M system bodies, EF/EF-S lenses and Teleconverters

In the on-going thread on buying the M6II today, there has been a good discussion of lenses. One of the replies commented about using the EF-S 55-250 IS STM with the Kenko HD DGX 1.4x teleconverter and it being a sweet setup. I had not really thought about that approach to extend the range, with what is a very light lens.

In my time as an APS-C DSLR user, I’ve really never spent any time understanding and looking at teleconverter options. (In fact I’m sure I could write my understanding of teleconverters in the palm of my hand and have lots of room left.)

Seeing the comment about the Kenko one has prompted me to ask which one(s) work well with the M mount bodies, and EF/EF-S lenses (both Canon as well as Sigma), and which ones are recommended/preferred by M system users? And do certain ones only work well with certain lenses?

Just looking at 1.4x for a moment, I know there is a Kenko one (actually aren’t there 2 Kenko 1.4x units — TELEPLUS HD and TELEPLUS HD pro — not sure which of the two was referred to in context with the EF-S 55-250). And I was looking at the Sigma 150-600 Contemporary lens recently, and noticed that Sigma has a 1.4x one (TC-1401) and I can purchase a Sigma package with the 150-600 Contemporary lens + TC-1401 and the TC-1401 is about half price in the package compared to buying the TC-1401 standalone. So I was thinking if I acquired the Sigma lens I might get the one with the included TC-1401. And I believe Canon has one as well.

And thoughts, recommendations for someone like me who is not super knowledgeable in this space?

Thanks in advance!

With EF lenses, pretty much any third part teleconverter will work. Genuine Canon teleconverters have protruding front elements that will sit inside compatible EF lenses.

The real issues comes with EF-S lenses as the rear element, and lens mount itself, protrude further to the rear. In some cases, this can lead to the rear element of the EF-S lens contacting the front element of the teleconverter. The EF-S 55-250mm does not have a protruding rear element, but the mount does have a protruding bumper. Some third party teleconverters have front elements that are recessed enough to clear this bumper. Alternatively, this bumper can be cut off of the lens mount to provide the needed clearance. If you want to get really fancy, the cleanest solution is to buy an aftermarket metal lens mount for the EF-S 55-250mm STM and swap out the original plastic mount. The new metal mount does not have the protruding bumper and will allow enough clearance for any of the third party teleconverters.

Larry Rexley has written a lot of posts about the various options and needed modifications and will hopefully chime in here with more details

hi, I have a meike 1.4x teleplus pro 300, i seem to remeber it worked on some lenses eg my efs-60 but i cant remember being impressed by its sharpness, and it never seemed to work at all with my 100-400 lens

I know the R folks all seem happy with converters on their R glass, but i've never seem much comments in the M forums
regards
jim

Yes, I posted many times on my experiences, too many posts to reference. This is a good thread where R2 actually did the same conversion I did to the EF-S 55-250 IS STM, and got the same Kenko 1.5x SHQ model teleconverter I got good results with, and removed the chip from the TC with good results. I would suggest reading through many or most posts in that thread, and looking at some of the linked posts, while they're still available.

www.dpreview.com/forums/post/66423462

The original thread where I hacked the EF-S 55-250 IS STM:
www.dpreview.com/forums/post/64824180

I still use the EF-S 55-250 IS STM with both the Kenko 1.5x SHQ and my home-made Kiron MC7 TC. I shot footage for a youtube video just yesterday with that setup. I even use 2 TCs stacked to get extreme range,but only when shooting video which is only 4k res! The 55-250 with a TC is a portable and light kit that can get you to the ~400mm range. For the full 32 MP resolution of the M6ii's sensor shooting still images, the 250mm with 1.5x TC is about as far as you can realistically go, both from the lens sharpenss point of view, and because of diffraction shooting at f11-16 on crop sensor.

The alternative for me is taking along the Siggy 150-600 C lens which of course gets better results -- however it is montrously large and heavy to take on a long bike ride.

Hi it was me, recommending the Kenko Teleplus HD DGX 1.4x.

You can see it Here

It produced quite sharp images, due to low degradation of the image quality and the fact that 55-250 IS STM lens is very sharp. I did compare it to no TC, then 2x, and the 1.4X really impressed me.

It added some purple fringing in corners, but that was easy to get rid of, and sometimes not even needed.

Being a pixel peeper, I have hard time adopting any teleconverter on most if not all/any other lenses except for good ones of Canon L, because ither lenses are not as sharp as the 55-250.

Unfortunately I don’t have the EFS 55-250 to modify and use Kenko TC. I actually bought a EF 70-300 USM II which is definitely heavier and larger (and probably not as sharp in an apsc camera) but it’s like having a 1.2 TC compared to the 55-250, or 1.5 TC compared to the 55-200, which allows you to shoot at f5.6 at the long end. Is there any TC that could be used with it without having to modify the lens given the need to use the ef-efm adapter?

I don't have experience with that lens, but it appears from this dpreview thread that it isn't compatible with the Canon TCs, may have AF issues with Kenko TCs, and may not be quite sharp when used with a TC anyway:

www.dpreview.com/forums/thread/4315791

Thanks for sharing Larry. The feedback is not positive indeed…in any case, not being into birding or wildlife at this point, the 480mm full frame equivalent I get with the M bodies has been enough for me.

