they probably will release with IS on PMA... thats the rumors.
they probably will release with IS on PMA... thats the rumors.
What exactly is it that you could do with the 17-55 that you can't with the 24-105? The 24-105 on a full frame body is wider at the wide end and longer at the long end than the 17-55 on a 1.6 fovcf body. It is also faster: f/4 on a full frame body is like f/2.5 on a 1.6 fovcf body, both in terms of dof and light gathering.
Jon,
I don't thinkits true tosay it is faster. I agree with the DOF comment. But f4 is f4. Full frame has better high iso, but thats not the same thing.
Tom
To me it seems to be exactly the same thing. If sensor 1 is twice as big as sensor 2, iso 800 on sensor 1 has the same noise as iso 400 on sensor 2. So you can get the same shutter speed with the same noise with f/4 on the bigger sensor as f/2.8 on the smaller sensor.
You could say, "well, the difference is the sensor, not the lens. F/4 is f/4." But if the f/2.8 lens can't illuminate the bigger sensor, I think the terminology is appropriate. The 24-105 lens is actually capable of getting more light onto a ccd at f/4 than the 17-55 is at f/2.8. Similarly, I would call an f/4 medium format lens faster than an f/2.8 35mm one, because the medium format lens gets more light to the sensor (or film).
That's just terminology, though, and if you think I am crazy for using the word "faster" that is coolMy main point is that I don't see any major disadvantage of the 24-105 f/4 on a full frame as compared to 17-55 f/2.8 on a 1.6 fovcf camera.
Yes please .... I want one.
The 24-70 is most probably my most used lens. I use it especially indoors (churches etc) and would love IS.
It isn't that a 24-70 is wouldn't be great. It would be.
But the two lenses I would most like to have with IS are the 100mm macro and the 135mm f/2.
Macro because you never have enough light for macro, it seems, since one is always stopping down to very large effective f/ numbers, and because one often does a lot of cropping. And it isn't always convenient or possible to follow a bee or butterfly or whatever through the bushes with a tripod. Yes, you can use flash, but sometimes one wants natural light. Am I the only one that has this problem? I've taken to using my 70-200 IS with extension tubes at times for butterflies.
And the 135 f/2 because, even at f/2, the thing isn't that hand-holdable in low light due to the long fl. A 4-stop IS would be huge.
Originally Posted by Jon Ruyle
To me it seems to be exactly the same thing. If sensor 1 is twice as big as sensor 2, iso 800 on sensor 1 has the same noise as iso 400 on sensor 2. So you can get the same shutter speed with the same noise with f/4 on the bigger sensor as f/2.8 on the smaller sensor.
You could say, "well, the difference is the sensor, not the lens. F/4 is f/4." But if the f/2.8 lens can't illuminate the bigger sensor, I think the terminology is appropriate. The 24-105 lens is actually capable of getting more light onto a ccd at f/4 than the 17-55 is at f/2.8. Similarly, I would call an f/4 medium format lens faster than an f/2.8 35mm one, because the medium format lens gets more light to the sensor (or film).
That's just terminology, though, and if you think I am crazy for using the word "faster" that is cool
there's still a difference.. trust me. i knew that 17-55mm like the back of my hand, and it was definitely a faster lens. you are spot on with the DOF comment, but that's not what i'm looking for.. the 24-105 pleases in every respect when it comes to DOF. when i'm having to use higher ISOs and/or shutter speeds with this lens wide open than i had to with my 17-55mm.. i would say that 2.8 is still faster, be it on a crop *or* a full frame.
Jon,
I think the 17-55 2.8 is able toget the same amount of light onto the cropped sensoras the 24-105 is on the larger one. They both use a 77mm filter so I am guessing they allow about the same in. The 17-55 just directs it into a smaller image circle. The light on that smaller circle will be brighter per unit area than the 24-105, hence 2.8.I think the ISO vs actual noise argument holds some water, I need to think about that one a bit. I am really not trying to argue and apologize if it seems that way.
Tom
No, it doesn't seem like you are trying to argue. We're both just trying to get at the truth, not to put each other down.
I think you are right about "same light but spread out" point, and that is a good way to think about it. But I don't think the filter size is a good indication of this. For example, the 17-40mm f/4 has at most a 10mm effective aperture when wide open (40mm at f/4 means 40mm/4 = 10mm aperture), so you might guess it has a tiny filter size. But it also takes a 77mm filter. I don't know anything about optics so I don't know why this is true. Maybe it has to do with avoiding vignetting on a lens that has to illuminate a sensor that is large compared to its focal length.
Quote Canon Rumors:
"EF 24-70 f/2.8L II IS
- Possibly the most sought after lens Canonites are lusting after. Match Nikon’s optics and add IS? You’d have a massive sales success. It almost wouldn’t matter what it cost."
True. I'll immediately sell my 24-70L and get one regardless how much it would cost.
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