Yes, the distortion is massive (it makes the lens also a bit wider), but Sony's 20-70 is even worse on the wide end in that regard. It has less vignetting though, which is quite bad on the Tamron.
It's time to get used to the fact that the new lenses are made to work with profiles. If you eliminate the flaws immediately in the body, the lens will immediately become larger / more massive / more expensive.
In set one (p.1 #19), the corrected version of the segmented cylinder building looks more odd than the uncorrected. To walk away from the river's edge on floor 25, you face a stiff uphill climb.
Tamron's designers 'pushed it' and 'left the moustache behind':
"The drama is at 17mm, where we can tell that Tamron’s engineers had to really push to get this wide. The barrel distortion is both pronounced and complex, requiring at +44 to correct and leaving a fairly obvious mustache pattern behind. Likewise the vignette was also very heavy, requiring nearly maxing out the sliders (+94 – nearly four stops) to properly correct it."
If you compare it to the sharpest lenses, e.g. 14-24DN, then you can see the Tamron is not as contrasty and punchy overall and the corners never get tack sharp...
j4nu wrote:
If you compare it to the sharpest lenses, e.g. 14-24DN, then you can see the Tamron is not as contrasty and punchy overall and the corners never get tack sharp...
The tester says that the edges and corners are not sharp and at the same time in the results says it is ideal for shooting landscapes.
That's been my confusion too; the lens seems to have strong pros and cons and they are often mixed up in the same review. I like the idea of the Tamron 20-40 or Tamron 17-50 to eventually replace my Canon 17-40 but I can't get good clear reviews on either lens.
My impression is that weaker corners + some funky field curvature make it somewhat difficult to get perfect across-the-frame sharpness. I don't really have a "flat" picture to show this, but maybe I can take one during the weekend...
I'm not saying the lens is not sharp, it's just not in the top league for the whole frame IMHO (might be my copy too).
j4nu wrote:
My impression is that weaker corners + some funky field curvature make it somewhat difficult to get perfect across-the-frame sharpness. I don't really have a "flat" picture to show this, but maybe I can take one during the weekend...
I'm not saying the lens is not sharp, it's just not in the top league for the whole frame IMHO (might be my copy too).
I downloaded your full-size snow shot and checked it with my Nisi 15 in similar conditions at 42mp versus your 17mm 60 mp. It's all subjective, but I see a similar scene. Like Tamron, Nisi's corners are not quite sharp.
You could take a series of pictures at the f11 aperture in the far field at focal lengths of 17mm/21/28/35/50 ?
I've used it recently to try to convince myself I need a GM, but at f/8 or f/11 it's a hard case.
I'll try to find a couple of shots that help evaluate sharpness later today...
Conclusion (English)
The Tamron 17-50 F4 Di III VXD (830 euros) is offering a unique range for landscape and architure lovers that also do street photography or occasionally portraits. Performances will be globally very good with sensor up to 33Mpix but on high demanding sensor like A1 or A7RV (61 Mpix) you better invest in the Sony 20-70mm F4 G (1600 euros)
The build quality and the AF are very good. Its constant length and reasonable weight makes it ideal for a gimbal. Main weaknesses are corners sharpness wide open and resistance to flare
Recommended on A7III or A7IV
Pros
Very good to excellent performances at 17mm
Unique Focal range unmatched by any competitors
Constant size (no zoom extension)
Light
Very good color rendition
Good Bokeh balls
Soft background blur as of 35mm
All Weather resistance
Very good build quality
Low CA
Very good AF
Min focusing distance
USB C port for customisation
Low focus breathing
Average
Price
Size
Ergonomics
Corners sharpness at all focal length required to be closed to F5.6/F8
Sharpness decrease below 3m
Performance wide open at 50mm
Resistance to flare
Cons
Distortion and vignetting at 17mm
Bokeh with onion rings
j4nu wrote:
I've used it recently to try to convince myself I need a GM, but at f/8 or f/11 it's a hard case.
I'll try to find a couple of shots that help evaluate sharpness later today...
That's the thing, it's not one of the sharpest corner to corner UWA zooms, in fact it might be the worst outside of the old 16-35/4 ZA... But stopped down it still seems more than enough to me and correctable distortion & vignetting aside it doesn't have any other huge flaws. What it does right makes up for that for me, namely the super convenient range, the MFD at both ends, flare handling, and the fact that it (mostly) zooms internally and uses 67mm filters.
I think for people that don't use the long end it their UWA zoom much there's better options, but as a walkabout option that I can easily crop to 75mm when I'm lazy I'm really gonna enjoy shooting the 17-50. Instead of pairing it with a 75mm I'll be pairing it with a 135mm and whatever other prime I can fit in my 6L sling, likely my 45mm, maybe 11mm... I think the reviews scared a lot of people away from it, maybe the $550 sales price will pull some in.
For my preference the range is even more convenient than the 20-70's, and that's what I buy zooms for zooms, sheer convenience vs my primes.
Adding to the above, I'd like to see more images and user affirmation of the 17-50/4. Currently I have a 17-28/2.8 and 28-200/2.8-5.6 as my main "travel" pair. Looking at "convenience," the 17-50/4 improves on the 17-28 for overlap and could be a walk-around by itself at times. I'm also looking at a 16-35 or the 20-70 to go with the 28-200. Just not sure if trading away too much image performance for the convenience.
