Dear a900 enthusiasts,

In my previous thread I tried to compare the resolution of the a900 to my Hasselblad system using the Minolta 24-105mm f3.5-4.5 lens vs. the Hasselblad normal 80mm f2.8 lens. Although my testing shows the Minolta zoom is an excellent general purpose lens, many asked me to repeat the test using the Sony Carl Zeiss 24-70mm zoom. Well the CZ lens arrived today, so I repeated the test. This time I was especially careful to make sure all the parameters were equal, following many of the helpful suggestions in the previous thread.

Here is the setup:
1. Hasselblad H1 with Phase One P30 back (31 mpixels) and 80mm lens vs. a900 with native 24.6 mpixels, and CZ24-70 mm f2.8 lens.
2. Used camera's exposure with matrix mode. Adjusted exposure slightly in ACR4.6 to match. Used mirror lockup for triggering.
3. Set the CZ zoom at 60mm which exactly matches the width of the two cameras field of view.
4. Imaged at ISO100 using f5.6 on both cameras. Near simultaneous exposures.
5. Waited for sunset and repeated at ISO800 f8 on both cameras.
6. Processed in ACR4.6 with sharpening and noise reduction set to zero. Everything else at default.
7. Produced comparison images at 100% crop
8. Here is a photo of the setup:
http://www.dboyd.com/Photos_08/HasselbladvsSony/IMG_0274.jpg
Here is the comparison at ISO100:
http://www.dboyd.com/Photos_08/HasselbladvsSony/Compare_at_ISO100.jpg
Here is the comparison at ISO800:
http://www.dboyd.com/Photos_08/HasselbladvsSony/Comparison_ISO800.jpg
Here is the comparison at ISO800 after application of Neat Image noise filtering:
http://www.dboyd.com/Photos_08/HasselbladvsSony/Comparison_ISO800_after_Neat.jpg
For those who want to review the RAW images used in these comparisons, you may find them here for download: http://www.dboyd.com/Photos_08/HasselbladvsSony

Compared to my previous images, the Carl Zeis lens does in deed exhibit improved contrast at mid to high frequencies. Readers can draw their own conclusions about the camera comparison, but in my own case, I no longer feel the need to own a P30 back.

The other comment I would like to make is it seems to me odd that so many reviewers concentrate their reviews on the efficacy of the built in camera noise reduction software. It seems to me that none of these will be as effective as external noise reduction software. Therefore, who cares about the lousy internal software?

==Doug