Regarding post #1
If you describe your setup, then we can offer some information that specifically addresses it.
Here is what is needed.
Once you’ve set up your camera on tripod and framed the scene as you want on the first format,
1. What is the distance from the nearest part of the scene you want well rendered to the lens? This is referenced to the first nodal point of the lens, which is generally about the center of the lens lengthwise. Call this distance D1.
2. What is the distance from the farthest point you want well rendered to the lens, distance D2?
3. What is the focal length of the lens, f1?
4. What is your format? This is needed to calculate the DOF.
5. If you want to reproduce this result from the same lens position on a second format, what is that second format? This will be used to determine f2 on the second format and to determine the required aperture of the second lens.
If we know these values, we can answer your questions.
Example: You’ve set up your 6 x 7 cm camera and 90 mm lens to photograph a studio scene that begins at 1.5 meters from the midpoint of the lens and extends to 2.2 meters. Where is the ideal point of focus and what aperture should you choose for good resolution over this scene?
Here, f1 = 90 mm, D1 = 1500mm, D2 = 2200 mm, and the second format is 4” x 5” (95 mm x 120 mm).
The ideal focus distance is 1784 mm. Set up at target in the scene at that distance, focus upon it, lock the focus, and remove the focusing target.
The required aperture is f/15.3, so set the aperture to f/16. This was computed with a circle of confusion diameter of c = 0.059 mm, which is standard for the 6 x 7 format. You can also choose a smaller value for c, depending on your requirements.
On the 4” x 5” format, the lens position and focus point at the same as with the 90 mm lens on the 6 x 7 cm format.
The equivalent lens on the 4” x 5” format is 150 mm. The required aperture is f/26, so close down to f/32. (Calculations based on circle of confusion diameter of 0.10 mm for the 4” x 5” format).
The photo taken on the 4” x 5” format in this setup should duplicate the one made on the 6 x 7 cm camera. The difference is the size of the negative. Since both of these formats have nearly the same aspect ratio (1.24 and 1.26 respectively), the in-camera framing will be nearly identical.
Before investing in a 4” x 5” camera, lens, and so forth, it would be useful to first make the best photo you can with your existing 6 x 7 cm equipment on a fine-grain film known to produce good resolution. Print this negative at the size you want and determine whether it has sufficient resolution for your requirements. You might find that satisfies your desire for a large finely detailed print.
Kodak T-Max 100 is a good film choice for such work. The lighting also plays an important role as well. Some lighting setups will reveal detail better than others.
Go figure!
