SuperflyTNT Loc: Manassas VA

It really comes down to the combination. Not only do on brand teleconverters work with just the lenses they are designed for, the quality with those different lenses will vary.

cactuspic Loc: Dallas, TX

While tubes don’t add optics, they can negatively impact IQ as the lens is being used outside its design criteria. The amount of the impact depends upon the particular lens and the amount of the extension added.

kenArchi Loc: Seal Beach, CA

My 2x teleconverter is my micro 4/3 camera system. No loss of light, 'half' the weight.

CHG_CANON Loc: the Windy City

One of the drawbacks of all types of 1.4 extenders is the modest 40% boost to the effective focal length. The longer the focal length of the lens, more oomph this 40% provides.

Examples:

200mm x 1.4 = 280mm, not much increase for a 1-stop loss, especially given the 300mm lens options.
300mm x 1.4 = 420mm, a bigger impact, especially as compared to increasingly expensive 400mm lenses.
400mm x 1.4 = 560mm, a bigger impact, especially as compared to increasingly expensive 500-600mm lenses.

Another example of genuine Canon equipment, here a legacy FD 1.4x extender behind an FD 300mm f/2.8L, mounted to a Sony full-frame a7II.

Meadowhawk by Paul Sager, on Flickr

gwilliams6

The best of the current manufacturers' teleconverters are really good, and priced as such. I am a longtime Nikon and Canon user, but moved to Sony in 2017, so I can speak about the current Sony ones. The Sony 1.4X has virtually no image loss, the 2x has about 10% loss, both very usable and acceptable. I use them on both my Sony 70-200mm f2.8 GM lens and my Sony 200-600mm f5.6-6.3 lens. You could only tell any loss if you pixel peep. I keep them in my bag all the time. Cheers https://www.facebook.com/GSWilliamsPhotography

Ed Commons

My experience (which goes way back) is that in a pinch a quality teleconverter does a fair job. I have a 1.4 x and a 2.0 X Nikon and get very little distortion and graininess in a normal photograph 11x14 or smaller. If I go larger or crop the image and make an enlargement greater than the 11x14, grain will start to show up.

Remember with a teleconverter you are adding two to three elements to you prime lense and degradulation is to be expected.

I have tried teleconvertors from other vendors than Nikon and found they have more graininess. Sigma seems to approach Nikon standards, but others we have tried do measure up.

If you are just wanting the close image for your self ... you only have one person to please. If you are wanting to sell your work, quality is what your customer is purchasing.

A teleconvertor is less expensive and doesn't weigh as much as an extra lense and is convienient. Just be aware that quality will be lessened

SuperflyTNT Loc: Manassas VA

I’ll give you mine if you give me $400. 😜🤪

Lawmanb2 Loc: New Smyrna Beach, FL

Yes, I use extension tubes a lot.

Bill

Properframe Loc: US Virginia

Hey if you don't have a 300 f4 you might as well not have a 600 f4 Fl ED and skip the TC.

SuperflyTNT Loc: Manassas VA

That’s a completely different thing. F-stop is not a fixed size, it’s a ratio based on the physical size of the aperture of the lens and the focal length, so on the telephoto lens the physical size of the aperture is much larger than the same F-stop on the wide angle, same amount of light, same DOF. With the teleconverter you’re changing the focal length but the physical size of the aperture remains the same, so your ratio changes. Less light is getting in and DOF increases.

SuperflyTNT Loc: Manassas VA

I’m ahead of the game. I have neither.

amfoto1 Loc: San Jose, Calif. USA

You should ask about a specific teleconverter for use with a specific lens.

Results vary wildly, there are so many possible combinations.

Some lenses simply can't be used with some teleconverters... they physically won't fit together.

All that said, in very general terms....

There is some loss of image quality any time you add a teleconverter to a lens. It might be very, very little with some combos. But it's often noticeable and then becomes a matter whether the results are "good enough" and acceptable for your particular purposes.

