Nikon Teleconverter for 18-300mm

[Beauty Through a Lens]

Is there a 2x teleconverter compatible with the AF-S DX Nikon18-300mm f/3.5-6.3G ED VR? I understand it may not have autofocus.

I was looking at this one but it apparently isn't compatible...

[Shadowman]

I think the problem with the teleconverter is that it extends into the lens and can come into contact with the rear lens.

[Manfred M]

Is there a 2x teleconverter compatible with the AF-S DX Nikon18-300mm f/3.5-6.3G ED VR? I understand it may not have autofocus.

I was looking at this one but it apparently isn't compatible...

The issue is that the autofocus mechanism needs a certain amount of light to function; on the older Nikon cameras one needed a minimum maximum aperture of f/5.6 although that has dropped to f/8 on some of the newer models. With a 2x converter, you will lose two stops so you would be shooting with a 36-600mm; f/7.1 - f/13 lens. So at the short end the autofocus might just work; on the longer end, it definitely will not work.

Teleconverters are an okay solution for fast lenses (image quality does suffer, especially with a 2x converter); on a relatively slow lens like the 18-300mm, it is not really a viable solution. On something like a f/2.8 70-200mm lens you would get a f/5.6 140-400mm lens with the 2x, and that is still fast enough to work with.

[Beauty Through a Lens]

The issue is that the autofocus mechanism needs a certain amount of light to function; on the older Nikon cameras one needed a minimum maximum aperture of f/5.6 although that has dropped to f/8 on some of the newer models. With a 2x converter, you will lose two stops so you would be shooting with a 36-600mm; f/7.1 - f/13 lens. So at the short end the autofocus might just work; on the longer end, it definitely will not work.

Teleconverters are an okay solution for fast lenses (image quality does suffer, especially with a 2x converter); on a relatively slow lens like the 18-300mm, it is not really a viable solution. On something like a f/2.8 70-200mm lens you would get a f/5.6 105-300mm lens, and that is still fast enough to work with.

Issue is my 70-200 has an f stop of 4 not 2.8.

Are there any teleconverters that would work for either of these two lenses

[William W]

IF you can find a x2.0 Tele-converter that will mount correctly to the lens and the camera without any physical interference, it will probably be a third party model: Tamron and Kenko come to mind as the better options in that bunch.

BUT – considering your previous thread about “Wildlife Lenses” where you also mention that particular lens, it is a reasonable assumption that you (think that you) want 600mm capacity for shooting Wildlife and a x2.0 tele-converter is in your present line of thinking – well if so - I suggest forget it.

*

Notwithstanding the issues already mentioned (possible physical interference when mounting; lack of Auto Focus) . . .

The biggest considerations, in my opinion, is that from about effective FL = 300mm to FL = 600mm (*1) you will be looking through and using a lens stopped down to F/13.

The issues expanded:

1. > Looking through an F/13 Lens:

IF you have a “Depth of Field Preview Button” on your camera, take an existing lens that you have and stop it down to F/13 and look through the lens for five minutes whilst taking photographs – have an headache yet?

2. > Using a lens stopped down to F/13:

Now try critical manual focusing through an F/13 lens - have a bigger headache yet?

3. > Using a lens stopped down to F/13:

Consider an overcast day and you are photographing wildlife, the EV = 12.

You have only F/13 or smaller to use on your lens. You have VR so you can crib some shutter speed with that.

But you must consider the animals’ movements and the subsequent BLUR you might get if your shutter speed is too slow (remember that you are using FL = 300~600mm and that's a lot of magnification - Subject Movement Blur is a bigger consideration as the FL increases)

So let’s say we agree that 1/250ths is the Shutter Speed Range that you need to pull to alleviate (That’s generous 1/320ths might be closer as the safe limit.)

So put all that assumption into the brain box and the result is:

You will need to be at around ISO1250 as a beginning point when using your lens wide open on an overcast day – and that is if the animal is out in the open – if it is under a tree for example, you might need two more stops – so requiring ISO5000 is not an incomprehensible thought.

I have seen, especially at camera clubs that I visit, a few people who thought that the tele-converter was a good, easy, inexpensive method of getting reach: but they now lament their waste of money.

Quality x2.0 Tele-converters / Tele-extenders are fantastic tools, but usually only for use on F/2.8 or faster lenses; and usually only for use on Prime Lenses - there are some notable exceptions: the Canon EF 70 to 200F/2.8L USM; the Canon EF 300 F/4 IS USM; and the Canon EF 70 to 200F/2.8L IS MkII USM being three.

There are probably some exceptions in Nikon also, but I don't follow Nikon gear with the same deal of detail, these days.

*

IF you really need FL = 600 – AND – you choose to buy that 18 to 300 lens – then a more elegant solution would be to:

use the lens at 300mm;
use the lowest ISO possible;
exposure the subject accurately;
crop the image in post production to the equivalent of the FoV of a 600mm lens.

WW

FOOTNOTE:

*1 as a rule of thumb:

A varying maximum aperture zoom lens will reach the smallest maximum aperture at the midway point of the zoom’s compass.

The lens mentioned is 18 to 300. The midway point is 159. With a x2.0 converter mounted that translates to FL = 320mm.

