Does the iPhone 3GS constantly pre-cache photographs? | Hacker News Reader

Does the iPhone 3GS constantly pre-cache photographs?

lonelysandwich.com

23 pointsmcantor16 comments

Interesting.

I pointed my iPhone 3GS at my (pretty neat) digital watch and tapped the shutter release the instant I saw the seconds display change. I did this 5 times. Each time, the seconds display in the photo was from just before it changed, and definitely before I tapped the button.

This is a great idea, but it's a little strange that the photo that got stored was consistently from just before I had actually tapped the button rather than just as I tapped it. Either there's a hard-coded time compensation that's too generous (in this case longer than my hand-eye reaction time), or there's some logic at work that tries to intelligently weed out significant visual changes that occur at roughly the same instant that the shutter is released.

From what I've heard, the iPhone does some pretty cool accelerometer processing behind the scenes to find the frame which is the least blurry. From this post, it sounds like it might be storing images for processing before you trigger the shutter, creating a buffer around when you wanted the shot. This makes a lot of sense, especially since the act of pushing the soft shutter button moves the device and could cause a blurry photo.

Casio (and i'm assuming others) have this as a feature already. Haven't seen it marketed in a cell phone yet though. Under the features tab it's the "PRERECORD CS" - storing a buffer of 30 photos.

http://exilim.casio.com/products_exfc100.shtml

Targeted at parents watching children's sporting events/not wanting to miss a moment.

I'm sorry to break it to you, but it's just a mere side effect of iPhone being slow at processing picture. iPhone freeze screenshot is taken separately from the full resolution image, so there is always a difference. You just happen to get lucky to have the one that is better suited for you.

Take a look at this site - www.snapturelabs.com. They do some pretty good work with the iPhone camera. Their quickview feature will help you do your comparisons easier. Give it a shot and let me know if I'm right. ;)

I say this not only because of the new focus and exposure controls that can elevate my pictures from snapshots to photographs

Yeah, who needs a good lense?

its not pre-caching anything. You can easily verify this by adjusting the light level really quickly. It if was taking photos from the by-gone video stream the exposure would be off in rapidly changing light situations. The shutter lag seems evident to me when I tried shooting an analog clock. Much of the perceived shutter lag is actually post processing the image to something that it can display. (remember the sensors on digital cameras produce a format that need some decent number crunching before it can be rendered.

All this said, the camera on the iPhone 3GS is mediocre at best. Compare it to any p&s produced in the last couple of years and you'll be sadly dissapointed. By the time Apple are at iPhone 7 it should be good enough for anything more than sleeping cute dogs.

By the time Apple are at iPhone 7 it should be good enough for anything more than sleeping cute dogs.

Unless the lens and the path that the light takes on its way to the sensor gets larger, I doubt this will happen.

I think you are right. I tried it and it takes the snap the very millisecond you click on it which means it is caching it. Awesome!!!

Why does that mean there's caching? I tried it and it was exactly on, not _before_ the shot.

Because usually there would be some lag time for the camera's electronics to actually process your actions and finally snap the shutter.

My SLR has no lag time and there's no caching there. It can just be "fast" too. Simplest explanation is always the best, and such.

SLRs work much differently and the lack of a delay is actually one of their selling points. A bit more on that topic:

http://www.nytimes.com/2007/05/10/technology/10basics.html

Those fast electronics cost extra time and money to design and build.

Nice! It's one of the perpetrators of You Look Nice Today, but this isn't, as I expected, a joke.

Mind completely blown. And yet another example at how far ahead Apple is over AT&T (Apple's building stupid awesome hidden features while AT&T can't even provide basic voice service).

Every time I think of ditching my iPhone I get reminded how far ahead the device is over everything else out there.

This is not new. Cool, but not new or a sign that Apple is "far ahead". Sony Ericsson was doing this years ago. They would even let you pick from a few frames in case you missed the action.

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