Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Brand | Product Name | Focal Length | 35mm EFL and equivalent aperture | Max. aperture |
| --- | --- | --- | --- | --- |
| Olympus | Olympus M.Zuiko Digital ED 12mm f/2.0 | 12mm | 24mm f /4 | f /2.0 |
| Olympus | Olympus 15mm f/8.0 Body Cap | 15mm | 30mm f /16 | f /8.0 |
| Olympus | Olympus M.Zuiko Digital 17mm f/2.8 | 17mm | 34mm f /5.6 | f /2.8 |
| Olympus | Olympus M.Zuiko Digital 17mm f/1.8 | 17mm | 34mm f /3.6 | f /1.8 |
| Olympus | Olympus M.Zuiko Digital ED 45mm f/1.8 | 45mm | 90mm f /3.6 | f /1.8 |
| Olympus | Olympus M.Zuiko Digital ED 75mm f/1.8 | 75mm | 150mm f /3.6 | f /1.8 |
| Panasonic | Panasonic Lumix G 14mm f /2.5 Asph. | 14mm | 28mm f /5 | f /2.5 |
| Panasonic | Panasonic Lumix G 20mm f /1.7 Asph. | 20mm | 40mm f /3.2 | f /1.7 |
| Panasonic | Panasonic Lumix G 20mm f /1.7 II Asph. | 20mm | 40mm f /3.2 | f /1.7 |
| Panasonic | Panasonic Leica DG Summilux 25mm f /1.4 Asph. | 25mm | 50mm f /2.8 | f /1.4 |
| Panasonic | Panasonic Leica DG Nocticron 42.5mm f /1.2 | 42.5mm | 85mm f /2.4 | f /1.2 |
| Panasonic | Panasonic Lumix G 150mm f /2.8 | 150mm | 300mm f /5.6 | f /2.8 |
| Schneider Kreuznach | Schneider Kreuznach Super Angulon 14mm f /2.0 | 14mm | 28mm f /4 | f /2.0 |
| Schneider Kreuznach | Schneider Kreuznach Xenon 30mm f /1.4 | 30mm | 60mm f /2.8 | f /1.4 |
| Sigma | Sigma 19mm f2.8 DN | 19mm | 38mm f /5.6 | f /2.8 |
| Sigma | Sigma 19mm f2.8 EX DN | 19mm | 38mm f /5.6 | f /2.8 |
| Sigma | Sigma 30mm f2.8 DN | 30mm | 60mm f /5.6 | f /2.8 |
| Sigma | Sigma 30mm f2.8 EX DN | 30mm | 60mm f /5.6 | f /2.8 |
| Sigma | Sigma 60mm F2.8 DN | 60mm | 120mm f /5.6 | f /2.8 |
Question:
What is the brand of the Sigma 30mm f2.8 DN, which has a maximum aperture of f /2.8 and a focal length of 30mm?
Answer:
Sigma