caterpillar
Veteran Member
No, it's you who is missing the point. If the f2.8 at the correct shutter speed is at iso 1600 and your f4 is at 3200, then your shot will have more noise. That is why the f2.8 is no pittance when it comes to action shots. Boosting the ISO, as any pro knows is what you want to do last if you can because you take a quality hit in dynamic range, noise esp in the shadows, etc.you are missing the point, I was talking about f2.8 vs f4 at the same shutter speed . what you end up with f4 shot using higher iso, and the point here is that the sharp f4 shot with higher iso gives you at the least the same amount of detail as the unsharp f2.8 shot with low iso.I was talking of the shutter speeds at f2.8 vs f4, not sharpness. Even a sharp lens will blur if the shutter speed is not there to support you.F2.8II is worth the money because it is sharp. F2.8I is not wroth the money because it is not sharp. it is that simple.
if it is between F2.8I and F4, then get F4. because it is so sharp.
in fact F2.8I at F2.8 is so unsharp you will end up with better image with F4 and twice the iso.
See, where you are not listening. But our mk-I is sharp at f2.8 at 200m! And we are on par with your f4! That is for sure. The difference is, we have f2.8 to play with. You don't. Why do you insist that our mk-I at f2.8 is soft? It isn't. And most lenses made sometime 2006 and later are usually sharp even at 200m.F2.8I can be sharp, yes, only if you slow it down to F4, so what is the point of carrying the extra weight and pay the extra dollar for it?
Again, not as sharp as the non-IS or the mk-II, but it is no slouch like in the early 2000-2005 releases where getting a good one is a hit-or-miss. Mostly the sharp ones are rarity. Not anymore. Now, it's the other way around.
Then I pity you. You haven't really used a good copy of the 70-200 f2.8 or f4.0. Having used many copies of these, I am privileged to know the potential of these lenses. Since you lack the experience, maybe you should take leaf from our book instead of insisting on your positionactually non-IS F2.8 isnt that sharp either.True, they are not as sharp as a non-IS or the new mk-II IS, but it is sharp enough. It is never soft.
See, you are comfused again. If the shutter speed is not going to stop the motion, then 3200 is not going to be close enough. And remember the noise of the 3200. To illustrate this further, what if both our headroom is 128,000 ISO and to properly stop the motion, I need f2.8, then you don't have any more room to move since you are stuck at f4! I have the shot, you won't.and maybe F2.8I it is "sharp enough", just like iso 3200 is "close enough" iso 1600, which therefore makes F4 just as "good enough", doesnt it?
And if it is sharpness you are talking about, even if I conceded that mine is "soft" (w/c I don't concede) at f2.8, I have f4.0 and know we are even. The thing is, my f2.8 isn't soft and I have f2.8. You don't. When you are at the end of your ISO threshold, you have nothing to hold onto. I have.
It is not an assumption. It is a fact. Look at the schematics. Look at the f2.8 at f4 schematics. Basically the same for all the lines (IS or non-IS) for the same class. So, you are the one making bald assumptions. And you have forgotten even for the same class (mk-I) the 2006 and up are sharper than the pre-2006 versions. Same everything. So, what does that tell you? Where does the difference lie - It's in the way they are made. The new factory that was inaggurated in Japan using newer machines, robots, collimaters, now can make them better, hence we get better performance across the board.that is some bald assumption, you odnt know if they are the same design, some schematics may appear similar, but I am sure there are plenty of detail that can vary. in any case, plain as the day, F2.8II is noticeably sharper than F2.8ITo say that a mark I is soft is not exactly true if they basically are of the same design
The f2.8-II is notiecebly sharper than the mk-I in some situations and if you really pixel peep. But in the center, they are about the same. Contrast is slight to the mk-II, but these are hard to detect in most shooting situations. As long as there is no light from the front, it's hard to tell them apart.
So, the difference bet the mk-I and II is there. But it is not night and day. And it becomes noticeable only in certain situations. Even the AF speed difference is hard to come by. It's like talking of .05 vs .04 sec. It's there, but will you miss the shot? Likely not.
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- Caterpillar