inconsistent focus on my 30mm 1.4

[CanCanTinTin]

Hi All,

I have recently acquired a Sigma 30mm 1.4 and was less than satisfied with its performance.

I face some issues with its inconsistent auto focus accuracy. At near MFD (i.e. 50cm), the focus was spot on. At range more than 3M, it back-focus by quite abit, resulting in OOF images. However, when using Live view, the focus was spot on.

Thus, I would like to consult fellow CSers on whether its a body issue or lens problem. I did some research but cannot draw a conclusion.

Thank you everyone.

 

[mds80]

Send it to the service centre for calibration

 

[SamTac]

Take the same object with the same distance on tripod & handheld. If on tripod can spot on then it due to ur shaky hands.

 

[CanCanTinTin]

Take the same object with the same distance on tripod & handheld. If on tripod can spot on then it due to ur shaky hands.

I did a test on multiple objects in very good lighting conditions, all of them shows similar result. I doubt its due to to shaky hands.

I'll do a more comprehensive test when I'm free. Thanks for the reply.

Cheers.

 

[rhino123]

I did a test on multiple objects in very good lighting conditions, all of them shows similar result. I doubt its due to to shaky hands.

I'll do a more comprehensive test when I'm free. Thanks for the reply.

Cheers.

If in doubt... always bring your lens to the service center to do a test. They have the equipment readily available and if your lens is covered by warranty, you should get calibration free anyway.

 

[SamTac]

I did a test on multiple objects in very good lighting conditions, all of them shows similar result. I doubt its due to to shaky hands.

I'll do a more comprehensive test when I'm free. Thanks for the reply.

Cheers.

For f1.4, a little shake make a diff. Learnt it from sigma service center.

 

[CanCanTinTin]

For f1.4, a little shake make a diff. Learnt it from sigma service center.

I am consistently getting the same result. And when I'm about 4M from my subject, I need to -10 micro adjust on my KR to get a in focus picture. at closer range, AF was spot on. Guess Sigma Svc Ctr is my only choice. :sweat:

Thank you everyone for your inputs.

Cheers

 

[hawthorne907]

I am consistently getting the same result. And when I'm about 4M from my subject, I need to -10 micro adjust on my KR to get a in focus picture. at closer range, AF was spot on. Guess Sigma Svc Ctr is my only choice. :sweat:

Thank you everyone for your inputs.

Cheers

It's normal. I took a few days to do some intensive tests with my micro adjustment before reaching -7 and from then on its been awesome

 

[CanCanTinTin]

It's normal. I took a few days to do some intensive tests with my micro adjustment before reaching -7 and from then on its been awesome

Hahaha.. but I got a more serious problem. when my subject is close, the focus is spot on.. when it's further away, I need a -10.

I can only use this as a headshot lens at the moment. haha. Otherwise, liveview can overcome the above problem too.

 

[Daoyin]

It is not uncommon for this model to focus well at some distances while making a mess of it at others.