Sigma 120-300 mm f/2.8 APO EX DG OS HSM
8. Vignetting
Using the 120 mm focal length and the maximum relative aperture you must take into account the brightness loss in the frame corners of just 17% (-0.55 EV). Applying f/4.0 aperture makes the problem disappear completely because then the vignetting decreases to the level of 7% (-0.21 EV). In the middle of the focal range the situation is even better because at the maximum relative aperture the vignetting reaches 14% (-0.45 EV) and on stopping down by one full stop it decreases to 5% (-0.14 EV).
Please Support UsIf you enjoy our reviews and articles, and you want us to continue our work please, support our website by donating through PayPal. The funds are going to be used for paying our editorial team, renting servers, and equipping our testing studio; only that way we will be able to continue providing you interesting content for free. |
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
According to our expectations presented in chapter 3 the biggest problems you can face at the maximum aperture. By f/2.8 the vignetting rises to a noticeable level of 25% (-0.84 EV), by f/4.0 it decreases to 14% (-0.44 EV) and it becomes negligible by f/5.6 where it reaches just 6% (-0.18 EV).
Very similar results can be observed when the Sigma lens cooperates with the 1.4x Sigma converter. At the maximum relative aperture the light fall-off in the frame corners amounts to 26% (-0.85 EV) and by f/5.6 it gets to 12% (-0.38 EV). That aberration becomes imperceptible by f/8.0 where its value is just 3% 9-0.09 EV).
Let’s pass now to the performance on full frame. The appropriate thumbnails are presented below.
For obvious reasons the results are higher here but the shorter focal lengths don’t give us any reasons to complain. Setting the lens at 120 mm and maximum relative aperture you get a brightness loss of 25% (-0.85 EV). On stopping down the aperture to f/4.0 you see the vignetting decrease to 15% (-0.48 EV). The problem disappears completely by f/5.6 where the vignetting reaches 10% (-0.29 EV).
Very similar results we got in the middle of the focal range. At the maximum relative aperture the vignetting is 27% (-0.92 EV) and it decreases to 18% (-0.57 EV) and 11% (-0.34 EV) on stopping down to, respectively, f/4.0 and f/5.6.
Once again the biggest number of problems we encounter at the maximum focal length and during the work with the teleconverter. At 300 mm and by f/2.8 the vignetting reaches a significant value of 34% (-1.18 EV). In this case the stopping down is not as efficient as it was previously. By f/4.0 the brightness loss in the frame corners amounts to 24% (-0.80 EV), by f/5.6 it reaches 17% (-0.54 EV) and by f/8.0 its value is still distinct, amounting to 13% (-0.40 EV). Only after using f/11 aperture you can reduce this aberration to a negligible level of 9% (-0.27 EV).
In the case of the vignetting on full frame the Sigma teleconverter becomes undoubtedly a bottleneck. After attaching it to the lens the vignetting increases significantly compared to the performance of the lens itself at 300 mm. At the maximum relative aperture which, in this case, is already f/4.0, the vignetting reaches a high value of 45% 9-1.74 EV). That aberration remains still significant by f/5.6, where it gets to 35% (-1.26 EV). Only after using f/8.0 you can reduce it to a moderate value of 21% (-0.69 EV). The vignetting becomes low by f/11 where it reaches just 10% (-0.30 EV).
 |
 |
 |
 |
