I am going to guess 3 seconds, what do you say Elisha?
Sony A700_____________Minolta AF 50mm. F/1.7
Minolta AF 70-210mm F/3.5-4.5 Tamron AF 17-50mm F/2.8 XR DiII LD Asp. [IF]
Tamron SP AF 70-200mm. F/2.8 DI LD [IF] Macro
Tamron AF 70-300mm F/4-5.6 Di LD Macro 1:2
Tokina AF 28-70mm F/3.5-4.5
Tokina AF AT-X 80-400mm F/4.5-5.6 http://flickr.com/
yes handheld, it was a choice i made, Don had given me a range last time i was shooting fireworks. I did some test shots and felt i was getting the best results around there. the globe was taken the same different aperture but i was happy with the deatail. got a lot of nice shots and some of the globe were overesposed in the bright spots but overall happy with the results.
Sony 18-250mm Lens
Sony 50mm f1.4
The thing about shooting fireworks is to get as much action as possible on the one frame and that means recording the "streaks" as well.
I think you did a pretty good job handholding @1/25th but to progress you need a tripod to increase the shutter times to 1sec and more without camera shake killing the image.
A black background makes no impression on the sensor so you can leave the shutter open as long as you like and the black will still be black.
Smoke and ambient light can affect the background. I get a lot of that from community fireworks where we had them, so there certainly can be a limit to how long you can leave that shutter open. Each shot actually can be different. Longer than 1.5 seconds I find detrimental ... but, sometimes necessary to get much of anything. You get what you get, more often than not.
You can see it here, with this shot, which is one of my personal favorites:
Don Schap - BFA, Digital Photography A Photographer Is Forever
Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography. flickr® & Sdi