Trevor: Are you using the tripod head to “scan” by pointing to different locations? If that is the method, then you need to get an offset so that the center post of the tripod is exactly at the optical center of the lens as it is focused. This assumes manual focus with autofocus turned off. One way to find the center is to focus on a pair of pins front to back on a suitably distanced target and then rotate the camera. If the center of rotation is at the optical center, then the alignment of the image of the pins will not change. If it isn’t, then they will appear to shift positions relative to each other. In your example, the pins should be at the same macro distance as the subject. It is possible (likely??) that the optical center will shift if the focus point is changed. A different method of doing the ‘scanning” is to have a horizontal shift bar that will allow you to move the camera back and forth in a plane parallel with the plane of focus. Then all the images in that shift line will be exactly the same size and allow for overlapping in a mosaic. For the next line, raise the camera using the tripods center post and begin again. If the object has significant three dimensional shape to it. You should be careful to do the overlaid images in the same pattern, row by row. For example, include the two outermost images first, then the next pair, and so forth until the central image is last is one pattern. Same thing for the rows. Cheers -----Original Message----- It's a tamron 90mm f/2.8 di macro. When I stop down to f22, once I focus into macro range it recalculates. Not sure of the mechanics on it, but aperture controls in camera will open it up again. |
