@Bill: The problem with the FF/GF issues with the Sigma lenses, is that (sometimes) depending on the focus distance, the same lens will either FF or BF. e.g. up close it might FF, but at longer distances BF - so can't always be corrected 'in-camera'. It's also very interesting with the lens performance between the two lenses. You would have thought if a lens performs much better at f1.4 than another lens, it would also perform better at smaller apertures (within reason) - but that's obviously not the case with these two lenses. But you are right, I'm probably very rarely going to be using the 50mm above f5.6.
I agree with Bill. I don't think you made w rong decision at all Simon apart from buying the CZ 24-70mm should you not have it yet... the only advantage I see with the 50mm over the CZ is weight. Can't see me using it a lot as I don't usually use my camera in crappy light anyhow. Hardly ever shot film with over ISO200 nor digital.
P.S. Yep- it is getting expensive...
If I'm honest and I know this will not go down well with the CZ2470 owners, but I'm currently holding off buying the CZ due to the poor bokeh under specific lighting conditions, which although not a deal breaker - before splashing out £1200 on the CZ I want to wait to see what my options are. I know the specific lighting conditions are usually
harsh lighting conditions which you usually shouldn't be shooting anyway, but I have seen a similar effect under other conditions (there were some examples to links that I posted in the other thread).
The new Sigma 24-70 f2.8 HSM is due soon (sometime in Feb for Nikon/Canon and a few months later for Sony) which RRP is £800 (currently £650 pre-order). As it's double the price of the previous version, I'm hoping that it might be an alternative to the CZ. It's not ideal as it's 82mm filter, which means probably spending a few hundred £ more for filters compared to the CZ (as I already have a set of 77mm's), but for me I only want to do these lens purchases 'once' from now on.
The second alternative might be (if it exists) the Sony 24-105G f4 SSM (there have been several rumours). For me, I'm thinking this might be a nice option for slightly better focal range.
I must admit that I kind of like my Tamron 28-75 at the moment. The bokeh seems pretty good (although I must admit we are not getting harsh lighting conditions at the moment). It's pretty sharp by f4 and I actually like the fact it's a little soft at f2.8. There is so much resolution with the A900, that I'm liking the option of 'toning it down' a bit. I use this focal length mainly for snapping photos of the children, so the reality is that I don't actually need super high resolution with this focal range (landscapes are usually 16-35) - and if I do, I'd switch to the 50mm or 85mm primes as they give me more options for larger apertures. I have been thinking about a 35mm f1.4 to add to the range of primes, but only thinking!
Just an observation with CZ (and I know this has been said before by other members), CZ do appear to go after absolute resolution rather than trying to get the best bokeh possible. I know someone stated this when I got the CZ85 compared to the KM85G - but I must be honest it didn't mean that much to me at the time.
Anyway, so thats where I am. Waiting for the reviews of the new Sigma, and then waiting for it's availability in Sony mount, and maybe if the Sony 24-105G is released - maybe waiting for that one. And if the other two don't meet expectations, I'll get the CZ.