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When will canon fix the focus issues with the 70D?

Photogirl55
Apprentice

I was "T.H.I.S." close to buying the 70D.  I have read WAYYY too many posts about issues with the focusing on the 70D.  How is Canon handling the issue?  I would love to buy this camera, but not willing to gamble with that much money.

223 REPLIES 223

That is an awesome graphic! I love your color sense and it could only be improved if you added a legend/key to explain the different colors.

 

BTW, where can I go to see the raw data behind your graphic? 😉

"Careful, ALL 70D have a particularity (even if the camera works fine)"

 

All cameras - from Canon, Nikon, Pentax, and everyone else - are exactly the same in this regard: it's absolutely not unique to the 70D.

 

Here's an article making the same point about the 7D:

http://blogs.stonesteps.ca/showpost.aspx?pid=54

 

I've seen the same thing about Nikons too.

@ KeithR :

I know this blog, I already pointed it out. Even bettter, the blog post you've pointed at shows clearly that on a 7D, the photographer has all his viewfinder's marks fully covered by the AF sensor. Look at focus points 6 to 11, in my case those are only half covered. I've tested the same thing on two 70D bodies, and even some pictures you've posted (grass strand in front of a road) point toward a similar "particuliarity" in your camera.

 

Here's some pictures showing how this can affect you :

 

I pictured a lightpole against some foliage (not the best subject but had nothing else laying around). The lightpole edge is the most contrasted element in the frame, no reason for the camera to focus elsewhere. I used a tripod, with cable release and turned off image stabilization.

There are four pictures :

- In the left column, the pictures I took with the 70D. In the right column what I see looking through the viewfinder.

- In the top row, is the case where the lightpole is in the naked side of the focus point : the camera focusses on the foliage. In the bottom row, is the case where the lightpole is in the other half of mark : the focus is on the pole.

 

test_Zone_AF.jpg

 

In my case, the 70D is the first camera i've come across with such "particularity". I'm calling this a "particularity" because otherwise the focus now seems to work well on my new 70D.

 

Don't get me wrong, I'm not criticizing Canon for having some overlap between each focus point, or for the focus sensitive area extending beyond the mark. What I'm criticizing Canon for, is that if they put in the 70D a different AF sensor than the 7D, they should have at least redesigned their focus screen marks to better take into acount the differences. I rely on those marks to frame my picures ! Now each time I take a picture I need to remember my graphic.

 

@cale_kat

I used these beautifull colors so you could easely differentiate each focus points, because some of them are overlapping. Other than that, the different colors don't mean anything.

 

For the data, I'm having trouble finding a way to send to you 334Mo of data (or more than 1Go if you want the RAW files), do you have any easy solution where I don't need to signin on some website ?

 

 

As for the legend, it was allready above the picture, but let me make it clear for you :

 

40mm_f2-8.jpg

 

LEGEND :

I overlaid several pictures on top of each other showing the sensitive areas for each 19 focus points measured on my 70D.

- In black these are the focus marks you see in liveview AF Quick mode or in Canon's DPP picture editing software (by pressing Alt+L)

- The red, green and blue rectangles are the different AF sensitive areas for each focus points, the colors are here to help differenciate each focus point.

 

Honestly, Molybdo42, if you're going to go so far as to make a graphic which "proves" a point, you ought to be prepared to back in up. Explaining that your data is so raw as to be un-presentable in its present form is not proof but a failure to acknowledge that evidence can only be offered if it is understandable and accessible. Your presentation fails to qualify as evidence of anything.

 

I don't ask for anything more than any other person asking for a complete description of something you say is scientific but which fails to meet scientific, even casual science, standards.

As a follow up to the earlier comment, I have to disagree with your statement, "The lightpole edge is the most contrasted element in the frame, no reason for the camera to focus elsewhere." I wouldn't start by deciding the outcome of my "experiment" before I began.

 

I don't think you're giving the camera credit for being as "smart" as it is. The autofocus is ignoring the pole because it has found a much higher contrast image in the back (the bush) and it focuses on that. The pole is a predictable undesirable-element (shape) in your picture and as a color it lacks contrast, being almost uniformly grey.

 

I would also take into account that in addition to the 19-focus "points" that the camera has at its disposal, there are 63 light sensing zones which are simultaneouly feeding "a light representation" of the image to the camera's CPU. By combining the light representation data with a "topographic" image from auto-focus, the camera analysies the data for predictable patterns, like your lamp post, and single them out when making a focus choice. (A good time to switch to manual focus if you're really intent on getting that pole.) The ability to recognize "predictable" patterns and single them out is what makes face recognition imaging so powerful. 

