The Sigma 18-50 is a very promising lens for the Fujifilm X Mount system.

With this lens, they’ve taken a constant f2.8 aperture like in the 16-55 and put it into a lens about the size of the 18-55.

Which sounds too good to be true.

For the past few weeks I’ve had the opportunity to test this lens out to see how it performs.

Unfortunately, I was just borrowing it so I’ll only be able to make a few first impressions.

But I’ll share with you what I think about the build, image quality, and functionality of this lens.

We’ll also talk about how it stacks up against Fuji’s own 18-55 and 16-55.

Lets get started.

General Impressions

When I first unboxed this lens, I was impressed with the build quality.

Unlike the Fuji lenses, it’s got a matte finish - which is nice to hold and look at.

I was also surprised at how small the lens was.

It’s very comparable to the 18-55 but just a tad thinner.

For indication, it’s got a smaller filter size of 55mm as opposed to the 18-55’s 58mm filter.

Another thing I noticed was how stiff the focus ring was.

When compared to the 18-55, the 18-55 zooms quick and smooth.

The Sigma 18-50 however is a bit stiffer.

Meaning, you there isn’t much “zooming” if you want to zoom.

All it takes is a slight turn to switch focal lengths.

The focal length markings are also very close together, so having a slippery focus ring would be impractical.

So it’s not a negative - it just takes some getting used to.

Similarly, the zoom ring turns opposite to the 18-55.

On the 18-55, you push right to zoom in and out, on the 18-50 you push left.

This also took some getting used to.

Something I like about the zoom ring is that there’s a marking for the 28mm focal length (aps-c).

This is a nice aspect of this lens because I quite like that focal length and both the 18-55 and 16-55 lack that marking.

Of course you don’t need the marking to shoot at that focal length but it’s definitely nice.

Another thing to point out is that there is no aperture ring.

Where you’d normally find an aperture ring, the Sigma 18-50 has it’s manual focusing ring.

To change apertures you’ll have to use your camera body.

I personally prefer having an aperture ring on my lenses.

It’s why I like shooting Fujifilm - many of their lenses have manual aperture rings with clicks and markings.

Again, not a good or bad thing, it just takes some getting used to.

So overall impressions of the lens, I found the build quality to be quite good.

The lens has a few things I’m not yet used to but none of which should be a problem.

Performance

General Image Quality

In the past few weeks I’ve taken this lens out a couple times to test it’s image quality.

Again, I’ve not been able to use it for long, so I only have a few photos.

But overall, the image quality is solid.

The lens is a good, solid, and sharp one - I haven’t noticed any problems in terms of image quality when compared to my usual lenses.

But you guys know I’m no pixel peeper - I care more about functionality and usability than pure image quality.

F2.8 Aperture

A big selling point for this lens is it’s constant 2.8 aperture.

Simply having that option is really nice.

Lenses like the 18-55 have a variable aperture, while can be annoying to change your exposure every time you zoom in and out.

Keeping my lens at f4 makes it so I don’t have to do that, but means I wont get the benefit of the wider aperture.

Again, not a big issue: most of my photography lately has been revolving around f4.

I’ve noticed f4 works well for sunset and daytime photography - it gets enough of the frame in focus, while letting light in.

I think the Sigma’s wider aperture would be great for something like street and portrait photography.

Both of which I haven’t been doing much of lately.

The point is, the wide constant aperture is a nice addition.

I personally don’t need it right now, but I know many of you would benefit from this.

Autofocus

Now in terms of autofocus, this lens is fast and accurate.

Surprisingly, I think this lens did better than the 18-55.

I tried taking a few thumbnail photos with both the 18-55 and the sigma 18-50, and where the 18-55 had trouble focusing, the 18-50 did well.

Which actually makes sense because the 18-55 is a much older lens.

So, overall the lens’ performance is very good.

Image quality is good, f2.8 is nice, autofocus is great.

I’ve got nothing to complain about and would love to use it in more scenarios like street photography and other travels.

How Does it Stack Up?

If you’ve been following this channel for a while you’ll know that I’ve had both the XF 18-55 and the 16-55.

I’ve never had the 16-80 so I can’t give any opinion on it.

However, these would be the lenses you’d look at when searching for a solid standard zoom for your x-mount camera.

When compared to the 18-55 and 16-55 the Sigma 18-50 is a great option.

It’s got a constant f2.8 aperture, much like the 16-55, packaged into the small size of the 18-55.

Similarly, it’s autofocus and image quality doesn’t lose out when compared to these lenses - all 3 are good.

Lets go through each of these.

OIS is most important for video or when shooting in low light.

Because the sigma has an f2.8 aperture however, I think low light photography won’t be as tough as with the 18-55.

If you’re a video or hybrid shooter however, the lack of OIS would be a missed factor.

I’m not entirely sure if there’s any weather sealing on this lens, so don’t quote me on this.

But I believe it’s partially weather sealed, which could help if you expect to be out in the rain or wind often.

As for the focal range, this lens has slightly less zoom on both ends.

It’s a small thing but: we’re losing out on 2mm on the wide end and 5mm on the telephoto end when compared to these other two lenses.

And finally, there’s no aperture ring.

So, you can determine whether or not these are caveats or deal breakers for you.

For me, the 18-55 suits most of my needs.

I value the OIS and don’t need the constant f2.8 as much as I thought.

As for the 16-55, I’ve since sold it because it was too big.

So I may pick up the Sigma in the future, but for now, I don’t really need it.

Which Should You Buy?

Overall, the Sigma 18-50 is a nice little lens.

Many people have compared it to being a bag full of primes and it certainly feels that way.

If you can’t decide which of these zoom lenses to buy, there are 3 main questions to ask:

how important is a constant f2.8 to me?
how important is size for me?
how important is price to me?

If you want a constant f2.8, grab either this or the 16-55.

If size is important, grab this or the 18-55.

If price is important, grab the 18-55.

I hope this helped - if it did, please do share this with a friend.

Also my new photography zine “The Sinking Sun” is finally out - order your copy while they’re still here.

Have a great day, thanks for reading!