Seriously, what are the benefits of a 2.8?


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gremlin

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#1
Just started to wonder. Taking an example of a 300mm f2.8 vs 300mm f4 lens. Are there much reasons for the 2.8 being more desirable?

Its heavy, and when shooting animals/birds you do not need the 2.8. I can only think of indoor events like fashion shows, etc where it might be more useful. Even then I may use flash which negates the 2.8. Don't tell me the IQ of 2.8 lenses are consistently better than f4 lens? Cannot be right?

Hmm... am I missing anything?
 

Feb 16, 2006
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#2
naturally 2.8 allows 1 stop higher shutter speed compared to 4. which may be critical to freeze movements of animals, birds.

flash used to be described as "portable sun light". but its effect can be harsh (when used incorrectly). sometimes, flash lights are not allowed (eg stage performance). perhaps, some ppl jus perfer natural light photography (me included).

another advantage of a fast lens is one can choose to use a tele-converter 1.4 or 2 x. slower lens (4 or 5.6) usually cant, cus the light lost will be too great liao.

guess its a matter of wat one needs. the difference in physical size between a 300mm, 2.8 and 4 is staggering.
 

zac08

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Feb 21, 2005
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#3
A bigger front element allows more light to enter and assists for better AF functionability.

And dun forget it allows the usage of TC's much better... With a 2.8 lens, you can add a 2x TC and still only drop down to f5.6... If you're using a f4, you'd be at f8 minimum, so which would be more desireable??
 

Kermitfm

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#4
Large aperture also comes in handy when shooting during dusks and dawns. Also when birds/animals are in the shade.
 

chong_lim

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Mar 19, 2005
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#5
if you dun find the benefit, that means u dun need it :)
 

geraldkhoo

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#6
Just started to wonder. Taking an example of a 300mm f2.8 vs 300mm f4 lens. Are there much reasons for the 2.8 being more desirable?

Its heavy, and when shooting animals/birds you do not need the 2.8. I can only think of indoor events like fashion shows, etc where it might be more useful. Even then I may use flash which negates the 2.8. Don't tell me the IQ of 2.8 lenses are consistently better than f4 lens? Cannot be right?

Hmm... am I missing anything?
A 2.8 lens dows not mean that the IQ is better. You can have a 2.8 lens with bad IQ, bad CA, bad viginetting, bad everything :(

But the reasons for a 2.8 lens (or those of smaller aperture numbers) would be:

1. Allow more light... which means can take a same shot with a faster shutter speed. This is great in low light conditions and also to freeze shots with faster shutter speeds.

2. It gives shallower depth-of-field, which can also be achieved by a long telephoto, but for close up, it can be a desirable effect.

3. The loss of stops with a TC does not impact as great.
 

lsisaxon

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Nov 29, 2004
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#7
if you dun find the benefit, that means u dun need it :)
:thumbsup: I think this is the best answer so far.. ;p Each lens has it's purpose, otherwise manufacturers will not make an f/2.8 version and an f/4 version of the same focal length.
 

waileong

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Feb 5, 2003
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#8
The benefit is that it will make you lose weight... your wallet won't be so heavy any more.

Just started to wonder. Taking an example of a 300mm f2.8 vs 300mm f4 lens. Are there much reasons for the 2.8 being more desirable?

Its heavy, and when shooting animals/birds you do not need the 2.8. I can only think of indoor events like fashion shows, etc where it might be more useful. Even then I may use flash which negates the 2.8. Don't tell me the IQ of 2.8 lenses are consistently better than f4 lens? Cannot be right?

Hmm... am I missing anything?
 

user111

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Jul 27, 2004
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#9
Just started to wonder. Taking an example of a 300mm f2.8 vs 300mm f4 lens. Are there much reasons for the 2.8 being more desirable?

Its heavy, and when shooting animals/birds you do not need the 2.8. I can only think of indoor events like fashion shows, etc where it might be more useful. Even then I may use flash which negates the 2.8. Don't tell me the IQ of 2.8 lenses are consistently better than f4 lens? Cannot be right?

Hmm... am I missing anything?
try it then you will know :cool:
 

cantaresg

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Feb 23, 2007
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#10
An additional advantage. Some camera has cross AF points that are sensitive to f2.8 and smaller.
 

Deadpoet

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Oct 18, 2004
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#11
Just started to wonder. Taking an example of a 300mm f2.8 vs 300mm f4 lens. Are there much reasons for the 2.8 being more desirable?

Its heavy, and when shooting animals/birds you do not need the 2.8. I can only think of indoor events like fashion shows, etc where it might be more useful. Even then I may use flash which negates the 2.8. Don't tell me the IQ of 2.8 lenses are consistently better than f4 lens? Cannot be right?

Hmm... am I missing anything?
No, you did not miss anything, because you do not need it.

I have a long argument with a very good buddy of mine over digital medium format backs. I found the differences not material enough and he swears by the digital medium format backs. Why? I don't need it but he does.

However, your arguement, and those of many others, over speed of the lens, sharpness and bokeh etc are valid, but you missed the point.

Most lens manufacturers put much higher quality glass with advance/multicoated lens in their flagship lines, for Canon, it's the L lenses, and in this case, the 300 2.8L. As a result, you have superior contrast, richer color, better ability to handle flares, less CA, better resolution and last but not least, a faster lens.
 

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