The Sony GM 100-400 f/4.5-5.6 is said to be Sony’s best ultratelephoto zoom. In this review I will show you how it performs combined with the Sony a7RIII.
- Build quality and handling
- Auto focus performance
- Flare resistance
- Chromatic aberrations
- More samples
- Further reading
This lens is the first and so far only 100-400 telezoom from Sony for E mount.
- Diameter: 93.9mm
- Length: 205mm- 285mm
- Weight: 1395g (without tripod mount) or 1476g (with tripod mount) Lens hood: 108g
- Filter diameter: 77mm
- Elements/groups: 22/16 (2x ED, 1x Super ED)
- Field of view: 24ﾟ-6ﾟ10′
- Number of aperture blades: 9 (rounded)
- Aperture: f/4.5-5.6
- Close focusing distance: 0.98m
- Maximum magnification ratio: 0.35x
- Mount: Sony FE
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Disclaimer: I bought the lens for full retail price from my own money.
Build quality and handling
The Sony GM 100-400 is made of metal and high quality plastics. The lens feels solid without play on the rings, the buttons and switches feel solid. There is a small rubber gasket around the mount but it is too thin to actually close the gap between the lens and the camera mount. The focus ring feels nice enough. There is no physical coupling, the focus ring only serves as an encoder. Focusing at infinity near the long end of the lens can be somewhat tricky though, and is not as easy as with a true manual focus lens.The lens focuses internally but it extends a lot when zooming.
There are quite a few buttons and switches on the lens.
- AF/MF switch
- focus limiter switch that limits the focus focus range between 3m and infinity
- on/off switch for OSS
- switch to set OSS mode
- There are three custom buttons that can be used as focus lock buttons etc..
The lens features a ring to tighten the zoom ring to prevent zoom creep. On my sample setting this ring to “tight” was sufficient to fully prevent zoom creep no matter how you hold the lens. However there are quite some claims that this setting isn’t tight enough to prevent zoom ring so I guess it varies a bit from sample to sample.
There is a tiny bit of radial play between the lens mount and camera mount. I found it in combination with the a7RIII as well as with the a7II. During use, it didn’t bother me and I only noticed it while testing for it.
The lens features a removable tripod collar that can be rotated which feels very sturdy. Unfortunately it doesn’t feature an Arca Swiss compatible foot so one still needs to attach a plate.
A large plastic bayonet hood is included in the box. The hood is covered with felt at the inside and sits tight. The hood also features a slider so you can make an opening to turn circular polarizers.
All in all handling was fine on my a7Riii with L-bracket. The three custom buttons were a big plus for me. Still, the lens is heavy and walking around with it for a few hours is a bit exhausting.
When using the Sony GM 100-400 on a second generation or higher Sony a7 body or a9, one profits from 5-axis stabilization.
In general stabilization works fine, at shorter distances (up to at least 10m) at 400mm I was able to get a decent amount of sharp images at 1/80 sec. At longer distances and near infinity a tripod is recommended though when there isn’t much light.
Vignetting is low which is usual for tele lenses. Wide open the following numbers were measured:
100mm f/4.5: 0.9EV
200mm f/5.6: 0.5EV
300mm f/5.6: 0.6EV
400mm f/5.6: 1.0EV
Stopped down to f/7.1 vignetting is negligible at all focal lengths.
Auto focus performance
Autofocus is fast and accurate on my a7RIII.
With AF-C I could easily track flying birds. Also tracking a dog that was running towards me very fast was not much of a problem, most pictures were well in focus.
Eye autofocus works accurate as well in AF-S, I did not notice any front or back focus issues.
The only scenario autofocus was a bit slower is near mfd, however I prefer to use manual focus anyway in such situations.
Center sharpness is very good from wide open at every focal length, the midframe always looks great as well. The corners are best at 200 and 300mm and a bit worse at 100mm and 400mm on this sample. Are the corners bad? No, but they simply look not quite as well as the midframe.
At 200 and 300mm sharpness in the extreme corners is almost as good as midframe sharpness, only contrast is a bit lower.
All in all, across the frame resolution the plenty good enough for landscape photography. Also remember that especially in summer you won’t be able to use the lens near 400mm due to heat haze which degrades sharpness a lot.
At 400 mm refocusing can make a significant difference as can be seen below. Both pictures were taken at f/11, I refocused without sacrificing center sharpness (focus on tower) to gain better corner sharpness.
400mm f/11 800*800 pix crop
Sharpness near MFD
The MFD of 0.98 meters at 400mm is a great feature of the GM 100-400. Near MFD sharpness is very good as well. The center looks great at all focal lengths from wide open. The midframe looks good from the start already and improves a bit on stopping down.
