IMHO, it shouldn't be such a big problem, although I doubt Nikon will go for it. Most of new lenses have VR already, so from economical point of view it's not beneficial to put such a product on the market. From the construction point of view, IMHO it shouldn't be such a big problem, it should be quite easy to implement it into regular TC.

Physical position in the barrel doesn't matter. Where are the VR elements in relation to the nodal point?

ok i see where you are coming from now.. but I dont think you are correct in your understanding of how vr is implemented. if you look at all the vr/is/vc/os lenses. you will see that the vr elements are always close to the sensor and not at the fulcrum of the teeter-totter. so the angle of correction is not the same for varying focal lengths. this will be more so for a tc with vr where the elements are not able to float along the axis of the overall lens.

if you look at similar lenses with and without vr you will see that the vr elements are additional elements that look like an integrated tc. IE the VR elements are additional elements that were included only for VR and thus degrades the IQ. I believe that this is the reason VR was not added to the 24-70 nikkor .. it degrades the IQ too much for what the primary function of the lens is.. the best IQ possible! It is known that the older Non VC version of the tamron 17-50 has better IQ than the newer VC version.

heartyfisher said:
It is also probably the reason a dedicated VR lens performs much better than sensor move VR compensation.

This is because sensor VR works by moving the sensor.

Let's make an analogy.

Sensor VR attempts to move the sensor to keep in-line with the end of a teeter-totter.
Lens VR attempts to bend the teeter-totter at the axis so the end doesn't deflect as much.

Same angular correction, but which involved less physical movement?

Since sensor VR is piezo-driven there is a very limited range of motion, and since it takes place far from the axis the movement is at its largest. This is why it sucks.

I am almost certain that the amount VR WILL need to be different depending on the focal length. So it either can find out from the electrical contacts or will need to be told what focal length the lens is. Just the fact that you need different shutter speed to compensate for focal length on non vr lenses should be enough evidence that that is the case. It is also probably the reason a dedicated VR lens performs much better than sensor move VR compensation. In cases like this i think I believe my observations more than the maths! .. I was never very good at maths anyway! LOL!

No I dont think you would loose infinity focus neither just like you don't loose infinity focus on a normal TC? Also loss of light would also be minimal ie. similar to standard TC. any loss would only be what you lose looking through some extra glass elements and I would say that would be minimal ( this is not including the light you would loose due to the TC magnification). I think there is no tc that can properly transmit all the light from a F1.4 lens I think the best you can do is 2.0 ie if you stick a 2X tc on a F1.0, F1.2, f1.4, or 1.8 lens you get a F4 lens.

Re IQ there is bound to be some loss in IQ just because there is probably 7-10 elements involved. but the best TC currently have 7 or more elements. so...

There used to be an auto focus TC as well that you could use on manual focus lenses. Would be good if they included that function in their product!!

Testing123 said:
Why? Vibration is a problem of angular velocity.

I believe if you write out some pseudocode for how you're thinking VR works you'll notice you're applying the magnification factor twice. And then if you refactor that pseudocode as a pseudoequation you'll notice that magnification is on both sides and you can cancel it out.

You may be right, but on the other hand: if pseudocode would work we would not need ED glas or aspherical elements ;)

VR is not really the latest technology breakthrough but it is on the market since quite a while and I wonder why there is no such thing as an 1.0x TC VRII available. Could be marketing reasons (companies might rather sell lenses with VR than a simple TC), product positioning (either make it cheap and low optical quality or expensive and good IQ) or technical (details like existing patents etc).

But who knows, maybe we will see one of those at the next Photokina. Anyways, it's an interesting idea!

NSXType-R said:
There most definitely will be loss of light, so you'd be losing stops if it can be done. Would you also lose focusing to infinity, because it's sort of like a extension tube?

You would loose light as additional glass-air surfaces are involved. The effect can be minimized by using some coating. You would loose more light if the lenses in the TC are not big enough for the attached lens (this would be some kind of aperture), but I would call that a design flaw.

In theory you should not loose the focus to infinity (just like with a normal teleconverter). But in real life I don't know if they would be able to make such a thing that does not introduce any distortion or vignetting, does not decrease the sharpness of the main lens, has little light loss and works for all focal length from wide to tele without loosing focus to infinity or close distance for all lenses. At least not for a reasonable price.

There most definitely will be loss of light, so you'd be losing stops if it can be done. Would you also lose focusing to infinity, because it's sort of like a extension tube?

Interesting stuff.

Correlli said:
I could imagine that the VR TC needs to know something about the lens that it is attached to as well. A "1° shake" of the camera has a different effect on the image if use a 20 mm lens or a 200 mm lens.

Why? Vibration is a problem of angular velocity.
The "effect" may be ten times as large when using a 200mm lens as opposed to a 20 mm lens, but that's a result of magnification. 1 degree of tilt is still 1 degree of tilt, and 1 degree of correction is what is needed, not X mm of correction.

I believe if you write out some pseudocode for how you're thinking VR works you'll notice you're applying the magnification factor twice. And then if you refactor that pseudocode as a pseudoequation you'll notice that magnification is on both sides and you can cancel it out.

Nice idea, but this is only a patent, not a product (yet).

I could imagine that the VR TC needs to know something about the lens that it is attached to as well. A "1° shake" of the camera has a different effect on the image if use a 20 mm lens or a 200 mm lens.

This is definitely an interesting patent but we will have to wait for the product to show what the performance really is like.

http://photorumors.com/2011/02/21/tamron-patents-image-stabilizing-teleconverter/comment-page-1/#comment-14636

Haha!!!! Told you j****. :-p

ted2001 said:
I'm not sure it would have as much effect on the focal length, as on the focus distance. Your lens would no longer focus to infinity. It would be like an active extension tube. Better to go after in-camera VR.

True, but if there is glass involved, as would be need for VR, then it would effect the focal length of the lens.

tferroato:
TCs are more like magnifying glasses, and they always effect focal length. Some TCs don't allow you to focus to infinity, under some conditions.

Is there an optical way to fix that? You're able to focus to infinity with TCs, so there must be a way to counteract it.
Like I said, I don't know much of anything about the physics behind lenses, so I'm just asking.

I'm not sure it would have as much effect on the focal length, as on the focus distance. Your lens would no longer focus to infinity. It would be like an active extension tube. Better to go after in-camera VR.

Adding something between the lens and the body would increase the focal length.

I don't understand. Why not?
Is it not possible to introduce an additional glass element to the back of a lens that stabilizes the image it produces?
VR lenses have an element that wiggles around to correct for image shake. Why can't that element be added to the back of a lens the way a TC can?
http://imaging.nikon.com/products/imaging/technology/vr/index.htm

It would not make any sense, and it actually can not be done at all because of the laws of optics and physics.

Is it possible for Nikon to create an adapter that attaches between the lens and the camera that would give non-VR lenses VR capability? Something along the lines of a teleconverter but instead of magnifying the image, it corrects for movement?
I'm not well-versed on the optics that would be required or the ins and outs of the Nikon VR system, but it seems to me that there would be a market for a VRconverter. Aren't there lenses that you have that you'd like to be able to VRify?
Or is this one of those things that Nikon simply won't make because then they won't be able to get you all to buy their newest lens updates