Specifications#
Equivalent focal length on different cameras#
Field of view and depth-of-field equivalence when this lens is used on bodies with different sensor sizes (natively or via an adapter).
| Camera format | At 17 mm | At 26 mm | At 40 mm | Equiv. aperture (DoF) |
|---|---|---|---|---|
| APS-C | 26 mm · 79° | 39 mm · 57° | 60 mm · 39° | f/2.7 |
| APS-C (Canon) | 27 mm · 77° | 42 mm · 55° | 64 mm · 37° | f/2.9 |
| Micro Four Thirds | 34 mm · 65° | 52 mm · 45° | 80 mm · 30° | f/3.6 |
Depth of field & background blur#
Computed on its native APS-C format (CoC 20 µm). “Blur @2 m” is the size of an out-of-focus point at infinity, as a percentage of frame width, with the subject at 2 m — a simple bokeh index. Full table: 16 mm f/1.8 on aps-c.
| Focal | Aperture | at 1 m | at 2 m | at 5 m | at 10 m | Hyperfocal | Blur @2 m |
|---|---|---|---|---|---|---|---|
| 17 mm | f/1.8 | 24.3 cm | 1.03 m | 9.61 m | ∞ | 8.23 m | 0.3% |
| 17 mm | f/4 | 57.3 cm | 3.02 m | ∞ | ∞ | 3.71 m | 0.2% |
| 17 mm | f/8 | 1.48 m | ∞ | ∞ | ∞ | 1.86 m | 0.1% |
| 26 mm | f/1.8 | 10.2 cm | 41.6 cm | 2.78 m | 14.2 m | 19.2 m | 0.8% |
| 26 mm | f/4 | 22.8 cm | 96.4 cm | 8.61 m | ∞ | 8.67 m | 0.4% |
| 26 mm | f/8 | 47.5 cm | 2.31 m | ∞ | ∞ | 4.35 m | 0.2% |
| 40 mm | f/1.8 | 4.2 cm | 17.3 cm | 1.10 m | 4.60 m | 45.5 m | 1.9% |
| 40 mm | f/4 | 9.4 cm | 38.7 cm | 2.58 m | 12.8 m | 20.5 m | 0.9% |
| 40 mm | f/8 | 18.9 cm | 79.6 cm | 6.34 m | 379 m | 10.3 m | 0.4% |
Handheld & night-sky limits#
NPF assumes typical 20–24 MP sensors (≈6 µm pixels on full frame, ≈3.9 µm on APS-C, ≈3.3 µm on Micro Four Thirds).
| Body | Min. handheld shutter (longest focal) | 500 rule at 17 mm | NPF at 17 mm, f/1.8 |
|---|---|---|---|
| APS-C | 1/60 s | 20 s | 11 s |
| APS-C (Canon) | 1/60 s | 18 s | 10 s |
| Micro Four Thirds | 1/80 s | 15 s | 10 s |
Compatible cameras#
Bodies in our database with a native Canon RF mount. Full-frame bodies switch to an APS-C crop with this lens.
- Canon EOS R6 Mark III crop mode
- Canon EOS C50 crop mode
- Canon EOS R50 V 2025
- Canon EOS R5 Mark II crop mode
- Canon EOS R1 crop mode
- Canon EOS R100 2023
- Canon EOS R50 2023
- Canon EOS R8 crop mode
- Canon EOS R10 2022
- Canon EOS R6 Mark II crop mode
- Canon EOS R7 2022
- Canon EOS R3 crop mode
- Canon EOS R5 crop mode
- Canon EOS R6 crop mode
- Canon EOS RP crop mode
- Canon EOS R crop mode
- Canon EOS R5 C crop mode
- Canon EOS R6 V crop mode
- Canon EOS R8 Mark II crop mode
Adapt it to other systems#
Similar lenses#
- Tamron 17-70mm F/2.8 Di III-A VC RXD f/2.8
- Canon RF-S 18-45mm F4.5-6.3 IS STM f/4.5–6.3
- Sigma 18-50mm F2.8 DC DN | Contemporary 021 f/2.8
- Canon RF 24-105mm F4-7.1 IS STM f/4–7.1
- Canon RF 24-105mm F4L IS USM f/4
- Canon RF 24-50mm F4.5-6.3 IS STM f/4.5–6.3
- Canon RF 24-70mm F2.8L IS USM f/2.8
- Canon RF 28-70mm F2.8 IS STM f/2.8
- Canon RF 28-70mm F2 L USM f/2
- Canon RF-S55-210mm F5-7.1 IS STM f/5–7.1
Frequently asked questions#
Is the Sigma 17-40mm F1.8 DC | Art 025 full frame?
No — it is designed for APS-C sensors. On a full-frame body it vignettes or triggers crop mode.
What is the Sigma 17-40mm F1.8 DC | Art 025 equivalent to on APS-C?
Its focal length is already the real value for APS-C: 17–40 mm frames like 26–61 mm on full frame.
What is the Sigma 17-40mm F1.8 DC | Art 025 good for?
As a standard zoom it suits everyday shooting, travel, events and walkaround use.
Sources & licences#
- Lensfun lens database — CC BY-SA 3.0
Last updated October 03, 2026 · How we calculate · Sources