Testing: Longitudinal Chromatic Aberration and focus shift
Lenses with focal ratios of f2.8 or larger are often prone to longitudinal color aberrations (loCA, a.k.a. “axial color” or “bokeh CA”). These normally show up as magenta coloration in the foreground and greenish hues in the background and are not easily corrected in post-processing. The new Tamron has very little loCA and there’s also no focus shift to speak of.
The following real life shot shows that the Tamron 28-200mm f2.8-5.6 Di III produces no purple fringing around high-contrast edges in the focal plane or green outlining around background subjects:
Sharpness and contrast
Let’s have a look at the theoretical performance of the new Tamron 28-200mm f2.8-5.6 Di III first and compare it to the performance of the Sony FE 24-240mm f3.5-6.3 OSS:
These MTF charts show the computed lens-performance of lenses wide open without influence of diffraction. Higher values are better (more contrast) and the closer the line-pairs are together the less astigmatism (= resolution depends on the orientation of the test-pattern) the lens has. The x-axis displays the distance from the optical axis (=center of the sensor) in mm. I’ll show you the real-life performance at 4 mm (center), 13 mm (APS-C-corner), and 20 mm (FF-corner) on a on a 42MP Sony A7R II camera (resp. 45MP Nikon Z7 camera for the Nikon zoom lens).
Contrast and resolution: Comparing the MTF charts is a bit tricky as Sony crammed both the wide open performance (green lines) and performance at f8.0 (red lines) into the same chart. Looking closely the Tamron shows less astigmatism on the wide end than the Sony with comparable overall contrast and better resolution towards the full-frame corner. At the long end the Tamron also shows some astigmatism but not nearly as much as the Sony and again the Tamron should be a bit sharper. The Nikon shows a similar degree of astigmatism as the Sony but should show a bit more contrast at the long end.
Let’s see how this theoretical performance translates into real life results in the sharpness test based on Siemens-stars. Processing was done in Lightroom 9.3/CRAW 12.3 from RAW to Adobe Color profile with the built-in lens profile for Vignette Control and CA compensation applied. Noise-reduction is set to 0, sharpening to 50/0.5/36/10, with no extra tone, color, or saturation adjustment. White-balance was adjusted to a neutral white and I did some exposure compensation to make the brightness of all crops match. So you will not see light fall-off in the corners.
The following are all 100% crops!
First up is an overview of the wide-open performance at different focal lengths. You can jump to the detailed results at different apertures and comparisons with the alternatives by clicking on the crops of the respective focal length.
Tamron’s new zoom lens performs astonishingly well across the high resolution full-frame sensor in this test at distances ranging from 1.3m (at 28mm focal length) to 9m at the long end: The center is mostly very sharp, the APS-C-corner only a little soft and even the FF-corner is well defined with quite some detail in it. But what’s most surprising is that this performance is pretty uniform across the 7.1x zoom range. And the lens exhibits only little field curvature over its zoom range.
The following 100% crops for each focal length show the new Tamron 28-200mm f2.8-5.6 Di III from wide open down to f11 compared to the Sony FE 24-240mm f3.5-6.3 OSS and the Nikon Z 24-200mm f4.0-6.3 VR. The Nikon was shot on a 45MP Nikon Z7 which has a 4% higher linear resolution. But this difference is practically irrelevant for judging resolution.
I also included the Tamron 28-75mm f2.8 Di III and Tamron 70-180mm f2.8 Di III in this comparison to show how big (or small) the differences in optical performance are.
So prepare for the pixel parade! Or you can fast-forward to the performance at long distances.
Performance at 28mm:
At 28mm focal length the new Tamron 28-200mm is a bit softer in the APS-C-corner but sharper in the FF-corner than the Tamron 28-75mm f2.8 Di III at f2.8. And at f4.0 it is a little sharper than the Sony and the Nikon.
Performance at 35mm:
At 35mm focal length the Tamron 28-75mm f2.8 Di III is a bit sharper in the APS-C image-circle at f2.8 than the new Tamron 28-200mm at f3.2 – which again produces the sharpest FF-corner of the lenses compared here. At f4.0 the Nikon, Sony and Tamron 28-200mm look very similar in the APS-C image-circle with a slight advantage for the Nikon – which is already at f4.8.
Performance at 50mm:
Similar picture like at 35mm.
Performance at 70mm:
At 70mm focal length the Tamron 70-180mm f2.8 Di III is the clear winner now followed by the Tamron 28-75mm f2.8 Di III. The Tamron 28-200mm now looks a bit soft in comparison at f4.0. But at f5.6 Tamron’s new super-zoom compares well against the Sony and the Nikon (which has the softest FF-corner).
Performance at 105mm:
At 105mm focal length the Tamron 70-180mm f2.8 Di III is clearly sharper than the new Tamron 28-200mm. But stop Tamron’s new zoom lens down to f5.6 and it comes pretty close – also clearly besting the Sony. The Nikon is comparable in the APS-C image-circle but loses again in the FF-corner.
Performance at 150mm:
Similar picture at 150mm focal length with the Sony now becoming the softest lens in this comparison and the Tamron 28-200mm also besting the Nikon.
