My favourite lens, my Sigma 30mm f1.4, has devel­oped a prob­lem. Fre­quently it does not respond to auto-focusing, and it makes a high-pitched sound almost like it is strug­gling to focus.

The Sigma 30mm f1.4 lens is my ‘work­horse’ lens, mean­ing the one I use the most. When I was using a 35mm cam­era (Pen­tax MZ-S!), my favourite lens was a 50mm lens. I found a prime/fixed lens encour­aged me to move around and exper­i­ment with view­points rather than be lazy and zoom from a sin­gle point.

With a dig­i­tal APS-C sen­sor with a 1.6x mul­ti­plier, a 30mm lens deliv­ers approx­i­mately the same as a 50mm lens on a 35mm film camera.

Pub­lic pay tele­phone in Santa Mon­ica, California

I have been very pleased with the results, being the sharpest out of any lens I have, and the lens hood makes it look for­mi­da­ble. The chro­matic aber­ra­tion was very low, and if any­thing was vis­i­ble it has always been easy to remove with Adobe Lightroom’s chro­matic aber­ra­tion correction.

It also works great when tak­ing long-exposure pho­tographs at night. It cre­ates pleas­ing star effects through its 8 blade octag­o­nal diaphragm:

Street scene at night in Santa Mon­ica, California

The large max­i­mum aper­ture of f1.4 is great for low-light and sit­u­a­tions requir­ing high shut­ter speeds. F-stopping writes about this. I took this pho­to­graph as the pas­sen­ger of a car trav­el­ling around 60mph on a dull Eng­lish day, and it still came out very usable:

Hunters gath­er­ing at side of a road in rural Not­ting­hamshire. Crop of a pic­ture taken at 60mph

A pho­to­graph using avail­able light in a bar also came out well:

Peo­ple at Bar Eleven

And finally I found the full-time man­ual focus very use­ful. This allowed me to refo­cus even if aut­o­fo­cus was switched on. Usu­ally if aut­o­fo­cus is acti­vated, a lens doesn’t allow you to man­ual focus and you can feel the focussing motors giv­ing resistance.

You can find an in-depth review of the Sigma 30mm f1.4 EX DC HSM at Ken Rockwell’s web site.

I’m going to con­tact Sigma Imag­ing UK sup­port, and fin­gers crossed they will be able to resolve the issue as I would like to get pho­tograph­ing again