Tamron 18-300mm f/3.5-6.3 Di III-A vs Tamron 17-70mm f/2.8 Canon RF (2026): Key Differences
As an Amazon Associate we earn from qualifying purchases. Links on this page are affiliate links.
The tamron 18 300mm f 3 5 6 3 di iii a vs 17 70mm f 2 8 di iii comparison highlights two distinct APS-C zooms. Both lenses offer image stabilization and autofocus for mirrorless systems. The key difference lies in their focal range and aperture. One provides a massive 16.6x zoom range for versatility. The other offers a constant f/2.8 aperture for better low-light performance and shallower depth of field.
Key differences
| Aspect | Tamron 18-300mm f/3.5-6.3 Di III-A VC Lens | Tamron 17-70mm f/2.8 for Canon RF APS-C |
|---|---|---|
| Focal Length | 18-300mm | 17-70mm |
| Maximum Aperture | f/3.5-6.3 | f/2.8 |
| Lens Mount | Sony E | Canon RF |
| Weight | 1.37 pounds | 1.2 pounds |
| Minimum Focusing Distance | not listed | 0.19m (7.5") |
Which one should you choose?
Choose Tamron 18-300mm f/3.5-6.3 Di III-A VC Lens if
- You need a single lens for travel or events with varying distances.
- You use a Sony E-mount camera system.
- You prefer a compact design that covers wide to telephoto.
Choose Tamron 17-70mm f/2.8 for Canon RF APS-C if
- You require a constant f/2.8 aperture for low-light shooting.
- You shoot on a Canon RF-mount APS-C camera.
- You want closer focusing capability for detailed subjects.
Verdict: Choose the 18-300mm if you prioritize range and versatility in one package. Pick the 17-70mm if you need faster optics and better performance in dim light. Your camera mount will ultimately decide which lens fits your system.
Focal Range and Aperture Comparison
Focal Length Range
The Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD offers a massive 16.6x zoom range, covering 18mm to 300mm. This makes it a true all-in-one lens for APS-C Sony E-mount cameras, ideal for travelers who want to avoid changing lenses. In contrast, the Tamron 17-70mm f/2.8 Di III-A VC RXD for Canon RF is a standard zoom with a much narrower 17mm to 70mm range. While the 17-70mm is excellent for portraits and everyday shooting, it cannot reach the telephoto distances that the 18-300mm achieves. You must choose between extreme versatility or a more focused standard range.
Maximum Aperture
Aperture controls light intake and background blur. The Tamron 17-70mm f/2.8 maintains a constant f/2.8 aperture throughout its entire zoom range. This allows for significantly better low-light performance and more pronounced bokeh compared to variable aperture lenses. The Tamron 18-300mm f/3.5-6.3 has a variable maximum aperture that narrows from f/3.5 at 18mm to f/6.3 at 300mm. This means less light reaches the sensor at longer focal lengths, requiring higher ISO settings in dim conditions. If you prioritize shallow depth of field or shooting in dark environments, the constant f/2.8 on the 17-70mm is a clear advantage.
Lens Mount Compatibility
Lens mount compatibility is critical for fitting your camera body. The Tamron 18-300mm f/3.5-6.3 Di III-A is designed exclusively for Sony E-mount APS-C mirrorless cameras. It will not physically attach to or function with Canon RF bodies. Conversely, the Tamron 17-70mm f/2.8 Di III-A VC RXD is built specifically for Canon RF APS-C mirrorless cameras. These two lenses are not cross-compatible. You must select the version that matches your existing camera system. This is a binary choice based on your hardware, with neither lens offering a broader platform support than the other.
Minimum Focusing Distance
Close-up capability affects macro-style photography. The Tamron 17-70mm f/2.8 features a minimum focusing distance of just 0.19 meters, or 7.5 inches. This allows you to get very close to your subject for detailed shots of small objects or flowers. The provided data for the Tamron 18-300mm f/3.5-6.3 does not list a specific minimum focusing distance. Without this specification, it is difficult to directly compare their close-focusing performance. However, the explicit 0.19m figure on the 17-70mm suggests strong macro potential, which is valuable for detail-oriented work.
