'''''Flash at dusk to evening is quite intense and will blind ....... It is so much of a concern, at known tourist spots there are rangers out who WILL confiscate any photographic equipment before you get near the beach ....
Brumby I take your point , any living thing can be upset with flash especailly in low light. However the discussion was about macro and flys ect and flowers do not have that problem. I will also give my weekends play in another post.
Agreed, it's not a problem for flowers nor would it worry me about insects. Just a bit of 'general' information - to help give an appreciation of one aspect of flash usage that may not be obvious. Photography is usually quite a benign activity - but, like most things, there are exceptions.
A couple of other points using flash - regarding distance:
* The effective distance for flash is the distance from the
flash to the subject - not from the camera to the subject. Usually these are the same, since the flash is most often located with the camera, but there are situations where you might want a flash located some distance from the camera. I won't go into the details here as this steps into another level of discussion.
* If you are up in the grandstand for a night-time event - sporting, concert, Olympic ceremony or whatever - your flash isn't going to do anything other than light up the backs of the heads of the people in front of you. Flash intensity drops off according to the inverse square law - which simply means that if something is twice as far away, there is only one quarter of the brightness. Once you get past a certain distance, there is not enough light to give you a good exposure and the subject will just get murkier, the further it is away. This distance will vary with the flash unit and the capabilities of the camera, but your average setup will struggle from around 20 metres (Shyer - is this still about right?). There is one good thing - if a TV camera is around and focussed on the grandstand when a celebrity or other 'interesting' thing happens - the resultant storm of flashes makes for a very attractive 'sparkly' effect in the crowd.
* Close-up, flash can be just too bright for the camera to cope. I think someone said this earlier (was it Shyer?) - just keep a plain white handkerchief handy and hold it across the front of the flash to reduce the intensity. You can adjust the amount of reduction by how many layers the hanky has been folded.
Only this last point is of any relevance for macro photography...