Issue with RF 24-105 L

Started 3 months ago | Discussions thread
OP f8f8f8 Regular Member • Posts: 192
Re: Issue with RF 24-105 L

As I previously stated, my R5 and lens are both back from the Canon Service Center. This was the second attempt by the service center to correct the problem I am having with my RF 24-105L lens and the first that also included the camera (per their request).

Their repair record stated for the lens: "Your product has been examined and it was found that the product performed according to specifications. The unit was cleaned and checked. Product functions were confirmed. lens was calibrated with camera for best focus."

The repair record for the R5 (which had no problem but I sent it in anyways since they requested both) stated: " Your product has been examined and it was found that the product performed according to specifications. The unit was calibrated for best focus and then calibrated to the lens provided. The unit was cleaned and checked and product functions were confirmed. However if the issue still seems to persist we recommend to send the unit with the images for testing and examination."

Now for the moment I will ignore the issue of  Canon calibrating the camera for focus to match the lens as there are numerous threads discussing that a microfocus adjustment is or isn't required/possible for mirrorless cameras. I have now had a chance to test the lens, this time with resolution targets. In in each pic the camera was on single shot, EFCS, AV, 1/250th sec, tripod mounted, Canon flash on, and Image Stabilization off. Please examine the following pics shot at both 24mm and 70 mm at both f4 and f8. I still feel that the left side of the pics, especially the lower left is sub-par. Do you agree? As a point of reference, the overall target area was approx 40" x 60" and the line that was supposed to be printed at 100 mm length I actually printed at 194 mm (Bob Atkins target towards lower left in the images). I have included, at great risk of being told why this is inappropriate, one image under identical circumstances taken with my Tammy 70-300 at 70mm f8. This is NOT meant to be compared to the RF24-105L images (apples to oranges comparison) in terms of resolution (but you can), rather, it shows that under identical test setup conditions MUCH sharper images are possible and the lower left issue is not related to how I tested the lens or a camera issue. DPP4 was used for RAW conversion with similar settings (lens corrections not possible for the Tammy shot).

Tamron 70-300 at 70 mm f8 IS off tripod mounted as a test control image

I must also share that Canon CPS called me earlier this week to see if this second repair did the trick. I let them know that at that time I had not tested the lens. They asked if it would be ok to call me back in another week or so to follow up on the repair. That was very professional of them.

Oh, please don't critique the horrible on-camera flash lighting and the glare in the center of the frame. I know the center resolution is fine. I am concerned about the lower left portion of the frame being unacceptable. This appears to me to occur at multiple focal lengths with the wider the shot the worse. So, is the lower left corner softer and with less contrast than the lower right and is the lower left acceptable to you especially at 24mm? Spoiler: I think Canon again did not correct the lens problem.

RF24-105L at 24mm f4 IS off tripod mounted

RF 24-105L at 24mm f8 IS off tripod mounted

RF 24-105L  at 70 mm f4 IS off tripod mounted

RF 24-105L at 70 mm f8 IS off tripod mounted

 f8f8f8's gear list:f8f8f8's gear list
Sony Alpha DSLR-A700 Canon EOS 5D Mark III Canon EOS R5 Canon EF 400mm f/5.6L USM Tamron SP 70-300mm F4-5.6 Di VC USD +7 more
Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow