Sigma 50mm 1.4 soft?

Started Apr 21, 2013 | Discussions thread
awaldram Forum Pro • Posts: 13,161
Re: Sigma 50mm 1.4 soft?

Aidan Gibson wrote:

Hi there,

I bought the sigma 50 1.4 a few weeks ago and I have noticed I don't get any sharp pictures till f2.0? Is that normal or did I just get a bad copy? Could it be focusing problems? Do I have to send it in, because as you may know K-5iis only can adjust to +and - 10.

Any thoughts, can anyone help?

When you go below the sensor native reading ability calibration is critical f`1.4 is below this level.

As Mike said without images we cant tell you anything as your softness may be related to PP or even incorrect expectation.

I take it from your comment on +-10 your not really sure what or how to calibrate your camera.?

This is the easiest and IMO most accurate method, As it caters for non 50/50 Front back focus (where most 'have a go' fail to calibrate correctly and destroy camera calibration).

Moire AF tuning

Don't forget to calibrate at an appropriate distance min 25x focal length ideal 50x focal length.

So for your lens 50mm X 25= 1.25M Min and ideally 2.5Metres.

On the subject of do I have t send it in.

You cannot send it to Pentax as they will reject the warranty repair because of the 3rd party lens so if you are 'sending' it in it will have to be to Sigma.

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