The Sigma 20mm f/1.8 D EX DG Aspherical Lens has a clutch-like system for switch between AF and MF modes. The system is very similar to the Sigma 105mm f/2.8 EX macro lens I reviewed previously. You push the manual focus ring forward to disengage the focus ring for auto-focusing. For manual focusing, you pull it toward you to engage the clutch. When the ring is set to AF, you can rotate the focusing ring all you want, you won't change the focus on the lens. When the lens is auto-focusing, it also doesn't effect the position of the manual-focusing ring. The manual focus ring is wide so there is no chance that you'll miss it in operation.
Return and Tax Policies
If you are not satisfied with your order and wish to initiate a return, please contact us via firstname.lastname@example.org. All returns must be accompanied with an RA number assigned by a Sixth Avenue Electronics Express representative. Products must be in Brand New condition, including the manufacturer's box with all included accessories. We will not accept any returns without the recorded serial numbers and upc numbers intact on the box. Returned items will be subject to a restocking fee of 5%-20% of the total price. Shipping price is not refundable. The buyer is responsible for shipping charges to return an item back to us. If an item arrives Damaged, please contact us immediately. We will file a claim with the shipper, and ship a replacement as soon as the claim is approved (between 1-6 business days). We hope items never arrived damaged, but unfortunately it does infrequently occur. We thank you in advance for working with us. Certain products are not eligible to be returned at all. Those include hygienic and personal care products (e.g shavers), a/v equipment, and special order products.
New Jersey residents are subject to sales tax.