Street photographers tend to like their cameras small and discreet, but Olmos is happy with his full-size, full-frame DSLR, and he carries no backup except an old iPhone 4 with a shattered screen. He uses the same DSLR for both his day job and his creative street photography, and the only thing he changes is the lens: Whereas he might use a range of focal lengths for newspaper portraiture, he sticks to a small, fixed wide-angle lens when he's on the street. Specifically, Olmos uses a 35mm lens, which is ideal for street photography since many photographers feel it comes close to matching the eye's natural field of view. (Note: If you're using a DSLR with a smaller, APS-C sensor, you'd need something like a 24mm lens to get a similar field of view.)
"Olmos uses a 35mm lens, which is ideal for street photography since many photographers feel it comes close to matching the eye's natural field of view."
The bulk of a single-lens reflex (SLR) camera is largely unavoidable. It's a by-product of the mirror-and-prism system that redirects light from the lens into the viewfinder, thereby allowing the photographer to see exactly what the lens sees. If you strip the mirror out of a digital camera, you end up with a "mirrorless" compact -- a design that benefits from being more portable, but which can't give you an immediate, optical view through the lens. Mirrorless compacts usually have electronic viewfinders instead of optical ones, producing a TV-like image of what the digital sensor sees.
It's also true that when you shrink a camera down, you reduce the room available for physical knobs and dials. The layout of the manual controls on his Canon 5D Mk II is what first made Olmos fall in love with it. In his opinion, Canon's design makes the best use of his right-hand thumb -- a digit that was once enslaved for the purpose of winding film, but which today is capable of making rapid adjustments to exposure. In turn, these manual adjustments lie at the heart of Olmos' dark visual style.