Is the Sigma 28-70mm sharp?
The Sigma 28-70mm is extremely sharp, especially when shooting wide open at f/2.8. Sharpness is one of the major strengths of this lens. The aspherical elements and three SLD glass elements help produce crisp images with high contrast. The sharpness is very consistent throughout the zoom range as well. For the price, the Sigma 28-70mm offers outstanding sharpness that will not disappoint.
How does the Tamron 28-75mm G2 compare?
The Tamron 28-75mm G2 is also an exceptionally sharp lens, though some reviews indicate the Sigma may have a slight edge in sharpness, especially at f/2.8. The Tamron uses specialized glass elements like XLD and LD to optimize sharpness and clarity. While very sharp, the Tamron shows slightly more distortion and vignetting. However, the Tamron has the advantage of going out to 75mm for more telephoto reach. For most users, the sharpness of either lens will be more than sufficient.
How is the Bokeh on the Sigma 28-70mm?
The Sigma 28-70mm can produce very pleasing Bokeh, which refers to the esthetic quality of the out-of-focus areas in an image. The f/2.8 aperture helps create shallow depth of field, which blurs the background and foreground. The 9-blade diaphragm also contributes to smooth, rounded Bokeh balls and soft transitions. The Bokeh quality is ideal for portraits, macro, and other imagery where subject isolation is important.
How does autofocus compare between the two lenses?
Both lenses use fast, precise autofocus systems suited for stills and video. The Sigma 28-70mm has a newly designed autofocus system with linear STM motors. It focuses accurately in most conditions, though may struggle in very low light. The Tamron 28-75mm G2 uses a ring-type ultrasonic motor for fast, silent autofocus. The Tamron system is slightly faster, but both lenses will work great for most autofocus needs. Manual focus override is available on both lenses.
What are the major differences to consider?
Some of the main differences to weigh are:
· Focal range: Sigma 28-70mm vs Tamron 28-75mm
· Weight: The Tamron (550g) is lighter than the Sigma (720g)
· Weather sealing: Tamron has moisture-resistant construction, Sigma does not.
· Price: The Sigma typically costs a bit less.
Overall, either the Sigma 28-70mm or Tamron 28-75mm G2 would make a fantastic lens for your Sony mirrorless camera. The choice comes down to your specific needs, priorities and budget. Both offer stellar sharpness and performance for the price.