Teleconverter for zoom lenses - is it worth it?

I tested three zoom lenses in very different price ranges to see whether a teleconverter is worthwhile or whether it is better to simply crop on the computer. But it's also about autofocus, weight and other aspects.

You can buy the equipment mentioned in the video here (affiliate link):

[wellingtoncrescent]

Thanks, Fabian. Very few reviewers note the improvement in AF performance when eye detect is applied to a small bird i.e. one that doesn't fill the field without the TC. That has also been my experience. My primary setup for birding is the R7 with RF100-500, where sensor resolution and lens optics are both high quality. Most of the time, this is sufficient. But for more reach, the 1.4x TC provides excellent image quality without a noticeable degradation in AF performance. Added to the compact size of the 1.4x TC, and I'm a big fan.

[stubones]

We don't all have 45+mp cameras. Also the 1.4 x iii or rf 1.4 x extender still allows for excellent sharpness and good AF performance on L zoom lenses.

[KurtisPape]

Finally, someone who has done an accurate tests that had similar results to my own personally testing. With the extender you capture more details but will have a slightly softer overall image. You can add sharpness but you can't add details, so the teleconverter wins. The converter also will see a good improvement in noise and detail if you lower the shutter speed to match the ISO's, which I have personally done, so i'm shooting at 1/800sec in sunlight.

Most peoples tests show you get better results cropping, but they going off of the sharpness and are not photographing a detailed enough subject to see the differences in details.

[RonBoger]

Thanks, Fabian. As always, you provide consistently great videos. I am using the RF 100-500 and just got the 1.4x TC to further my reach. I am impressed with the clarity. I will be looking into the RF 200-800mm once Canon increases production (if ever). I would like the extra reach without the TC, but for now, I am happy with the 1.4 setup.

[tonigenes]

I have the same finding for Olympus 300mm F/4.0 + TC 2X. The teleconverter brings significant more details.
And the 2x teleconverter slows down the autofocus and the precision. It is still fine in good light, but in low light you start to feel a big difference.
With so many good Noise Removal Software, I don't mind to loose 2 stops and go to a higher ISO. I also upsize pictures when I need more magnification and get good results. I have the same opinion as you that a 1.4x TC does not make a big difference, you can crop and upsize the picture and get similar result as TC 1.4x.

[przybylskipawel]

@6:35 Can you explain how did you manage to take this photo? Gear, setting, setup. I have tonns of common swifts around where I live. I tried to shoot them with E-M1 II and OM-1 and G9II + Olympus 100-400mm, and with R5 and R7 with 800mm f11 with and without Olympus EE-1 dot sight and still most of them looks like garbage. Only few came out semi-decent. Despite shooting at golden hour where they wer basically lit from the belly up. And your image is stunning: perfect pose and perfect light.

[wellingtoncrescent]

Fabian convinced me to buy the 1.4x TC!

A number of YT videos claim that image quality may actually improve with the 1.4x TC on the R5/ RF 100-500, presumably because there are "more pixels on the subject". I was a bit sceptical that image quality could be preserved with additional optical elements in the light path, but I'm seeing it now that I added an R5 to the R7 I previously used for birding. While both produce excellent images, the R5/RF100-500 shows no hit in image quality or AF speed/tracking performance, so the only real compromise is the loss of 1 stop in light. I don't believe this is a big deal with modern mirrorless cameras, where AF is still working even at F22. Add in de-noising software, and the 1.4x TC provides a focal length of 700 mm, comparable to the effective field of view of 800 mm with the R7 and the same lens. Thanks for the nudge :)

[mogenshansen]

Thanks for a good comparison, and many good points

You touch a bit on camera resolution in the beginning. But you don't mention which camera you are using for tje comparison. I assume it is R5.
On a lower resolution camera, like R3, TC's are more important than on R5.
With sufficient high camera resolution (whatever that is), there is no benefit from using a TC.