Physical Weight and Size
Portability matters for travel and all-day shooting. The Tamron 18-300mm measures 4.9 inches in length, 3 inches in width, and 3 inches in height, weighing 1.37 pounds. The Tamron 17-70mm is slightly more compact, measuring 4.6 inches long, 2.9 inches wide, and 2.9 inches high, with a weight of 1.2 pounds. The 17-70mm is lighter and shorter, making it marginally easier to carry for extended periods. The 18-300mm is heavier due to its extensive optical range, but remains relatively portable for its class. Both lenses are designed to be manageable on APS-C bodies, though the 17-70mm holds a slight edge in compactness.
Autofocus Mechanism
Autofocus speed and precision impact shooting success. The Tamron 18-300mm utilizes a VXD linear motor focus mechanism, described as providing extremely fast and precise autofocus. This is beneficial for tracking moving subjects across a wide zoom range. The Tamron 17-70mm uses an RXD autofocus motor. While both offer reliable autofocus for their respective mounts, the specific VXD motor in the 18-300mm is highlighted for its high resolving power maintenance and speed. The 17-70mm includes an AF/MF switch for manual override, a feature not explicitly listed for the 18-300mm in the provided data. The VXD system in the 18-300mm suggests a focus on high-speed performance.
Which Tamron Lens Fits Your Needs
Travelers wanting one lens for everything
You need a 16.6x zoom range covering 18mm to 300mm. This all-in-one design eliminates the need to carry multiple lenses. The VXD autofocus motor ensures fast and precise focusing. It maintains high resolving power from center to corners. The moisture-resistant construction adds durability for outdoor adventures.
Canon users needing fast constant aperture
You shoot with Canon RF APS-C cameras and require a constant f/2.8 aperture. This lens offers superior low-light performance and background blur. The RXD autofocus system provides smooth operation. You get a minimum focusing distance of 0.19m for close-ups. The compact size fits well with smaller camera bodies.
Photographers prioritizing lightweight and portability
You value a lighter gear setup for daily carry. This lens weighs just 1.2 pounds. Its dimensions are 2.9 by 2.9 by 4.6 inches. The constant f/2.8 aperture allows for better image quality in various lighting conditions. The built-in VC stabilization helps keep your shots sharp without needing a tripod.
The products compared
Tamron 18-300mm f/3.5-6.3 Di III-A VC Lens
Best for: Travelers needing one versatile lens
- Lens Mount
- Sony E
- Focal Length
- 18-300mm
- Maximum Aperture
- f/3.5-6.3
- Sensor Format
- APS-C
- Focus Type
- Autofocus (VXD)
- Color
- Black
View on Amazon: Tamron 18-300mm f/3.5-6.3 Di III-A VC Lens Affiliate link
This Tamron lens covers 18-300mm on Sony E APS-C cameras. It uses a VXD linear motor for fast autofocus. The aperture ranges from f/3.5 to f/6.3. It weighs 1.37 pounds and measures 4.9 x 3 x 3 inches. This all-in-one zoom suits travelers who want one lens for many situations. You get a wide 16.6x zoom range without changing glass.
Pros
- 18-300mm focal length covers wide to telephoto
- VXD linear motor autofocus mechanism
- Moisture-resistant construction with fluorine coating
- Compact size at 4.9 x 3 x 3 inches
Cons
- Variable aperture of f/3.5-6.3 limits low light performance
- Heavier at 1.37 pounds compared to standard zooms
- No constant f/2.8 aperture for shallow depth of field
Good fit if
- You want a single lens for travel and everyday use
- You shoot varied subjects from wide landscapes to distant details
- You prioritize versatility over maximum aperture speed
Skip if
- You need a constant f/2.8 aperture for professional work
- You prefer lighter gear for long hikes
- You shoot primarily in very low light conditions
Verdict: Tamron 18-300mm F/3.5-6.3 Di III-A fits travelers who need one lens for everything. It offers a huge zoom range but sacrifices aperture speed for that versatility.
Tamron 17-70mm f/2.8 for Canon RF APS-C
Best for: Canon APS-C shooters needing constant F/2.8
- Lens Mount
- Canon RF
- Focal Length
- 17-70mm
- Maximum Aperture
- F/2.8
- Sensor Format
- APS-C
- Minimum Focusing Distance
- 0.19m (7.5”)
- Color
- Black
View on Amazon: Tamron 17-70mm f/2.8 for Canon RF APS-C Affiliate link
This Tamron lens offers a constant F/2.8 aperture across its 17-70mm range. It includes built-in VC image stabilization for sharper handheld shots. You get a minimum focusing distance of 0.19m for close-up details. The lens weighs 1.2 pounds and fits Canon RF APS-C cameras. It suits photographers who need consistent exposure and close-focusing capability in a compact zoom.
