wapiti Loc: round rock, texas

I own [2] 1.4's, a 1.7, and a 2.0. All are Nikon. I use the latter two so infrequently that it would take some time to put my hands on either. The TC1.4's are a different situation and are used quite frequently. As previously recommended, I would buy the best available.

TheShoe Loc: Lacey, WA

The only experience I have would be the Olympus 1.4 converter for the 4/3 format DSLRs. As noted above, the brand converters are a bit pricey, but the Oly converters did their job quite nicely. At a price that was about the cost of one of their budget lenses, they did produce good results at the expense of one stop. And they were weather sealed.

Sir Motley

CanonTom Loc: Birmingham

Good advice. Thanks!

jackpi Loc: Southwest Ohio

For best results, use a Tamron teleconverter with a Tamron lens. All teleconverters reduce image quality. Expect a 10% loss of IQ with a 1.4TC; 30% with a 2.0TC. Most people find the 10% loss barely noticeable and the 30% loss noticeable. Your autofocus system will also degrade with a TC: by 1 stop for the 1.4TC and 2 stops for the 2.0TC. You camera may autofocus with only a single AF point at f/8.

James R. Kyle Loc: Saint Louis, Missouri (A Suburb of Ferguson)

For my Canon lenses = I use a Canon tele-converter.
For the Tamron Lenses = I use a Tamron.

Whatever lens make you are using - get the converter (extender) that is the same make as the lens.

-0-

jnuss

I use a 1.4 TC on a 500 mm Nikon lens. Have had no issues with it other than losing a couple of f stops on exposure. Most of the problems I've heard about
involve usage of TC's on zoom lenses, especially 3rd party brands. Check with your photo buddies or your local camera club and I'm sure you'll get a lot of
other opinions and advise.

amfoto1 Loc: San Jose, Calif. USA

Some general rules of thumb regarding teleconverters...

#1. They work best on prime lenses, less well on zooms.
#2. There is always some loss of image quality with any TC, so they work best with extremely high quality lenses that can tolerate some loss of IQ.
#3. With few exceptions, a more powerful telephoto lens without a TC will out-perform a less powerful telephoto with a TC.
#4. A weaker 1.4X or 1.5X teleconverter will "cost" less loss of image quality than a stronger 1.7X or 2X. Even stronger 3X are largely worthless.
#5. There is ALWAYS light lost to a teleconverter, which will slow autofocus a little to a lot... or cause it to completely fail. A 1.4X "costs" one stop. A 2X costs two stops worth of light.

A Tamron 70-300mm f/4-5.6 lens will "become" a 98-420mm f/6.3-8 with a 1.4X attached. Or, it would "become"a 140-600mm f/9-11 when combined with a 2X TC. You didn't indicate what camera you will be using this on, and need to check if its autofocus system is able to work with slower than f/5.6 or less than f/8 max aperture. Many cameras will not be able to AF the lens + 1.4X and likely none would be able to do so with the 2X, due to insufficient light.

It also would help to know what camera, because there are different possibilities. For example, Canon's 1.4X III and 2X III are very high quality and cost about $430 apiece, but have a protruding front element that needs to fit inside the rear barrel of any lens they're use upon.... and most 70-300mm cannot accommodate them. I don't know whether or not they can be used with the Tamron. Nikon's 1.4X III and 2X III are also excellent, cost almost $500 each, but are recommended for use only on select lenses (consult the Nikon website). I have no idea what's offered for use with Sony, Pentax, Olympus, etc.

There are third party teleconverters, too... though with all the possible combinations, it's hard to predict what will work well and what won't.

Kenko offers two 1.4X models that are affordable and have a good reputation.. But which would be best to try once again depends upon the camera it will be used upon (as well as the type of photography being done, to some extent). The Kenko 1.4X "MC-4" is quite sharp in the center with most telephoto lenses and it only costs around $110. It is not quite as sharp in the corners or at the edges, but for many types of photography that might not be a concern. It also may be a good choice for use with an APS-C sensor camera that's only going to utilize the central portion of the image anyway. A "full frame" camera user might prefer the Kenko 1.4X "Pro 300" model that's a little more expensive at about $140, but has better sharpness in the corners and at the edges. Kenko has recently introduced an "HD" version of their teleconverters for some lens mounts. I don't know how their image quality compares and they tend to be a bit more expensive. I also don't know how their 2X compare.

