Why am I doing it again?
It’s been two years since my comparison article between the Sony 24-105mm and the Tamron 28-75mm. It is still one of the most popular ones, together with the corresponding video. In that article I concluded that I will pick Sony over the Tamron, because of a few reasons. The Sony has optical stabilization (Optical Steady Shot or OSS). It has an assignable button. Has better corner sharpness. Has better range, and on a high megapixel camera like A7RIII or A7RIV you end up with a 37-152mm lens in APS-C mode.
Two years later, with a A7RIV in hand, and after 1-2 major firmware updates from Tamron, I decided to test and compare the two lenses again. First to see if Tamron improved the video autofocus, and second to see how both lenses handle the 61Mpx resolution. In addition, Tamron increased the price of their lens with $80 and Sony reduced theirs, so they are now even closer price-wise. I’m currently preparing two videos (comparing sharpness and AF speed in stills and video) to supplement this article. I will place a link here once they are live.
The Tamron 28-75mm
Before I start with the comparison, I would like to share with you my thoughts about the Tamron. The handling is not bad, the lens is small and light, the focus ring is smooth but the zoom ring is very stiff. Although the plastic material feels “soft and velvety” the whole package somehow speaks “cheap”. That includes the lack of buttons and optical stabilization, and even the boxing is very basic with cheap cardboard inside. From another side, Tamron has a 6 years warranty for the USA and Canada. The Tamron 28-75mm similarly to 17-28mm and 70-180mm have 67mm filter size (like the Batis series), making it easy to use the same size filters for all of them.
Last time I compared the two lenses in 3 lengths, in 3 different aperture values, and in 3 zoomed positions bottom-left, center and top-right. To the already compared 28mm, 50mm and 75mm this time I added 35mm, slightly changed the 75mm with 70mm. To the aperture values I added f11 and decided to compare the lenses in their max open aperture – the Sony in f4 vs. the Tamron in f2.8. Lastly, last time I used screenshots from 3 different parts of the image zoomed in – the center, bottom-left and top-right. This time I compare the 5 positions, adding the top-left and the bottom-right as well. As you will see especially the Tamron, shows different results in the different lengths there.
In each comparison block of images there are 5 rows for each focal length. In the first one I compare both lenses wide open, then on the second row both lenses at f4, then f5.6, etc.
At 28mm wide open (The Tamron at f2.8 and the Sony at f4) I don’t see any sharpness difference in the center. The Sony outperforms the Tamron in the three extreme corners, except the bottom left, which will be consistently sharper on Tamron up to 50mm.
At 35mm wide open the Sony is sharper in the corners and the Tamron in the center.
Interestingly, the bottom left corner is not the strong point for the Tamron anymore. Instead we see increasing sharpness in the top right corner (the “…MONOV” text), but at the very extreme corner Sony is still better. It is the same all the way to f11, where both lenses are again pretty much even.
At 50mm wide open the test results are similar to 35mm – the Sony is sharper in the corners and the Tamron in the center.
At f4, the Tamron gains advantage in the entire right side – top to bottom, even in the corners. This continues all the way until f11, when again, both lenses are equally sharp. It is interesting how Tamron shifts sharpness in the different lengths. And I really spend a lot of time making sure the setup is near perfect and the lens is at the same plane of focus for the center and the corners.
Not too much different, at 70mm wide open the Tamron is sharper only in the center and the Sony dominates in all four corners.
From f4 to f11 the Tamron is slightly sharper in the center, and also gains some advantage in the right side. At f11 the lenses evens out in the center, as they did in the other lengths.
Defocus & Chromatic Aberration
Speaking about aberration in its different forms I think it is very safe to say that Sony is the better performer from the two. The Tamron 28-75mm suffers a lot from what I think is a combination of defocus and chromatic aberration – especially wide open. I made a comparison picture for you, so you can see how much contrast and sharpness the Tamron is losing, caused by the lens imperfections.
Conclusion: Sony or Tamron?
What I can conclude is that the Tamron 28-75mm consistently outperforms the Sony in the center (even wide open). The Sony catches up the center sharpness at f11, although by no means it is a soft lens. Just the Tamron is really good in the center. In the corners Sony shows consistently sharper images. Tamron shifts sharpness around 35-50mm and from the bottom-left corner the “sharp spot” moves towards the top-right corner. But not the very extreme one. There Sony still rules.
So which one should you get? Of course it depends. I know, I hate that answer too… But here are my thoughts:
If you shoot primary single objects (portrait for example) or group of objects close to each other in the center of the frame, then the Tamron 28-75mm will definitely shine with it’s unbelievable center sharpness. If corners are important for you (for shooting landscapes for example) I would definitely pick the Sony 24-105mm – not only for the more even sharpness throughout the frame, but for better zoom range and versatility it offers. Plus the Sony is already very sharp wide open, so you don’t have to stop it down to achieve better results. Although you will get better results when stopping it down a bit.
I think the Tamron is a great lens for event shooting, including sports and weddings. Plus the closer focusing distance helps a lot when shooting in tight spaces, or use it for detailed shots during weddings.
I still keep my Sony – mainly because of its versatility and even sharpness throughout the frame, starting at f4. But the Tamron is definitely a good choice. Stay tuned for my video review to learn about their AF performance.