I often meet street photographers who refuse to shoot on the streets with an ISO higher than 200 because fear of grain. What may be a problem with this? Well if you are shooting with a high f-stop to get a deep depth-of-field (like f/8) your shutter speed will often be too slow.
How did the masters shoot their film?
Well in the early days of photography (late 1800’s to early 1900’s), street photographers were constrained by relatively slow films like ISO 25 film. But as technology advanced (and ISO 400 film became available) some legendary street photographers like Joel Meyerowitz and Garry Winogrand were pushing their ISO 400 film to 1200 ISO. This allowed them to shoot at the maximum shutter speed of the Leica’s they were using (1/1000th of a second).
A higher ISO adds grain and contrast. Not a lot of photographers like that. For me personally, even grain structure adds a peculiar charm, especially in my opinion it is suitable for street photography.
However now we are now blessed with technology and cameras that have ridiculously good high-ISO performance. We can shoot at ISO 1600 without seeing any noise. I even have shot with some new cameras that can shoot at ISO 25,000 with minimal noise. It is a brave new world.
If you are shooting street photography and want minimal blur and sharp photos, shoot with a high-ISO. Don’t be afraid to push your camera to 1600 or even 3200. Even if you are shooting street photography during the day.
Based on my experience you need a shutter speed of at least 1/250th of a second to photograph someone walking at a moderate pace (without them blurry). If someone is running, you want at least 1/1000th of a second.
Let me give you an example (for those with digital cameras that have fast shutter speeds): If you are zone-focusing at f/8 during the day in the sunlight (at ISO 1600) your shutter speed will adjust itself to probably be in the range of well over a 1/1000th of a second. However once you shoot in the shade, your shutter speed will drop to 1/250th a second (the minimum shutter speed to capture motion)– even with ISO 1600.
Don’t be afraid to shoot with ISO 1600 or even faster when you are shooting on the streets. It will better help you capture “the decisive moment”.