Some lenses simply work well with certain teleconverters, while others don't. And it's a bit subjective.... results that you find acceptable, I might not.... or vice versa. It also depends upon what you want to do with the images.... if you just post them online at typical internet sizes and resolutions, you may not notice the loss of IQ due to the teleconverter. But if you make large prints from your images, you're likely to be less tolerant of IQ losses.

I have Canon 1.4X II that I frequently use with 500mm f/4, 300mm f/2.8 and 300mm f/4.... and more rarely with 135mm f/2, 70-200mm f/2.8 and 70-200mm f/4. It's said to work well with a 100-400mm I recently got, too... but I haven't really tested it much yet.

I also have Canon 2X II... but pretty much limit using it with 300mm f/2.8... occasionally with 500mm f/4 though unable to autofocus on some of my cameras.

Ultimately....

If money is not a concern, you'd almost be better buying a more powerful lens such as a 100-400mm or 150-600mm or 200-500mm (depending upon what's available for your particular camera). This will be larger and heavier than what you have now... enough so that there's good possibility you'll also want a good stable tripod or at least a monopod to use with it.

But for travel and

amfoto1 Loc: San Jose, Calif. USA

The Canon teleconverters are NOT compatible with that lens. The rear barrel of the lens is not large enough diameter to accommodate the protruding front elements of the Canon TCs.

You might try the Kenko 1.4X MC-4 or 1.4X Pro 300... Those will physically fit the lens, although you'll be focusing manually because 60D is not "f/8 capable". (80D, 7DII, 77D, T7i are.)

Forget about using a 2X on that lens. I have no idea if there are any that give acceptable image quality, plus it would effectively become a "140-600m f/8 to f/11" lens that won't be able to autofocus on any Canon camera and also makes for a very dim viewfinder to try to manually focus (might be possible to manually focus in Live View with Exposure Simulation enabled... but it will be a slow process).

CanonTom Loc: Birmingham

Thanks Alan! Very educational as always! I am very happy with my new lens as is so no problem. If I get more into shooting birds, well I will worry about it then. Sounds like a different lens if I ever go that route.

imagemeister Loc: mid east Florida

My best advice - forget the TC with THAT lens.

Use your Tamron lens only to 250mm, if using a "protective" filter - take it off - stop the lens down to f8, use good support and good appropriate shutter speeds, at lower ISO's and CROP - AND- if making a larger print, use well applied pixel enlargement.

Otherwise, I would recommend the latest and greatest Nikon FX 70-300 - and again, cropping from there. If you have high ambitions and deep pockets, get the Nikon 200-500.

cjc2 Loc: Hellertown PA

I own both a Nikon 1.4x and a Nikon 2x teleconverter. IMHO, they are really designed for Fixed Focal length LONG lenses. I use the 1.4x all the time on my 400/2.8 and, upon rare occasion, I will use the 2x as well. For my work, the 400/2.8 is much more versatile than either the 500/4 or the 600/4 and that is why I use the Teleconverters at all. I shoot mostly sports action an will often use the 1.4 TC in daylight, but for night football games under the lights, not really. Upon occasion I will use the 2x on the same lens, mounted on my D500 to shoot the outfielders in baseball under good light. As far as TC use on other lenses, I do not use them at all. YMMV. Happy Holidays to ALL!

sathca Loc: Narragansett Rhode Island

I wouldn’t t use a tele on anything but a top quality lens. A fixed aperture 2.8 at least. 1) the image quality is better from the start and 2) you need that wide aperture since you’re going to lose stops of light to the tele. I have a Nikon 300 AF-S f4 ( a very sharp lens ) and a Nikon 1.4 tele and I hardly use it. If I do it’s a bright day on a tripod.

Architect1776 Loc: In my mind

If you were using Canon you would not have such restrictions.
For example the Canon 100-400mm L MII works beautifully with 1.4x and 2X teleconverters.
Check the MTF charts for it with the converters and be prepared to be astounded.
PS, I have used the 2X on mine and the chart proves it out.

Too bad you are so restricted with what you have.

agillot

a high quality lens with a matching tele converter also high Q , does well .anything else is usually not that great .