[tomdearie]

Just a hint about photo comparisons — flip one photo right to left so that one can zoom in and compare the same region on the two photos. 👍

[vudo]

Fabian….can you tell me if the 1.4 Extender actually ‘hits’ the glass elements at the back of the 100-500 when zooming back out to 300mm. I have asked this question to a few other content creators and no one has yet to respond. I feel it’s detrimental to get some explanation on whether it’s actually safe longterm to be utilizing the 1.4 on the 100-500mm if you are continually slamming the internals into the extender each time you zoom back to 300mm? To me this seems like it would be putting a serious amount of wear on the 100-500mm’s integrity. What is your opinion on this?

[WernerBirdNature]

Thanks for this balanced overview Fabian ! Maybe one detail was missing: the cheaper the lens, the more you may need to stop down when using an extender in order to improve sharpness. And in such case you can't keep the same depth of field.

I'm also enjoying a lot your Costa Rica series as I'm planning to go there next year .. As I don't have room (nor the bucks) for a 600/4, would you think it's worth taking both the 100-500 and 200-800, besides my wide zooms?? Given the 100-500 is also great for 'skittish' macro subjects, I may leave the EF100 macro home .. hmmm, in case of macro the 1.4x could still make sense on the 100-500, because the 200-800 cannot focus as close ..

[staiain]

I guess not all teleconverters are made the same. On fujifilm, the 2x TC makes both my 80mm and the 150-600mm look like kit lenses

[_Dibbler_]

11:35 Its official now, the currency of Switzerland is Bucks :) I´d be interested how the results would be on a camera with less megapixels. I have a S5II and cant crop in as far as on a high megapixel camera, so the teleconverter should have better results compared to the cropped picture then, shouldn't it? 🤔

[dasaen]

I agree with you, they are better than cropping, sometimes by a lot. The statement of them being worse I feel is a missconception from the fact they are not better than a lens of equivalent focal length. But I have used them on manual and old primers and they have some advantages such as allowing you to reach over 600mm on a budget, and turning a good telephoto into a “telemacro” lens for butterflies and dragonflies.

[alansach]

Always match the teleconverter to the lens brand for best possible results. If possible, use only with the manufacturer's premium lenses (for example "L" lenses for Canon). Remember that, whether using a teleconverter or cropping, atmospheric interference (commonly known as heat waves, or atmospheric waves), and just plain distance, can affect sharpness WAY more than the choice of teleconverter or cropping. Sometimes the subject is just too far away.

[GremHopkins]

I am struggling here to decide - I was thinking about r7+100-400+2x extender - I often go riding bycicle, and see some birds/animals in fields - I need good AF, need minimum weight, so I can handle all in hands while in bicycle, it should be compact and have maximum possible zoom. I tried out r10 with 600 f11, it was working well, but in one case reach was not enough, and I felt I am missing some zoom capabilities

[jamesseward]

Speaking of tele-converters and having the Canon 200-400mm I was toying with the idea of buying the Nikon 400mm f2.8 with Built in TC and having a Canon RF 70-200mm f2.8 on an R8 for a light weight setup and better image quality going from 70mm to 800mm f5.6 with an additional 1.4 TC. This also might be the ultimate light weight hiking set up for you also ? Any thoughts ? 😊

[tonysvensson]

I think that the more acurate question is "Should i use a extender, or should i use a program like the Gigapixel AI and be able to use the same shutterspeed and ISO?". I would like to se a test from you (I think you do good field tests) and see if you come to the same result as I. ( Cheaper and often better with the Gigapixel instead of extenders was my result of a simple field test)

[Karkawry]

Would have been good to see ISO values on these, as well as f stop, I think dynamic range will be better at lower ISO and may well lead to a better contrast, and perceived sharpness in images. These tests are never perfect though I realise, as not 'real life' scenarios.

[undifinder]

Mine got diffraction issue I think with photos being soft resulting loosing details, and CA got worst on the RF 100-400 with RF 1.4x + R7 at 2500+ ISO at maximum focal length 896mm yet the lenses alone with crop is sharper. Probably going back to the shop to figure this out since other people can get good details from this.