Performance at 200mm:
At the long end the Tamron70-180mm f2.8 Di III comes out on top followed by the new Tamron 28-200mm, the Nikon and the Sony.
Overall Tamron’s new 28-200mm f2.8-5.6 Di III zoom lens compares favorably against Sony’s and Nikon’s super-zooms in this test and is pretty close to Tamron’s own 28-75mm f2.8 Di III. Only at 70mm focal length and beyond the Tamron70-180mm f2.8 Di III dominates the comparison: not only is it sharper than any of the super-zooms but it also collects 1-2 stops more light.
Performance at long distances
The Siemens-star test-targets are shot at a distance of 45x focal length (i.e. at around 3m for 70mm focal length). But performance of lenses also depends on the shooting distance. Therefore I present another series of test-shots of a city around 1 km away. Processing was done in Lightroom 9.3/CRAW 12.3 from RAW to Adobe Color profile with the built-in lens profile compensating CA. Noise-reduction is set to 0, sharpening to 50/0.5/36/10, with no extra tone, color, or saturation adjustment. I used manual focus at the largest aperture and did not change focus for other apertures. All shots were made at ISO 100 and image stabilization switched off.
Following is an overview of the wide-open performance at different focal lengths. You can jump to the detailed results at different apertures and comparisons with the alternatives by clicking on the crops of the respective focal length. As usual I have selected the diagonal that provided the better corner results as almost any lens is a bit decentered.
In this long-distance test the new zoom lens looks (again) very good. There’s only a little purple fringing at high contrast edges in the APS-C corner at 28mm f2.8.
The following images show the complete scene wide open to give you an impression of the angle of view and to judge vignetting. Following the main image are 100% crops from the center, APS-C-corner, and FF-corner for each focal length from the new Tamron 28-200mm f2.8-5.6 Di III down to f11compared to the Sony FE 24-240mm f3.5-6.3 OSS and the Nikon Z 24-200mm f4.0-6.3 VR shot only minutes apart. The Nikon was shot on a 45MP Nikon Z7 which has a 4% higher linear resolution. But this difference is practically irrelevant for judging resolution. I also included the Tamron 28-75mm f2.8 Di III and Tamron 70-180mm f2.8 Di III shot at different days.
You can access the large originals but please respect our copyright and only use those images for personal use.
If you don’t want to see all the details and comparisons fast-forward to the next chapter on vignetting and distortions.
Results at 28mm:
In the center both Tamrons and the Nikon look neck-and-neck while the Sony is a bit softer. The Sony is also clearly the softest in the FF-corner with both super-zooms from Tamron and Nikon looking better. The best FF-corner comes from the Tamron 28-75mm f2.8 Di III.
Results at 35mm:
As the Tamron 28-75mm f2.8 Di III became a little softer outside the center at 35mm the super-zooms from Tamron and Nikon are now pretty close, even a bit sharper at the APS-C corner than the f2.8 zoom lens. The Sony looks a bit softer than the other three lenses across the full-frame sensor.
Results at 50mm:
At 50mm all four lenses seem to have sharpened up a bit and are almost indistinguishable in the APS-C image-circle. But in the FF-corner the Sony and the Nikon are softer than both Tamron zoom lenses.
Results at 70mm:
At 70mm focal length the Tamron 70-180mm f2.8 Di III enters the fray – but it does not dominate the field as in the preceding test. The performance of the new Tamron 28-200mm is very close to its f2.8 siblings from Tamron even rendering the slightly sharper FF-corner (compared at f4.0). And at f5.6 its FF-corner is also clearly sharper than from the Sony and slightly sharper than from the Nikon.
Results at 105mm:
At 105mm both Tamron lenses and the Nikon look very close while the Sony is visibly softer outside the center.
Results at 150mm:
Similar to the results at 105mm with the Sony again being the softest of the four lenses.
Results at 200mm:
At 180mm f5.6 the Tamron 70-180mm f2.8 Di III seems slightly ahead of the super-zooms from Tamron and Nikon – which both vie for second place. The Sony 24-240mm again looks a bit softer and less contrasty than the other lenses.
The new Tamron 28-200mm f2.8-5.6 Di III again performed very well in this long-distance test: It is clearly better than the Sony, at least as sharp as the super-zoom from Nikon and astonishingly close to its larger f2.8 siblings.
Vignetting and distortions
To make it easier to see light fall-off in the corners of a full-frame sensor I’ve arranged a series of three shots each with the new Tamron from f2.8 to f5.6 at 28mm and f5.6-f11 at 200mm focal length. All images were developed to the same brightness in the center and with the built-in lens profile compensating vignetting:
The sample images above show that even with the lens profile applied vignetting is not completely eliminated. But on the long end it’s pretty inconspicuous. At 28mm f2.8 automatic shading compensation lifts the extreme corners about 1 EV. Adobe’s RAW converter automatically applies shading compensation as it was set in camera – but you cannot alter the setting in postprocessing.
