The A850 and A900 are optimized for low ISO shooting. They use a stronger Colour Filter Array than anything else short of a MF system which gives them the best colour at low ISO's at the cost of poor high ISO performance.
Note that if you downrez A900 files to APS-C resolutions you pick up performance, the A900 downrez'd to 12MP delivers high ISO results only about a half-stop behind a D700. But you need to downrez to get that performance. I'd expect the K-5 to provide similar performance in most regards, with better High ISO performance out of the box and worse low-ISO performance. Dynamic range should be similar though (the A900/A850 give up a bit of DR as well for the stronger CFA). -Adam On Tue, Jan 11, 2011 at 1:05 PM, paul stenquist <[email protected]> wrote: > Good post. I suspect that the K-5 can outperform the A850 in all but pixel > count. But that's just a guess based on sensor tests and a wedding > photographer friend's comments regarding his A850. > Paul > On Jan 11, 2011, at 7:07 AM, Boris Liberman wrote: > >> Hi! >> >> As I wrote earlier, my friends from DC (well, actually it is MD, but I like >> to think of this as DC) came for a visit and left. Among other things I did >> back up photos for my friend and I was given an opportunity to keep them for >> my examination. He has Sony A850 and an assortment of lenses, notably the >> famous Minolta Beer Can, Tamron 17-35/2.8-4.0 and Tamron 90/2.8 macro. >> >> I have looked and processed and examined and pixel peeped few dozen images >> and compared some of them side by side given that we were shooting at the >> same time on the same location. >> >> Few ideas crossed my mind: >> >> 1. Under bright day light Sony wins hands down. The exposure latitude and >> color fidelity are ahead of those of K-7. The dynamic range difference is >> evident once you start to play with curves and look into shadow-to-light >> transitions. >> >> 2. Under low light both cameras struggle, though my friend does not shoot >> above ISO 1600, while I shoot at ISO 3200. Given pixel count advantage, I >> think it might be possible to downsize Sony images to take care of some of >> the noise. >> >> So, on the surface it looks like naturally one might want to upgrade to >> either full frame or another Pentax camera with better sensor. >> >> On the other hand, I had to look at 1:1 or even 3:1 (300% magnification) and >> really side by side to see those differences. Of course playing with >> exposure slider makes different impression immediately, but beside that I >> really don't think that Pentax is so much behind. Let's say that the >> difference is 10-15% although I do admit and do realize that these >> percentage points are meaningless. What I am trying to say is that the >> difference is relatively small. >> >> I have some reservations about the aforementioned lenses' performance in >> some of the situations, but that's a different matter. >> >> Thankfully, I don't feel like I should or even must update from K-7 to K-5 >> or to Canon 5DMk2 or whatever. I kind of used to feel that way having seen >> Paul's comparison shots from his basement. >> >> I also think that to say that camera A offers revolutionary improvements in >> IQ dept over camera B (*) would be a serious overstatement or simply a >> market speak. >> >> Well, at least I had my chance to vent. >> >> Boris >> >> (*) As long as both A and B are of similar general class. It stands to >> reason that 16x24 and 24x36 cameras are closer than it might have seemed >> initially. >> >> -- >> PDML Pentax-Discuss Mail List >> [email protected] >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> to UNSUBSCRIBE from the PDML, please visit the link directly above and >> follow the directions. > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. > -- M. Adam Maas http://www.mawz.ca Explorations of the City Around Us. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
