Can someone answer whats the point of getting a FAST Lens when..

[black.ink]

the user is almost always recommended to use it STOPPED DOWN in actual practice!!!:angry:


...from a glamorous F2.8 to a paltry F4...:cry:
*fair remark: except the rare few that do actually 'perform' at F2.8 (or lower)


isnt that sort of like buying an expensive suit, but putting aside the classy pants and coat to wear only the white shirt to work, becos the classy pants and coat are somewhat PURPLE

 

[Astin]

Hmm, to me fast lens means f1.4 leh.

 

[overdodo]

depends on your focal length.
f/2.8 might be considered slow at 50mm, and f/1.4 considered fast.

while at longer focal lengths (200+mm ? ) f/1.4 is unheard of ?
(at least to me)

I think the idea of a fast lens is best seen in the context of sports photography.
Although f/2.8 and f/4.0 is only 1 stop away, this might be the limiting factor when you are trying to shoot at 1/1000s for sports. If its gloomy, pushing the ISO to 1600 at f/4 might not be enough to shoot even at 1/500s. As such, this one stop with f/2.8 might just help you take such shots.

In brighter, situations, it allows use to shoot at 1 iso stop less, reducing noise.

Another thing would be that at f/2.8 the depth of field is reduced, thus creating that "sports photography" feel, with the clear subject, and blurred out background.


cheers

 

[Zerstorer]

the user is almost always recommended to use it STOPPED DOWN in actual practice!!!:angry:

Whose recommendation? You use what you need.

 

[black.ink]

well yes to some fast means 1.4 or less. Doesnt matter, principle applies.

a lot of reviewers (do a quick search on any favored item) recommend to stop down.
heck, a lot of CS-sers recommend to stop down.

I make me think thrice abt getting so-said FAST lens (again fair remark: except those that actually..blah blah blah)

 

[foxtwo]

just because you fix a fast lense on doesn't mean you shoot every image on its largest aperture. Actual practise would mean normal usage, advising you to shoot stopped down to get the best image quality. BUT when you need to shoot fast then shoot fast and you would know what are the things you give up on.

use some common sense. why else would lense manufacturers spend big money building fast lenses and photographers paying big money to buy them.
are you willing to give up shooting images in low light because you cannot get the best quality image shooting at f1.0-f1.8 (35mm)?
or do you find f1.0-f1.8 image quality acceptable so long as you manage to capture it?

when you do not need it you will not understand it. and when you do need those 2 extra stops you will pay dearly for it.

 

[espn]

use some common sense.

:bsmilie: :bsmilie: :thumbsup: :thumbsup:

 

[mpenza]

...from a glamorous F2.8 to a paltry F4...:cry:
*fair remark: except the rare few that do actually 'perform' at F2.8 (or lower)

Several reasons:
1. With a faster lens, you have the option to use the wider aperture in the following scenarios (just a few of the top of my head):
a. available light shooting at lower ISO to minimise noise
b. need for fast shutter speed to freeze subject
c. need for longer flash range
d. shallow depth of field for creative effects

2. Also, a F4 lens will usually be less sharp at F4 than a F2.8 stepped down to F4, so you "gain" sharpness with a faster lens.

 

[foxtwo]

just to add,

basically for any lense, its advised to stop down because the light physics just doesn't work with full apertures without a lot of help. so on a normal lense, f5.6 is shot at f8.0 for optimum image quality. in that case, can you imagine the 35mm lense manufacturer saying, "well ok, since everyone is going to say shoot stopped down, let's do the job for them and save everyone the hassle. for this lense instead of building the usual aperture range of f5.6-f22, we'll just jump to f8.0-f22. f8.0 being the largest aperture that gives the optimum image quality, so that makes everyone happy!"