Teleconverters typically work best with prime lenses instead of zooms.

Less powerful 1.4X (and more uncommon 1.5X) teleconverters usually do quite a bit less "harm" to image quality than stronger 2X (and less common 1.7X) teleconverters. I've even seen a few 3X teleconverters... but never one that was worth using on any lens, due to horrendous image quality.

You also "lose light" with teleconverters, which in turn can cause autofocus to fail. A 1.4X "costs" one stop, while a 2X reduces light passing through the lens/TC combo by two stops. For example, an f/2.8 lens will become f/4 with a 1.4X added... or an f/5.6 with a 2X. That shouldn't cause any focusing problem with most modern cameras. But if you put a 1.4X on an f/5.6 lens it becomes f/8... while 2X on that same lens will make it an f/11. Depending upon the camera, those may cause autofocus to hunt badly or fail completely. Overall, the loss of light might slow AF, especially in more challenging lighting conditions.

This light reduction will also dim down a camera's optical viewfinder, potentially making manual focusing difficult. An electronic viewfinder (such as some mirrorless cameras use) or Live View (in both DLSRs and MILC) might be a workable alternative that allows manual focus... But in all cases this will likely be a slower process and will probably be impractical with active, moving subjects.

In some camera systems teleconverters are referred to as "extenders" (in that they "extend" a lens' focal length).

This should not be confused with macro extension tubes, which make a lens capable of focusing closer. Extension tubes come in various lengths and fit between the lens and the camera. They have no optics inside, so are generally less "harmful" to image quality. And, while there is some light "falloff" inside an extension tube, there's usually not as much light lost as there is with a teleconverter, unless you add a whole lot of extension!

With modern, electronically controlled lenses, it's advisable to use extension tubes that maintain connectivity so that autofocus and images stabilization are able to work. But even more important with many modern lenses, that connectivity is needed to be able to control the lens aperture. There are cheap tubes that lack this... but are virtually unusable with many modern cameras and lenses.

A teleconverter increases lens focal length and increase potential magnification without changing a lens' minimum focus distance (MFD). For example, I have a 300mm lens that has an MFD of approx. 5 feet and renders 0.24X maximum magnification. It works very well with a 1.4X teleconverter, to make for a "420mm f/5.6" combo. It's MFD is still 5 feet, but because the focal length is now longer, it can render nearly 0.34X maximum magnification.

Extension tubes don't change lens focal length, but increase magnification by reducing a lens' minimum focus distance (MFD). The longer the lens focal length, the more extension that's needed to significantly change MFD.... For example, I've used a 12mm extension on a 20mm lens and had subjects touching the front lens element in focus. Normally that lens has a 9 or 10" MFD! In contrast, I've added 36mm of extension to a 500mm lens so that it's able to focus at 12 or 13 feet, instead of approx. 15 feet. Maximum magnification with that telephoto isn't very impressive... only about 0.12X. I don't know exactly what max mag is with 36mm extension added, but it isn't changed very much (but it can be enough to make a difference in a shot of a small subject).

wdross Loc: Castle Rock, Colorado

It depends. If it is matched for your lens, you lose the least in image quality. The least image quality is lost with the least magnification also. And the image quality will not match an equal prime or zoom of the same new focal length or zoom range. If the image quality is acceptable for your shooting, versus the cost of buying a new lens of that increased focal length, it is definitely worth the price. If the image quality is not acceptable, then you will be required to buy the lens that you need. And generic teleconverters do not provide image quality as good as matched teleconverters. All my teleconverters have worked perfectly and provide some great images.

dave.m

agreed - I use the canon x1.4 III with the canon 100-400L II and the results are excellent - even enlareged to equivalent 600mm, better than a Sigma 150-600 to by a noticeable margin - BUT it did cost a smidge more And its a lot smaller and a lighter to hump arounf

ecurb Loc: Metro Chicago Area

TCs cost image quality and lens speed. They work best on fast prime lenses. They do not work on all lenses.