My mostly used lenses are four zoom lenses in the range 10-600mm: except the 200-600mm, they are quite compact and easy to carry along. The price to pay for this is to give up with very fast apertures: when I bought them, they were all ƒ/4 lenses. After many years, the Sony Zeiss Vario-Tessar T* E 16-70mm F4 ZA OSS broke and was replaced by the Sigma 18-50mm F2.8 DC DN C, so I gained a full stop, and in theory I could gain it also in the 10-18 range with another Sigma lens. But ƒ/2.8 on APS-C is not a very fast aperture when it comes to the requirement for shallow depth of field. Now this is mostly a non problem for classic landscape shots, but if you want to have more flexibility with depth of field you have to look elsewhere. For price, but above all weight and space reasons, I think the proper choice is to pick a few small and light prime lenses. FIRST THE SAMYANG 75mm ƒ/1.8. The latest fast lens that I bought exactly a year ago is the Viltrox 56mm F1.7.

I had been looking at this focal length since when the Sigma 56mm f/1.4 DC DN C came out with very good reviews, but the price around 400€ kept me from buying it because it was too much for a focal length I wasn't sure about. Things changed when the Viltrox came out, at less than half the price. In terms of sharpness the two products are similar; with Sigma you gain a neglectable fraction of stop and probably a better handling of flares, but the Viltrox lens is smaller and lighter.

The Viltrox lens is part of a very “aggressive” and effective marketing strategy by Viltrox: high quality lenses, both optically and from the building point of view, where you give up to something (generally there are no extra controls in addition to the focusing ring, and in this case you have a subpar autofocusing system) for a very competitive price (under 200€). As it often happens with “minor” brands, the quality assurance is relaxed and there is high quality variance about copies: you should consider to buy from a seller that accepts one or two return requests without objections (my first copy of the Viltrox 56mm was returned because it was clearly decentred).

A 56 mm lens in APS-C mode, whose field-of-view is roughly equivalent to an 85 mm lens, is typically used for portraiture. But it’s not my kind of job, even though I sometimes take a portrait of a tame animal, such as this cat. The bokeh is creamy and the background blur is quite smooth — and this shot was done in an ancient village alley, so there was not a huge separation from the wall in the background.

When the subject is not very close, the shallow depth of field can be used to reduce complexity and properly funnel the viewer’s attention. But note that the foreground bokeh is not so smooth as the background one, so if the foreground is busy the trick works only up to a certain point.

I’m using the lens mostly for landscape and architecture — and what’s the utility of a fast lens for that? To avoid having all planes tack sharp and to help in selecting the one where I want to draw the viewer’s attention; such as in this case, where I wanted to bring the attention on the door (indeed this shot is not perfect, as I back-focused a bit).

Another option is to have a landscape that must be present only as a blurred context for a close range subject.

When the subject is at medium distance, the background blur is really minimal, but it’s often enough to make the subject pop a bit.

When the subject is far away, the focal length is too short for blurring the background. In this case the lens turns into a “normal” landscape lens, exceptionally sharp even at full aperture. The only problem in this scenario is a noticeable vignetting, that it’s only partially corrected by the post-processing software; I don’t know whether it’s a problem of Capture One, which doesn’t have specific profiles for Viltrox lenses, even though it should do with the embedded one. In any case, it’s easy to fix it in post-production; but stopping down a bit is a better way to deal with the issue.

Even though so far with this lens I didn’t manage to be in a good place for an outstanding picture in a woodland, I really enjoy the capability of insulating a single element from a multiplicity, such as a tree.

Note that in the photos below the blur is minimal and you should open the larger image version to appreciate it.

Another use case is to dial a really fast shutter time while not under-exposing: for instance, 1/4000s or 1/8000s (available with the electronic shutter of my Sony ALPHA-6700) that freeze the water droplets of surf on a cliff.

I found that it’s not uncommon to get over-exposure even with the fastest shutter time in a bright day, so in some cases a neutral filter can be required.

Bokeh balls

Bokeh balls are usually pleasing, but they lose the circular shape already at ƒ/2.0: clearly nine blades are not enough (probably they are not rounded). Cat’s eyes are clearly visible and when stopping down further the shape of the balls can become irregular, because of a not perfect aligning of the blades. I’ve seen that this is a frequent problem with inexpensive brands (I experience the same thing with a Samyang 75mm ƒ/1.8, that was perfect in this respect when I bought it, but got the defect after some months of use).

Against the sun

Unfortunately, shooting with the sun in the frame can create very large green blobs which can be hard to fix in post-processing, unless you have a lot of negative space where you can try to put them. The good news is that stopping down the blobs shrink a lot and dim, so the problem becomes manageable. In the latter photo of the pair below a small flare under the boat was easily masked.

A severe problem occurs when the sun is just outside the frame, as it creates a lot of veiling and contrast reduction; sometimes also introducing a colour cast. The only way to work around this is by blocking the sun, with an object in the scene or with a hat. I think that part of the problem here is the ridiculously small lens hood — for instance, the already mentioned Samyang 75mm ƒ/1.8 has a much deeper one. Probably a screw-in third party hood would be a good idea.

A firmware bug

Just from the first test day I noted that shooting with fast shutter times and wide aperture produces a strong uneven exposure, with a dark band at the bottom of the frame. I was quite disappointed, but I was relieved when I found that using the electronic shutter fixes it. Of course this introduces a slight decrease in quality, as 2 bits of pixel depth are lost; they can be useful in post to recover burned highlights. Anyway a recent a firmware update (v 1.0.4) fixed the problem. The firmware can be easily upgraded without the need of installing software on your laptop: when the lens is connected with an USB-C cable, it appears as a virtual volume where you just need to drag and drop a file.

A few months ago, Viltrox introduced a faster lens: the AF 56mm f/1.2 Pro. While it's interesting for the even wider aperture, it's definitely more expensive, heavy and larger. Not an option for me, at the moment.