Sony 24-70mm Lenses Compared
Ever since the introduction of the new Sony FE 24-70mm f/2.8 GM lens, we have been getting a lot of questions about how it compares to its smaller counterpart the Sony FE 24-70mm f/4 ZA OSS. Today we take a closer look at the two lenses.
Size & Weight
As you can see in the picture above, the new 24-70mm f/2.8 is pretty massive compared to the 24-70mm f/4. The 24-70mm f/2.8 has an 82mm filter thread, is about 5.35" long, and weighs in at 1.95lbs. The 24-70mm f/4 has a 67mm filter thread , is about 3.72" long, and weighs in at just under 1lbs. The size disparity should be no surprise since there is a one stop difference in the maximum aperture of the two lenses.
Handling & Design
The 24-70mm f/4 is extremely well balanced on the current full-frame Sony cameras like the A7R II and A7S II. The 24-70mm f/2.8 does take a little getting used to handling on the same cameras since it is much larger by comparison, but doesn't feel too unbalanced. The zoom and focus grips on the 24-70mm f/2.8 are rubberized like many Nikon & Canon lenses, making it a little easier to handle compared to the metal zoom of the 24-70mm f/4. Both lenses utilize an electronic focus-by-wire system like many of the Sony FE lenses. Auto focus is very fast and snappy on both lenses, with the 24-70mm f/2.8 slightly edging out the f/4
One of the key, and a little surprising differences is the 24-70mm f/4 includes Sony's Optical Steady Shot while the 24-70mm f/2.8 does not. This is not as important on newer cameras like the A7R II & A7S II since they do have in-body stabilization. It is worth noting though for cameras like the original A7S, new A6300, & video cameras like the PXW-FS5 & PXW-FS7.
This is what most people are interested in, the resolution. We use Imatest to test all of our lenses when they come back from customers to make sure they are performing within the specification of our other copies. We have a chart that we shoot and run through the Imatest software. The software measures the resolution of the lens at various points through the frame. In the most simplistic terms, the higher the resolution - the "sharper" that an image appears. Here's what the two lenses look like compared on a Sony A7R II.
FE 24-70mm f/2.8 GM @ 24mm:
Edge Average: 1616
FE 24-70mm f/4 ZA OSS @ 24mm:
Edge Average: 582
FE 24-70mm f/2.8 GM @ 70mm:
Edge Average: 656
FE 24-70mm f/4 ZA OSS @ 70mm
Edge Average: 1046
Let us start by saying the center resolution of the 24-70mm f/2.8 GM is among the best we've seen for a Sony FE lens. It performs very strong in the center and there's only drop off in performance towards the very edge of the frame. As you can see, the 24-70mm f/4 at 24mm is not too far behind in the center. As we move to the edges however, you can see that the 24-70mm f/2.8 is the clear winner. When we move to 70mm however, things change up a bit. The 24-70mm f/2.8GM is still very strong in the center, but the edge performance does drop off a little. The interesting thing about the 24-70mm f/4 is while the center performance drops off compared to 24mm, the edge performance improves quite a bit.
It's sometimes hard to compare lenses with different aperture ranges, but many will draw comparisons between these two lenses since they cover the same range. In the end, both lenses definitely have their strong points. If you're looking for the best sharpness or are going to be shooting in low light conditions where that extra stop of light will make a difference, the FE 24-70mm f/2.8 GM is the clear winner. Sony definitely has a lens that competes very well with the comparable Canon and Nikon 24-70mm lenses. However, the 24-70mm f/4 ZA OSS is certainly no slouch. It might be a better choice for those looking for a more compact set-up or with a camera that lacks in-body stabilization. Either way, these are both very solid lenses in the Sony FE range.