Sony FE 100-400GM + 1.4 TC Review

Started Aug 21, 2017 | Discussions thread
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Kev The Doc Senior Member • Posts: 1,539
Sony FE 100-400GM + 1.4 TC Review

Below is a preliminary review from spending 4 days with the 100-400GM & 1.4 TC. My benchmark lens is the 70-300G so comments are mostly relative to that lens. So why right a lens review after just 4 days, well it’s a rental lens and so I want to capture the learnings while it’s all fresh in my mind.

All testing was done using an A6500 body.

Build quality / functionality


· Overall build construction is good with weather sealing as an additional bonus.

· Lens Hood – particularly impressive with a positive locking mechanism and a sliding port to access circular polarizers.

· Full set of on lens controls including MF/AF, Focus range, OSS on / off, OSS modes (full or pan), and three focus hold buttons for accessibility irrespective of holding position.

· Even with the 1.4TC this is lighter and smaller than a typical 150-600mm alternative.

· Built in tripod collar which can be easily rotated with alignment markings to switch from landscape to portrait mode. Would be nicer if the tripod collar had an arca plate?


· Zoom control has a somewhat sticky dry feel imho? Is this an artifact of a large lens with weather sealing or perhaps just a new lens then needs breaking in?

· Zoom resistance adjuster – On the tightest setting the zoom still creeps when walking with the lens pointing vertically down, and then when using I found the “smooth” (loosest) setting to work best. I’d therefore prefer to have the lock switch that the 70-300G and this is a step backwards in my opinion.

· The markings on the lens are not recessed and for this price I would expect recessed markings for longevity. As an example the non recessed markings on my 70-300G are showing signs of wear and tear.

· Heavier and larger than the 70-300G, though I found the extra size and weight ok.

Vs the 70-300G, the GM has better lens hood, build in tripod collar and weather sealing. Other than that I found them quite similar and actually preferred a few aspects of the 70-300G such as the zoom mechanism and the lens FL lock. Clearly size difference is there and this is a very personal choice on what’s acceptable or not.

Focus speed and precision


· Generally, I found the focus on this camera to be fast and precise just like the 70-300G and in low light possible even better than the 70-300G, though I’d need more time with the lens to totally conclude that. The extra FL also helped nail focus in numerous circumstances such as when focusing on creatures that don’t fill much of the frame with BIF being an example of that where again particularly with the 70-300G the object is often extremely small in the frame making it harder for the camera to focus on it.


· The only time I found the focus a little slow was macro focusing where it appeared to hunt back and forth (in good light) more than a 70-300G.

Optical quality

Firstly here’s a link to my previous posts showing some photo’s, in these early examples I shot in raw:

After realizing there is no lens profile yet in my raw converter I started shooting everything in jpg E.Fine, profile “Standard” and the shots shown are non processed OOC jpg’s accordingly. Postings using OOC jpgs can be found:

Initial real life photo observations

· Sharpness was clearly as good if not better than the 70-300G from the get go, though the 70-300G is no slouch in this regard. Probably the biggest initial observation was the contrast and color saturation from the images produced, they were / are very pleasing. Clearly this is something that people need to make their own mind up, by looking at the shots shared by myself and several others in this forum.

Comparative shots

I wanted to take some like for like shots as a shootout between:

· 100-400GM + 1.4 TC

· 100-400GM

· 70-300G

Test setup

· I placed a Canadian moose in the garden about 40 ft away from the shooting spot with some foliage about 15 foot behind the moose.

· All shots were taken from the same spot i.e. the same distance from the object.

· I was braced against a wall to keep the camera steady as lighting wasn’t quite as good as I would have liked.

· I took three shots of each setting to validate consistency and can say no differences were observed between repeat shots.

· Key settings used were:

o Auto focus, flex spot medium

o OSS / IBIS on

o ISO locked at 400

o OOC jpg’s used, E.Fine, standard profile

Comparison 1: Max FL’s

· The first comparison I wanted to do was compare each lens at their max FL ,and then apply a modest post crop with re-sampling so that the moose was the same size on the screen i.e. I am determining if the extra reach is delivering superior results and if so by how much vs using shorter FL lens and simply cropping more. Below you will find the following shots:

o 100-400GM + 1.4TC @ 560mm FL & F8

o 100-400GM @ 400mm FL & F8

o 70-300G @ 300mm FL & F8

100-400GM + 1.4TC @ 560mm FL & F8

100-400GM @ 400mm FL & F8

70-300G @ 300mm FL & F8

Comparison 1 observations

· The main difference I see in these results is the slight softening of the 70-300G shot and although generally speaking shutter speeds were on the low side I quite regularly shoot at this shutter speed with the 70-300G without a problem and also this should / would have effected the 100-400GM & 100-400GM + TC more (longer FL) so I don’t believe this is a factor.

· The 100-400GM + TC & 100-400GM results look quite similar to me at this stage.

I then wanted to explore a more extreme crop of the same three photo’s to see if this highlighted any further differences, these photo’s can be found below:

100-400GM + 1.4TC @ 560mm FL & F8

100-400GM @ 400mm FL & F8

70-300G @ 300mm FL & F8

Comparison 1 extreme crop observations

· The slight softening of the 70-300G is more apparent here, but in the defense of this lens, this is a very extreme crop of a 300mm FL shot.

