for this lens at wide open, this is too soft. i think just bring down to CSC and do a recalibration. it should solve the problem.
Advise needed: My 70-200mm IS F4 is soft! Pics inside
- Thread starter yanyanyan881
- Start date
Hi everybody. I have sent my 70-200 and 550D down to CSC. I tried explaining to the lady but she seems like ???. I know its quite complicated. hopefully the engineers can find out the problem by himself.
The lady said they will do a calibration. But i told her that it needs more than a calibration becoz i tihnk that this word means front/back focusing only.
The lady said they will do a calibration. But i told her that it needs more than a calibration becoz i tihnk that this word means front/back focusing only.
Keep us posted after they have done the calibration. Actually forgot to mention to you that you can do front / back focusing test using the below chart and technique.
http://regex.info/blog/photo-tech/focus-chart
-------------
Would be helpful if other owners of 70-200 f4 IS do a similiar test to know if the AF does go off quite easily for this lens.
No problem. Ill keep you guys updated. thanks for being helpful.
i actually have tested using focus chart. seem like a tiny bit off focus. when using MF with the target spot on, its still relatively soft. thanks once again.
i actually have tested using focus chart. seem like a tiny bit off focus. when using MF with the target spot on, its still relatively soft. thanks once again.
MWP
Could you shoot a text or sth at higher Fstop 5.6, 8
Mine still has the same problem. It back focus heavily at f8, 5.6.
at f4 its still soft.
really angry now.
take off from work just to go down and collect.
canon doesnt open on weekends
im really going to make some noise there.
Could you shoot a text or sth at higher Fstop 5.6, 8
Mine still has the same problem. It back focus heavily at f8, 5.6.
at f4 its still soft.
really angry now.
take off from work just to go down and collect.
canon doesnt open on weekends
im really going to make some noise there.
Last edited:
I did some test and conclude that you should not hold the DoF button when focusing when using this lens. My tests are done at f5.6, 8 and 11. When I focus normally, I get the same sharpness as when I am using liveview x10. On the same sharpness. when I press the DoF button, the focus is off. The reverse is also true. When I attain sharp focus using DoF, switching to OVF and LV also show OoF subject. The accurate and sharp pictures are taken without the DoF button depressed.
Further test shows that f4 is the only aperture when OVF, LV and DoF all show the same sharpness at the same focus. I also tested with a variable aperture zoom lens, 70-300 DO, which exhibit OVF, LV, DoF focus point to be aligned at all apertures. So I believe this is by design in order for 70-200 f4 IS to maintain a constant aperture across all focal length.
I think the main point is if your AF is able to get you reasonably sharp image. Alternatively, you may want to invest in a matt screen if you prefer manual focus or want tack sharp images.
Last edited:
thanks MWP.
cant believe they just did a focus calibration only.
at F4 its still soft. and back focus at 5.6 and f8. im guessing the softness of f4 is affect the back focus at 5.6 and 8 because the cam focuses at largest aperture.
cant believe they just did a focus calibration only.
at F4 its still soft. and back focus at 5.6 and f8. im guessing the softness of f4 is affect the back focus at 5.6 and 8 because the cam focuses at largest aperture.
Maybe you can bring your cam and let them calibrate the lens with your body. They may have done the calibration and tested with their test set which may yield results different from yours.
On a separate subject, I have been taking moon shots these 2 nights. I noticed that even with a geared head and a bloody heavy tripod, this lens is still subjected to vibrations with the slightest of breeze, the movement of camera strap, or even the tension on the remote trigger. I switched on IS and 10s delay for better results.
My 550D was there with my 70-200. They calibrated to my 550D
Results after Service
100% crop
focus at the center
F4. Focus seems right but its very soft
F5.6 Back focus
F8 heavy back focus
All in all, really angry at CSC.
I need to bring down the chart to test next time.
Results after Service
100% crop
focus at the center
F4. Focus seems right but its very soft
F5.6 Back focus
F8 heavy back focus
All in all, really angry at CSC.
I need to bring down the chart to test next time.
Last edited:
Best is to compare with the same lens.
Sometimes we can't rely too much on reviews
Manufacturers sometimes give reviewers "special" sets
If the camera performs well with other lenses, just ask them to adjust the lens
Sometimes we can't rely too much on reviews
Manufacturers sometimes give reviewers "special" sets
If the camera performs well with other lenses, just ask them to adjust the lens
Yanyanyan881, your 2nd and 3rd pictures seem to show focus shift as the aperture is stopped down. I don't think this can be fixed. See http://toothwalker.org/optics/spherical.html.
Your 1st picture shows the lens to be soft at f4. I'm not sure whether this is a defect -- it may be that this Canon lens is just like that. My own experience with this lens is that it is spectacularly sharp for general shooting. But, around the minimum focusing distance, it's somewhat soft towards it's long end.
Why don't you repeat your sharpness tests at a focusing distance of 2.5metres or greater and see how the lens performs? I suspect that you might find that it is sharp at such focusing distances.
Your 1st picture shows the lens to be soft at f4. I'm not sure whether this is a defect -- it may be that this Canon lens is just like that. My own experience with this lens is that it is spectacularly sharp for general shooting. But, around the minimum focusing distance, it's somewhat soft towards it's long end.
Why don't you repeat your sharpness tests at a focusing distance of 2.5metres or greater and see how the lens performs? I suspect that you might find that it is sharp at such focusing distances.
If you look at my earlier test, I shot from 1.5m. This lens MFD is 1.2m. It is reasonably sharp. I have also tried from more than 2.5m(switching the AF switch to 2.5-infinity) with reasonably sharp results. Nothing like what TS has posted.
guys,
do you think canon will says this is the way the 70-200mm is.
its the last thing i want to hear.
i expect an exchange if they cant fix.
do you think canon will says this is the way the 70-200mm is.
its the last thing i want to hear.
i expect an exchange if they cant fix.
Any updates? A few friends waiting for the results.
Someone mentioned we can't compare a fix lens with zoom lens.
Someone mentioned we can't compare a fix lens with zoom lens.
Similar threads
