You can probably put a Kenko converter on it but I think it would work badly teleconverters are made to be used with long lenses with narrow angles of view and can lose badly with short lenses. You probably can't put a Nikon teleconverter on the 40mm macro because Nikon puts tabs on their converters to make it harder to do bad stuff. They don't increase the focal length because that's a property of the lens itself. What don't you like about the lens? Is it the working distance? Extension tubes decrease the working distance but increase the magnification. The only way I can get it is with the object at 80 mm and image 80 mm using the extension tube. Hate to be picky but how do you get 1:1 mag at 6.3 inches. It's a macro lens with a slightly longer than standard-angle field. With a TC you will have more working distance for the same magnification than without the TC. At its asking price, the image quality that the Nikon AF-S DX Micro-Nikkor 40mm f/2.8G (279.95) delivers is staggering. The extension tube will increase magnification and reduce working distance.
The min focus distance is measured from sensor plane so not much space left between front of lens and subject for lighting, etc. This lens focuses to 1:1 magnification at a minimum focus distance of 6.3 inches with out accessories. It is not clear if you seek more magnification or more working distance. I heard using teleconverters will reduce light gathering capacity according to its magnification. but i dont know whether it will reduce light gathering capacity. to incrase focal length i can use extension tube.
Nikon AF-S DX Micro NIKKOR 40mm f/2.8G is a budget macro lens. Use the resuting magnification in the above approximation to estimate how you are affecting the lens brightness. Now, when you add extension tubes, you further darken the effective f-stop by further incresing the focal length. So, at 1:1 magnification, the 40mm lens's f/2.8 f-stop would have an effective f-stop of roughly f/5.6. The rule of thumb for approximating the effective f-stop is to multply the f-stop shown on the lens by (1 + the magnfication). The usual term for this is to talk about the "effective f-stop," but it is really just the "real" f-stop of the extended lens. Since the aperture size doesn't change, the increased focal length makes the f-stop smaller. As a result, even without an extension tube, you have a smaller f-stop - which, recall, is the ratio between focal length and aperture size. Basically, a macro lens by itself increases the focal length as it focuses at high magnifications. How much depends on the "length" of the converter, the longer the converter the more light you will lose.ĪIUI, this is false. A teleconverter on the other hand does have more "glass" between the lens and the sensor. In practical terms, an extension tube will not lose any light as there aren't any elements between your lens and the tube. A teleconverter gives you a longer focal length. You aren't really increasing the focal length when you use an extension tube. Extension tubes allow you to get closer to the subject for greater magnification.
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