Field of View Comparison between the 28-45mm f/4.5 and the 25mm f/4.0
Some of you are probably curious to find out whether the 28-45mm ED AW SR is able to replace the 25mm f/4.0 at 28mm. 3mm focal length reduction isn’t really a lot, especially if you consider that you gain a total of 20mm zoom range, making this a much more versatile wide to ultra-wide lens for the Pentax 645 system. Image quality wise (non scientific just by looking at the crops), the 28-45mm offers greater center sharpness (and resolution) at 28mm, whereas the 25mm seems to have a slight advantage as you go look further towards the edges of the frame. YMMV.
This is taken with the 25mm at f/9, 125th/sec.
This is taken with the 28-45 at f/9, 125th/sec.
Both images were shot from the same position on a tripod (SR disabled on the 28-45mm). To really get an idea what you will gain (or lose) when shooting with the 25mm or 28-45mm I decided to overlay both images. They are not a perfect fit (because of different distortions), but I am sure you get the idea.
Shake Reduction aside, both are heavy lenses, but I feel that at a similar price point, the 28-45mm ED AW SR is a more versatile choice, which also happens to offer better center sharpness. All images shot on a 645z.