donweiner Loc: Boston

I am wondering if a 2X teleconverter (or other suggestions) will work for me......I am getting mixed reviews.

Nikon D3100
Tamron 18-270 mm F/3.5-6.3 PZD
Nikon DX AF-S Nikkor 55-200 mm 1:4-5.6G /ED
Nikon DX AF-S Nikkor 18-55 mm 1:3.5-5.6G
Nikon AF-S Nikkor 50 mm 1:1.8G

I trust UHH answers more than any other site

Dngallagher Loc: Wilmington De.

I use a 2x extender on many of my lenses at times.

It will double the length of the lense, but it also will reduce the light entering the camera, but that may be
compensatable with ISO & shutter speed.

BUT you did not mention what it is you expect it to do?

joer Loc: Colorado/Illinois

A 2X TC will also double your f stop. They work best with long, fast lenses.

You won't be able to auto focus with the zooms you have.

Dngallagher Loc: Wilmington De.

I am able to focus with EVERY AF lens I have with my 2x extender... both AF-S type and AF-D type that rely on the internal motor.

SOME extenders have pass thru electrical contacts and focusing lugs, some do not...

BTW - Lenses that work AF for me with my 2x extender:

Nikon 55-300 AF-S f/4.5-5.6
Nikon 18-55 AF-S f/3.5-5.6
Nikon 50 f/1.8
Nikon 28 f/2.8
Tokina 11-16 F/2.8
Sigma 170-500 f/5-6.3
Quantaray 28-90 f/3.5-5.6
Nikon 35-70 f/3.3-4.5

And my 2x extender is a not real expensive Quantaray from Ebay.

jr168

The Nikon teleconverter will not work with the lenses that you have. You might have luck with the Kenko or other brands but I would double check to make sure. You will lose 2 stops of light with the 2x converter thus making your f/5.6 lenses f/11. Your camera will not be able to use auto-focus since it is only capable to focus down to f/5.6. You will also notice quite a bit of softening in your images.

Leitz Loc: Solms

Here are Nikon's current teleconverters. When you select one, there is a link to a Nikkor lens compatibility list.

http://www.bhphotovideo.com/c/search?atclk=Brand_Nikon&ci=278&N=4077634487+4291315846

f8lee Loc: New Mexico

Not to reiterate what has been said, but a 2X TC will "cost" 2 f-stops worth of lens speed.

But what has not been mentioned is that the ability to autofocus has much (or everything) to do with the specific camera body - AF requires a certain amount of contrast and without enough light getting to the AF mechanism it just won't work. I cannot speak for the D3100 you have, but generally speaking the higher-priced (and newer) cameras ghave more sensitive AF systems than less costly/older models - the march of technology and all.

That said, using a TC on a wide angle lens is just silly, so let's look at the telephoto side of your gear: the Tamron will effectively become an f14 or so lens when at the 270MM end; I don't think ANY camera out there (not even the D4) would be able to AF in that circumstance. At 200MM the f5.6 effectively becomes f11, and that might be workable if there is enough ambient light. As for the 50, again, why bother? You basically end up with a 100MM f-what, 3.9?

Someone here who actually has a D3100 will be able to give you real world experience, but the point is that it's the camera itself that matters more when it comes to whether AF will work.

Mark7829 Loc: Calfornia

High TC such as a 2x will degrade image quality by 26% as reported by analysis online. Less at 1.7 and 1.4.

rehess Loc: South Bend, Indiana, USA

Just out of curiosity, how do they measure IQ?

Mark7829 Loc: Calfornia

They looked at sharpness.

rehess Loc: South Bend, Indiana, USA

How do they measure sharpness??

In other words, what does it mean to be 26% less sharp?
I understand that you can look at two images and declare that one is sharper than the other, but a number like 26% implies precision in making that measurement.

OddJobber Loc: Portland, OR

:?: Got a link to that analysis?

26% is a pretty broad generalization. It's variable with every lens/TC combo and it's heavily influenced by the quality of the TC. Bear in mind also that a TC will also magnify any deficiency of the lens.

romanticf16 Loc: Commerce Twp, MI

A 2X converter will magnify 2 times but will also decrease light by 2 f stops. Recommended for tele use: f6.3+2=more than f11; f5.6 + 2 stops = f11. Your camera will not autofocus at f11, so anything you do would be manual focus with a dark, stopped down lens.

romanticf16 Loc: Commerce Twp, MI

The top of the line Nikon D4s ($6,000+) can only autofocus to f8- There is no way a D3100 will do better than this camera.

rehess Loc: South Bend, Indiana, USA

How much of this is what the camera can do and how much is what the camera will do, I wonder. I have an elderly Canon Rebel, which I use with an older Kenko doubler and a Tamron 18-270mm f/3.5-6.3 lens. I was told that there was no way that this combination would provide autofocus, especially at maximum extension. I was told that the camera wouldn't even try to focus because of the doubler, but this particular doubler doesn't report itself. The camera doesn't know that it can't focus ... so it has tried to autofocus, and it has succeeded in autofocusing the few times I've tried it at maximum extension ... admittedly under good lighting conditions.