As of 2 days ago, Rs 300.
By Indian standards, that’s a lot to pay for a camera (especially when you pay it, and then see everyone else whipping out their mobile phones to take photos. For free). To put it in context, a local ticket to the nearby Red Fort costs Rs 10, and even a foreign ticket costs Rs 250, so, yes, Rs 300 is pricey.
The ticket looked doctored, but since there is a printed sign up, also quoting Rs 300, there was nothing to do except pay up.
And I did get smashing photos.
By the way, there is no point in saying you will put your camera away and not use it. If you have a camera, you either pay the fee or deposit it with the mosque authorities before going in.