aetas you and I are both a free agents!

roflol. I think we all need to step back from the keyboard and take a breath sometimes. I have stopped arguing sometime because I have caught myself trying to make a point to someone that either does not understanding me, does not care to debate like adults or just plain does not want to listen to anything other then themselves=)
~Cheers..

Plus I love the dark and bokeh Does that make me from the Dark King or the Bokeh Warriors camp TaoTeJared?

PB PM said:
Da da da da da da da da da da DA?

Thank you for proving my point.

And you think you're adding something valuable by adding useless spam videos?

http://www.youtube.com/watch?v=KRWJybzkwN4
Seriously this is how all these most recent threads sound like!

Funny thing is, when I hear higher usable ISO I immediately think cool, higher shutter speeds, not stopping down. What I shoot is dancers and musicians on poorly lit (or sometimes just dark) stages. To me, two more usable stops of ISO would mean two steps faster shutter speeds. bumping from 1/125 to 1/500 would be absolutely fantastic.

Get slower lenses? Not likely.

Testing123 said:
The difference (when talking about DoF OR light capturing) between a 300 f/4 and a 300 f/2.8 is significantly larger (both as a percentage and as an absolute) than the difference between a 50 f/1.4 and 50 f/1.2, yet people seem more than willing to sell their mother up the river for the latter. ;)

Oh I am certainly one of those - bring me the Noct 1.2!

It seems like there are four camps in this discussion:
1) Bokeh Kings - The DOF camp.
2) Dark Warriors - Low light camp
3) The AF Speed Demons - Need for AF speed Camp
4) 56ers - those shooting 5.6 and above.

The "night vision" sounds similar to what my sb-900 throws out in low light to focus and is less intrusive than that damn white AF assist light that I always forget to turn off. Niko is right about Sony and I think Canon (at least from film days) used something similar.

My last true AF film camera was a Canon Elan IIe that tracked my eyeball to help with focus. That was about the coolest thing ever and worked quite well for fast action but not so well when I was looking around the frame for exposure points. I often thought that would still be a great feature if it was improved on.

I think the High iso quality and ability to stop down lenses to get additional DOF is a huge plus. Shoot someone at an angle, in low light, with a 85mm and getting both eyes in the focus plane can make or break the photo.

donaldejose said:
Will Nikon destroy sales if it starts to put "night vision" in the new camera bodies?

My Sony cameras literally do have "nightshot" and "nightframing" modes. But they use built-in IR lamps and project a laser grid to focus and see in total darkness. I don't expect Nikon's supposed "nightvision" mode to be anything like that.

Night vision isn't going to kill f2.8 lenses either.

rumor

"Some rumors indicate that the Nikon D5100 will have a new “Night Vision” mode allowing you to take photos in near darkness. I am not sure if this will mean a new high-ISO level or just a software solution."

Read more on NikonRumors.com: http://nikonrumors.com/2011/03/27/more-on-the-nikon-d5100-announcement.aspx#ixzz1I7W9u4DL

Will Nikon destroy sales if it starts to put "night vision" in the new camera bodies? I am assuming night vision just means better focus ability in low light and better image quality in low light. I think we are going to see a trend in electronics and software technology which will make the f2.8 lens unnecessary for many of the low light situations in which they are needed today. That doesn't mean people who prefer to use them won't still use them; just that they will no longer be the only choice to get a good photo in low light. But we will have to wait and see what Nikon announces over the next year. It may be a reason for some to hold off spending many tens of thousands building a collection of those big lenses. I, for one, hope that option becomes available to us. I want to take high shutter speed photos in low light but I don't want to haul around those huge lenses or spend the money needed to purchase them.

Of course not, but that's not really the point, it's about given the fact that you need more light, is it better to up the ISO or to open up?
Though part of the debate has also been on comparable lenses in terms of focal length but different in terms of max aperture. I think one more argument for the large aperture lenses is that their sharpness is often better. For instance, my 50mm 1.4 starts yielding excellent sharpness from f2.8 and at f5.6 or so the quality is simply outstanding.

Oh BTW one more point: it's never as black and white as either large aperture OR high ISO of course. I just came from shooting a theater play at a really dark venue. I brought all my fast glass but even so I like to just keep the ISO at 1000 (I've got a D90) in conditions like that. It gives me the room to adjust the aperture as I like, like anywhere between f2 and f4. On some shots I could go for lower ISO and a larger aperture or slower shutter speed but it's just too much effort for me to constantly change the ISO.

There are some good points about fast glass here, and I agree with them all. Of course those are all irrelevant if you need to shoot at F16 without a flash at dusk. So the question is, what are you shooting?

For example, the 17-35mm F2.8D is a great lens for low light shooting, but at F16 are you likely to notice any difference between it and the 16-35mm F4 VR? Most likely not.

Coming back to the title of this thread: F-stop vs ISO, the answer is pretty clear: open up first, then if that doesn't do the trick, up the ISO. Doing it the other way around is just plain madness, save some situations where you absolutely want to use a certain aperture. I always try to keep the ISO down as much as possible, because if you really care about noise, you'll notice that pretty much any setting above ISO 400 will start degrading image quality. Of course this differs for each camera model but every camera has a point where image quality starts degrading. Sure, it may still be acceptable, but why settle for acceptable when you can just open up?

