Modifying the DA* 60-250mm F4 for Full Frame
Optical Test: Sharpness
The 60-250’s sharpness was evaluated with both replacements and compared with the original baffle. Since in some circumstances the APS-C baffle generates fully black vignetting, the test chart was offset slightly from the corners to be positioned at the limit of the usable area.
These images will highlight any eventual loss of resolution caused by the removal of the flange.
Results at 60mm
Center sharpness
The following images compare the center sharpness using the original APS-C baffle and the two modified baffles. Focusing was performed by using focus peaking in live view. It was corrected after each lens movement. You can click on images to see full resolution crops.
APS-C | Cutout baffle | Round baffle | |
F4 |  |  |  |
F5.6 |  |  |  |
F8 |  |  |  |
F11 |  |  |  |
F16 |  |  |  |
F22 |  |  |  |
Edge sharpness
The following images compare the edge sharpness using the original APS-C baffle and the two modified baffles. Focusing was performed by using focus peaking in live view. It was corrected after each lens movement. You can click on images to see full resolution crops.
APS-C | Cutout baffle | Round baffle | |
F4 |  |  |  |
F5.6 |  |  |  |
F8 |  |  |  |
F11 |  |  |  |
F16 |  |  |  |
F22 |  |  |  |
Corner sharpness
The following images compare the corner sharpness using the original APS-C baffle and the two modified baffles. Focusing was performed by using focus peaking in live view. It was corrected after each lens movement. You can click on images to see full resolution crops.
APS-C | Cutout baffle | Round baffle | |
F4 |  |  |  |
F5.6 |  |  |  |
F8 |  |  |  |
F11 |  |  |  |
F16 |  |  |  |
F22 |  |  |  |
In the center, there is no difference whatsoever between the three tested baffles. This means that the modification has no impact in the center and the lens' excellent resolution figures are preserved.
On the edges, there is again almost nothing to mention. The cutout baffle might have a small advantage wide open, but it's subtle.
In the corners, the results are surprising. While again differences are minimal, the APS-C baffle appears to deliver a lower level of sharpness. In a full frame field of view, the modified baffles actually offer an advantage.
Results at 250mm
Center sharpness
The following images compare the center sharpness using the original APS-C baffle and the two modified baffles. Focusing was performed by using focus peaking in live view. It was corrected after each lens movement. You can click on images to see full resolution crops.
APS-C | Cutout baffle | Round baffle | |
F4 |  |  |  |
F5.6 |  |  |  |
F8 |  |  |  |
F11 |  |  |  |
F16 |  |  |  |
F22 |  |  |  |
Edge sharpness
The following images compare the edge sharpness using the original APS-C baffle and the two modified baffles. Focusing was performed by using focus peaking in live view. It was corrected after each lens movement. You can click on images to see full resolution crops.
APS-C | Cutout baffle | Round baffle | |
F4 |  |  |  |
F5.6 |  |  |  |
F8 |  |  |  |
F11 |  |  |  |
F16 |  |  |  |
F22 |  |  |  |
Corner sharpness
The following images compare the corner sharpness using the original APS-C baffle and the two modified baffles. Focusing was performed by using focus peaking in live view. It was corrected after each lens movement. You can click on images to see full resolution crops.
APS-C | Cutout baffle | Round baffle | |
F4 |  |  |  |
F5.6 |  |  |  |
F8 |  |  |  |
F11 |  |  |  |
F16 |  |  |  |
F22 |  |  |  |
At 250mm, the analysis is short and straightforward : there is no measurable difference between either configuration. The baffle modification has no negative impact on the lens at 250mm.
Verdict
Modifying the baffle has no practical impact on resolution. The cutout baffle might have a slight advantage in the corners at 60mm, but the differences are subtle. Any version can be used with confidence.
