isn't the battle over 2.8 and 4.0 a little ridiculous?

What kind of low light situations are YOU talking about?

If it involves stopping motion on the subject, then it's pretty simple. The faster the better. End of story.

So for indoor concert photography, where let's say my 200L f2 would be at 200mm f2 1/160 ISO3200, the shooter next to me with his 70-200 f2.8 would be at 200mm f2.8 1/80 ISO3200 or f2.8 1/160 ISO6400, and the shooter with the f4 version would be at 200mm f4 1/40 ISO3200 or f4 1/80 ISO6400.

Further, with an IS lens, you can get away with hand holding at 200mm 1/160 and still be able to reasonable stop moderate action and keep the images sharp. Not so simple without IS.

Your 40D doesn't have ISO6400 does it? Good luck with that f4 lens.

Jerobean wrote in post #7836007
Thanks for all the great replies. I totally understand that you get a faster shutter speed with 2.8. It seems that a lot of you can get by with 2.8. It just seemed to me that when I'm using my lenses, 1 stop of light wouldn't be enough for what I want to capture in the low light situations I'm in.

I guess for what I shoot, f4 will work, or I need something f/2 or faster. I never seem to be on the fringe where f4 is barely not enough.

I guess the camera body plays into this as well. As a 5dmk11 with a 2.8 is going to be much better with its high iso capabilities over my 40d.

nureality wrote in post #7836003
yeah along with more noise than you'll ever be able to eliminate.

Better than a blurry shot! And typically when resized for web or print you can't see the noise anyway.

No worse than avoiding ISO1600 like it has swine influenza.

f/2.8 is a "God send" if you shoot in low light. Take a band I shot recently, if all I had was f/4 lenses I wouldn't have gotten any usable shots without a flash. Since flashes were not an option, I would have gotten... nothing.

The singer moved around a lot, so I had to keep my shutter speed up.

IMAGE IS A REDIRECT OR MISSING!

Jerobean wrote in post #7836007
Thanks for all the great replies. I totally understand that you get a faster shutter speed with 2.8. It seems that a lot of you can get by with 2.8. It just seemed to me that when I'm using my lenses, 1 stop of light wouldn't be enough for what I want to capture in the low light situations I'm in.

1 stop of light is a huge difference, it's twice as much light.

You don't think there's a huge difference between 1/50 and 1/100? You're going to find that twice as much light and double the shutter speed is in fact critical in many applications.

As previously mentioned, good luck with the f/4 lens.

All my 5 primes and 1 of 3 zooms are f/2.8 or wider. Yes, I don't "need" f/2.8 or lower most of the time, but when I need it>>I wouldn't be able to use it, if I ain't got it.

Since I don't mind using high ISO (grain is OK!), I can see the point about just using f/4.0 and upping the ISO. But, being able to use ISO greater than 1600 will only make many of us shoot in darker and darker situations; so we will still use f/2.8 or wider.

It is no rocket science. Faster is faster.
And f/2.8 is faster than f/4 in terms of shutter speed.

Jerobean wrote in post #7832716
I constantly see people talking about 2.8 like it's a godsend. In real world shooting, if you can't get an image with f4, how likely is it that it will be a great shot at f2.8?

I agree with you, for the most part. That was my thinking until my 'real world photography' took a turn into shooting my kids' sports, partivularly basketball. I tried, tried, and tried to make do with a f/4.0 lens and kept walking away disappointed. Until I broke down and started buying lenses that are f/2.8 and faster and realized what a difference that made in capturing the shots I wanted. So in parts of my real world photography, going from 4.0 to 2.8 made a huge difference.

Everybody's real world photography demands its own unique gear

No it's not, often 2.8 is too slow and the reason I carry a couple of primes and use them a lot.

I've noticed that most of the time if there's not enough light to use f/4 then there's probably not enough light available for f/2.8. At some of the events I've shot at f/2.8 was not enough. Fast primes were the only option in those dark settings.

Once I had lenses that shot at a 2.8 or below, I let go of my 24-105 f4 and got a 24-70 2.8 and haven't looked back.

If I was shooting outdoors during the daytime then I'd be fine with an f4 lens.

Jannie wrote in post #7838479
Once I had lenses that shot at a 2.8 or below, I let go of my 24-105 f4 and got a 24-70 2.8 and haven't looked back.

If I was shooting outdoors during the daytime then I'd be fine with an f4 lens.

The 24-105 is a great lens and many people enjoy them. But most of the pro's I've chatted with go with the 24-70 as it is far more versatile.

I personally have no use for the IS feature, I would gladly trade a faster lens for IS.

I hear rumors of Canon working on a 24-70 f/2.8 IS - now THAT is a cool lens!!! I hope they do it.

Also, f/2.8 delivers better subject isolation, and provide more accurate autofocus.
On top of that, it allows you to use 2x extender with non-1D series body.

Once you expand your horizons to include action and low light situations, you will realize the difference and need for the 2.8 and faster lenses.

If you plan to shoot non-sports shots outdoors, and also take the weight of the lens into consideration, wouldn't it be OK to get the f4 IS instead of the 2.8 IS?

It seems like, from comments about actual results, that the 2.8 is needed when shooting indoors like concerts and basketball, or possibly outdoors at a low light sporting event.

Tks.