Remember the Loxia 21 has mild field curvature at infinity distances, so I focused at infinity but in a way that center and extreme edges look best. (If I had just focused on the infinity center, it would look even better)
The zoom is impressive! At f/2.8 the image of the zoom appears even sharper than that of the Loxia. Does it have to do with the field curvature of the Loxia and the way you focused it then?
It seems that the sweet spot of the zoom at 24mm is at f/5.6 while at 70mm, it is at f/8.
It'll be interesting to see how all that new Sony lens voodoo looks when this thing is shot at 24, wide-open and close-focussed in Photojournalist mode. It's certainly more than sharp enough for those f/8 pictorial tasks.
AGeoJO wrote:
Does it have to do with the field curvature of the Loxia and the way you focused it then?
Yes, If I would focus on the center, the extreme edges would suffer slightly and vice-versa. The way I focused gives the best of both worlds. I agree that the zoom at 24mm is really good. Still, the Loxia takes the cake at the edges.
Look at the extreme corners. Very little change from f/4 until f/8.
I am surprised. Sony's stated philospohy was to make a sharp lens with a high level of pleasing bokeh. But even with the chasing of extreme micro-contrast more typical of Zeiss lenses, it holds its own quite well. The Loxia 50 sure has the edge at wider apertures, probably due to a combination of micro-contrast optimization, faster native aperture (f/2.8 is already stopped down a full stop), and the Zeiss T* coatings. This looks to be a seriously good lens. And Fred has done nothing with Bokeh, one of its strongest design goals. Pretty impressed all around with this lens.
At 24mm the zoom is still getting sharper in the corners/edges @ f/8 before entering diffraction territory, so IMO it's sweet spot is f/8 for landscape use. The edges are much better than the 24-70 f/4 FE but I'm not sure if the performance is commensurate with the price.
Fred Miranda wrote:
I was afraid the Loxia 21 would suck and Guy would put it for sale!
I just checked the stock of that lens at B&H again and it is still available . Not that I didn't get tempted but I am holding out for the new Batis 18mm, which will transition better from the 24mm end of this G Master zoom.
Much better, AG. No contest in the corners, which is to be expected. Micro-contrast is the essence of 'sharpness', which is why CZ have been using it since the '50s.
The L50/2 is very strong in the center AND the far corner at best aperture of f5.6 - it makes 65-75% contrast (modulation) in these areas. This is why the 'extreme edges' L50 f5.6 crop looks so good vs the zoom, and why the zoom gets better at f8 but not the L50.
The zoom won't match the Loxia or any very good 21-25mm Distagons in the outer frame at its wide end (at any working aperture), but will get close in the center. The zoom does better than expected, these are very high magnifications. At 70mm you should see a better result for it at f8 than at the wide end, going by Sony's data. Thanks Fred.
Fred Miranda wrote:
Yes, If I would focus on the center, the extreme edges would suffer slightly and vice-versa. The way I focused gives the best of both worlds. I agree that the zoom at 24mm is really good. Still, the Loxia takes the cake at the edges.
With the same token, Fred, it is also possible that the zoom suffers some field curvature also albeit not as bad as the Loxia, right? What I am trying to say is with some slight focus adjustment, the corners may be rendered better than what it did in corner or extreme edges here in this test. It is too early to rule that out or in at this point, correct?
I didn't expect the GM to match any of the Zeiss or Sony CZ primes like the 55 1.8, but for a zoom it looks quite good. Thankfully, I'm not in the market for a standard zoom .
Just out of curiosity and because I haven't used any standard zooms in what feels like ages, how does the GM stack up to other 24-70 2.8's like the version II of Canon's 24-70?
Looks quite good overall, definitely better than the zeiss 24-70mm f2.8 in the corners all around, and at 50mm and 70mm. The more central parts don't look terribly different
! Why not?
.