December 03, 2016, 05:18:41 AM

Author Topic: Softness in the top left corner of the frame  (Read 949 times)

Mancubus

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Softness in the top left corner of the frame
« on: November 17, 2016, 03:16:12 AM »
I've been using a 5d Mark III for the past 2 years, and I've recently noticed that when I take a photo of a group of people, the ones in the top left of the frame always come out noticeably softer than the ones on the right or in the center.

This apparently does not depend on the lens used, I've tried both a 70-200mm 2.8, a 16-35mm f/4 or a 40mm prime. I get excellent sharpness in the middle and right parts of the frame, but the people on the top left appear as if they were a bit out of focus, regardless of the aperture used and even if I focus on them.

Is that a common issue? Not a deal breaker to me, but I wonder what could be causing it.

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Softness in the top left corner of the frame
« on: November 17, 2016, 03:16:12 AM »

Valvebounce

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Re: Softness in the top left corner of the frame
« Reply #1 on: November 17, 2016, 04:00:20 AM »
Hi Mancubus.
If you go back to early shots with the camera do you see the same thing? Has the camera received a knock, it seems from previous posts that a small impact in the wrong direction can cause issues where an impact of a higher magnitude in a different direction may cause no damage at all.

Cheers, Graham.

I've been using a 5d Mark III for the past 2 years, and I've recently noticed that when I take a photo of a group of people, the ones in the top left of the frame always come out noticeably softer than the ones on the right or in the center.

This apparently does not depend on the lens used, I've tried both a 70-200mm 2.8, a 16-35mm f/4 or a 40mm prime. I get excellent sharpness in the middle and right parts of the frame, but the people on the top left appear as if they were a bit out of focus, regardless of the aperture used and even if I focus on them.

Is that a common issue? Not a deal breaker to me, but I wonder what could be causing it.
7DII+Grip, 7D+Grip, 40D+Grip, 5D+Grip, EF 24-105 f4L EF-S 17-85, EF-S 10-22, EF 70-200 f2.8 L IS II, EF 2x III, EF 100-400 f/4.5-5.6l IS II, Σ17-70 f2.8-4 C, EF 50mm f1.8, 550EX, Triopo TR-985, Filters Remotes Macro tubes Tripod heads etc!

5D, 20D, 24-105, BG-E4, BG-E2N, 17-85, Nifty 50 pre owned.

Alex_M

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Re: Softness in the top left corner of the frame
« Reply #2 on: November 17, 2016, 06:12:24 AM »
Likely, this issue caused by the CMOS sensor misalignment. It can be adjusted. Give local Canon repair centre a call to see what cost is involved. It should not be too costly to adjust.

see the following page for details:

https://canonrepair.wordpress.com/2012/12/30/how-to-adjust-the-position-of-the-sensor-in-a-dslr-camera/

Mancubus

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Re: Softness in the top left corner of the frame
« Reply #3 on: November 20, 2016, 10:36:32 PM »
Thanks for the replies, I think sensor misalignment seems quite likely. However, it's a very minor thing for me at the moment and since Canon usually takes a month to do anything around here I can't afford the time to service it.

The camera has never taken a significant bump.

One question on the matter: does it get worse with time?

Mt Spokane Photography

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Re: Softness in the top left corner of the frame
« Reply #4 on: November 21, 2016, 12:12:24 PM »
Usually a issue like this is a lens issue.  The sensor does not easily get misaligned unless the camera is severely damaged and the mirror box is deformed.  The sensor uses shims for alignment.  Each sensor is factory checked and carries a marking for the shim thickness.  A new mirror box would be required if the old one is damaged.

Another possible issue is the lens mount on the camera being deformed a tiny amount.  The mount tolerance is so tiny, that you would not be able to see a change in it, but it can be measured with a dial indicator that reads to 0.001 inches or 0.01mm, better camera repair shops can check it, no disassembly is required.


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Re: Softness in the top left corner of the frame
« Reply #4 on: November 21, 2016, 12:12:24 PM »