Marcelo:
Thanks very much for your explanation. This really helps.
If I understand you correctly, the working distance would be the Nikon published "minimum focus distance" from the sensor plane minus (a) the thickness of the body forward of the sensor plane (b) the length of the lens and (c) the distance from the front of the lens and the outside of the port.
In your example with the 105, some simple arithmetic yields the sum of a + c to be about 2.4 inches. Using this number with the lens length of the 60 (shorter by 1 inch), further assuming that the "c" distance is the same with the proper port and the shorter plane-to-subject minimum focus distance of 7 inches yields an answer of a working distance for 1:1 of about one inch. That would be "really close", as you say.
In fairness to my comparison with the Nikonos, however, using my close up lens over my 35 mm UW Nikor lens gives me a reproduction ratio of only 1:4.5 at 10 inches away. I don't know how to do the math, but I'm guessing I might be that distance (10 inches or so) with the digital 60 rig to get the same ratio. Is that about right?
Am I getting this?
The beauty of the digital setup, of course, is (a) I can choose my working distance; (b) autofocus will take a lot of guesswork out; and (c) with the 12+ megapixel files from the D90 or D300, I can crop, within limits, to the shot I want, if I can't get close enough.
Thanks very much for your explanation. This really helps.
If I understand you correctly, the working distance would be the Nikon published "minimum focus distance" from the sensor plane minus (a) the thickness of the body forward of the sensor plane (b) the length of the lens and (c) the distance from the front of the lens and the outside of the port.
In your example with the 105, some simple arithmetic yields the sum of a + c to be about 2.4 inches. Using this number with the lens length of the 60 (shorter by 1 inch), further assuming that the "c" distance is the same with the proper port and the shorter plane-to-subject minimum focus distance of 7 inches yields an answer of a working distance for 1:1 of about one inch. That would be "really close", as you say.
In fairness to my comparison with the Nikonos, however, using my close up lens over my 35 mm UW Nikor lens gives me a reproduction ratio of only 1:4.5 at 10 inches away. I don't know how to do the math, but I'm guessing I might be that distance (10 inches or so) with the digital 60 rig to get the same ratio. Is that about right?
Am I getting this?
The beauty of the digital setup, of course, is (a) I can choose my working distance; (b) autofocus will take a lot of guesswork out; and (c) with the 12+ megapixel files from the D90 or D300, I can crop, within limits, to the shot I want, if I can't get close enough.