Since I bought the Nikkor 50mm with an extension tube, I decided to play with the combination of the 2x converter, the extension tube, and the 50mm lens.
I took pictures of the LCD panel of my notebook. The purpose of the test is just to see how big I can get a subject onto the CCD sensor.
Here are the results:
The pictures were taken at the closest distance possible without going out of focus. I screwed up the test by subconsciously changing the shutter speed between the first, second, and third shot because of the drop in light level. The first was shot at 1/160 sec. The second at 1/100 sec. The last three shots were taken at 1/40 sec.
Anyways, from an image size point of view, the 2x converter does what it does -- magnifies the image by 2. The extension tube does what it does -- allows you to get much closer to the subject.
Notice how adding the 55mm extension tube behind the 50mm lens (i.e. between the 50mm lens and the camera body) gets me so close to the subject but at the same time cuts out so much light. You lose about 2 f-stops by adding either a 55mm extension tube or a 2x converter on.
Notice also how the order you add the 2x converter and the extension tube makes a huge difference. With the 2x converter in first, followed by the extension tube, then the lens, you can obtain a 2:1 reproduction ratio -- that is better than life size! Excellent. You lose about 4 f-stops though. Ouch. Oddly, if the 2x converter is placed between the extension tube and the lens, the image is much brighter. Now, I gotta think about the physics to explain this, or maybe I made some other subconscious change during the test.
For bigger pictures, visit http://www.utm.utoronto.ca/~advu/test-macro
I am now tempted to buy an extension tube with electronic contacts for my Nikkor 18-200mm lens. This is a G lens that has no aperture control ring so you would need a tube that can relay the aperture control signals from the camera to the lens.
Well now you can go beyond the human eye. I checked the pictures in full size and you can see the pixels of your LCD monitor, specially in the last two pictures. I guess Macro photography is another world that you can explore.
ReplyDeleteFinding a small insect that will not move will be next to impossible though, unless it likes to play dead. I think I will do flora and static objects for now.
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