Uh oh....

It's just plain user error, Ed.

j/k. Hope you get it squared away soon.

Isn't it normal to get the occasional mis-focused shot? I've had a number of my 40D shots OOF (all completely static subjects; slowest shutter speed of these shots being determined by the camera, which seems to be 1/focal length by default)... Are you guys telling me that there should be zero OOF shots produced by the camera at reasonable shutter speeds (but no tripod, no MLU, etc.)?

SilverOnemi wrote in post #4087300
also u are aware of this :

https://photography-on-the.net/forum/showthre​ad.php?t=376605

it might be fooling the big focus point.. just an idea.

I'll give the thread a thorough read later on. After reading the initial post I guess it sounds logical.

Yohan Pamudji wrote in post #4087467
Looks like front-focus to me. Personally, I would find some static subjects just to make absolutely sure, but I would be leaning toward there being a focus miscalibration at this point.

One thing that might have helped keep your track photos in sharper focus despite this suspected front-focus issue: the AF lags behind the action slightly, so as the runner moves forward he/she moves into the in-focus area of the camera's current AF position before the camera has a chance to adjust the AF further forward to compensate for motion. So in essence your front-focusing is being nullified by the speed of the action moving toward you.

We'll find out if it's miscalibration soon enough. She's taking a trip to the service center one way or another. The AI Servo explanation you just gave makes sense.

S2000 wrote in post #4087495
LM:

for what it's worth, I've noticed the same thing occasionally on my 40D. BUT..it only seems to happen in lower light shot. in bright light I don't seem to have the issue. it's never real bad, but a "tad" off.

Very interesting. I noticed that in the shots were the focus was off the lighting wasn't all that great. But in the shots where the sun was directly on my intended target the focus was spot on. hmmm....

SilverOnemi wrote in post #4087244
check if it's also mirror slapping too hard.

IT'S NOT MIRROR SLAP, my young friend. Am I going to have to go to Portugal and slap some sense into you?

PacAce wrote in post #4087558
It's just plain user error, Ed.



j/k. Hope you get it squared away soon.

Funny, but I usually do chalk up things like that as user error. Sadly, in this case, the evidence points towards the gear and not the boneheaded user.

Lord_Malone wrote in post #4087799
Very interesting. I noticed that in the shots were the focus was off the lighting wasn't all that great. But in the shots where the sun was directly on my intended target the focus was spot on. hmmm....

I 1st saw this when I was shooting some ducks and the sun was coming through trees. When I had the center point on light spots...GOOD, dark spots...SOFT. I noticed it a second time with a 50mm 1.4 (@2). I was just shooting off some random shots at 1600. They came out soft. So much so that I thought it was the lens. I tested it outside in daylight and it was spot on.

I've seen it occure on 3 lens now.

I don't think it's a front/back focus issue but rather an issue with the cross sensor and light choosing a point to focus on.

It's so small of an issue with me that I have pretty much blown it off.

If you want to test it lets set up a similar test and post results of objects.

S2000 wrote in post #4088104
I don't think it's a front/back focus issue but rather an issue with the cross sensor and light choosing a point to focus on.

Good point.

Malone, I like your incorruptibility on this but its hard to conclude if its FFing from those type of shots as skin is quite flat area and AF can be easily fooled and pick the prominent part i.e. the nose. Its typical habit of tightly placed cross sensors i think.

farrukh wrote in post #4088190
Good point.

Malone, I like your incorruptibility on this but its hard to conclude if its FFing from those type of shots as skin is quite flat area and AF can be easily fooled and pick the prominent part i.e. the nose. Its typical habit of tightly placed cross sensors i think.

I haven't given up hope and I haven't yet resorted to rulers and charts. You have a point about the cross type focusing sensors and it's definitely worth exploring. I'm going to give it another "real world go" and then run it through some formal testing, which I dread to do.

lol dude, i said ALSO check if it's ... i'm not saying IT IS, i just wanna know if i was the only 1 with this problem, my new 40D arrived and i see no more slappin' anymore.

How did you look at the focus point data?

BenJammin wrote in post #4089740
How did you look at the focus point data?

ZoomBrowser EX. It's part of the software bundle that comes with your camera.

I am going to have to agree with farrukh on this. I say this because I have experienced the same thing with my 20d and my grandson. I have no problem getting sharp facial pics of his sister but he is very fair skinned and doesnt have much contrast to his face. White hair, white eyebrows and eyelashes, light blue eyes. I have to be very careful where I focus. He also won't stand still for 2 seconds. His shirt will always be sharp but the eyes and face where I focused will not.

