Exactly as you described. The teleconverter will double your focal length, and by doing this, double the magnifacation and narrow your angle of view. Remember with the decrease of your aperture, your light gathering capability is down, and your shutter speeds are lower, and image blur is more possible. Use or tripod or be in a very good amount of light. A lot of teleconverters will disable autofocus when used at any narrower than f/4... i.e.
So be sure to check this before you buy one..
An Extension ring, or commonly known as an extension tube, is used like a teleconverter... but this will decrease the Minimum focus distance. This will allow for you to get even closer to your subject when using a macro lens, and still have your subject in Focus..
Hope my 2 cents helps...~ The Real dj Tru ~.
'Image quality is not the product of the machine, but of the person who directs the machine.' - Ansel A...
Yes those answers made a bit less confused..
Could I use an AI or AIS teleconverter with an autfocus macro lense? Of course in manual mode with manual focus, but it would harm the lense?..
I know that if I use a 2xteleconverter with my 200mm f4, it wouldgive me 400mm f8(?). But what if I use at 2x teleconverter with a50mm g 2.8 macro? It will then give me a 100mm f5.6..
I would not risk connecting the 50mm lens to the teleconverter. Not all combinations are compatible, and there is pretty good risk of doing damage to the glass in one or the other. The teleconverters are designed for longer lenses, and even then, you better check the compatibility charts..
Plus, surely you can buy a good 100mm f/5.6 lens or better, for greatly cheaper than you can buy the teleconverter, and it will be a lot better quality than a 2x teleconverter. Just seems a generally bad plan..
But what will itdo to magnification? Will it give a greater magnification than 1:1?And what will a extension ring do if used with a macro lense?.
Probably should ask "what is your goal?".
The teleconverter will not change the near or far focus distance but it increases the focal length of the lens. You get the same effect as if you used the actual longer lens standing in the same spot (however quality suffers). This is magnification of that distant object, same as zooming in, same as any longer lens, but the focus range of the lens (say for example 5 feet to infinity) is not changed. Aperture is affected, 2x loses 2 stops..
The extension tubes increases magnification, but it now focuses closer than marked, therefore it does not focus as far out (it wont reach focusing at infinity any more, by a long ways). Focusing up closer is close up magnification, the image is simply larger up close. 50mm extension on a 50 mm lens should give 1:1 when the lens is focused at infinity. It does not much matter where the lens is focused, the focusing range is near zero at 1:1, and you instead focus by moving the camera back and forth. Focal length is increased, 50 to 100mm, so you lose 2 stops of aperture at 1:1 (on macro lenses too). But 50mm extension on a 200 mm does not do much, a much smaller percentage of change.
Bellows are the basically the same thing, an extension between lens and camera, typically a greater extension range. When you increase the extension so the magnification is greater than 1:1, this means there is more distance behind the lens than there is in front to the subject. Lens design expects more distance in front, so it is often a good plan to reverse the lens, installed backwards, pointing into the camera, to correct this again..
A close up lens is another choice... basically a magnifying glass that mounts on the filter threads in front of the lens. Any lens of any focal length now pretty much focuses at the focal length of the closeup lens. The lens is marked in diopters, and it will focus at 1/diopters meter. 2 diopters focuses at 1/2 meters which is nearly 20 inches. Aperture is not affected, but it is best used stopped down to f/16 or so, for quality, and sharpness towards the edges..
The true macro lens is by far the best quality for closeup work...
I would not risk connecting the 50mm lens to the teleconverter. Notall combinations are compatible, and there is pretty good risk ofdoing damage to the glass in one or the other. The teleconvertersare designed for longer lenses, and even then, you better check thecompatibility charts..
Plus, surely you can buy a good 100mm f/5.6 lens or better, forgreatly cheaper than you can buy the teleconverter, and it will be alot better quality than a 2x teleconverter. Just seems a generallybad plan..
I don't understand why it would harm anything? It should not harm the camera, because it is AI-Mount. And AI and AIS mount lenses do fit with my D70s without harming the camera. So I would guess the same is for the teleconverter.So you think it would do some harm to the connecting to the lense?.
The teleconverter I wanted to try out, was a " 2X TAMRON F MC4 AI". And the lense I wondered if I could use it with, was a Sigma AF 50mm macro (the newest one).
I found this chart some place: http://blog.nikonians.org/.../archives/Nikonians%20Teleconverter%20Table.pdf , and as I could understand from that, the Tamron 2x should work with most type lenses with Manual Focus?..
It is a difficult design to pull off and make work. The Nikon teleconverter glass elements are sometimes curved enough to stick out past the metal frame. Two incompatible glass elements (lens and teleconverter) may touch and will likely be scratched. Perhaps some are different, but Nikon publishes compatibility charts of what is designed and what will work. The long lenses say "works with these A, B, and C teleconverters". The teleconverters say "works with these A, B, and C lenses".
So plan this out carefully...
I wouldn't worry about physical fit issues on the Tameron. There's a limit on how far the prime lens can protrude rearward (contacting the teleconverter) because it has to be limited to clear the mirror..
Photographic results might be another story but your basic assumptions are correct...
What about the Nikon 2x tc TC-200? Would that be safer to use with a setup like that? With the Sigma macro I mean. Off course with manual focus and manual exposure which I use with macro anyway...