Why choose a f2.8 lens over f4?

[kei1309]

Or simply leave quality of bokeh out of discussion because it varies with different lenses. I thought it started out to be a discussion betw. why F/2.8 over F/4?

yeah seems like a slight bit off the subject of the thread to do so... or perhaps a related corollary but only a small part of the whole

this topic on bokeh will come up, especially when people start slinging "bokeh" all over the place while misinforming what it actually is.

 

[Rashkae]

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?

Depends on the lens. Different lenses have different sweet spots. Most lenses are at their sharpest between f/5.6-f/8, but this is variable.

 

[gohjialong]

Depends on the lens. Different lenses have different sweet spots. Most lenses are at their sharpest between f/5.6-f/8, but this is variable.

I take landscape with my tamron f2.8. would it be better using 17-40 f4 L for landscapes? cos landscapes usually go for f8~f11 right? does this mean that my pictures will be sharper using the 17-40?

 

[rhino123]

I take landscape with my tamron f2.8. would it be better using 17-40 f4 L for landscapes? cos landscapes usually go for f8~f11 right? does this mean that my pictures will be sharper using the 17-40?

Check out this site, it did a good comparism.

http://www.the-digital-picture.com/...meraComp=474&SampleComp=0&FLIComp=0&APIComp=5

 

[gohjialong]

Check out this site, it did a good comparism.

http://www.the-digital-picture.com/...meraComp=474&SampleComp=0&FLIComp=0&APIComp=5

i must say im sorry but i havent learnt how to see those graphs. =(

 

[Rashkae]

I take landscape with my tamron f2.8. would it be better using 17-40 f4 L for landscapes? cos landscapes usually go for f8~f11 right? does this mean that my pictures will be sharper using the 17-40?

Not necessarily. You'd need to read the lens reviews. They usually discuss performance at various focal lengths and apertures.

 

[rhino123]

i must say im sorry but i havent learnt how to see those graphs. =(

It is not showing any graphs. It shows you the pics, you can judge by yourself the sharpness.

 

[gohjialong]

It is not showing any graphs. It shows you the pics, you can judge by yourself the sharpness.

erm ok i see 17-40 sharper than 17-50 at f8 corner.

 

[gohjialong]

Not necessarily. You'd need to read the lens reviews. They usually discuss performance at various focal lengths and apertures.

found this "Wide open center of the frame sharpness ranges from great on the wide end to good on the long end. Wide open corner sharpness is also relatively good, but as usual, the corners are not as sharp as the center. Stopping the 17-40 L down to f/5.6 brings along a nice improvement in sharpness. Common landscape apertures f/8 through f/11 look very good. " in the digital picture website.

Thanks!

 

[Kenneth67C]

Correct, ZerocoolAstra understands it perfectly. Those sort of sweeping statements with no real link are a folly.

Apologies for that post. I've deleted it.

 

[daredevil123]

Apologies for that post. I've deleted it.

No big deal bro. why apologize?

 

[spree86]

Apologies for that post. I've deleted it.

No need for apologies bro but respect to you for acknowledging that there was a misunderstanding. Not many people in this forum is able to do that.

 

[lcheowl]

imho, for this discussion to have any meaning at all, you guys may have to come up with an agreement on what "better bokeh" means... (which by itself may be argued til death)...

+1 to that, Better is very subjective.

Basically, if TS need to shoot in low light condition, it is better to get the biggest aperture that Ts can afford.

 

[daredevil123]

+1 to that, Better is very subjective.

Basically, if TS need to shoot in low light condition, it is better to get the biggest aperture that Ts can afford.

Actually, the consensus is that the more gaussian the blur is, the better it is. For OOF light blobs, the round the more consistent, the better it is.

 

[NikF601]

You may come to dislike the weight 'penalty' that the f/2.8 zoom lens forces you to incur, compared with the variable-aperture or smaller-aperture alternative

With one weight 'penalty' len+ body to carry, it is OK for me... It is our mindset not to focus on the equipment but the surrounding to take sharp and good shoot that the public will look at your photos twice and find interesting... that is my challenge and I will achieve... my mindset

 

[neech7]

Actually, the consensus is that the more gaussian the blur is, the better it is. For OOF light blobs, the round the more consistent, the better it is.

Ahh, OOF light blobs. When I watch TV dramas, I like to look for them and even though I don't know what lens they use for the shoot, at least I know how many aperture blades it has (seems to be always 6).

 

[ZerocoolAstra]

With one weight 'penalty' len+ body to carry, it is OK for me... It is our mindset not to focus on the equipment but the surrounding to take sharp and good shoot that the public will look at your photos twice and find interesting... that is my challenge and I will achieve... my mindset

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?

 

[ZerocoolAstra]

found this "Wide open center of the frame sharpness ranges from great on the wide end to good on the long end. Wide open corner sharpness is also relatively good, but as usual, the corners are not as sharp as the center. Stopping the 17-40 L down to f/5.6 brings along a nice improvement in sharpness. Common landscape apertures f/8 through f/11 look very good. " in the digital picture website.

Thanks!

There you go

 

[rhino123]

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?

To me... the main deciding factor is the cost. Weigh wise... unless the lens weighed more than 2kg, it is still okay... afterall, I shoot with my monopod or tripod most of the time and I can handle some weigh for prolonged periods of time.

 

[GSiGuy]

Actually, the consensus is that the more gaussian the blur is, the better it is. For OOF light blobs, the round the more consistent, the better it is.

well, if that can be agreed upon as the foundation of "better bokeh" then i think you will have a more meaningful discussion on which is better, prime v zoom, rounded v straight blades, # of blades, aperture width, etc...