Why choose a f2.8 lens over f4?

[Rashkae]

Apologies for that post. I've deleted it.

No need for any apologies bro... We're just trying to make sure that newbies don't get the wrong definitions and concepts in their head...

 

[gohjialong]

Im thinking of getting 17-40 f4 L to replace the 17-50 f2.8 non vc. what are your views people? i mostly use the lens to take portraits on outings with my friends but also like to take landscapes of sg in some evenings.

 

[ME Photo]

Another thing is , if f2.8 is sharper at like f4 , then what is f4 sharpest at?

If my situation would most likely be casual portraits on the streets or in restaurants, would 2.8 be a better choice given its ability to go for faster shutter speed at low lit areas?

this is not a fixed number.
i find that my 24-70mm F2.8 is sharpest at F5.6.
every lens varies.

 

[ZerocoolAstra]

Im thinking of getting 17-40 f4 L to replace the 17-50 f2.8 non vc. what are your views people? i mostly use the lens to take portraits on outings with my friends but also like to take landscapes of sg in some evenings.

My personal opinion would be to keep the 17-50/2.8

 

[desertstrike]

My personal opinion would be to keep the 17-50/2.8

i agree with ZerocoolAstra

 

[commoner5]

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?

Slight detour, nothing on subject matter.

Your profile name is Kenneth but your gender is female !?!

 

[spree86]

Slight detour, nothing on subject matter.

Your profile name is Kenneth but your gender is female !?!

How did you arrive at the conclusion that Kenneth is a female? This is the internet, we can put whatever we want :bsmilie:

 

[ManWearPants]

maybe the TS can specify which f2.8 and which f4 lenses he is looking at so that the rest can advise on the OoF, bokeh and lens rendering characteristics.

Assumig you are taking outdoor xmm portraits, the 70-200 f2.8 has a versatile FL and rather good subject isolation capability.

 

[gohjialong]

maybe the TS can specify which f2.8 and which f4 lenses he is looking at so that the rest can advise on the OoF, bokeh and lens rendering characteristics.

Ok since you mentioned, I actually wanted to compare the 70-200 but just wanted to ask the question in a general manner cos it suited what I want to know abt my tamron 17-50 f2.8 and canon 17-40 f4L.

 

[commoner5]

How did you arrive at the conclusion that Kenneth is a female? This is the internet, we can put whatever we want :bsmilie:

Reread my post 5 times.

 

[spree86]

Reread my post 5 times.

Answer still doesn't change, why are you surprised at the male female things?

 

[tehzeh]

if you are considering the canon 70-200 f4 or f2.8, and if you ask me, i would get the 70-200 f4 IS anyday. the zooming feels so much smoother than the f2.8 IS. and it's freaking light.

 

[ManWearPants]

Ok since you mentioned, I actually wanted to compare the 70-200 but just wanted to ask the question in a general manner cos it suited what I want to know abt my tamron 17-50 f2.8 and canon 17-40 f4L.

Maybe you should take this to the Canon sub section cos there are a lot of lenses that falls into the f2.8 vs f4 , if it is not specific enough.

I have the 70-200 f2.8 IS MkI previously and 70-200 f4 IS now. My take on zoom lens for human portraiture, get the 70-200 f2.8 IS MkII. My reason is the wider aperture allows for more creative control. Also the lens is very sharp that it allows you to crop much more than you can imagine. The MkII has a closer MFD than the MkI so you can get closer, meaning even fuzzier OoF area. I switched from f2.8 to f4 cos I needed a lighter lens for travel. While the f4 is sharp but I have never managed to isolate the subject in a manner that the f2.8 allows me to.

If you do not mind a manual focus lens. You may want to consider a Mamiya 150/2.8 lens. This is a lens for Mamiya medium format but can be adapter to be used on Canon body. The con is that it is manual focus and aperture. The pro is that you can have a very affordable f2.8 lens for portrait. I am always using it wide open so the manual aperture does not bother me.

cross post from alternative thread on mamiya 150/2.8
Being a medium format lens, it has a larger image circle so the cateyes effect is less pronounce.

the larger image circle also allows center to edge sharpness. 150mm at f2.8 has very thin DoF. The lens also renders skin colour very nicely. The book is slightly tilted. The focus is on the name "Lee Kuan Yew"

Without going into controlled tests, this is how the 70-200f4 OoF area will look. Compare to the f2.8 above.

 

[gohjialong]

I haven got to the stage of getting a 70-200 yet but those information were very helpful so thanks guys, just wanna see your takes on those 2 aperture.

 

[ManWearPants]

I haven got to the stage of getting a 70-200 yet but those information were very helpful so thanks guys, just wanna see your takes on those 2 aperture.

On the Tamron 17-50/2.8 and 17-40/4, these are completely different from the 70-200. IMO, you main consideration for the wider angle lenses should be more based on low lights capability more so than thin DoF.

 

[lcheowl]

if you are considering the canon 70-200 f4 or f2.8, and if you ask me, i would get the 70-200 f4 IS anyday. the zooming feels so much smoother than the f2.8 IS. and it's freaking light.

that must depends on TS going to use it mostly in day time or night time.

a normal people will choose F4 over F2.8 due to the weight and the cost. But if TS is doing his shoot in low light condition, then I feel a f2.8 will be a more suitable lens than a f4.

 

[bonrya]

Slight detour, nothing on subject matter.

Your profile name is Kenneth but your gender is female !?!

Kei is female also. :bsmilie:

 

[NikF601]

Good for you

I would say the 2 main 'obstacles' to a large-aperture lens are bulk (weight/size) and cost. Otherwise they are generally the preferred choices, wouldn't you say so?

I can't say because I have yet own one..haha

 

[wakaowalao]

Answer still doesn't change, why are you surprised at the male female things?

Thanks to this kind of answers always lead closure of some very good discussion thread.

 

[wakaowalao]

One very good example of a not-so-good bokeh from a prime lens will be the Canon F1.8 II.