Apple - What are the shutter speed and ISO ranges for the iPhone 4S camera?
You can scrape that information off photos on flickr taken with an iPhone 4S:
http://www.flickr.com/cameras/apple/iphone_4s/
Here are a few examples of extremes. The dark end seems to show a max ISO of 800 and max shutter of 1/15, which several dark photos agreed with, and none of the ten I looked at went further, so here are two examples:
http://www.flickr.com/photos/funinthegym/6328079422/in/photostream/
0.067 sec (1/15)
800
http://www.flickr.com/photos/matthewthecoolguy/6534661585/in/photostream/
0.067 sec (1/15)
800
Looking at very bright photographs, I saw a few claiming very high shutter speeds (1/9259 and 1/2600) but none of them matched the same exif format for the shutter speed field as the rest of the iPhone 4S photos I reviewed, suggesting that these fields were modified in post processing. The lowest shutter speed I saw that matched the format of the other 4S exif files was 1/1842, and the lowest ISO was 64:
http://www.flickr.com/photos/67660035@N04/7110241863/in/photostream/
0.001 sec (1/1842)
64
http://www.flickr.com/photos/xiahou/6298147263/in/photostream/
0.001 sec (1/1842)
64
This should answer your question for highest and lowest ISO, and highest and lowest shutter speed. Keep in mind I only sampled a few dozen photos on flickr, it's possible I missed the ends of the ranges.
A random sampling from the "interesting" section, showing the mid range of shutter speed and ISO combinations:
Shutter speed ISO
0.008 sec (1/122) 64
0.05 sec (1/20) 200
0.008 sec (1/120) 100
0.002 sec (1/550) 64
0.025 sec (1/40) 64
0.002 sec (1/464) 64
0.004 sec (1/242) 64
0.042 sec (1/24) 64
0.059 sec (1/17) 800
0.067 sec (1/15) 640
0.006 sec (1/170) 64
0.067 sec (1/15) 640