The new Sony FS7 zoom lens, the Sony SELP18110G.

AJC03714-1024x681 The new Sony FS7 zoom lens, the Sony SELP18110G.
Sony SELP18110G servo zoom lens.

When Sony launched the FS7 II they also launched a new lens to go along with it. The previous zoom lens that was bundled with the FS7 was the SELP28135G, a 28-135mm f4 zoom lens that would work with Super 35mm, APS-C and full frame cameras. While generally well received this lens is not without it’s problems. For a start it’s not really wide enough for use as a general purpose lens on an APS-C or Super 35mm sensor. The other problem is that the zoom is very slow. Even when set to manual zooming in and out takes a long time. You turn the zoom ring and then have to wait for the lens to catch up.

The new lens is a wider 18mm to 110mm f4 lens. This is a really useful zoom range for a Super 35mm camera. But the new lens can only be used on S35mm and APS-C cameras. It can’t be used with full frame cameras like the A7s in full frame mode.

AJC03718-1024x681 The new Sony FS7 zoom lens, the Sony SELP18110G.
The front element of the Sony SELP18110G.

But what about the zoom speed? Well this has been addressed too. On the 28-135mm lens the zoom function is electronic. There is no mechanical connection between the zoom ring and the optics of the lens. The 18-110 has a proper mechanical connection between the zoom ring and the internal lenses, so now you can crash zoom in and out as fast as you want. In addition the zoom servo motor is much faster and motorised zooms take place much more rapidly. One downside to this is that it’s a bit harder to control the zoom speed. You can do slow creeping zooms if you are very careful with the cameras zoom rocker, but it’s hard to do. The difference in pressure on the zoom rocker between creeping zoom and medium speed is tiny. The lens tended to change zoom speed quite quickly. While it is indeed very nice to have a variable speed motorised zoom, don’t expect the fine degree of control that you get from admittedly more expensive traditional ENG lenses. Lets face it this lens is only around £3K/$5K which is remarkable cheap for a parfocal s35mm zoom. Take a look at the video below for an idea of the zoom speeds etc.

Is it really parfocal? Well yes, it does seem to be parfocal. I only had the lens for a morning to play with, but in all my tests the focus remained constant throughout the zoom range.

So, what about focus? Like the 28-135mm lens there is a nice big focus ring that slides fore and aft.

AJC03723-e1487017741838 The new Sony FS7 zoom lens, the Sony SELP18110G.
Focus, zoom and iris rings on the SELP18110G.

In the rear position the focus is manual and there are calibrated focus markings and end stops. You get about 180 degrees of focus travel from 0.95m (3.1ft) to infinity (in autofocus you can focus slightly closer when the lens is at the wide end). The focus ring has 0.8mm pitch teeth for use with most standard follow focus units, although this gear ring is very close to the end of the lens, so it may be tricky to use if you have a matte box in place. Breathing is very well controlled and barely noticeable unless going through very large focus throws. Out of focus Bokeh isn’t bad either, I didn’t observe any nasty surprises in the limited time I had to play with the lens.

Bokeh-1024x576 The new Sony FS7 zoom lens, the Sony SELP18110G.
Frame Grab. Near and far out of focus bokeh is reasonable on the Sony SELP18110G. Click on the image to view a full size copy.

Sharpness and flare. The lens appears to be nice and sharp at the wide end but just a touch soft at the long end. It’s not bad overall but when shooting at 4K I could just about detect the lens becoming marginally softer as I zoomed in. The sample I had was a well used pre-production prototype, but I’m going to guess that the production lenses won’t be hugely different. Shooting the roof of a house against a bright sky revealed only a small amount of flare, certainly nothing out of the unusual for a zoom lens.

18110-110-1024x576 The new Sony FS7 zoom lens, the Sony SELP18110G.
Frame grab from the Sony SELP18110G at 110mm. Click on the image to view a full size copy.
18110-18-1024x576 The new Sony FS7 zoom lens, the Sony SELP18110G.
Frame grab shot with Sony SELP18110G at 18mm. Click on the image to view the full size image.

Overall I really like this lens. It even has a support point at the front of the lens body for additional stability. While f4 isn’t the largest of apertures it is quite usable and even wide open the lens performs well. For the money it is a lot of lens. I think we need to be realistic with our expectations for zoom lenses and large sensors. Bigger zoom ratios require bigger lens elements if we want to maintain a constant aperture. Bigger lens elements cost more to produce.

AJC03729-e1487018834354 The new Sony FS7 zoom lens, the Sony SELP18110G.
Underside of the Sony SELP18110G showing the extra lens support points. A lens foot that attaches to the rear mounting is included with the lens.

One advantage Sony have over the competition is that it’s easier to make zoom lenses for the very short flange back distance of the E-Mount cameras compared to the deeper flange back of PL or Canon mounts. The closest competition to this lens is the Canon 18-80mm T4.4 (f4 ish) which is a fair bit more expensive (£4K/$6K). If you want a similar zoom range then you’re looking at the beautiful  Fujinon 20-120 T3.4 at around £14K/$19K.

