Have I gotten a Lemon?
- Thread starter ehwhatthe
- Start date
'10mm' and '14mm' texts look quite sharp. My guess is that your lens is back-focusing.
If under warranty, bring to CSC for a check-up.
If not, then see if your AF micro-adjustment can overcome this problem.
Last check: You didn't select the AF point that is above the center spot, did you?
Well i set the AF point on the center black line in the focusing chart which says "focus here".
Ok did what you recommended.
1. F2.8 ISO400 70mm Distance approximately 1.5m
2. F2.8 ISO 400 70mm Distance approximately 1.5m - 2nd shot
3. F2.8 ISO 400 70mm Distance approximately 1.5m, -12 on microadjustment
4. F2.8 ISO 400 70mm Distance approximately 1.5m, -12 on microadjustment - 2nd shot
5. F2.8 ISO 400 70mm Distance approximately 1.5m, -12 on microadjustment - 3rd shot
the chart seemed slanted but even with such a slight slant, the discrepancy should not be so huge.
definitely need to make a trip down to CSC.
I think it is >.<
Sigh i have already resigned to my fate. brought my cam to hall. tml heading down to keppel bay in the morning. haha. bye bye $60 bucks
your..F2.8 wide open shots are mostly either out of focus or very soft..
yea i think we got a problem here.
yea i think we got a problem here.
Got my Cam back from CSC.
Realized they included an extra 18-135mm lens in the invoice when i didn't pass them any hahaha but didn't take it la.
Calibration charges only for the lens at 64.20 bucks after GST.
Can't really test it now without a tripod. Can only do so after my exams are over (that's when i go home haha)
Will update yall.
But one thing i'm a little peeved about is.... they used around 2.4k worth of shutter count to calibrate it ?!? :/
Realized they included an extra 18-135mm lens in the invoice when i didn't pass them any hahaha but didn't take it la.
Calibration charges only for the lens at 64.20 bucks after GST.
Can't really test it now without a tripod. Can only do so after my exams are over (that's when i go home haha)
Will update yall.
But one thing i'm a little peeved about is.... they used around 2.4k worth of shutter count to calibrate it ?!? :/
Do not simply test for front/back focusing.. You should be able to fix that by the auto-focus compensation function you have on the 7D
You could be having a centering issue. That is, a lens element is probably mis-aligned. This is common in zoom lenses, particularly large ones. No lens is perfect, but sometimes it goes out of acceptable limits. 24-70mm seems to have quite a high number of de-centered lens. Its probably a hard lens to make.
To test for this, you need a chart that has horizontal and vertical lines. You can use live view and manually focus. Just turn your focus ring until your lines become in focus.
If you have a decentered lens, you will notice that your horizontal lines may be in focus but your vertical lines are out of focus, or vice versa.
Usually, when that happens, one side of the chart will be sharper than the other, this is the more common way to test but less absolute in discriminative ability. Because this can be caused by your camera not pointing perfectly perpendicular to your chart.
You could be having a centering issue. That is, a lens element is probably mis-aligned. This is common in zoom lenses, particularly large ones. No lens is perfect, but sometimes it goes out of acceptable limits. 24-70mm seems to have quite a high number of de-centered lens. Its probably a hard lens to make.
To test for this, you need a chart that has horizontal and vertical lines. You can use live view and manually focus. Just turn your focus ring until your lines become in focus.
If you have a decentered lens, you will notice that your horizontal lines may be in focus but your vertical lines are out of focus, or vice versa.
Usually, when that happens, one side of the chart will be sharper than the other, this is the more common way to test but less absolute in discriminative ability. Because this can be caused by your camera not pointing perfectly perpendicular to your chart.
Oh this is interesting!.
I haven heard of this. Will test this as well.
But i do notice the images are sharper now then they used to be. At least from the LCD. Or maybe its my mind justifying the 60 bucks spent haha.
Decentered lens. will google that. Thanks for the info!!
i used to have this lens on my 7D and i find that it performs pretty sharp at F5.6..
actually u should try to do micro adjustment before sending them down to CSC.
it seems like u left your 7D and lens there for them to calibrate it for u.
could they be also just doing the micro adjustment?
or did u check if they calibrate your camera or the lens?
actually u should try to do micro adjustment before sending them down to CSC.
it seems like u left your 7D and lens there for them to calibrate it for u.
could they be also just doing the micro adjustment?
or did u check if they calibrate your camera or the lens?
Yea man the first thing i checked is whether they did only the micro adjustment. Thank goodness they did something more then that if not i would have kicked up quite a fuss lol.
They calibrated my lens to the body. Body required no calibration. So free on that part. shutter count around 21k after the 2k increase from csc... haha
But i'm still wondering why the 2+k shutter count add on...
Hey guys just an update on the condition of the lens calibration since i just got home.
1. Taken at F2.8 ISO 400 Shutter 1/100. Tripod Mounted, Timer release
2. Taken at F2.8 ISO 400 Shutter 1/100. Tripod Mounted, Timer release - 2nd Shot
Guess I'm making another trip to Canon CSC. Focus has improved from previously. But back focus issue still visible.
1. Taken at F2.8 ISO 400 Shutter 1/100. Tripod Mounted, Timer release
2. Taken at F2.8 ISO 400 Shutter 1/100. Tripod Mounted, Timer release - 2nd Shot
Guess I'm making another trip to Canon CSC. Focus has improved from previously. But back focus issue still visible.
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