why favor 2.8 lens??


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Big aperture = big lens

And big lens = impressive lens

And impressive lens = "pro" photographer

"pro" photographer = impressed girls.

impressed girls = happy person. :bsmilie:
 

No wonder i'm not happy...


i shall go buy a big lens right away! thank you master! :bsmilie:
 

wats the size of 50 1.8 relative to 50 1.2 ?
f1.8 can fit into your pocket easily while the f1.2 is rather like the size of a large orange.
 

BTW,alot of the info you are looking for can be found using google.;)
 

the 50mm f1.8 gives you horrible and rough bokeh, but more dof. the 17-55 f2.8 gives better bokeh, 7 blades as compared to the 50 prime 5 blades.

Comparing the 50mm f/1.8 and the 17-55 f/2.8 at 50mm, how can an aperture of f/1.8 possibly give you more DOF than an aperture of f/2.8, at the same focal length and subject distance?

Horrible and rough bokeh?

I
beg
to
differ

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Sure there are lenses that produce better, smoother, silkier bokeh out there, but for its price point, there's no reason to complain, and it's not as if it produces truly horrendous OOF area.
 

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Nice examples by bro Calebk. Cheapo lenses may not mean they aren't good, it could also mean they are well engineered to reduce cost.

There are other reasons for getting lenses with larger apertures. Some people associate "fast" lens as the ability to shoot at faster shutter speeds thus freezing motion while maintaining good exposure. Another point to add on is the focusing speed, the camera always uses the widest aperture during AF to get the most contrast out of the scene, this helps the AF processor do its job correctly. Some photographers might couple teleconvertors/extension tubes to their lenses for longer optical reach and shorter focus distance respectively. This also means cutting down light entering your camera. The camera's AF system requires a certain amount of light for it to do its job. Therefore, having a wide aperture not only allows for faster focusing, it also maintains AF functionality when teleconvertors & extension tubes are attached.
 

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sorry calebk, was doing speed typing. Yes its gives thinner DOF instead of more DOF. my bad.

But when the 50 f1.8 prime is stopped down to 2.8, dont u think the one from 17-55 or 50mm f1.4 stopped down to f2.8 will give smoother bokeh?
 

To answer the TS, its all about stopping motion.

Try shooting indoors...subjects like ur kids running around, dogs, cats etc.

You can learn the difference instantly instead of reading through so many posts.

Moral of the story: shoot more to learn

Just my 2 cents.
 

sorry calebk, was doing speed typing. Yes its gives thinner DOF instead of more DOF. my bad.

But when the 50 f1.8 prime is stopped down to 2.8, dont u think the one from 17-55 or 50mm f1.4 stopped down to f2.8 will give smoother bokeh?

It is unfair to compare them tit for tat, because just one look at how much more you are paying for a 50/1.4 or 17-55/2.8 compared to a 50/1.8 is enough to justify their better quality; for it's really low price point and aperture that is 1 1/3-stop faster than a f/2.8 zoom, no one's really complaining man.

I find myself shooting at f/2 or f/2.2 most often with the 50mm f/1.8. Why buy such a fast lens only to stop it down to f/2.8 almost all the time (unless you need the DOF)
 

okay, this is really what i wanna know about 2.8 lens.

FIRST POINT

okay i know its faster. simple explanation: as you can go down to lower aperture (2.8 compared to 2.5 and above) , you can use higher shutter speed to freeze the motion.

HOWEVER, i have 3.5-5.6 lens and its fast enough to stop the motion. i can use speed up to 1/500 in the afternoon and it can freeze the motion of taxi.
so why do we need 2.8??? like freezing the speed of sport car?? and how much faster is 2.8 really??



SECOND POINT

i am also confused about 2.8 aperture VS VR (vibration reduction).

people said, with VR, we can shoot objects in low light situation. okay, i get the logic.
because when there is low light, you want to make your shutter speed lower to allow more light to come in. but as you lower your speed, and if you shake your hand while the camera taking pics, then you will blur the image. in this case, VR will negate your hand movement. okay, i got it.

but technically 2.8 can do the same thing then but in a different way ofcourse.

2.8 can allow you to have lower aperture so that you have more light to come in.

so in low light situation, which one is better then?? 2.8 or VR?? this is so freakin confusing.


please enlighten me everybody as i really need to know this to upgrade.

thanks.

Shallow DOF ;)
 

Shallow DOF, agreed. Photography is the art of exclusion, shallow DOF helps isolate subjects from distracting backgrounds. Even shallower DOF helps isolate objects in a foreground. Hehe, not counting the plus of higher shutter speeds...
 

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