Why choose a f2.8 lens over f4?


gohjialong

New Member
Jul 16, 2010
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#1
Hi guys, I'm thinking of getting a new lens but not sure whether I should spend more to get a f2.8 rather than f4. I intend to take more of portraits for that lens. Should I spend more to get the 2.8? What benefits do I have over the f4?
 

Kenneth67C

New Member
Oct 20, 2010
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#2
Quite frankly, if you want to get better bokeh, go for a prime with >f2. You will be much happier with the quality of the photos.

If you use flash/strobes and shoot at f8-f11, then save your money and get the f4.
 

Rashkae

Senior Member
Nov 28, 2005
19,105
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#3
Hi guys, I'm thinking of getting a new lens but not sure whether I should spend more to get a f2.8 rather than f4. I intend to take more of portraits for that lens. Should I spend more to get the 2.8? What benefits do I have over the f4?
In addition to the extra low-light ability the larger aperture will give you, most lenses are usually sharper stopped down. So an f/2.8 lens at f/4 will be sharper in most cases than an f/4 lens at f/4...
 

Rashkae

Senior Member
Nov 28, 2005
19,105
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#4
Quite frankly, if you want to get better bokeh, go for a prime with >f2. You will be much happier with the quality of the photos.
Nope. I've seen some very bad bokeh even from large aperture prime lenses. Remember, bokeh is a lens characteristic and dependent on lens design, lens elements and aperture blade design.
 

luckyorange

Senior Member
Jan 13, 2011
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#5
hmm not sure what to get? can try a used 50mm its cheap and good =x
 

wdEvA

Senior Member
Sep 1, 2006
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#6
Hi guys, I'm thinking of getting a new lens but not sure whether I should spend more to get a f2.8 rather than f4. I intend to take more of portraits for that lens. Should I spend more to get the 2.8? What benefits do I have over the f4?
a 2.8 lens will mostly be sharper at f4 than an f4 lens at f4
a 2.8 lens gives u a shallower dof, for better subject isolation
 

ZerocoolAstra

Senior Member
Mar 13, 2008
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rainy Singapore
#7
The f/2.8 lens gives you the flexibility to use f/2.8 when the situation arises.

Also, the f/2.8 lenses are usually built to be tougher, for heavier usage. For example an 18-55 f/3.5-5.6 kit lens vs a 17-55 f/2.8

You pay significantly more, though you do get what you pay for.
 

Anthony Lee

Senior Member
Feb 12, 2009
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Shunfu Road, Singapore
#8
Generally, an F2.8 lens will be bigger, heavier and more pricy than an F4 lens. Apart from shallower DOF, an F2.8 lens will provide a brighter view finder which will allow both the photographer and camera to see better and thus, take better photos. To me, this is the most important advantage.
 

ZerocoolAstra

Senior Member
Mar 13, 2008
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#9
Generally, an F2.8 lens will be bigger, heavier and more pricy than an F4 lens. Apart from shallower DOF, an F2.8 lens will provide a brighter view finder which will allow both the photographer and camera to see better and thus, take better photos. To me, this is the most important advantage.
ahhh you are right on that point.
It is beneficial for sure :)
 

NikF601

Senior Member
Jul 26, 2010
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#11
The f/2.8 lens gives you the flexibility to use f/2.8 when the situation arises.

Also, the f/2.8 lenses are usually built to be tougher, for heavier usage. For example an 18-55 f/3.5-5.6 kit lens vs a 17-55 f/2.8

You pay significantly more, though you do get what you pay for.
I see,,, need to save more $$$ for F2.8 instead F4 with VR
 

bonrya

Senior Member
Dec 16, 2010
2,632
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In a mobile cage
#15
gohjialong said:
Hi guys, I'm thinking of getting a new lens but not sure whether I should spend more to get a f2.8 rather than f4. I intend to take more of portraits for that lens. Should I spend more to get the 2.8? What benefits do I have over the f4?
Because its usually more expensive and expensive things are supposed to be better!!! :bsmilie: if not then u can still carry it around to show off. ;)

But seriously ah.. If u dunno why you should get one over the other, then you don't need the other. no need to spend so much on "frills".
 

Dec 12, 2009
1,961
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#16
Go to Canon's section google f2.8 vs f4 there's quite a few threads discussing this same issue.
My advice is don't spend money buying if you don't know why you need the f2.8. Also having f2.8 doesn't make a lens better than say one with f4.

One more advantage of f2.8 is of course allowing faster shutter speed to freeze motion.
 

Rashkae

Senior Member
Nov 28, 2005
19,105
12
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#17
and you are the only one who knows, is it?
Nope, it's very common knowledge, well-documented in many sites across the web and is easily researched, and anyone who tries to talk about bokeh should at least know what it really means.

Just because you don't know what it is, does not mean you need to try to defend yourself with aggression. Try to learn a bit instead.
 

rhino123

Moderator
Staff member
Sep 1, 2006
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#18
Lets see if I get it correct, bokeh is not determine by whether you are using a prime lens or a zoom lens... neither was it determine by whether your lens has variable aperture or fix value aperture. It is determine by the design of the aperture blades, the number of the aperture blades.

Prime lens are generally sharper, due not because it is prime or not, but because there are less optics in the lens, and also the control during manufacturing of these lens is easier, also it had less moving parts too... but that had absolutely no effect on the bokeh.
 

Rashkae

Senior Member
Nov 28, 2005
19,105
12
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#19
Lets see if I get it correct, bokeh is not determine by whether you are using a prime lens or a zoom lens... neither was it determine by whether your lens has variable aperture or fix value aperture. It is determine by the design of the aperture blades, the number of the aperture blades.

Prime lens are generally sharper, due not because it is prime or not, but because there are less optics in the lens, and also the control during manufacturing of these lens is easier, also it had less moving parts too... but that had absolutely no effect on the bokeh.
Correct, but also the lens elements. Some lenses have elements designed specifically for better bokeh. Bokeh is the subjective quality of blur, not the amount of blur. You can actually even get nice background blur with compact zoom cameras, and some of them have nice bokeh too!
 

Kenneth67C

New Member
Oct 20, 2010
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Shanghai, China, China
#20
Nope, it's very common knowledge, well-documented in many sites across the web and is easily researched, and anyone who tries to talk about bokeh should at least know what it really means.

Just because you don't know what it is, does not mean you need to try to defend yourself with aggression. Try to learn a bit instead.
Excuse me, but it IS common knowledge, so why should you suggest that I don't know what it is?
Isn't that presumptuous on your part?
 

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