focus front then back then middle....?

These are 2 of 3 pics right after another. Any idea why it would focus near, then center (in focus) then focus far?
7d
50 1.8II,
F3.5
1/250
Iso640
Camera flash

I have this same lens. Mine does the same thing with my 40D. I sometimes have to double focus (press shutter button half way twice) just to make sure I have it focused where I want it to focus.

CameraMan wrote in post #17028810
Mine does the same thing.

well this is good to know. does seem a bit odd though, maybe its a 'fifty' thing..

Well, because it's the 50mm f/1.8, the cheapest lens Canon makes. Seriously, everything in that lens is cheap. It's sharp enough I suppose but it's also loose, sloppy, falls apart, and very inaccurate.

gjl711 wrote in post #17028839
Well, because it's the 50mm f/1.8, the cheapest lens Canon makes. Seriously, everything in that lens is cheap. It's sharp enough I suppose but it's also loose, sloppy, falls apart, and very inaccurate.

But other then that its a great 100 dollar lens

gjl711 wrote in post #17028839
Well, because it's the 50mm f/1.8, the cheapest lens Canon makes. Seriously, everything in that lens is cheap. It's sharp enough I suppose but it's also loose, sloppy, falls apart, and very inaccurate.

Scoobert wrote in post #17028842
But other then that its a great 100 dollar lens

Yeah, I was going to say, what do you expect from a cheap $100 lens.

Its pretty cheap but I've got some great shots with it. Mine tends to hunt for focus a lot in low light or changing light conditions.

Yeah, it's not the perfect mechanical lens. Heck, I'd be afraid to manually focus this thing for fear of tearing it apart.

Not that it would cause this, but why are you shooting at f/3.5 and not f/1.8?

What is your distance to target?

Does the flash have auto assist? You might do this shot again without the flash as the auto assist beam might be throwing it off.

gjl711 wrote in post #17028839
...sharp enough I suppose but it's also loose, sloppy, falls apart, and very inaccurate.

Thought you were talking about me there...

On a serious note, I think this happens with quite a few wide aperture lenses. I have had variable results like the OP's from my Sigma 30mm f/1.4, my friend with his Canon 50mm f/1.4 and there are lots of similar examples posted on here.

Heck, the 50mm f/1.4 isn't all that spot on at 1.4. I tend to use it as a MF lens.

CameraMan wrote in post #17028861
Yeah, I was going to say, what do you expect from a cheap $100 lens.

I hear ya there!

Gregg.Siam wrote in post #17028889
Not that it would cause this, but why are you shooting at f/3.5 and not f/1.8.

it doesn’t matter how wide, flash or no flash, inside/outside, so was just curious..

JohnB57 wrote in post #17028967
I think this happens with quite a few wide aperture lenses.

perfect, thank you.

gjl711 wrote in post #17029196
Heck, the 50mm f/1.4 isn't all that spot on at 1.4. I tend to use it as a MF lens.

Thanks for everyone’s answers, being it’s a cheap little lens, seems it acts similar to everyone that uses it.
FYI I am spending more time refining my picture taking abilities, and more or less second guessing myself..

Get some more light on that in lieu of the flash. If you have to use flash, then it could be that the lighting is a bit too low to get a perfect lock. Move that outside perhaps onto a patio table or something and try that again without the flash. Also, did you set the AF point manually to center point before the test, or are you allowing the camera to choose points?