 

Just my $.02.

@cale_kat

 

 

"I don't think you're giving the camera credit for being as "smart" as it is. The autofocus is ignoring the pole because it has found a much higher contrast image in the back (the bush) and it focuses on that. The pole is a predictable undesirable-element (shape) in your picture and as a color it lacks contrast, being almost uniformly grey."

 

I'm sorry but you don't understand how phase AF works, read this and understand it before saying anything else :

http://graphics.stanford.edu/courses/cs178/applets/autofocusPD.html

 

Regarding face detect, the phase AF simply can't detect faces, where did you learn this ? Face detect is only available in Liveview.

 

That's because phase AF only takes a small portion of the picture, to be more precise, the AF system only sees a line or two of the picture. I can only say that my "focus sensitive area" term is incorrect, because in reality I should have drawn a cross and not a rectangle. But in no way can the camera guess from a simple profile plot where a face can be. Also, the metering system hasn't got enough resolution to detect faces, it is constituted of 63 pixels.

So phase AF system can't make any face recognition. In other words, the camera is simply not intelligent enough to ignore the pole. The only intelligent thing the camera can make is to track a moving subject. That "intelligence" must come from the fact that a tracked moving subject will keep a similar contrast pattern in regard to a moving background contrast pattern. But in the picture I presented, I wasn't tracking a light pole, I was on a tripod, with ONE SHOT enabled.

 

But maybe you can provide me a link of a Canon engineer saying that the 70D can do face detect while aiming through the viewfinder...

 

 

Also in my post, I spoke of the LIGHTPOLE'S EDGE ! The edge of the pole is the most contrasted element in the picture and, photogenic or not, that will be used by the camera to focus. How can't that black/white edge be less contrasted than the background ? I ploted below an horizontal grayscale profile plot across the entire picture. DO UNDERSTAND that this plot is across the entire picture, and not on the small area covered by the AF system. The light pole is the one with the highest intensity value between 2000 and 2500 pixels. That the kind of data the AF works with.

 

In conclusion, what I'm trying to point out is that the AF system simply can't see the pole's edge until it is well inside the viewfinder's mark. It's not a problem of the camera being smart or not.

 

 

Capture.JPG

 

 

"Honestly, Molybdo42, if you're going to go so far as to make a graphic which "proves" a point, you ought to be prepared to back in up. Explaining that your data is so raw as to be un-presentable in its present form is not proof but a failure to acknowledge that evidence can only be offered if it is understandable and accessible. Your presentation fails to qualify as evidence of anything."

 

I finally managed to find a way to post it (not because you helped). I took me hours to upload them but here you go, the raw data as you asked :

http://wikisend.com/download/316742/40mm_f2-8 RAW.zip.001

http://wikisend.com/download/152468/40mm_f2-8 RAW.zip.002
http://wikisend.com/download/962854/40mm_f2-8 RAW.zip.003
http://wikisend.com/download/288176/40mm_f2-8 RAW.zip.004

 

I had to split the archive in four, download the files (there's a 7 days time limit); put the files in a folder and follow these instructions to uncompress them :

http://www.techulator.com/resources/6601-How-split-join-files-using-7-zip-free-tool.aspx

 

 

I don't ask for anything more than any other person asking for a complete description of something you say is scientific but which fails to meet scientific, even casual science, standards.

 

If you were that "scientific" in your methodology, you would have already done the same test as I did and posted a similar picture.

 

BTW, the description of my measurement method can be found here :

http://photography-on-the.net/forum/showpost.php?p=17046799&postcount=1088

 

I then used a MATLAB code to merge the different pictures :


clc;
clear all;

NameFichier='_MG_94';
extImg = '.jpg';
threshold = 0.3;

for i=1:4:4

imageResult=NaN;
for j=i:i+3
imageData = imread(strcat(NameFichier, num2str(j), extImg));
imageDataBW = im2bw(imageData, threshold); % turns image in black and white
if isnan(imageResult)
imageResult = imageDataBW;
else
imageResult = and(imageResult,imageDataBW);
end
end
imwrite(imageResult,strcat('Merge',NameFichier, num2str(j), extImg));

end

Reading carefully is important in communication. Because you start off on the wrong foot, I'll respond that far and no further. I never said face detect is available in phase detect, I said that the camera's ability to recognize patterns, like faces is an example of the camera's focus system.

