With the new HDR feature on the iPhone 4, a feature that came out of nowhere and surprised me, you can now take HDR photos on your iPhone and upload them to your usual services without any real effort. Rather than go into the quality of the software, something I plan on doing if I get the time, I thought I’d focus on just one aspect. If you don’t know how HDR works, have a look at my beginner’s guide. If you’re familiar with HDR, you’ll know that you have to take two or more photos (preferably three or more) and merge them using software to take the shadows from one photo and the highlights from another and to create areas of local contrast. What this means is that your iPhone 4 will take three photos (one normal, one under-exposed, one over-exposed) and merge them together, but if you want to take HDR photos of moving objects, you need to know how often it takes the photos. Well, from my reckoning, it takes the photographs every quarter or eighth of a second. If you look at the chronograph’s second hand, you can see that it featured in two of the three photos that were merged and the time elapsed was a quarter of a second with 1/100th shutter speed on the first photo.
I hope this is useful to some of you. Comments, as always, appreciated. Oh, and no, Macro HDR photos don’t usually work out well as the slightest movement is amplified by the closeness to the subject.