As of June 2010, according to the Rules of Conduct of the New York City Metropolitan Transportation Authority, photography is legal in the subways of New York City.
Restricted areas and activities.
3. Photography, filming or video recording in any facility or conveyance is permitted except that ancillary equipment such as lights, reflectors or tripods may not be used. Members of the press holding valid identification issued by the New York City Police Department are hereby authorized to use necessary ancillary equipment. All photographic activity must be conducted in accordance with the provisions of this Part.
Go to Rules of Conduct.
Scroll down to 1050.9c, number 3.
Subway stations, platforms, and cars, are dim.
Use a high ISO setting.
Go to ISO.
Or, a fast lens.
A fast lens lets in more light.
If you're using a digital SLR, get a 50mm lens.
Go to 50mm Lens.
A fast lens on a point-and-shoot camera is f/2.8.
Many people dislike being photographed.
Such people may feel especially cornered in a subway car or platform.
Therefore, you need to be sensitive.
The police may not be well informed of the Rules of Conduct.
No Photo Ban in Subways, Yet an Arrest by Jim Dwyer
Set the camera white balance to the florescent tube icon
Go to White Balance.
Flash will attract attention to your photography, of course.
If you have a digital SLR, set the exposure mode dial to P (Program).
Some Canon cameras have a no-flash icon on the exposure mode dial.
If you're using a point-and-shoot camera, press the lighting-bolt icon until you see the no flash setting.
If you're using flash, you can match the color of the light from the flash with the florescent lights in subway cars.
Use a green filter on the flash, and set the camera white balance to the florescent tube icon.
Go to Flash Filters.
Bruce Davidson photographed on the subways for over two years back in the 1980s.
Rather than doing candids all of the time, he often asked the people if he could photograph them.
Davidson showed them examples of his work and offered to send them a print.
He said that people usually got bored with him and went back to doing what they were doing.
Go to Bruce Davidson's Subway.
Walker Evans hid his camera.
Many of the strategies used by street photographers applies to subway photographers.
Go to How to Photograph Strangers.