Having trouble with focusing with a f/1.8 lense

[jgomez65]

I bought the Canon EF 50mm f/1.8 II lense. It is great for low light enviorments, and DOF, however I find it very difficult to focus whenever I put the lense on f/1.8. I have gotten many indoor pictures completely out of focus. I am using a Canon 580EXII Flash for indoor photography, but still I am having problem with this.

Any tips on what I can do to solve this issue?

[i speak in math]

don't use it at f/1.8

[Krusty79]

Are focusing manually? If so, using Live View instead of your viewfinder may help you to see what is in focus.

[OsmosisStudios]

If you're indoors, you may have trouble in low-light condition with focusing because the camera simply doesnt have enough light.

[sk66]

I suspect your working distance is rather short. Combined w/ a very wide aperture the DOF will be VERY thin making focus very critical.

I personally think the wide aperture bokeh craze is a bit overdone and misguided.

[mshockley]

Originally Posted by i speak in math

don't use it at f/1.8

would really have to agree with this one. And if you've got that handy speedlight you don't really need that lens wide open like that do you? I'm all for the shallow depth of field/blurred background look, but you can still get that even if you stop that lens down a bit.

[inkista]

Aside from stopping down a bit, I'd also recommend selecting a single AF point and then aiming it at an area of high-contrast (ideally, a sharp edge where black meets white. Lettering is a good focus target). When you have the full AF matrix activated, the AF system can often latch onto something other than what you want as the subject of the image.