· A difference between the 100-400GM + TC (@560mm FL) and the 100-400GM (@400mm FL) shots can now be seen also concluding there is a noticeable difference when heavy cropping as the shorter FL shot is being cropped significantly more.

To demonstrate how much cropping is done here’s the above 70-300G shot uncropped as a reference.

70-300G @ 300mm FL & F8

Comparison 2: 400mm FL’s

· The next comparison I wanted to do was with and without the TC but at the same FL to see if the TC is degrading image quality. Below you will find the following shots:

· 100-400GM + TC @ 386mm FL & F8

· 100-400GM @ 400mm FL & F8

100-400GM + TC @ 386mm FL & F8

100-400GM @ 400mm FL & F8

Comparison 2 observations

· The shot with the TC holds up very well in my opinion and I see minimal difference.

Again I decided to perform a heavier crop to see if that revealed any differences:

100-400GM + TC @ 386mm FL & F8

100-400GM @ 400mm FL & F8 Comparison 2 extreme crop observations

· A very slight difference can be seen with the non TC shot giving a slighter better result, but very very slight.

Comparison 3: 300mm FL’s

· In order to give the 70-300G a fair crack at the whip and not be penalized with cropping more I also decided to test all three setups at 300mm FL. I also wanted to start looking at performance wide open as that is the desirable setting for most occasions, this comparison looks at the following:

o 100-400GM + TC @ 309mm FL & F8

o 100-400GM @ 297mm FL & F5.6

o 70-300G @ 300mm & F5.6

100-400GM + TC @ 309mm FL & F8

100-400GM @ 297mm FL & F5.6

70-300G @ 300mm & F5.6

And again I have done some extreme crops of the above three shots as follows:

100-400GM + TC @ 309mm FL & F8

100-400GM @ 297mm FL & F5.6

70-300G @ 300mm & F5.6

Comparison 4: Max FL’s wide open

· As a last comparison I wanted to repeat comparison 1, but instead of all being at F8 I wanted to compare with all setups wide open as follows:

o 100-400GM + TC @ 560mm FL & F8

o 100-400GM + TC @ 400mm FL & F5.6

o 70-300G @ 300mm FL & F5.6

100-400GM + TC @ 560mm FL & F8

100-400GM + TC @ 400mm FL & F5.6

70-300G @ 300mm FL & F5.6

Comparison 4 observations

· As the performance of both the 100-400GM & 70-300G is quite good wide open the conclusions of this comparison are the same as comparison 1 above.

And again with extreme crops for consistency:

100-400GM + TC @ 560mm FL & F8

100-400GM + TC @ 400mm FL & F5.6

70-300G @ 300mm FL & F5.6

Comparison 4 extreme crop observations

· As the performance of both the 100-400GM & 70-300G is quite good wide open the conclusions of this comparison are the same as comparison 1 above.

100-400GM Summary


· There’s some aspects of the build quality / functionality to show improvements vs the 70-300G such as weather sealing, lens hood, and tripod collar.

· In terms of optical quality, the 100-400GM clearly brings some improvements to the table not just in terms of additional sharpness but more so in the contrast and color from the real life images in the linked posts at the beginning. I found the images more pleasing than the 70-300G. Having said that I believe the 70-300G stands up well and is still a lens I really like. The decision on whether or not the 100-400GM is worth the extra money is a personal choice that these forums spend too much time arguing imho.

· Extra reach making focusing easier in certain circumstances and ultimately delivery shots that don’t need cropping / need less cropping to preserve image quality.


· Size & weight

· Price

· There were some aspects of the 70-300G I prefer such as the zoom lock switch vs the zoom resistance adjuster on the 100-400GM, but these are just personal preferences.

1.4 TC Summary


· Overall I was very pleasantly surprised with the performance of the 100-400GM lens with the 1.4 TC connected, I’ve never used a TC before but read a lot of bad “stuff” about how they can degrade image quality substantially and slow focusing down in addition to the one stop light loss. The 100-400GM + 1.4TC doesn’t seem to suffer any of these issues in my experience so far.

· Optical quality with the TC connected showed v.minimal loss of quality if any.

· Extra reach

· Focus speed and short focus distance didn’t seem to be noticeably effected either. Again the additional FL can make focusing easier as noted above with the 10—400GM vs the 70-300G by simply making the objects larger in the frame they are inherently easier to focus on.

· The size of the TC is so small and weight minimal I didn’t find this to be an issue or of any relevance.


· Except when significantly cropping, “similar” picture quality can be obtained using just the 100-400GM and simply cropping a little more in post processing.

TC Conclusion

· As the TC performs well, the question of whether or not somebody needs it comes down to common sense in the end, it depends on what they’re shooting, to summarize, for extremely small / distance objects the TC offers some clear advantages in terms of ease of focus but more importantly picture quality, but if 400mm FL plus a “little” post cropping gets you there then you don’t need the TC.


As this lens is new it would be great to get some feedback from others to see if they have similar or different findings to mine so far?

Also let me know if you spot typo's that need cleaning up, quite a long post

 Kev The Doc's gear list:Kev The Doc's gear list
Sony a7R II Sony a6500 Sony Vario-Tessar T* E 16-70mm F4 ZA OSS Zeiss Loxia 21mm F2.8 Sony 1.4x Teleconverter (2016) +3 more
Sony a6500
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