Front Focusing Problem on my 400d?

I've been testing my new lens (85L) all night long and i'm very upset becoz it has a focusing problem (i think it's front focusing), and when i test with my other lens it does the same problem, and my conclusion is that my camera have the focusing problem not my lenses, here are the test, (sorry that i don't use the testing meter)

My Focus at letter "A" on the word : "ACCESORIOS EN OPCION"

#1 With 10-22

It looks to be back focusing, not front but really, that is not a very good target. Try this focus chart. You need a good bar to focus on.
http://www.focustestch​art.com/chart.html
There is a pdf file towards the end that has instructions and a focus chart.

Your tests are not able to demonstrate either front or back focus, I'm afraid. The focus 'points' are actually focussing areas, about 3 times larger than the boxes you can see in the viewfinder. The camera is free to focus on anything in that area. In your pictures, the camera may focus on the text either in front of or behind where you want it to.

gjl711 wrote in post #5460531
It looks to be back focusing, not front but really, that is not a very good target. Try this focus chart. You need a good bar to focus on.
http://www.focustestch​art.com/chart.html
There is a pdf file towards the end that has instructions and a focus chart.

Ok, i'll try it asap... thx for the link

gcogger wrote in post #5460568
Your tests are not able to demonstrate either front or back focus, I'm afraid. The focus 'points' are actually focussing areas, about 3 times larger than the boxes you can see in the viewfinder. The camera is free to focus on anything in that area. In your pictures, the camera may focus on the text either in front of or behind where you want it to.

Uhm, yeah ur right about that, thx 4 the info

But i've been wondering or is it just my camera body(400D) that can't go well enough with the 85L, they say that the 85L needs a good body to focus better? is it true? i'm still testing the 85L with 400D and 30D. The 30D perform better on focusing let say 70% is on focus, than my 400D just 10-20% on focus. or is it just me(human error) perhaps???

I have the same problems with my 400D (XTi). Basically, it is doing what it is supposed to be doing, you are running some very shallow DOF tests and the sensors margin of error is larger than the depth. I've be willing to bet that you decided to test after some missed focus images? Maybe? Atleast that's what lead me to run the same sort of tests with my 50 f/1.8. Anyway, the XTi dosn't have the best focus sensor. I'm looking forward to picking up a 40D sometime this year. The 40D has a new sensor that is supposed to be pretty good.

snails wrote in post #5460967
I have the same problems with my 400D (XTi). Basically, it is doing what it is supposed to be doing, you are running some very shallow DOF tests and the sensors margin of error is larger than the depth. I've be willing to bet that you decided to test after some missed focus images? Maybe? Atleast that's what lead me to run the same sort of tests with my 50 f/1.8. Anyway, the XTi dosn't have the best focus sensor. I'm looking forward to picking up a 40D sometime this year. The 40D has a new sensor that is supposed to be pretty good.

Yes they said again that the 40D handles the 85L quite well,
ohman,.. do i need to sell my 17-55 to get 40D just to get the 85L focus on target better, i'm not happy with the focusing problem with my 400D , really anoying,.. ,

another question, the 5D focus better than the 40D? or the 40D perform better on focusing????

I've heard different stories on that end. The 40D has a newer sensor than the 5D's, but I don't think that one is necessarily better than the other.

snails wrote in post #5460967
... the XTi dosn't have the best focus sensor. ..... The 40D has a new sensor that is supposed to be pretty good.

The XTi has the same focus mechanism and sensor as the 30D. The 40D is not all that different than the 30D. It's a bit faster because of the new processor, but not that much faster.

gjl711 wrote in post #5461729
The XTi has the same focus mechanism and sensor as the 30D. The 40D is not all that different than the 30D. It's a bit faster because of the new processor, but not that much faster.

40d's sensor is actually quite different, sort of like comparing the 1dmkii to 1dmkIII.

as for the OP, i'de suggest you get used to your camera before starting to complain about front/back focusing. it's clear here that you don't know all the quarks of your camera just yet. it's like having a carpenter that still hasn't learned how thick a cut his saw will make. since you haven't noticed anything before, it's likely that there actually isn't a problem.

basroil wrote in post #5462008
40d's sensor is actually quite different, sort of like comparing the 1dmkii to 1dmkIII.

as for the OP, i'de suggest you get used to your camera before starting to complain about front/back focusing. it's clear here that you don't know all the quarks of your camera just yet. it's like having a carpenter that still hasn't learned how thick a cut his saw will make. since you haven't noticed anything before, it's likely that there actually isn't a problem.

I agree with both points. The sensors are quite different. And I bet one would find the same problem with the 30D that he is having with the 400D.

Secondly, it's like I said before, the camera is doing what it is supposed to. It's just that the depth of field is so shallow that it is smaller than the sensor's margin of error on such a subject. The only time you'll ever see this, is right here in these kinds of tests; at the full 1.2 and near the mfd.
Shoot the 85L at 12 feet and f/2.8 and you'll never be able to tell if the focus was slightly front or back.

thx all, maybe i give it a test shots for a week, and see the results between the 30D and the 400D, and maybe i'll give some sample picts in here,.. and i really hope it's just my error that cause it,..

but again, i'm getting better on focus results in the same situation (my room and the same object) with the 30D that my friends lend me for a while to test if my 400D is wrong, need to test it again and again until the battery runs out

if only the 400d or the 30D have that "AF Microadjustment" feature that the 1dmkIII had,

Has anyone noticed any front/back focusing issues with the 400D (XTi) and Sigma 150-500 lens ??

I posted a few 100% crops earlier (in another thread - https://photography-on-the.net …php?p=5885881#p​ost5885881) and someone suggested that despite the focus (in the 2nd pic) being the bird's eye (which I had to clarify), the focusing is bit-off. He also added that it might be because of front-focusing.

Wanted to know if anyone else faced a similar issue ?? If so, what's the solution ?

Thanks.