 

[jOhO]

think u need to shoot more and worry less.

mpenza has listed the main points why there are "fast lenses"

if u never had the need to address any of those points, go back to my first statement.

and yes.. at some point, i agree with astin, 2.8 isn't fast to me anymore. :bsmilie:

sad case of the chase for bigger holes... :embrass:

 

[n0d3]

You pay a premium for fast lenses, e.g. the 16-35mm f/2.8L, 24-70mm f/2.8L, 70-200mm f/2.8L etc. And USUALLY most of these lenses are already quite sharp wide open, no need to stop down unless you need to control the DOF etc.

 

[Zplus]

the user is almost always recommended to use it STOPPED DOWN in actual practice!!!:angry:


...from a glamorous F2.8 to a paltry F4...:cry:
*fair remark: except the rare few that do actually 'perform' at F2.8 (or lower)


isnt that sort of like buying an expensive suit, but putting aside the classy pants and coat to wear only the white shirt to work, becos the classy pants and coat are somewhat PURPLE

So.... following your line of thinking.... you would:
1) buy a f2.8 and stop to f4....
2) buy a f4 and stop to f8???
3) And at f8 you'd realise that shutter speed is too slow to shoot anything
4) So.... you end up buying a f2.8 to get a f4....

And that is the reason why you buy a f2.8.... in your case....:bsmilie:
Its like you buy a Porsche and realise its Singapore here and then you only go at 90kmh... Except for days when you encounter a chicken pox Lancer willing to race with you....:bigeyes:

For me.... I buy a fast lens so that I can shoot in low light and also get nice bokeh...

 

[justarius]

the user is almost always recommended to use it STOPPED DOWN in actual practice!!!:angry:


...from a glamorous F2.8 to a paltry F4...:cry:
*fair remark: except the rare few that do actually 'perform' at F2.8 (or lower)


isnt that sort of like buying an expensive suit, but putting aside the classy pants and coat to wear only the white shirt to work, becos the classy pants and coat are somewhat PURPLE

Nope... a close analogy is more like buying an expensive suit and insisting that you wear it in the shower, at the hawker centre, at the gym, etc. You should only wear your expensive suit when the occasion calls for it... sometimes you will be better off wearing singlet and shorts.

 

[Astin]

Its like you buy a Porsche and realise its Singapore here and then you only go at 90kmh...

Another analogy, buy a first class air ticket and sit at economy, because the air stewardess is prettier in economy...:lovegrin:

 

[student]

Several reasons:
1. With a faster lens, you have the option to use the wider aperture in the following scenarios (just a few of the top of my head):
a. available light shooting at lower ISO to minimise noise
b. need for fast shutter speed to freeze subject
c. need for longer flash range
d. shallow depth of field for creative effects

2. Also, a F4 lens will usually be less sharp at F4 than a F2.8 stepped down to F4, so you "gain" sharpness with a faster lens.

Three more

1 For SLR/DSLR the brightness of the screen depends on the widest aperture of the lens. This brightness remains the same whether you stop doen of not.

2 With brighter viewfinder from a wider lens, focussing (auto or manual) is faster and easier.

3 This may be more controversial. But on the whole, faster lenses are usually better built.

 

[Canonised]

Both Kancil (700cc) and Benz (2400cc) can both be driven at 100Km/hr ....... test drive them and you can understand why ppl go for the fast lens. :lovegrin:

 

[student]

Both Kancil (700cc) and Benz (2400cc) can both be driven at 100Km/hr ....... test drive them and you can understand why ppl go for the fast lens. :lovegrin:

I will be brief.

Try the Benz and Porsche.

 

[black.ink]

Another analogy, buy a first class air ticket and sit at economy, because the air stewardess is prettier in economy...:lovegrin:

oh i can definitely affiliate with that...but only if becos economy class dress allowances are lesser, so split slits run MUCH higher up...:bigeyes:

 

[rainman]

y r u so angry in the first place?

There are more than "yi wan ke wei se me"....

 

[sriram]

the user is almost always recommended to use it STOPPED DOWN in actual practice!!!:angry:


...from a glamorous F2.8 to a paltry F4...:cry:
*fair remark: except the rare few that do actually 'perform' at F2.8 (or lower)

It's for you to show off that you can afford / carry a huge f/2.8 zoom. Why else?