So, effectively, if you are using the x2.0 converter with the lens mentioned, for all of the Focal Length gain that you get (i.e. 300 to 600), the lens will be used at F/13, or smaller.

[William W]

Are there any teleconverters that would work for either of these two lenses [Aside from price/weight what are the pros and cons of these two lenses? [18-300mm f/3.5-6.3G ED VR Vs. 18-300mm f/3.5-5.6G ED VR]

The gain of maximum aperture from F/5.6 from F/6.3 is negligible – only ⅓Stop.

My previous commentary (post #5) applies, as an answer to this question.

WW

[Polar01]

Simple answer to your question for a teleconverter for your 70-200mm f/4 or 18-300mm, there is none from Nikon.

Cheers: Allan

[mrinmoyvk]

The issue is that the autofocus mechanism needs a certain amount of light to function; on the older Nikon cameras one needed a minimum maximum aperture of f/5.6 although that has dropped to f/8 on some of the newer models. With a 2x converter, you will lose two stops so you would be shooting with a 36-600mm; f/7.1 - f/13 lens. So at the short end the autofocus might just work; on the longer end, it definitely will not work.

Are you saying that auto-focus does not work at f/13 with tele-converter attached or it won't work with normal lens stopped down to f/13? Also it is specific to any camera?

[Dave Humphries]

Are you saying that auto-focus does not work at f/13 with tele-converter attached or it won't work with normal lens stopped down to f/13? Also it is specific to any camera?

Ignore 'what the lens is stopped down to' - a lens will always AF (Auto-Focus) at its widest aperture (assuming it is an 'electric interface' AF lens, not an old manual lens with its own aperture ring and no means for the body to control it).

The problem is that with a TC (teleconverter) fitted, the widest aperture then is f/13 (at some focal lengths) - e.g. f6.3 + 2 stops, as Manfred showed.

There is an element of camera specifics, but I'd be surprised if ANY camera could AF at f/13.
For many years AF only worked at apertures of f/5.6 (or wider), in last few years, some AF points (not all) on some camera models, will AF at say f/8 (like the centre point on my D7100), the really pro bodies might do better still.
Occasionally, you might get lucky, with a really good contrast transition in the focus point area, you might achieve AF a stop or so below what the 'spec' says is possible, but it won't be reliable.

++++++

Also (Adrian), don't overlook about the physical and ergonomic inconveniences* of having to fit (or remove) a TC in the field - compared to the smooth benefit of say, that Tamron 150 - 600mm lens.

* e.g.

risk of dropping camera, TC or lens
risk of getting dust and/or moist atmosphere inside the camera
the time it takes to fit/remove
even the risk of leaving the TC behind if you move off having 'put it down' somewhere while stalking your subject

ISO and shutter speed

Even with my f/5.6 (at 300mm) lens, for birds, in dull weather, I do often shoot at the ISO5000 William mentioned above (to get a high enough shutter speed to prevent subject movement blur) - implying you'd need to go even higher if you'd lost 2 stops with a TC.

+++++++

I struggled with this problem; reach for birds vs cost and weight - I discounted TCs, so did not waste my money with them. Instead I tried a superzoom bridge camera, with a 1200mm equivalent focal length (Nikon P510), but I admit; that was a waste of money - IQ is not great, but worse is (on this model) the appalling AF performance (Soooo frustrating) and the electrical zoom, which means you can't zoom out quickly enough to find a bird, zoom in to frame it, focus and shoot before it has moved Grrr

So I am forced to stick with my 70-300mm and crop aggressively in PP when I can (and not many shots are sharp enough), as I don't have the 'hobby funds' to buy anything better.

In fact my current thinking is that funds might be better spent learning how to get close to your subjects by other means; persistence in the field + self teaching, photo-experience days at zoos and reserves/refuges, use of hides/blinds, training from a pro, safaris, etc.

Just don't do anything that harms the wildlife in any way, or puts yourself or others at risk (as I'm sure we wouldn't).

[William W]

^ that's a really REALLY good answer for Mrinmoy and an excellent summary of practical advice for Adrian.

Well done Dave.

Best,

Bill

[ajohnw]

I bought a 2x converter off some one who was trying to use it on a zoom lens with a max aperture that reduced with focal length. The AF would work providing F8 was still available but only on the centre spot.

The other problem with 2x converter is that they are often a step too far in respect to the image quality they produce.They are far more likely to produce acceptable results on better quality primes. Some of that of course relates to how large the final image is. One thing for sure is that teleconverters do reduce image quality. A 1.4x is far more likely to produce acceptable results on many lenses.

To be honest though on a 18-300mm where the image quality wont be stupendous at the long end already I would be very dubious about fitting any teleconverter to it. I suspect you would find that 2x view crops out of shots would be the same or better than the ones taken with a teleconverter on. Actually I take the view that a zoom lens that can't have it's focal length at least effectively doubled by cropping isn't much good and not really worth having other than perhaps convenience, I do own a 10:1 zoom. In fact I expect to be able to use crops from 100% resolution views but I am only really interested in web shots which will generally be 1500px wide.

John
-