narrower aperture?
Handling and Everyday Use
Zoom range changes how you work. With a 24-105mm you can capture a wide room, then step to a tight detail without changing lenses, which helps in dusty or wet conditions where you would rather keep the camera sealed. With a 24-70mm you may crop more, but you gain a brighter viewfinder image and often quicker autofocus in dim light.
FAQ
Is 24-105mm a good only-lens for one trip?
Many travellers like it because it covers wide scenes and moderate telephoto without a lens change. If you often shoot indoors in low light, you may want a faster lens as well.
Does a wider aperture matter for blur?
It helps, but focal length and subject distance also affect background blur. At 105mm, even f/4 can give pleasing separation when the subject is close.
The Short Version
Choose the 24-70mm when light gathering and a wider aperture matter most. Choose the 24-105mm when range and convenience matter most. Always check the exact model, since designs vary by maker.