Pros
- Constant F/2.8 maximum aperture
- Built-in VC image stabilization
- 0.19m minimum focusing distance
- AF/MF and VC switches on lens
Cons
- Shorter 70mm maximum focal length
- Heavier at 1.2 pounds
- Limited to 17-70mm range
Good fit if
- You need constant F/2.8 aperture
- You shoot close-up subjects
- You use Canon RF APS-C bodies
Skip if
- You need longer telephoto reach
- You prefer lighter glass
- You shoot full-frame cameras
Verdict: Tamron 17-70mm F/2.8 for Canon RF APS-C delivers constant speed and close focus for Canon APS-C users. It fits those prioritizing aperture control over zoom range.
Specifications side by side
| Spec | Tamron 18-300mm f/3.5-6.3 Di III-A VC Lens | Tamron 17-70mm f/2.8 for Canon RF APS-C |
|---|---|---|
| Lens Mount | Sony E | Canon RF |
| Focal Length | 18-300mm | 17-70mm |
| Maximum Aperture | f/3.5-6.3 | F/2.8 |
| Sensor Format | APS-C | APS-C |
| Focus Type | Autofocus (VXD) | not stated |
| Minimum Focusing Distance | not stated | 0.19m (7.5”) |
| Color | Black | Black |
| Aperture | not stated | f/2.8 |
| Lens Type | not stated | Zoom |
| Dimensions | 4.9 × 3 × 3 inches | 4.6 × 2.9 × 2.9 inches |
| Weight | 1.37 pounds | 1.2 pounds |
| Size | Sony E Mount | not stated |
| Model | AFB061S700 | AFB070R700 |
Frequently asked questions
Which lens is better for travel photography?
The Tamron 18-300mm f/3.5-6.3 Di III-A VC is the superior choice for travelers. It provides a massive 16.6x zoom range, covering 18mm to 300mm. This versatility allows you to capture wide landscapes and distant subjects without swapping lenses. It fits perfectly into your camera bag for trips where carrying multiple lenses is impractical.
Which lens offers faster aperture for low light?
The Tamron 17-70mm f/2.8 delivers a constant f/2.8 aperture throughout its zoom range. This allows more light to reach the sensor compared to the variable aperture of the 18-300mm lens. You get better performance in dim environments and more control over background blur. It is ideal for shooters who prioritize aperture speed over reach.
Can I use these lenses on Canon cameras?
Only the Tamron 17-70mm f/2.8 is compatible with Canon cameras. It features a Canon RF mount designed for Canon APS-C mirrorless bodies. The 18-300mm lens uses a Sony E-mount, so it will not fit Canon cameras. You must choose the lens that matches your specific camera brand and mount type.
How do the physical sizes compare between the two?
The 18-300mm lens is slightly larger and heavier. It measures 4.9 inches in length and weighs 1.37 pounds. The 17-70mm lens is more compact at 4.6 inches long and weighs 1.2 pounds. The difference in weight is small, but the 17-70mm is easier to hold for extended periods due to its smaller profile.
Which lens has a longer focal length range?
The Tamron 18-300mm f/3.5-6.3 has the significantly longer range. It zooms from 18mm to 300mm, offering a 16.6x magnification factor. The 17-70mm lens covers a much narrower span from 17mm to 70mm. If you need to capture distant subjects, the 18-300mm provides the necessary reach that the 17-70mm cannot match.
Are both lenses suitable for APS-C sensor cameras?
Yes, both lenses are designed specifically for APS-C format sensors. The 18-300mm is optimized for Sony APS-C bodies, while the 17-70mm targets Canon APS-C users. Both utilize the full image circle required for these smaller sensors. They will not work correctly on full-frame cameras without significant vignetting or image circle issues.
Which lens is better for general purpose shooting?
The choice depends on your priority for speed versus range. The 17-70mm f/2.8 is better for portraits and indoor events due to its fast, constant aperture. The 18-300mm is better for general use if you need one lens for everything. It sacrifices speed for the ability to shoot wide angles and telephoto shots in a single package.