I'm sure more people with more technical knowledge will chime in here, but I have the K200D and print at 20" x 30" (which, to my understanding, is the closest US size to A1) with no problems and no up-resing. I also don't crop my photos, though, so if you tend to crop heavily, then the K20D might be of more use.Keitha McCallPentaxian and Shapshot Shooter since April 2007http://flickr.com/photos/aravis121/http://www.ascenicworld.com..
I wouldnt limit yourself to Pentax just because of a tripod and lens. The tripod you can use with any camera, and you may not find the lens that useful given the size difference between the 35 mm film frame and Pentax digital sensors..
As for printing sizes, it is really too subjective to answer. Pesonally, I wouldnt print larger than A2 even with the 12.8 Mp of my Canon 5D, but I wouldnt have printed A3 from 35 mm film..
I am currenylu using a Horseman Veiw camera. So I am probably spoilt at the moment!.
Any others you would suggest in the sub 600 price range? I am taking pictures of architecture and trees..
There is a thread on this subject here with some useful posts:.
I would suggest obtaining uncropped, full sized images, preferably of material you want to shoot, from the cameras you mention. Then crop them to an 1/8th of their size and printing them on A4, which is 1/8th of A1. Then view the crop next to one of your A1 prints at the viewing distance of the A1. There would be a tendency to view the A4 handheld, but this would be unfairly detrimental to the A4. You could also try 1/4 and 1/2 crops at A4 and view them close up with your images to evaluate where the resolutions correspond..
I think that to go to A1, you would have to go with at least 20+ Mp and thousands of pounds..