[stoppingdown]

So, the Sony 16-70 f/4 has been repaired and it come back worse than it was. The lab refuses other repairs saying it's within the specifications. I'm now going to replace it with a new lens.

Rumours about a new 16-70 lens from Sony haven't been confirmed, so the game is: Tamron 17-70 mm F/2.8 Di III-A VC RXD or Sigma 18-50mm F2.8 DC DN?

In short: Tamron is a more complete replacement of the focal range, but it's large and slow. More in detail my current evaluation is:

Reasons for Tamron 17-70 mm F/2.8 Di III-A VC RXD:

• Almost full replacement of focal range; I lose 16mm, but they are covered by the Sony 10-18m; in any case it covers 17-18mm, which Sigma doesn't; and while the 10-18mm covers the missing range, it's handy to have one mm more without the need of changing lens; on the long side, it covers the 50-70mm range, even though can be emulated with cropping without an excessive loss of quality;
  
• Stabilisation (maybe useless for the wide end, but not bad for the long one). I only have a single camera body with IBIS and it's the one being more frequently matched with macro or long tele lenses. OTOH since I'm now routinely using auto ISO, a safe shutter time is always used at the expense of higher ISO; but this is not a problem unless in some critical light conditions.
  
• If I'm not wrong, some reviews say this lens is sharper at corners in the wide end. Looking at the numbers in the OL reviews, tough, I have the impression that Tamron performance is more uniform from the center to borders, while the Sigma has a slightly better centre. Probably not much difference.
  

Reasons for Sigma 18-50mm F2.8 DC DN Contemporary Sony E:

• Cheaper (489-505€ vs 597-619€), but 130€ don't make a big difference;
  
• Lighter (290g vs 525g) and smaller (75mm vs 119mm in length); the size difference is really tempting me.
  
• Substantially better flare, especially at long end. I value this feature because it's not unlikely that I have the sun in the frame.
  
• Better built, even though this is a less relevant point for me.
  
• Better quality of bokeh, considering that both lenses are obviously mediocre in this aspect. Not really important for a landscape lens, but I've occasionally used the 16-70mm for plants.
  
• It has a specific lens profile in C1 (no profile for the Tamron).
  

While many points are subjective, an objective one that I'd like to clarify is about sharpness: is it my last point about Tamron correct?

Thanks.

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Just to have an idea of sizes, here are the two lenses compared with the Sony 16-70mm ƒ/4 and the Sigma 105mm ƒ/2.8.

https://camerasize.com/compact/#831.938,...5.445,ha,t