Fast glass didn't go away when flash guns became smaller and easier to use. Even if the "D4" can go up to 819200 ISO, how would you auto focus or see anything through the viewfinder in total darkness? High ISO is great but there comes a point when it becomes just another marketing ploy.

The difference in light gathering capacity between the Nikkor 300mm f4 and the 300mm f.28 is huge! The front element on my old f4 is 90mm and the front element on the f2.8 that I own now is 133mm. Sure, it weighs a freakin' ton and with both its hoods on is ridiculously long, but its pulls so much more light that the inconveniences are trivial.

The difference (when talking about DoF OR light capturing) between a 300 f/4 and a 300 f/2.8 is significantly larger (both as a percentage and as an absolute) than the difference between a 50 f/1.4 and 50 f/1.2, yet people seem more than willing to sell their mother up the river for the latter. ;)

I completely agree with tcole... as nice as it is to have the flexibility of shooting at iso3200+, i try to avoid it within reason, which is where the faster glass comes in. In addition you also get the larger apertures to have a greater selection of DOF.

@donaldejose - No the DOF wouldn't differ too drastically at that focal length (300+), but why would Nikon ever cannabilize itself by selling cheaper telephoto primes when they know that people who use those lenses are more than willing to shell out several thousand dollars? They know that people know that those lens cost more because they are better, and until that it is proven 100% that an f/4 300mm is just as good as a f/2.8, they'll continue producing them, and even if that does happen - they'll find ways to get the price up that high.

Lol donaldejose you are set on that D4 aren't you?

Although this is an old thread...higher ISO has it benefits, but for me it is the last effort I would use since it degraded the picture quality. Faster glass is better. I don't know anyone that would give up a lower f-stop to be able to move the ISO up a notch or two. Plus having an expanded ISO doesn't mean it is really all that usable at high ISO's. So to me usable fast aperture compared to unusable high ISO there isn't really any competition.

The more isolated DOF offered by 2.8 over f4 will never change since it is a law of physics.

However, almost all other factors could possibly change as digital cameras get better. The D4 if said to offer two higher f stops with the exact same image quality. That could be significant because it takes 2.8 down to 5.6. Nikon should be able to produce an f4 prime lens for quite a bit less money than a f2.8 prime lens, if they want to. People should prefer the lightness of an f4 prime over the heaviness of an f2.8 at the same mm. The quality of "consumer" zooms could be improved for less than the cost of prime 2.8 telephotos since they are produced and sold in larger quantities. Could autofocus be as fast at f2.8 as it is now at f2.8. Sure, in fact the D4 is said to have a revolutionary fast autofocus so that change may occur this year. Could viewfinders be produced which are as bright at f4 as the current ones are at f2.8? I don't know if we are currently at any physical limits of light transmission through the pentaprism. Would the smallest DOF provided by an f4 300mm really be so much worse than the smallest DOF offered by a f2.8 300mm lens? Just take your 300 mm f2.8 and bracket some shots at both f2.8 and f4 to see how important that difference is to you. I am going to try that myself. I am suggesting that if camera bodies continue to get better and better perhaps f4 will be able to do all f2.8 now does at far lest cost IF the smaller DOF at 2.8 isn't really worth thousands of dollars to you.

My main reasons for faster glass is much better than higher ISO:
-Much faster and accurate AF in lower light with a faster lens.
-Shallow DOF to isolate the subject.
-Better built, longer lasting lenses.
-They hold their re-sale value much more.
-You also loose resolution as ISO rises. This makes a big difference when you crop your photos. Little Johnny may look good at 3200 with half a soccer field in the photo but if you just want to isolate him and crop, your image will look more like a Van Gogh than a photo.

@NikoDoby: You are right, the added value from a clearer and brighter viewfinder helps a lot.
.. Also the effect you get like Bokeh (or how you spell it) with fast glass is different than with a smaller appertures in teleobjetives.

I am not sure if this applies to all lenes, but fixed aperture professional zooms seem sharp wide open, but variable aperture consumer lenses need to be stopped down a bit.

No question, the fast glass (like f2.8) provides a nice shallow depth of field when that is the effect you want. Yet, f4 at 300mm, for instance, will also blur the background if that background is some distance behind your subject. You cannot change the physics of light with a camera body which has a very high clean ISO ability. But the shallow DOF of a 2.8 300mm lens many not actually be needed as much as we think. In many situations f4 may sufficiently isolate the subject. It all just depends upon the situation you are working with and the desire of the photographer.

I expect Nikon to be making great strides with cleaner higher ISOs in their digital cameras over the next 10 years and then we will see just how many of those $6,000.00 fast tele lens people really find they need for their work.

As the others have said the faster lenses do give you a brighter view and faster focusing due to shallower DOF. For me it also allows me to control DOF more precisely how I like it especially for fast moving wildlife.

"Once, I tried taking a picture of a rattlesnake's fangs with a 35mm lens at f/1.8 but I wasn't fast enough :^)"

LMAO!

"also, there's always situation where a fast prime + high iso is needed, and sometimes 6400 iso is not even enough. (you have to understand that I dislike flash)"

Well said jbl and I also dislike flash.