Image Stabilization

Our standard image stablization test is done by shooting 10 frames at our test target, starting with one over the focal length and working our way downward in intervals of 2/3-stops using a neutral density filter (to maintain the same aperture). We first did this with IS on, and then with IS off. The images were then assessed to the following standard:

Excellent Some softness
Noticeable blur Unusable

1) Excellent - the best the camera is capable of
2) Some softness - only distinguishable from Excellent by comparison
3) Noticeable blur - blur can be perceived without reference to another image
4) Unusable - significant motion perceptible

24mm Equivalent
50mm Equivalent
200mm Equivalent
Stabilization On Stabilization On Stabilization On
Stabilization Off Stabilization Off Stabilization Off

*It's important to note that this is our own assessment of real-world performance and always gives results significantly lower than the CIPA test methodology.

After rating the images shot in our IS test, we look for a comparable pattern of success (50% of shots or greater rated acceptably sharp) between IS On and IS Off.

At 24mm the a7 III was able to maintain a 60% hit rate down to 1/3 sec with IS on compared to a 60% hit rate at 1/30 sec with IS off. This equals a 2 2/3 stop advantage at 24mm.

At 55mm (tested using the 55mm F1.8 ZA) the a7 III maintained a 70% hit rate down to 1/5 sec but fell to a 40% hit rate at 1/3 sec - meaning at 1/4 sec, the hit rate would likely be 50% or greater. With IS off, only a 40% hit rate was achieved at 1 over the focal length - but we can also safely assume that would jump to 50% or greater by 1/60 sec. Comparing 1/4 sec to 1/60 sec gives us approximately a 4 stop advantage at 55mm. Being conservative, 1/5 sec compared to 1/60 sec would still result in 3 2/3rd stops at 55mm.

At 200mm a 60% hit rate was achieved down to 1/13 sec with IS on. With IS off, an 80% hit rate was achieved at 1/200 sec, but fell to a 30% hit rate at 1/125 sec. This means the camera could likely achieve a 50% or greater hit rate at a/160 sec, giving the a7 III a 3 2/3rds stop advantage at 200mm.

The takeaway

This is the first modern Sony Full Frame camera we've run through our complete IS testing. Compared to the Sony a7 II IS tests, the results are pretty similar. On the wide end you can expect about 2 2/3rds stops advantage with IS on, 3 2/3rds - 4 stops at normal focal lengths and 3 2/3rds stops at the tele end.