The new Pentax 645Z sensor is 51.4 megapixels. Great for image quality and an amazing amount of detail, but this can lead to a few issues. A 64GB memory card can hold only 566 images.   (Compared to 712 images on the 40MP 645D  or 1198 on the Pentax K3) Larger files mean that it’s slower to download the data from the SD card, and slower to import into Lightroom, and slower to create 1:1 previews, and slower to edit in Photoshop. With the 645D, I’d got used to setting things running on my old Mac Pro 1.1 and then taking the dog for the walk or making a cup of tea. Recently, however,  when shooting more frames, and at higher resolutions the speed of my workflow was no longer efficient. I wanted a Mac with 32GB RAM, and a PCIe SSD with about 500GB of memory. The easy option would be to look at the new Mac Pros, but a model with the specs I wanted would be around 5,000 dollars. Instead, for around half …