It’s been cloudy and rainy the last few days here in Tucson, so with no real work taking place, I decided to do a stamp shot comparison using the fabulous Sony 85mm F/2.8 SAM against the Sigma 85/1.4 HSM (just reviewed) and the Sony Carl Zeiss 85/1.4. Obviously, there’s a two stop difference in light gathering ability, but I know the little Sony 85/2.8 is super good wide open, so I wondered how it would fare against the faster, and much more expensive F/1.4 lenses.
Astonishingly, the Sony 85/2.8 is optically superior to both the fast lenses at F/2.8-4; at smaller apertures the results vary depending on location within the image, like corners, centers etc.
Since the diminutive and inexpensive Sony performs very well wide open, it makes a great walk around lens for hand-held low-light shooting. You might think a larger aperture is always better for dark conditions because it allows you use lower ISOs right? Have you every tried photographing subjects (or worse, moving subjects) in low-light at 85mm, F/1.4? It’s mostly a game of luck, the depth of field is very slim; it’s hard enough to focus properly in daylight! I normally use F/2-2.8 for hand-held low-light shots using a focal length around 50-85mm, it gives me a little more DOF to play with.
You’ll spend $800-1200 extra for the larger, heavier and faster F/1.4 versions. Although two stops of light is huge, there are also huge compromises in designing those lenses, that’s why you pay big bucks and get only marginal (if any) performance gains.