So is f/2.4 better than f/2.8? And f/2.2 would then be even better? I don't know much about photography but I'm curious to see what difference it makes
That's an amazing photo with some great depth of field. Is that the 4s?
RE depth of field, what's the next barrier towards getting SLR depth? (focused foreground/background with the blur visa versa)
Absolutely but as with everything a bigger aperture usually increases cost and size so there's a limit.
Also it's hard to directly compare aperture to another camera when the sensor size is different. For instance, the Nokia N8 has a f/2.8 lens but its sensor is larger than other camera phones so the total amount of light collected is more than other f/2.8 camera phones. Ditto for DSLR f/2.8 lenses against f/2.8 equivalents from smaller cameras. (This is actually flame bait material in many parts of the internet.)
2.0 is where the magic starts to happen though.
Some folks in here need to read a little photography 101 before making the blanket statement that it's a huge improvement. Yes, low light photos will be slightly better but it makes absolutely no difference in bright light.
Optics will have a far more significant effect on image quality than the fact that you gain about a 1/2 stop. Also keep in mind that as aperture increases, Depth of Field decreases and vice versa. That means the bigger the aperture you are shooting at, the less that will be in focus in your photo.
Now, that's fine if you are trying to a achieve an effect with a blurred background such as in my photo below where I wanted to draw focus to the front most parts of the scene. (f/3.5 here)
BUT, if you want the entire scene in focus you want to use a higher f/stop (f/11 here)
Since the iPhone lacks manual control much of this is a moot point since the device will do whatever it thinks is best to get a proper exposure, but if you want to learn about aperture here is a good article - http://www.digital-photography-school.com/aperture
Some folks in here need to read a little photography 101 before making the blanket statement that it's a huge improvement. Yes, low light photos will be slightly better but it makes absolutely no difference in bright light.
Optics will have a far more significant effect on image quality than the fact that you gain about a 1/2 stop. Also keep in mind that as aperture increases, Depth of Field decreases and vice versa. That means the bigger the aperture you are shooting at, the less that will be in focus in your photo.
Now, that's fine if you are trying to a achieve an effect with a blurred background such as in my photo below where I wanted to draw focus to the front most parts of the scene. (f/3.5 here)
[url=http://farm7.static.flickr.com/6064/6158932394_ae0d71d41d_z.jpg]Image[/url]
Niagara Falls Botanical Gardens by zerind, on Flickr
BUT, if you want the entire scene in focus you want to use a higher f/stop (f/11 here)
[url=http://farm4.static.flickr.com/3072/5707746168_6faea05961_z.jpg]Image[/url]
Place of Refuge - Big Island, Hawaii by zerind, on Flickr
It's a lot more complicated than just what I said but since the iPhone lacks manual control much of this is a moot point since the device will do whatever it thinks is best to get a proper exposure, but if you want to learn about aperture here is a good article - http://www.digital-photography-school.com/aperture
When I said higher aperture meant better depth of field, I was considering the guy was asking what makes your background more blurry, cause that's probably what he wants. It has to do with the style of the picture, not the quality. If what you want is a sharp picture, yes, good optics is what you're looking for. I never said a bigger aperture meant more depth of field, not sure who your photography 101 thing was targeted at.
And yes, aperture matters even in bright light. Your shutter speed will be much faster, meaning less blurry shots even in movement, and if the iPhone has auto ISO (not sure), it will be lower meaning less noise. Not that there's usually a lot of noise in bright pictures, but a lower sensivity never hurts.
Outside on a bright sunny day at f/1.8, if I don't lower my ISO too much I can almost run while taking shots and my pics won't be blurry.
And yes, aperture matters even in bright light. Your shutter speed will be much faster, meaning less blurry shots even in movement, and if the iPhone has auto ISO (not sure), it will be lower meaning less noise. Not that there's usually a lot of noise in bright pictures, but a lower sensivity never hurts.
I'm pretty sure you meant to say 'significant'.A .4 difference is significative. Photographers often pay hundreds more for a SLR lens that's faster by that margin.
Expect better low-light performance, less noise, less blurry shots, and shallow dept of field like that:
http://images.apple.com/iphone/includes/camera-gallery/downloads/IMG_1295.JPG
Everybody will agree that 2.4 is better than 2.8 if everything else is equal.
2.4 is faster. Drinks more light.
Better sharpness, creamier bokeh for portraits.
better in lower light situations.
etc