bleirer

Can you explain why one would choose a 1.4x extender instead of a 2x extender? Especially if it is a zoom being extended. Is there a huge cost in image quality between the two or are there other reasons?

cjc2 Loc: Hellertown PA

First, there usually is a HUGE cost via the loss of two stops which, in some cases, will render AF useless if not difficult, on many zoom lenses. The 1.4x, OTOH, usually works much better with only a minimal loss of quality, as only 1 stop of light is lost. Sometimes 2x are unavoidable, but I'd recommend you stay clear. Personally speaking, I only use extenders on lenses such as a 400/2.8. YMMV. Best of luck.

PixelStan77 Loc: Vermont/Chicago

I am not a fan of extenders. Why? From my experience with them, they take a good lens and give you that extra push at a price. Sharness at the outer ranges.

https://shuttermuse.com/ultimate-guide-to-extenders-teleconverters/

CHG_CANON Loc: the Windy City

If your camera can't autofocus with the resulting 2-stop loss, that would be a major determining difference. It depends on the lens(es) and the camera, technical details to be closely investigated before making a purchase. Even the use of a 1.4x can be problematic, depending on the lens(es) and extender / teleconverter brand and model.

pesfls Loc: Oregon, USA

I have never owned a 2X tc. However I can tell you I very often use a Nikon 1.4 tc on a Nikkor 300mm with very good results. That combo achieves very crisp images edge to edge plus great color and as noted above sacrifices only one stop. I was given a Sigma 1.4 tc by a friend. It was awful. Hope that’s of some help.

Architect1776 Loc: In my mind

Depends on the quality of the converter.
For example no converter, 1.4x converter and 2x converter on the Canon 100-400mm MII shoes that a superior lens with superior converters whether 1.4x or 2x makes no perceptible difference.
In lesser lenses than this one the answers saying yes are true. But in this case they are completely wrong.
So the answer is it depends on the quality of the lens and converter.

BebuLamar

Perhaps one only needs 1.4x instead of 2x. Perhaps one rather lose 1 stop than 2 stops. The 1.4 could be less expensive and doesn't hurt the image quality as much.

wdross Loc: Castle Rock, Colorado

Less image quality loss. It bents the light less and therefore loses less image quality. The image loss usually is in the chromatic aberrations. The loss is totally dependent on the "compatibility" of the optical design of the lens and the teleconverter. That is why some manufacturers make a specific special teleconverter for a specific lens.

DWU2 Loc: Phoenix Arizona area

A 2X extender is likely to produce a softer picture than a 1.4X.

LFingar Loc: Claverack, NY

As others have said, it depends a lot on the camera and lens you are using. I have a Canon 1.4x III that Canon designed to work best with the EF 70-200 f/2.8 L II and the EF 100-400 L II lenses. Both lenses are ones that I have but I use the extender primarily with the 100-400. With a bit of practice you can achieve excellent results, although if you pixel peep you can see some degradation. You do lose 1 stop though, so, with the 6D you have no auto-focus. With the 7DII you only have the center focus points. With my current camera, a 5DIV, I have all my auto-focus points.
I just bought the EF 2x III extender. FedEx delivered it yesterday. It too is designed to work best with the 2 lenses I mentioned, but, because of the loss of 2 stops my 100-400 f/4.5-5.6 becomes a f/9-11. That means that even the 5DIV will not auto-focus, since it requires a minimum of f/8.
Fortunately, I have an EOS R. It will focus to f/11, so, the 2x and the 100-400 work just fine. I have all my auto-focus points, although, the auto-focus is noticeably slower. I just did some shooting with it this morning and the IQ seems very good. Because of its superior auto-focus the EOS R with the 1.4x gives slightly better results then the 5DIV with the 1.4x.
I haven't practiced much with the 2x yet but it appears that the EOS R with the 2x gives about the same results as the 5DIV with the 1.4x.
Extenders can give you a lot more reach for a lot less money and can be used on multiple lenses with very good results with the right gear and proper usage, but you lose light. That can be a real problem at times. Being able to shoot at 800mm, even at f/11, with some IQ loss of course, can be very handy. It's also a lot cheaper then Canon's alternative, the EF 800mm f/5.6 L IS at about $13,000.

Architect1776 Loc: In my mind

Operative words "Pixel peeping "

Strodav Loc: Houston, Tx

Take a look at your camera's spec auto focus section to see what the largest f stop your auto focus system can handle. For example, my D850 has 15 (of 135) f/8 sensors. On the other hand, my D7200 "f/8 supported by 1 sensor". So, on the D850 I could use a 1.4x teleconverter with a f5.6 lens as it will get me to f8 and will probably work OK. A 2x teleconverter would take me to f11 - not so good.

Bill_de Loc: US

I have always been told to stay away from 2x extenders. I still don't use one, but here at UHH I learned that on the right camera, in the right hands, they work beautifully.

Check out the images Regis posts. He routinely uses a 2x.

https://www.uglyhedgehog.com/user-topic-list?usernum=38916

One of my favorites.

https://www.uglyhedgehog.com/t-580929-1.html

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bleirer

So the camera specs say this about the af working range: EV -5 to 18 (f/1.2, at 73°F/23°C, ISO 100, One-Shot AF).

I know what ev is, but not sure how to turn that knowledge into practical application. I know the Canon site lists compatible lenses for their extenders, so I'd be sure to pick something on the list. I guess the debate in my mind is whether the converter is worth it, or for the money just buy the best longest used prime lens my budget will allow. Seems like the price leaps big-time after 400mm.

imagemeister Loc: mid east Florida

Yes, there CAN be and usually IS a huge cost in IQ with a 2X extender...

1. 2 f-stops light loss with commensurate increase in ISO or decrease in shutter speed and loss of speed and accuracy of AF sensors.

2. Apparent smaller DOF

3. Dimmer optical VF

4.Most zooms have poorer edge IQ and this is where the most degradation from extenders is the most.

5. More magnification means harder to stabilize and less pointing accuracies ( for both AF and compositionaly ). Subject relative speed of movement is also magnified !

6. Zooms IQ is traditionally boderline to begin with due to design/cost compromises - especially at the longest focal length where you are most likely to be using the extender.

If I were using a 150-600 lens with an extender it would very much mostlikely be on a tripod. I would use a 1.4X @ 600 @f8 to give effective 840mm. If I were to try and use use a 2X it would be with the new Canon R with which it will AF (F13) - according to Ken Rockwell !

I have used the Sigma 100-300 f4 with the Canon 2XII and the results were unbelievably GOOD ! (f8)

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Canon 60D, Canon 300 2.8 W/2XII from bodypod, bright mid day sun

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Sony A99, Tamron 300 2.8, 1.4Xextender and 1.7X Clear Image Zoom (714mm) @ f4

(Download)