Sigma 30mm 1.4 DC HSM woes

[Xanctum]

Hello again,

Got my 30mm in the mail the other week and admittedly haven't really taken a lot of shots with it, but the pones I have taken all seem very OOF. I did the battery test on it and it seemed pretty good, but when it comes to shooting with it handheld I can't seem to get it to focus properly.

It may just be me, but some shots I tested out and really tried to nail here at home all turned out blurry. Could this just be a front focus issue (being objects in front of my focal point in focus and focal point OOF I think is front focus) and would you recommend I sent it in to get callibrated? If I did send it in would that affect my other Sigma lens that seems pretty spot on? I love the lens but thinking I may let it go and try a different prime. Thoughts?

[rjd]

Always good to post some examples. Is it nikon , canon or?

Canon you can use dpp to show where the focus point is.

Remember usually the point is bigger than the box in the viewfinder and will grab things closer if it can.

Also any focus and recompose at f1.4 will typically go wrong.

[riley989]

You can print off focus charts to test if it is back or front focusing.

[mesodan]

How old is the lens? Older third party lenses often don't focus too well on newer bodies.

[Xanctum]

First time adding pics. Meant to the other night, but got pulled away before I could. These were shot with my 60D. My camera says the first shot AF just above her left "eyebrow", second shot just under left nose hole, and third shot left eye. Did buy the lens second hand and the guy told me it was about a year and a half old. Let me know what you think.

[JED]

None of the focus points you have described sound like very good targets. As described they all seem to be on lower contrast areas. Also the stated focus points seem to be off centre which with a fast lens increases the chances of error. Having said that it looks like a general case of front focus to me. Without manual focus tuning you do not have many options to resolve the problem other than live view focusing or being very careful with technique.
What focus mode were you using?

[Xanctum]

I was using One shot focusing and I do have a hard time with Manual focus tuning. I guess I may just need to learn more about focal points and where to land them. Admittedly I am very novice and this lens has shown my pitfalls thus far.

[Desmond]

I would suggest having the camera on a tripod and perhaps take photos at various points along something like a wooden fence at an angle so you can see which focus point lights up and where the actual focus is.

[rjd]

1 & 2nd could easily be grabbing closer subjects, grass, snout etc.

3rd looks way off

Are you using a single point in single focus mode?

[Xanctum]

Yes to both rjd. She was standing still and hadn't moved in the last one. I can see the lens grabbing something closer in the first 2 shots. Here is one I took yesterday with the focal point right in the middle of the old man in the middle shot at 1/8000 f2.0:

(Not sure if I am posting these correctly. Limiting the size to 2000k out of lightroom.)

[sooshee]

Just building upon Desmond's idea, take a picture of a ruler at an angle with the camera on a tripod set to widest aperture. Remember which measurement you focused on and compare it withe the image. You should be able to work out exactly how much the focus is off.

[Xanctum]

Here is one at MFD on the 900 on the left side. With this result I can probably assume I need much more practice with my focal point decision making or something.. not entirely sure what I do wrong when actually taking photos..