Corners look good to very good at 100 and 400mm but suffer a bit at 200 and 300mm.
Sharpness at 4m
At 100 and 400mm, center and midframe are excellent from the start with very good to excellent corners, especially the performance at 100mm is remarkable.
at 200 and 300mm center and midframe are great as well, only the corners fall behind and never get great.
Flare resistance is the only real weakness of the Sony GM 100-400 f/4.5-5.6. With the sun just outside the frame veiling flare can be a serious problem. With the sun in the corners one can observe significant ghosting and some loss of contrast. The lens hood does an OK job but this isn’t enough to prevent serious flare.
In many situations slightly recomposing helps a lot to get rid of ghosts or to at least mitigate them.
Longitudinal chromatic aberrations
There is LoCA visible in very demanding situations like in the example below, but in general LoCA are not a problem at all.
Lateral chromatic aberrations
LaCA correction is very good, only in a few demanding cases I could notice some. Levels were low enough to make correction in post easy.
Despite the slower speed of the lens, bokeh in general is very smooth at all focal lengths. Bokeh balls usually show barely any outlining or onion rings.
In the comparison below I did not change my position
Only with objects in the foreground like grass one can observe double edged structures in the bokeh which can be distracting like in the two examples below.
This happened only in a few occasions. To get a better idea of the bokeh in general use, see the photo’s below.
At the short end distortion is negligible, at 200, 300 and 400mm there is some pincushion distortion present that you want to correct. If you enable the automatic distortion correction in camera, the camera does it for you.
Canon 100-400 f/4.5-5.6L IS II USM
The Canon is quite a bit cheaper but you will need an adapter to use this lens on a Sony camera which probably has a negative impact on AF speed. Furthermore the Canon 100-400 is +/- 170g heavier without an adapter, with the Sigma MC II the difference is almost 300g. The Sony is should be sharper, especially at the long end, but I did not test them side by side.
CONTAX ZEISS VARIO-SONNAR T* 4.5-5.6/100-300
The Zeiss is much cheaper, and significantly lighter. The Zeiss is also shorter and offers no AF. The Sony has smoother bokeh and is better corrected for CA, sharpness is very good on the Zeiss though.
Both are lighter and cheaper, bokeh is less smooth and the Sony is sharper. However, if you don’t have an infinite budget they might be a good choice.
Sony FE 70-300 f/4.5-5.6G OSS
The 70-300 is quite a bit cheaper and lighter than the 100-400 (+/- 600g). A good sample of this lens is very sharp but it has a bad reputation for high sample variation.
Sony FE 200-600 f/5.6-6.3G OSS
In case birds and wildlife are your main focus this one might be the smarter choice since it offer significant more reach. However, the 200-600 f/5.6-6.3 also is much larger and heavier than the 100-400 (near 700g).
The Sony GM 100-400 f/4.5-5.6 is a very solid performer, as it should be with its price tag. Sharpness is great for a zoom, bokeh is very smooth, CA correction is good and AF is fast and precise.
Besides the optical qualities, build quality and handling are very good as well.
Despite 400mm being a bit on the short side, the lens delivered satisfactory results when I used it for photographing birds from wide open. Sharpness is great combined with great bokeh even at longer distances.
Due to the good bokeh, the Sony GM 100-400 can be used for portraiture as well despite its limited speed. However a faster lens like the 70-200/2.8 will deliver some more blur and is more suitable for this purpose.
The minimal focus distance of only 0.98 m at all focal lengths makes it a semi macro lens which makes it two lenses in one. For me personally this was one of the main reasons to buy this lens. Especially the great resolution near mfd is a huge plus. It makes it a very useful tool to take pictures of frogs and insects with coming too close.
Due to the very good sharpness across the frame near infinity the 100-400 GM is a fine landscape lens as well. You won’t be using the long end near infinity a lot though, heat haze often spoils the game.
After 3 months of use, the Sony GM 100-400 still finds its way into my bag very often. On shorter hikes through nature I always carry it with me to take pictures of birds and wildlife. Was it worth the high price? For me it was. The Sony GM 100-400 enables me to take pictures I couldn’t take before.
Since I didn’t use the lens very often for landscape photography yet, I will update the review as soon as I have the change to evaluate the performance on this aspect a bit more.
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Most photo’s in this review can be found in higher resolution in this Flickr album.
- FE list
- Canon FD 300mm f/4
- GUIDE TO THE BEST 50MM LENSES FOR FULL FRAME SONY E-MOUNT CAMERAS
- SONY FE 4/70-200 G OSS
- Viltrox 1.8/85