While not technically a liturgical question, lax practice on this matter is so widespread that we include it here.
It is categorically forbidden for any person, of any rank, to take photographs within the Holy Altar without express, advance permission from the Bishop (whether or not he is present at the Divine Service), and which will only be granted for a single occasion at a time, and only for the most extraordinary of circumstances (e.g. an ordination).
It has become too commonplace in our day and age to ‘live’ so extensively through and in our technology, that we lose sight of the need to be wholly, undistractedly, piously present in important moments of life. Service within the Holy Altar is a work of the highest spiritual significance, and it is belittled by the over-use of photography in this most sacred of spaces. Moreover, that which takes place in the Holy Altar is meant to be experienced by the Christian faithful in a liturgical setting, through the opening and closing of the Royal Doors, the processions and exclamations, etc. — none of which is maintained when the sacred activities of the Altar are simply laid bare in photographs, outside of that sacred experience. We must strive to do better! While there are legitimate moments when the Bishop might bless a few photographs to be taken in the Altar as memorials of significant occasions (e.g., once again, an ordination or significant event in the life of a parish), on all other occasions the Holy Altar should be a place wholly devoted to Divine Service, without the worldly distraction of photography.
It should go without saying — but again, widespread laxity requires that we say it — that this likewise means that the use of mobile phones within the Altar is also categorically forbidden for all persons, of any rank, including the checking of text messages or other ‘silent’ activities. Mobile phones should not even be brought into the Altar; but if they are, the must be switched completely off before entering in, and not switched back on until after one has left the Altar.
(The only exception to this rule might be a Priest who is monitoring a life-or-death situation of a parishioner, and wishes to check on his/her status if the person is near death, so that s/he can be prayed for appropriately; but apart from this exception, this rule applies to Priests as much as it applies to everyone else.)