It appears that some models of the 70D has issues with accurate focus when using the center focus point through the viewfinder with lenses wider than f/2.8.  The images below illustrate the problem on my 70D.   To be fair I had to go looking for this issue and in the 6 months that I have used the camera I hadn’t noticed an issue.  It is unclear how widespread the issue is. Many German users are unhappy while here in the United States I haven’t heard a peep from a single user.  Is it because so few of us have used fast lenses and carefully pixel peeped?  Or?  At this time I don’t want to speculate more. I have contacted Canon and am waiting for a response.  Please don’t assume if you have taken a blurry photo that your 70D also has the issue.  Watch the video and follow the directions below for testing your own 70D.

tl;dr 70D doesn’t focus properly using the center focus point with lenses faster the f/2.8.  Use the LCD to focus and take photos at those wider apertures.

 

Full Image 50mm f/1.2- Rollover to view image taken with LCD. See the difference? Slight change in sharpness.


100% crop of above image 50mm f/1.2- Rollover to view image taken with LCD. See the difference? Slight change in sharpness. Point of focus is chip on far beam.


Now with the 85 f/1.2 lens. Shooting at f/1.2 and a distance of 15′ – Your depth of field at this aperture and focal length is 5.04 inches (very shallow)


100% crop of image above. Brace yourself for this difference


35mm f/1.4 at 100% crop – The difference isn’t huge but it is noticeable.

 

More Samples can be downloaded from this Dropbox folder – All are labeled and should be self explanatory. There is a folder of the smaller 100% crops or just zoom to 100% of the images in the main folder.

I was careful to eliminate ALL other variable.  I used a sturdy tripod, set a fast shutter speed at least 2x the focal length and used 2-second delay with mirror lockup to avoid any blur from movement of any kind.  For each image you see I took at least three others under the exact same settings and picked the sharpest of the four.  So  the sharpest viewfinder image vs the sharpest LCD image.  There rarely was little difference between the shots.

What about Autofocus Micro Adjustment(AFMA)?  I tried it and could occasionally get a matched focus at one distance (meaning the sharpness of images taken using the viewfinder to focus was the same as the image taken using the LCD to focus) but at other distances it would still be noticeably different and AFMA should generally correct across the range.  I do plan on testing more.

At shorter distances with some lenses no issues were seen and only presented themselves at 30′(roughly 10 meters). I also tested the 50mm f/1.4 and the 85 f/1.4 and saw equally disappointing results.

Test your 70D

  1. Put a lens that shoots at f/2.8 or wider (preferably wider) on your 70D
  2. Put your 70D on a sturdy tripod and carefully aim it at a target about 30′(roughly 10 meters) away
  3. Turn mirror lock up on (how to turn mirror lock up on)
  4. Turn on 2-second delay
  5. Switch to Manual mode – set aperture to the widest possible for the lens. Set shutter speed to be 2x focal length and ISO high enough to center exposure(hopefully this isn’t above ISO 2000 – if it is you should consider testing in an area with more light)
  6. Switch to your center focus point
  7. Focus through the viewfinder
  8. Take a photo and repeat several times – Use autofocus each time
  9. Switch to Live view  and choose FlexiZone single – the white rectangle should be on the same mark as the center point was when looking through the viewfinder – if you need to move it slightly you can.
  10. Take several photos
  11. Review these images on the LCD at full magnification- push the zoom button until the image doesn’t increase any more.  Switch between the images taken with live view and through the viewfinder.  you WILL see a difference in sharpness – with the live view images being sharper. This is guaranteed and known.  By how much and whether you can correct it using AMFA is key.  The Digital Picture has a great set of AFMA tips.
  12. It may also be useful to review the images in Lightroom

Findings?  Leave them below- Let me know what lens you used. Questions? Concerns?

Leave a comment. Please do not assume that if you have taken one blurry photo your 70D is broken.  You MUST make sure you have eliminated all variables except the method of focusing used.

 

 

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16 COMMENTS

  1. OMG my camera is borked !!!! Sorry just had to say it 🙂

    But seriously my keeper rate was much higher on my t4i then it is with the 70D. I often attributed it to its me, its a new camera that I am not used to yet. The reason is pretty clear now because I take 99% of my shots with the CFP.
    While I dont think moving the focus point is going to solve all my problems, I bet my keeper rate goes up.

    Its going to be a nice day out tomorrow I will go outside for more test. But if the test from the basement are any indication, its going to be a bad day.

  2. Hi Toby,
    I have followed your test protocol for the focus issue with the 70D and sadly found the same results. With a Sigma 85mm f1.4, the shots are clearly and consistently better with the liveview. I also found that by forcing the device to refocus between each shot, some of the viewfinder shots, around 20%, were actually ok.

  3. Hi toby,

    Also followed your test protocol with the 70d and a canon 100mm macro 2.8 isusm and the canon 17-55 2,8 isusm.
    no problems at all with the macro, but terrible focus results with the 17-55 and the centre focus point. Other focuspoints selected or LV and the problem is gone.
    Did the same tests with a canon 600d… No problems at all.

    • Leroy, Thanks for sharing your results. Interesting that you found differences between lenses and the center point. It should be consistently bad- hmmm. strange!

  4. must have the problems with 2.8 lenses. did not know they existed. thought it was my fault. when i use anonther focus points more photo’s were sharp.

  5. And is the issue still persist for this model? Because I’m going to buy this camera and it’s important for me. Thanks for your time 🙂

    • Not all cameras are affected. I have heard from only a handful of people that have this issue and many more than have the camera and are very happy. There is a chance you will get an affected copy but it is a small chance.

      –t

  6. THANKSSS TOBY!!!!!
    It works! At least, is better keep mirror locked instead get blurry images… :))))
    I set micro adjustment to W+9 and locked the mirror. And i shoot, i dont use center point and teh images taken with view finder is almost the same as live view! THANKS!!!

  7. I can confirm this. I own a 6D and a Sigma ART 50mm. The 6D and the 50mm are razor sharp at all times. On BOTH of my 70D bodies, centre point is inaccurate. I suspect the max aperture on the centre point is around f2 or so. Disappointing, but not a train smash as this is my f4 and above body for telephotos.

    • Thanks for sharing, glad it doesn’t really matter to you but still a bummer. When did you purchase your 70D?

  8. Very sorry for you to say, but I did above test and I have NO issue at all, also generally I keep much more picture since my upgrade from a 700d to 70d . Tested with sigma 2.8 and Canon 1.8, so it’s not every body as you seem to believe. I know several people having this body but never heard of this issue before until I found it on a forum.

    • Excellent – you are commenting on an old post and it seems they have fixed this issue in the last 6 months- I have heard from very few people with the issue and they fixed mine. Thanks! I have a video coming out in a few days that shows you how to make sure ALL your leneses are as sharp as possible with your 70D – Subscribe to be notified when released.

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