[y0chang]

Oh well... just a bunch of speculation. Before I read this thread, I already figured we were going to be talking ~$2000 for the lenses I'd desire, and I could never go there. Bought a 60-250 instead. I'm not a professional either, so that purchase makes more sense for me. I'll keep an eye on what the real prices end up.

That is the thing, even if these lenses come out, the 60-250 and 50-135 will still be there, and are high quality products. The 60-250 isnt quite a super zoom but is compact and a good range. The 50-135 will be an affordable yet flexible alternative to a 70-200mm. Of course I'm assuming that these lenses will not fall out of production...

[starjedi]

100-400 f4. No, it's to small. Maybe f5.6, because the frontal element most be only 72mm wide. At f4 must be 100mm, at least.

Looking at both lenses, 70-200 f2.8 and 100-400, it seems to be very close in diametre. and the 70-200mm must have a 72mm frontal element, to be f2.8.

100-400 F3.5-5.6 should be a reasonable assumption. If it is 6.3 at 400 side it is not worthy to buy it at price above $1000...

[Flugelbinder]

That is the thing, even if these lenses come out, the 60-250 and 50-135 will still be there, and are high quality products. The 60-250 isnt quite a super zoom but is compact and a good range. The 50-135 will be an affordable yet flexible alternative to a 70-200mm. Of course I'm assuming that these lenses will not fall out of production...

And there's always the Tamron...

[normhead]

My A-400 ƒ5.6 is 77mm. If it's 72mm it's 6.3.

[JimmyDranox]

My A-400 ƒ5.6 is 77mm. If it's 72mm it's 6.3.

I think that 77mm is the size of the filter thread. Did you measure the real diameter of the frontal element? I did with the Tammy 70-200/2.8 and Sigma 70-200/2.8. The frontal element was around 71-72mm, and of course, filter thread was 77mm.

72mm is the size of the clear opening on the level of the front element, because 400/5.6=71.428. Of course the frontal element can be bigger than 72, but cannot be much smaller. For f6.3, the frontal element must be 63.49mm, minimum. And generally, manufacturers didn't put oversize lenses, for obvious reason.

Of course, in reality, the frontal element can have 71mm, or somewhere around, some lenses branded as f2.8 are actually f2.9, and so on. but the theoretical figures are clear f = focal lens / diameter.