Steve Marshall
August 20th, 2010, 01:58 PM
Hello,
I’m uncertain as to my XL2 having a back-focus problem. After speaking with Canon extensively via phone, my only option now is to drive to their NJ facility (which is close to 90 miles each way), tie up the camera and probably pay for a diagnosis.
I’m about to finish the final shooting for a DVD project in a cyc studio. During the first phase of shooting I noticed that manual focus would go soft about 1/2 - 2/3 of the way to full wide after establishing critical focus using my human subject’s eye and toggling the auto-focus switch. I’ve also tried achieving critical focus at full zoom with the focus ring and it still goes soft approximately 2/3 of the way to full wide.
As I’d prefer not to use gain above +0, I’m relegated to a 2.6 aperture to achieve proper exposure at 60fps @ 60i (must be 60i – exercise video) in the studio lighting conditions. The reason I’m unsure about the back-focus issue is that I think the fairly wide aperture of 2.6 may be affecting the overall focus at full wide due to bokeh (shallow depth of field). When I shoot with say a 5.6 aperture, I don’t notice quite the discernable softening I see at 2.6. I also have read that when shooting with a 1/3” chip camera one should stay at or numerically below f4.0 anyway – not that I have much choice.
Am I correct in surmising that the relatively large aperture is responsible for the softening of the focus at 1/2 - 2/3 wide or should focus stay sharp regardless of aperture?
Is this a back-focus issue or just a limitation of the XL2?
Thanks in advance.
Steve M.
I’m uncertain as to my XL2 having a back-focus problem. After speaking with Canon extensively via phone, my only option now is to drive to their NJ facility (which is close to 90 miles each way), tie up the camera and probably pay for a diagnosis.
I’m about to finish the final shooting for a DVD project in a cyc studio. During the first phase of shooting I noticed that manual focus would go soft about 1/2 - 2/3 of the way to full wide after establishing critical focus using my human subject’s eye and toggling the auto-focus switch. I’ve also tried achieving critical focus at full zoom with the focus ring and it still goes soft approximately 2/3 of the way to full wide.
As I’d prefer not to use gain above +0, I’m relegated to a 2.6 aperture to achieve proper exposure at 60fps @ 60i (must be 60i – exercise video) in the studio lighting conditions. The reason I’m unsure about the back-focus issue is that I think the fairly wide aperture of 2.6 may be affecting the overall focus at full wide due to bokeh (shallow depth of field). When I shoot with say a 5.6 aperture, I don’t notice quite the discernable softening I see at 2.6. I also have read that when shooting with a 1/3” chip camera one should stay at or numerically below f4.0 anyway – not that I have much choice.
Am I correct in surmising that the relatively large aperture is responsible for the softening of the focus at 1/2 - 2/3 wide or should focus stay sharp regardless of aperture?
Is this a back-focus issue or just a limitation of the XL2?
Thanks in advance.
Steve M.