Distortions are of a light barrel type at 28mm focal length and turn to pin-cushion from 35mm focal length onward. This is highest at 70mm (see below) and abates somewhat towards the long end. The setting for distortion compensation in camera is currently ignored by Adobe’s RAW converter and treated as OFF and there is also no lens profile for the new Tamron in Lightroom 9.3 / CRAW 12.3. This hopefully gets remedied in a later version. But when shooting JPGs the camera at least does a pretty good job with Tamron’s lens profile to correct for distortions:
Rendering of point-light sources at night-shots
Night-shots pose a different challenge for lenses as the contrast is even higher than under bright sun and point-light sources can reveal some weaknesses such as coma, haloing and colour-aberrations that do not show up as prominently in other test-shots. The 100% crop below the main image show the effects at the center and in the FF-corner of the new Tamron 28-200mm f2.8-5.6 Di III compared to other lenses:
The Tamron shows some coma in the corner, but then it is at f2.8 here. The Sony at f3,5 has a little less and the Nikon almost none. Coloration around point-light sources in the center is minimal.
Rendering of out-of-focus point-light sources
This test is for the rendering of point-light sources in an out-of-focus background. The circle of confusion that is produced by this test is pretty indicative of Bokeh performance (in the background) and light fall-off. Ideally the out-of-focus image of the point-light is evenly lit and perfectly circular, with no “onion-rings”, and without coloration. There’s also an effect known as “cat’s eye” the further away from the optical axis the point-light is projected. This is due to optical vignetting in the lens barrel when light enters the lens from an angle.
All images were shot at the longest focal length and largest aperture. The new Tamron is first followed by the Sony FE 24-240mm f3.5-6.3 OSS and the Nikon Z 24-200mm f4.0-6.3 VR. Crops are from the center, APS-C-corner, and FF-corner resized to make them comparable across all my reviews.
The Nikon has the smallest entrance pupil of the three lenses compared here so it should produce the smallest Bokeh balls. The Tamron should produce 10% bigger Bokeh balls and the Sony even 20% bigger ones. This is not fully reflected in this test as I could not match magnification of the three lenses perfectly. Regarding onion rings: The Sony has the strongest while the Nikon is the smoothest. Outlining is visible on all three lenses but there is very little coloration. Looking towards the corners all three lenses develop a very similar degree of cat’s eye effect in the FF-corner. But compression is quite visible already at the APS-C-corner – where the Nikon has the benefit of a slightly fuller circle.
Now let’s see how this analysis of out-of-focus point-light sources translates into Bokeh-performance shooting a book-shelf. Crops are from the foreground, middle-ground, and background resized to make them comparable across all my reviews. I used the longest focal length that I could to produce a comparable shot to my other reviews which was in the case of the new Tamron 162mm. The other lenses had to be zoomed in to 165-172mm to achieve the same magnification from the same distance:
As was to be expected from the night shots all three super-zooms have a pretty similar background Bokeh. Some small differences: The Sony is a tad more nervous than the Tamron and the Nikon seems a little smoother. The real eye-opener in this comparison are the last crops from the Tamron 70-180mm f2.8 Di III at 165mm f2.8: It clearly shows how much more blur you can produce with a larger aperture lens.
The new Tamron goes down to 1:3.0 magnification at 28mm focal length. The following images were shot at 1:4.1 magnification where the area of sharp focus is just 148 x 98mm. The crops shown below are from 0mm, 12mm, and 18mm off the center of the sensor respectively:
The Tamron 28-200mm f2.8-5.6 Di III produces very good results in the center even wide open. But for a larger area of good sharpness you need to stop down to f5.6 or even f11.
Using the lens at 200mm focal length produces softer results but at a much more usable working distance. The following images were shot at 1:3.6 magnification where the area of sharp focus is 129 x 86mm. The crops shown below are from 0mm, 12mm, and 18mm off the center of the sensor respectively:
The center is not bad at f5.6 but even at f11 results are less sharp than at 24mm focal length and f5.6.
Flare, ghosting, and sun-stars
Catching a strong light-source shining directly into the lens is always a risky business: it could produce strange colorful ghost-images or reduce contrast considerably through flare and glare. The appearance of flare and ghosting depends on factors like the aperture and the angle of the light hitting the lens. So to judge the proclivity of the new Tamron 28-200mm f2.8-5.6 Di III for these artifacts I went through a series of well calculated shots against a strong light source to provoke glare and ghosting.
The new Tamron 28-200mm f2.8-5.6 Di III produces some ghosting artifacts and flares at at the short end and overall contrast is visibly reduced through veiling glare when the light source is within the APS-C image-circle. Contrast improves markedly when the light-source is closer to the FF-corner although it can produce a strong flare there:
The little bright square inset in the upper left of both images shows the respective area with an exposure compensation of +3 EV to make it easier to see which levels of black the lens renders at that point. What you can also see in the images above: The new Tamron 28-200mm f2.8-5.6 Di III does not produce well defined sunstars at f11.
Next check out my sample images!Check prices on the Tamron 28-200mm f2.8-5.6 Di III at Amazon, B&H, Adorama or WEX! Alternatively get yourself a copy of my In Camera book or treat me to a coffee! Thanks!