Why do fast primes not have IS?

[bdunbar79]

I think people want absolutely IS, but don't know why..

Cameras have good higher and higher ISO..
Very good lens have a lot of light...

-> you can have enough light for fast speeds (> 1/100 or 150)... So why do we bother for IS....
I was useful when camera couldn't go (good) over ISO400.. but know, IS is more and more useless.

I see utility only for long lenses.

While it's true that high ISO performance is good on newer cameras, it's still the case that image quality is better with lower ISOs (esp. if you want or need to crop, and esp. with smaller sensors); so IS/IBIS can be useful even with short, fast primes. Unless there's clear evidence that putting IS in a very fast lens reduces its image quality, I really don't understand why people object to the idea.

+1

I've been in situations where I'm at 1/125s, f/2.8, and ISO 8000 and shooting stationary objects. If IS lets me lower my shutter speed so that ISO is 2000, then that is a very good thing.

 

[mackguyver]

I've got steady hands and don't see a huge need for IS in fast lenses where I'm usually shooting wide open, but I would definitely be first in line if Canon releases an updated 135 f/2 with even sharper optics and IS ;D

 

[dgatwood]

By the way, there are *some* fast primes with IS - e.g. Sony makes some 1.8 APS-C e-mount primes that have it (35mm & 50mm; maybe others).

1.8 ASP-C is not really fast glass...

May not be fast, but it has a nasty bite. I hear the lens is fit for a queen, though.

I have a 400mm f2.8 LIS. It's a fast prime and it's got an image stabiliser.
I have a 24mm f1.4 L, it doesn't need and IS unit because it can be shot hand held at 1/25th second easily and due to it's huge light gathering capabilities, it can shoot at light levels several stops below what an f2.8 lens can achieve. So what could an Is offer a 24mm f1.4? Very little.

Because fast is never fast enough. Some of us like to shoot sports at night without artificial lighting.

But in all seriousness, as other folks have said, for every stop that IS buys you, you can take the same shot with one stop less ISO gain and the loss of dynamic range that comes with it. And when you're dealing with the sort of poor lighting where f/1.2 is most critical, the noise starts to matter. IS on a fast lens gives you the ability to trade shutter speed for less noise. Whether you're doing that at f/1.2 or f/4 is immaterial; the advantage is still the same.

 

[davidcl0nel]

35 IS can be used to 1/4sek most of the time, maybe 80% are successful.
For non moving objects this is fantastic. Something in a museum with ISO800 and 1/4 or ISO8000 and 1/40 - what gives you a better image?

So a 24 IS can be used to 1/2sek, maybe more. 24 1.4 with ISO800 f/2 should be sufficent to use it in any night handheld, and you can leave the tripod one more time at home...

 

[Mr_Canuck]

I used both Sony and Pentax before switching to Canon this year. I'd say that I'm happiest with my system now... except I didn't realize how much of a benefit was sensor-shift shake reduction in both Pentax and Sony. Currently, any lens you use will be IS with their systems. But then you put up with noisy and slow screw driven lenses on way too many of their lenses.

 

[Deleted member 91053]

I don't know why Canon's fast (short) primes don't have IS - but I hope this continues to be the case.
My concern with IS is that it introduces a dead element in the focal path (this is my description for a piece of glass that does nothing) also IS slows up AF acquisition. On longer lenses (300mm +) then I agree that IS can be handy (to have in reserve) though I very rarely use it these days.
Back in January I turned off the IS on My Canon 800 F5.6 L IS and was happier without it. AF is faster and I have had no problems regarding shutter speeds (note I use ISO's of up to 12800) also due to the improved AF my "Hit Rate" is higher. Since then I have turned off the IS on all my IS lenses (300 F2.8 L IS, 70-200 F2.8 L IS and 24-105 L IS) and have noticed similar improvements. IS can be handy to have in reserve but on my 300 F2.8 and shorter lenses I really don't have much use for it, on the 800mm it can be handy for Dawn/Dusk shots but as soon as the light is near passable I turn it off.
Just my 2p.

 

[bdunbar79]

I don't know why Canon's fast (short) primes don't have IS - but I hope this continues to be the case.
My concern with IS is that it introduces a dead element in the focal path (this is my description for a piece of glass that does nothing) also IS slows up AF acquisition. On longer lenses (300mm +) then I agree that IS can be handy (to have in reserve) though I very rarely use it these days.
Back in January I turned off the IS on My Canon 800 F5.6 L IS and was happier without it. AF is faster and I have had no problems regarding shutter speeds (note I use ISO's of up to 12800) also due to the improved AF my "Hit Rate" is higher. Since then I have turned off the IS on all my IS lenses (300 F2.8 L IS, 70-200 F2.8 L IS and 24-105 L IS) and have noticed similar improvements. IS can be handy to have in reserve but on my 300 F2.8 and shorter lenses I really don't have much use for it, on the 800mm it can be handy for Dawn/Dusk shots but as soon as the light is near passable I turn it off.
Just my 2p.

That's why I don't shoot moving objects or sports with IS. I shut it off on my 300 and 400 f/2.8's because my miss rate increased with IS turned on.

 

[Deleted member 91053]

That's why I don't shoot moving objects or sports with IS. I shut it off on my 300 and 400 f/2.8's because my miss rate increased with IS turned on.

+1
That's exactly what I was getting at, only you said it with FAR fewer words!
Additionally I really find little use for IS on stationary subjects unless the light is stupidly low!