Expanding on the loading the images into a stack of layers - you could load all images into layers in a stack, then crop your document to your desired size. You need to make sure that you do not delete the cropped pixels - in PS CS6 there is a check box for this option (uncheck it). Now the crop window acts like a mask, and you can move the image layers underneath that mask to view just the portion of the image visible through the crop mask. Using the crop tool permits you to specify the location and size of the crop window precisely by entering the numerical values for these parameters, if you wish.
Once you have your crop window set up over the area of the image you want to sample, use the Comps window to set up a comp for the visibility of each layer - name each comp appropriately ("f/2.8_Upper_Left", "f/4_Upper_Left" etc). If you have not used Comps before, google it. It is pretty straightforward - you set the visibility and position of the layers in your stack and then make a new comp that records all of that state info. So, you want to make each of your layers visible, one at a time, and record that state as a comp. Then you can repeat this for as many areas in your image that you want to sample at 100%.
To move to another area of the image, select all of your layers and move the layers so that the next area you want to export as crops is within the crop window - moving all of the layers together will keep them aligned and registered to each other. Again, make a comp for each layer and name the comp appropriately. Repeat until all areas have been comp'ed. Make sure that when you are making the comps, you enable the "Visibility" and "Position" checkboxes.
Then choose "File > Scripts > Layer Comps to Files" - this will automate the process of exporting each comp as a file, in the format you choose in this dialog. The name that you give each comp is included in the exported image's filename automatically, so no manual renaming necessary.
See if that speeds things up.
Also, if you are shooting raw and need to adjust some settings in ACR prior to bringing all of your images into PS, do this (so that the XMP sidecar is written for each file). Then dismiss the ACR window (choose "Done" in ACR instead of Open images.
Now the images are all set for the automated process of bringing them into PS as layers in a stack: choose: "File > Scripts > Load files into Stack..." and select all of the files you have set up in ACR already, in the series of images you would like to compare and PS will load them all as layers in a single document. The only problem with this is you need to know what parameter in your test is associated with each layer - however, PS names each layer in the stack with the filename of the image imported into that layer, so you should be good to go.
And, of course, you could probably record an action to do all of this automatically, as long as you keep the input image format (order of images, number of images, etc.) tidy and uniform. A little bit of preparation on the front end will speed up the automation and make things easier and quicker on the back end, with less chance of error.
Hope this helps - us Kirks have to stick together.
kirk
