problem focusing with my 50mm f/1.8

[anything you synth]

when i use autofocus, everything comes out blurry. the pictures look fine on my lcd, but when i upload them to my pc, they are worthless. this lens sucks at focus speed. seriously.

 

[LaFoto]

That lens focuses less willingly than any of the others I have. Agreed. But once it did and I got the "Beep!" that shows me that it did focus, I get clear photos! But yes, it is the one that takes the longest and therefore requires a bit of patience (or to be used manually!)

 

[dxqcanada]

What camera are you using ?

 

[usayit]

also post examples and exif data.

Is the whole frame blurry or just focused on the wrong plane as you intended?

Shooting wide open? Many have a habit of "leaning" into their shots.. remember shallow DOF.

 

[anything you synth]

canon 450d

 

[benhasajeep]

If they are looking good on the LCD and bad on the computer, your not getting critical focus then.

Have to determine if its motion blur (camera shake), front or rear focusing.

Is anything in the scene in focus?

Take a picture of something at an angle like at 45 degrees (picket fence would be perfect). Use the center focusing point on an obvious point (something you will remember). Then go to the computer and see the results. Make sure you use a good fast shutter speed. And a couple different aperture settings.

The point you centered on should be in focus. And the focus depth should increase as you close down the aperture. Now if you find the slat that is in focus closer to you, the lens is front focusing. If its further back than the centered spot, its back focusing.

Edit: I saw the pic after I posted. Was the subject moving away from you? Looks like the aperture was fairly opened up too. That would give smaller focusing depth. What was the light like at the time. Picture is under exposed or its light is not that bright.

 

[dxqcanada]

[hmm typed too slow ...]

Are you saying that the image appears sharp in the LCD when you are using LiveView ?
Does the image appear sharp in through the viewfinder ?

Does the AF indicator state that the focus has been achieved ?

 

[anything you synth]

pic posted ^

as for live view? no, i dont use that.
it appears sharp after i have taken the picture and it's displayed on my lcd.

yes, AF indicator blinks

 

[LaFoto]

Never trust the tiny pic on the back of the camera. It is so small, anything will look sharp there (or at least close to sharp), you cannot really tell if it really IS sharp until you see the larger pic on your computer.

The example photo looks like you had only VERY low light, you took this while moving, and the subjects were moving away from you. Assuming you had opened the aperture to the maximum f1.8, you have a very shallow DOF, so your subject may too easily and fast have moved out of your narrow range of focus before you even took the photo. And assuming the light was really low, camera shake might also have come into play...

 

[dxqcanada]

Can you take a photo of some well lit object right now, and post the image.

 

[benhasajeep]

Also what focusing mode where you in - Single, AI Focus, AI continious?

 

[anything you synth]

one shot AF.

 

[benhasajeep]

Is that the only pic or is it consistantaly producing oof pictures?

I am not sure of the XS monitor's dot count but its much lower than a computer monitors. Pictures can look in focus on the camera. But once you open the file on the computer you see it wasnt that good after all. It may be a combination of low light (slow shutter) and moving subject. And it just missed. It happens.

 

[anything you synth]

i'm well aware that pictures that look clean on the lcd, but wont look the same on the pc. its just frustrating that all these pictures i expected to come out good, were crap.

i think you're right about low light and slow shutter. is there another autofocus mode that would work better?

 

[dxqcanada]

I would think that you could get an acceptable image with a 50mm lens @ 1/80s.

I have hand-held my 50mm at lower speeds than that.