19 thoughts on “The new Sony FS7 zoom lens, the Sony SELP18110G.”

  1. Out of pure curiosity, I’d love to see an image quality comparison between this lens and the other Sony G f4 lens of similar focal length the 18 to 105 mm. Operations wise, the two would be worlds apart.

    1. I didn’t test side by side, but I know that I would always want this lens rather than the 18-105. The distortions in the 18-105 are pretty bad and focus is “interesting” to say the least. However the compact size of the 18-105 makes sense if you have an FS5.

  2. My own thoughts on this lens. I cannot understand why an APS-C lens, even though it is wider than it’s full frame equivalent is a $1000 more expensive than it’s predecessor? Yes it compares favourably in price to those other lenses but as you’ve already said in your review it is quite soft at the tele end (something the 28-135 suffered from as well) . Those other more expensive zooms are sharp throughout the range. I notice you also didn’t mention CA – my copy of the 28-135mm suffers quite badly from CA in hi con situations. I’m guessing that is because I use it on an FS700 which has no internal correction for the lens. It will be interesting to compare to the 18-110..

    1. I expect the cam operated mechanical zoom costs more to design and manufacture than the slow motorised zoom. With the slow zoom of the previous version it would have been easy to hide any parfocal problems with an electronic focus offset. Much harder to do when you can crash the zoom in and out. I didn’t test for CA without the cameras internal correction. CA correction is now common place and this is how this lens is supposed to be used.

  3. I have the FS5 and kit lens, and its the focus breathing which I find the most frustrating part – whilst I mainly use manual, there are times (especially in motion tracking) when auto-focus is essential. So my question is, Alister, how much better is the control of focus breathing on the new lens in auto? Thanks for your great blog by the way, I really appreciate your work.

  4. Thanks for doing this test, I really appreciate it. It’s one of only two (legitimate) tests that I could dig up anywhere on the internet.

    One question, if you have a moment. Since the FS7 can’t correct for optical geometry while shooting in UHD or 4K (though it can in 2K), do you know if the FS7 will be able to correct for CA with this 18-110mm in 4K? Or are absolutely all lens corrections not applicable to 4K recordings on the FS7? Thank you Alister!

    1. I’m not really sure to be honest. I’ll try to find out. But I didn’t notice any bad CA when shooting in 4K.

  5. Hi,
    Sony say its a 4K lens..what about its performance beyond 4k..6k etc?

    Is it “sharper” than the 18-105 lens?


  6. from the B&H site: “According to Sony, the lens acts like a parfocal lens with the electronic autofocus function engaged.” I’m still trying to figure that one out. Does that mean that if you critically focus, and engage the electronic autofocus, the lens will compensate when zooming, to keep that distance in focus? Would it be “distracted” if something else appeared in the focusing area? If not, and the 18-110 is not parfocal in manual mode, it is not parfocal, period. If it “appears” to be, that would be very interesting.

    1. The lens is not optically par-focal but it uses clever electronics to compensate for this adjusting the focus so that in most cases it appears to be par-focal, even with manual focus. However if you zoom in and out really fast, while the zoom is taking place, the lens will often loose focus while the electronic corrections catch up. From a practical point of view for the vast majority of applications the lens will behave the same as a par-focal lens.

      1. That is fascinating. If that electronic compensation is reliable, it will make all the difference for this lens, particularly for interviews shot at a wide aperture. To be able to zoom in, focus, and then zoom out and reframe without verifying focus, would be great.

        Here’s what puzzles me. I looked for information on this feature on Sony’s website, but it is not mentioned anywhere that I could see.

        I would love to see a wide-open test of this feature.

        1. The compensation works very well but can be beaten if you manually zoom very quickly, however it soon catches back up.

  7. Hi Alister,

    How would you compare the SELP18-110 to an 3/2″ ENG lens setup with your MTF-converter in fullframe mode on the FS7?
    Is there a lot of difference in DOF wide open?
    What about sharpness and CA with ENG lenses? Is it much worse than the SELP18-110? (I guess it also depends on the ENG lens you use)
    Many thanx in advance!

    1. The SELP18-110 will be sharper, faster and have a better bokeh than any 2/3″ lens via an adapter. In UHD/4K this will be fairly obvious, in HD the difference may be small, but it will depend on the exact lens used. The 18-110 is only a 6x zoom and most modern ENG zooms have much, much greater zoom ratios, typically 20x. A typical 20x 2/3″ lens will give the equivalent of 18-360mm. For very long lens work you can use something like a 44x extending the focal length to close to 1000mm.

  8. I’m personally finding that as my body has advanced so much (I’m talking about an upgrade from the Sony A7iii to the Sony A7Sii) I’m able to get more out of my lenses.
    Really frustrated with the standard 50mm with all of the focus hunting, until I upgraded my body and the autofocus worked a treat.

    1. If your only definition of cinematic is ultra shallow DoF then using a larger aperture will make footage more “cinematic”. But in reality DoF is rarely this shallow in features and film productions.

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