The issue I see is the M6II is very demanding on the lenses without a TC in terms of resolution - plus diffraction slowly kicks in at relatively wide apertures - so other than the L big whites and equivalently super sharp bare lenses - I don't think TC's are generally worth it on the M6II. It is already in effect a 1.4X TC over the 7D series in terms of "pixels per duck". I like the 55-250 STM, it's pretty good but I can see on my copy it is not quite as good as my 70-200 2.8 II - well no surprise there! I have also tried the sigma 150-600 C - a very nice lens but not quite pin sharp at 600mm f/6.3 although good - better at f/8. But I don't think the 1.4X TC will add much extra resolution in the field in real use, even if it may in very controlled tests.

As a long-time user of Canon DLSR’s 20d followed by the 6D, I switched to the M6 Mark ii and enjoy its low weight and compact form factor. So far I only used native Canon M lenses, most of the time the 32mm. Recently I visited an island in the north of the Netherlands (Vlieland) and tried bird photography using the 55-200mm. I’m pleased by the results (sharpness is OK but I really needed a bit more reach). I do have the old 400mm f5.6 L lens and I wonder whether this has been used on the m6 m II with the EF-M adapter. I realize the size and weight are problematic but I can envisage situations to cope with it e.g. in a shelter maybe with a tripod. How does this lens compare to the the 55-250 discussed in this thread or with the large Sigma 150-600mm regarding sharpness? I am considering to buy the adapter.
I appreciate the wealth of information in this thread, it is a joy to read.

Leo

I have no experience with the L 400mm, but maybe thedigitalpicture has some comparisons to offer. 55-250mm IS STM is VERY sharp lens, best wide open or half stop closed. Further stopping down only brings more diffraction.
To my knowledge, the Sigma is not very sharp. You can go see Christopher Frosts review on Youtube.

I am looking for some solution above 55-250mm STM for my M6 II, and quite frankly, I don't know what to do. Any other lens brings great drawbacks. Prime, or dimmer, or not as sharp, or more expensive than the rest of the M6II setup with all lenses combined.

Tuff stuff.

Thanks for the suggestion, I tried to compare the Sigma 150-600mm at 400mm with the Canon 400mm 5.6 L USM. It very much depends on the body/lens combination. Using a 7D body, the test images of the resolution look similar. However for the 400mm it is possible to select 5DSr body with its whopping 50 MP pixel count. The resolution is far superior for this 400mm - 5DSr combination. Unfortunately the combination of this body with the sigma lens is not available. If I interpret this correct, it seems that the 400mm is at least not the limiting factor for the images taken with the 7D full frame camera. In addition, (again if I can make this comparison(?)) the 32 MP sensor in M6ii has roughly a similar pixel size as the pixel size of the 50 MP full frame 5DSr. which suggest at least that the resolving power of the 400mm lens is a good match to the sensor in the M6ii.

I don't know how to judge a comparison with the very sharp 50-250 EF-S lens since the images cannot be compared at the same focal length and moreover have a different magnification. The ability to separate the lines seems to be similar but I don't know what this means in practice.

Reading the reviews again (nearly 15 years after I purchased the lens) makes me realise that the lens holds well in the sharpness compartment but its largest disadvantage is the lack of IS. However, with the much lower noise and higher possible ISO of the M6, shorter exposure times are possible. This makes me feel optimistic. I think I'm gonna buy the adapter. As you say, very little options in tele-range are available and since I own the 400mm, it is worth to try. I always loved the 400mm on my DSLR's, it was one of the sharpest lenses that I own.

Looking at the comparisons, I would say you are on the right path to give it a try. I mean, if you won´t be happy with the image quality of your 400L, then tough times are coming for you anyways. Sooo, you better be. :-D

Larry's teleconverter project for the 55-250 STM is very worthwhile (follow it to the letter). It's inexpensive and pretty straightforward too. It's a very lightweight setup and basically takes you to 600mm (equiv). Sharp enough for the M6ii's 32 MP sensor too! Some 2160 px samples...

Note: All were shot through a double-paned argon-filled window. Spot autofocus, RAW processed with DxO PL5 Deep Prime. As the TC is non-reporting, the correct EXIF is 375mm @ f/8.

J&H

It's an inexpensive way to get a light telephoto lens to the ~400mm range, and it's just good enough to get good sharpness, especially in conjunction with DxO PhotoLab 6, using a little extra CA and sharpness than DxO lens corrections default for the bare EF-S 55-250 IS STM lens. Software won't have the corrections for the combo, so you have to compensate yourself for best results.

That being said, I have the Siggy 150-600mm f5-6.3 C lens, and by itself if's sharper with more micro-contrast than the EF-S 55-250 IS STM alone, or with the Kenko 1.5x SHQ combo, as you'd expect. However, it's a whale of a lens, and even though it's hand-holdable it's a hard piece of kit to take far from your house or vehicle. The Siggy works with the Kenko 1.5x SHQ, but the pixel-level images don't hold it together as well as the EF-S 55-250 IS STM does with that TC. Images with the Siggy + TC have almost zero croppability and works better with vertical composition with lower output pixel resolution.

When I go out with a lot of kit and 'may' need a telephoto to shoot trains or other subjects, I'll take the 55-250 + 1.5x TC. If I am specifically going out birding or wildlife shooting, or for astrophotography, no question it's the Siggy 150-600 for the job. The extra range and brightness make the difference between 'very good' and 'outstanding' results. If I see birds and I happen to only have the 55-250 klt with me, I'll still shoot with it - and with work I can usually make the results look pretty good.

Exactly! I was actually a bit surprised how well the combo’s IQ holds up, even wide open. It’s a very viable option when the heavy-weights aren’t available.

Similarly, I shot with the Canon EF 100-400ii +/- 1.4x iii extensively on the M6ii, and it was a handful (but produced beautiful results). I could use this combo successfully for everything except BIFs. The ultra-light 55-250 STM +/- TC scores way higher on the fun factor however!

J&H