I am also wondering because you said you focused and recomposed, or was that the good shots?

I took my 40d out tonight to test it out after reading your thread. No rulers or anything but I took a lot of shots in cluttered areas that would show up back-front focusing and I am happy to report that mine is spot on and tack sharp with the 17-55.

I later pulled out the batteries and did that test. It was spot on. Hope you get it worked out. Don't keep us in supsense!

Do it! Do it! Get out the rulers and charts!!

Lord_Malone wrote in post #4089662
I haven't given up hope and I haven't yet resorted to rulers and charts. You have a point about the cross type focusing sensors and it's definitely worth exploring. I'm going to give it another "real world go" and then run it through some formal testing, which I dread to do.

When you are testing the focus on your 40D, here is something to take into consideration -- the focus area is actually somewhat larger than the box that you see displayed in the viewfinder.The focus sensor will lock onto the sharpest contrast line that it can find in its search area. The consequence of this is that what you may be intending to focus on that is within the displayed focus box may not necessarily be where the focus occurs if a strong sharp contrast line is nearby, but outside of the box.

S2000 wrote in post #4087495
LM:

for what it's worth, I've noticed the same thing occasionally on my 40D. BUT..it only seems to happen in lower light shot. in bright light I don't seem to have the issue. it's never real bad, but a "tad" off.

I have noticed the same thing. I do a lot of birding and if the bird is in shadow, I've noticed the images can end up just a bit OOF. In normal sunlight they are tack sharp. Thankfully, I tend to go for the lit up birds as hteir coloring is always better in bright sunlight.

I have not had much time to play with it lately with work but I am hoping to try some bright sunlight tests either today or tomorrow after work to ensure it's only in shadowed shots.

As an aside, when my 28-135mm is tripod (or solidly) mounted with IS off, that thing is insanely sharp. I may be the only POTN member who wants to keep his.

queenbee288 wrote in post #4090160
I am going to have to agree with farrukh on this. I say this because I have experienced the same thing with my 20d and my grandson. I have no problem getting sharp facial pics of his sister but he is very fair skinned and doesnt have much contrast to his face. White hair, white eyebrows and eyelashes, light blue eyes. I have to be very careful where I focus. He also won't stand still for 2 seconds. His shirt will always be sharp but the eyes and face where I focused will not.

I am also wondering because you said you focused and recomposed, or was that the good shots?

I took my 40d out tonight to test it out after reading your thread. No rulers or anything but I took a lot of shots in cluttered areas that would show up back-front focusing and I am happy to report that mine is spot on and tack sharp with the 17-55.

I later pulled out the batteries and did that test. It was spot on. Hope you get it worked out. Don't keep us in supsense!

I'm going to take some real world shots and then run it through the focus chart test under various lighting conditions. I'll also compare it with the 5D and 20D while I'm at it. I hate setting up tests like this, but if it's for the good of the community...

Wait a minute... I don't even know you people!

mebailey wrote in post #4090222
Do it! Do it! Get out the rulers and charts!!

Should I send you my 40D for testing, Mike?

Grimm75 wrote in post #4092801
I have noticed the same thing. I do a lot of birding and if the bird is in shadow, I've noticed the images can end up just a bit OOF. In normal sunlight they are tack sharp. Thankfully, I tend to go for the lit up birds as hteir coloring is always better in bright sunlight.

I have not had much time to play with it lately with work but I am hoping to try some bright sunlight tests either today or tomorrow after work to ensure it's only in shadowed shots.

As an aside, when my 28-135mm is tripod (or solidly) mounted with IS off, that thing is insanely sharp. I may be the only POTN member who wants to keep his.

Another one who has experience tack sharp images with good lighting. Maybe I need to go take another look at some of the shots I've taken under less than adequate lighting conditions with the 1D2N, 5D and 20D. I can't recall if I ever noticed this before. This forum has made me anal.

I'll be back, folks.

bill boehme wrote in post #4092286
When you are testing the focus on your 40D, here is something to take into consideration -- the focus area is actually somewhat larger than the box that you see displayed in the viewfinder.The focus sensor will lock onto the sharpest contrast line that it can find in its search area. The consequence of this is that what you may be intending to focus on that is within the displayed focus box may not necessarily be where the focus occurs if a strong sharp contrast line is nearby, but outside of the box.

Good point and I do try to use the edge of the red box as my focus point. So if I'm aiming for the eyeballs I try to cut it in half with the edge of the red square if possible, esp. when shooting wide open. If I'm using an aperture like f5.6 or something I should be able to aim anywhere on the face and it should all still come out tack sharp.