 

Regarding the rest of your nonsense. If you have something to present, do it up front, not after being asked to make a reasonable claim, while using the opportunity to disparage another etc. You're not very nice, I'm out of here.

"Reading carefully is important in communication. Because you start off on the wrong foot, I'll respond that far and no further. I never said face detect is available in phase detect, I said that the camera's ability to recognize patterns, like faces is an example of the camera's focus system.

 

Regarding the rest of your nonsense. If you have something to present, do it up front, not after being asked to make a reasonable claim, while using the opportunity to disparage another etc. You're not very nice, I'm out of here."

 

Regarding face detect, you edited your post while I was writing mine.

 

Maybe I read it to quickly (in which case I'm sorry) but what I said in the rest of my post is still true. You should really try to understand what I said, because this is vital information on how to properly use the 70D's AF system.

 

So I still hold my ground : the camera's phase AF system can't recognize things like "face patterns". Otherwise Canon wouldn't use black and white targets to calibrate their camera, they would use family pictures. The camera can't guess  what it is pointed at only from the data provided by the AF system and the 63 light metering zones.

 

As for the pictures, I wasn't holding information, it really took me several hours to upload them. So now that you have the data you must do your part of the job and analyze it to tell me what's wrong in my methodology.

 

I might seem "not nice", but I'm really trying to help you here ! I'm trying to at least get you to get your camera out and test like I did. You should at least consider my hypothesis. Any good scientist would do the same.

 

Have a good night rest to let the steam out and think on this issue, trust me, you won't be disapointed.


@pdqgp wrote:
Robert...I see your point, but the part I can't figure out is where MFA will come into play. The lenses and camera are spot on in terms of focus when shooting still shots, thus no MFA is needed. My camera was clearly exhibiting a problem with AIServo, thus I hope whatever they fixed corrects that but doesn't impact the single shot quality.

I get frustrated easily and I suppose it's because I didn't like the answer Canon Gave regarding 3rd party lenses and trying to focus blame on them. My Tamaron 70-200 is amazing and works great on still shots. No go on AIServo. however, niegher do any of my Canon's.

I also didn't like the fact that they said that just because my 40D works great with all of them, that it doesn't mean my 70D will. WTF, in that case the 70D is a major downgrade for me then. I see their point that the two cameras have different AF Systems, but for one to work fine with all my lenses and the other not and for them to say that's within tolerance and acceptable is total garbage. I shouldn't have to send in my new camera and all my lenses to get them to work as they should.

In the end, I'm only going to tollerate so much and only because I have my 40D as a backup. However I won't do it for long. I'll take a loss and sell the 70D on craigslist and test out a 7DMKII but my fear is then simliar.

Canon needs to work on Customer service. If this can't be resolved, swap out my camera and don't send me one that doesn't work.

I'm jumping to conclusions though. Camera is do to arrive today. We'll see.

Well, I did some extensive testing on my 70D with AIServo issues and to no avail. it's either a full blown issue or a one-off problem.   Either way, it's going on Craig's List for sale and for the past couple weeks I've been enjoying a perfectly fucntioning and kick-butt 7DMKII.   Absolutely should have waited for this camera to begin with, but I wanted a camera in early summer.  Lesson learned.

 

In the end, my 70D focused fine and worked great with single shots but failed miserably with AIServo.   Overall I'm happy with the 7DII is proving way better and has a lot more functionality and features, especially focus wise.   The only two things I miss are touch screen and to a minor extent the flip out LCD. 

I received my new 70D a week or so ago and have been doing a ton of trials with it and definitely have experience the focus issues.  I've been shooting for 15+ years and there is no way this is a "user error" issue.  If I use the center focus point on my model's eye and shoot, it's blurred.  If I use the next spot (in either direction) from the center on her eye and shoot, her eye is razor sharp clear.

Looks like I'll be sending this in for repair/service to Canon and, if that doesn't fix it, I'll be returning it.  This is inexcusable and no amount of MFA will help.  And this is nothing I've ever experienced before with any other equipment.  My guess is the dual-pixel technology has some issue with viewfinder focusing.  I'm tired of digging through the hundreds of posts about it to see no explanation of a user-based fix and a select few posts making it sound like this is "user error" from experienced photographers.

I'm sorely disappointed and somewhat frustrated but have hope that Canon can recalibrate this if I send it back.  <crossing fingers>

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