Are FAST lens really good?

[mazeppa26]

how good are lens like those f2.8, f1.4 etc...
for one are very expensive... but how good are they.... if we talk about being fast, how well can they actually take photos in poor lighting? using a tripod will reduce the shakes already, so is a fast lens still necessary? etc...etc...
just some thoughts and questions about fast lens...

 

[ricohflex]

f2.8 is not fast for standard lens
f1.4 ...hmm.... so so only.

well again depends on focal length.

if 400mm then f2.8 is fast.

for std lens
fast is f1.2
fast is f1.0 -- Leica Noctilux
Canon had a f0.95 lens.

Good in the sense that you buy them for special reason. i.e. shoot at full aperture in low light. You get the shot without flash.

Do not expect them to be as sharp as your f4.0 macro lens.

 

[Deadpoet]

how good are lens like those f2.8, f1.4 etc...
for one are very expensive... but how good are they.... if we talk about being fast, how well can they actually take photos in poor lighting? using a tripod will reduce the shakes already, so is a fast lens still necessary? etc...etc...
just some thoughts and questions about fast lens...

Why don't you try out a fast lens and tell us!

Really, if fast lenses are not good, you think they can sell that many and charge that kind of price?

 

[waileong]

In an age of clean ISO 800/1600 and noise ninja, fast lenses are not as necessary as they once were. Nevertheless, if you want the DOF/bokeh, or if you need the high shutter speed at low light, they are indispensable.

 

[2100]

They also help in helping you focus fast AND accurately under low light condition. Else you will find that even with ISO ramped up to 3200 for shutter speed and tripod everything, you won't get many usable shots because it backfocused etc....esp if your body is lower-end based. If subject is moving slightly, then even more so.

 

[Stoned]

Do not expect them to be as sharp as your f4.0 macro lens.

I'd venture to say the 85/1.2L is sharper than the f4.0 macro lens ;p

 

[~Arcanic~]

most of the fast lens are not just 'fast', like what 2100 mentioned, they tend to focus better, faster and more accurately, they have more solid builts and gives better colours too..

so the price you are paying for one is not just about the f-stop..

 

[surge]

if you do quite a bit of shooting in the streets. fast lens can come in very handy. esp. in badly lit wet markets for eg, place is too busy for you to setup tripod.and i dont think the ppl will like it when so many ppl looking at you taking pic of him.

at ISO400, a 35/f2 lens can give a 1/125 in a wet market( may vary due to ligthing in e market)

if you are using a f4-5.6, the shutter is reduce to 1/60. even if you have very steady hands, the subj's movement is gonna blur your photo.

get a 50/1.8 to try. is sharp, fast and cheap

 

[yyD70S]

most of the fast lens are not just 'fast', like what 2100 mentioned, they tend to focus better, faster and more accurately, they have more solid builts and gives better colours too..

so the price you are paying for one is not just about the f-stop..

With the added plus of a 'slightly brighter VF'.

 

[Zack]

how good are lens like those f2.8, f1.4 etc...
for one are very expensive... but how good are they.... if we talk about being fast, how well can they actually take photos in poor lighting? using a tripod will reduce the shakes already, so is a fast lens still necessary? etc...etc...
just some thoughts and questions about fast lens...

In some situation, you simple cannot use a tripod or a flash. Sometimes, a difference of one f-stop can determine whether you can handhold or not.

 

[sk.images]

Most good lenses are fast, but not all fast lenses are good.

As others have already stated, there are a number of factors which make a lens good, how large the aperture is but one of them.

Good lenses are generally more well know for the colour, contrast and sharpness (and lack of BD, CA, etc...) they produce first and their speed second. Even the 'icon' lenses like the EF 85 1.2 will give better results when stopped down 1 or stops.

The legendary Canon 50 1.0 (very rare and expensive) is one of the fasteset around, but by all the accounts I've read is far from a 'good' lens, especially at the price.

 

[roti_prata]

generally, fast lenses r better thn slower 1s. my tokina 28-80/2.8 is sharp by f4, can a 17-70/3.5-4.5 claim the same? wait, it cant even be f4 at tele.

bottom line, fast lenses r the pro series of a manufacturer's line up. slower lenses r the consumer series.

 

[jeryltan]

They are good for indoor, low light conditions and when you can't use / don't have / too lazy to use a tripod..

Not all fast lens are good, and not all good lens are fast

how good are lens like those f2.8, f1.4 etc...
for one are very expensive... but how good are they.... if we talk about being fast, how well can they actually take photos in poor lighting? using a tripod will reduce the shakes already, so is a fast lens still necessary? etc...etc...
just some thoughts and questions about fast lens...

 

[jeryltan]

Fast lens not only less noise.. Also less handshake and motion blurr..

In an age of clean ISO 800/1600 and noise ninja, fast lenses are not as necessary as they once were. Nevertheless, if you want the DOF/bokeh, or if you need the high shutter speed at low light, they are indispensable.

 

[jeryltan]

1st time Iheard this..

generally, fast lenses r better thn slower 1s. my tokina 28-80/2.8 is sharp by f4, can a 17-70/3.5-4.5 claim the same? wait, it cant even be f4 at tele.

bottom line, fast lenses r the pro series of a manufacturer's line up. slower lenses r the consumer series.

 

[Zack]

1st time Iheard this..

I consider the 50mm F1.8 a fast lens even though it's only $140 and not a pro series.

 

[mazeppa26]

Actualli was thinking about getting a 50mm f 1.8 to try, its a cheaper 'fast' lens compared to those hi end zooms... the problem is the digital magnification of 1.5x will make the lens 75mm yup...

 

[blimmer]

Actualli was thinking about getting a 50mm f 1.8 to try, its a cheaper 'fast' lens compared to those hi end zooms... the problem is the digital magnification of 1.5x will make the lens 75mm yup...

get a 35mm f/2 then. it'll be more expensive than the 50mm f/1.8 though

 

[syl]

generally, fast lenses r better thn slower 1s. my tokina 28-80/2.8 is sharp by f4, can a 17-70/3.5-4.5 claim the same? wait, it cant even be f4 at tele.

bottom line, fast lenses r the pro series of a manufacturer's line up. slower lenses r the consumer series.

I agree!

 

[jumbocrab]

at ISO400, a 35/f2 lens can give a 1/125 in a wet market( may vary due to ligthing in e market)

if you are using a f4-5.6, the shutter is reduce to 1/60. even if you have very steady hands, the subj's movement is gonna blur your photo.

I think in your example, at f4-f5.6, the shutter speed will be reduced to 1/30-1/15...?