[Squawk]

Really struggling with this decision. I really like the 20-40 but it's reviews have not been stellar but the actual user reviews are great. Versatility as far as zoom ranges is not a concern. I am just wanting the best IQ and low light capabilities. However, for the price of the 20-40 I could get the 16-85 and the 50 1.8 for low light. I will be using it in the K3 II. Looking for suggestions...please.

[Bunch]

You should get a fast 50 no matter which direction you go for the zoom. If pure IQ is the determining factor over reach, I'm sure the 20-40 wins.

[esrandall]

I like my Sigma 17-50 for that range (though I only seem to use it at 17 or 50). The f/2.8 is there for low light, and the IQ is definitely there, as well. The 20-40 has always intrigued me, but like you, I see enough mixed reviews to make me hesitate. I've actually set my 17-50 aside, and have made myself go with the combo of my HD 21 Limited, and a DA50. Nice to have it all in one lens, but I like the extra speed with the DA 50, and I'm really liking the 21 for mountainscapes, and stuff like that. Has really good colors. If you aren't in need of WR, I would take a strong look at the Tamron/Sigma 17-50's. I've had them both, and while I prefer the Sigma, the Tamron definitely gets the job done -- and they both have the lowlight advantage.

[cali92rs]

If pure IQ is the determining factor over reach, I'm sure the 20-40 wins.

Based on...?
A lot of what I have seen is talk of "pixie dust" (placebo) but when it comes to actual photos, they look pretty similar.

[Fookus]

you have to focus on the functionality and application first: what (low light, mm, weight, size, WR) do you use and appreciate the most?

The 20 40 is a jewel! very light, very sharp, high IQ, and very good looking!..low light will be solved by K3II i think....
I have the Sigma 18 35 and all Samyangs too; just as good, but bigger and heavier...but...low light!

[Kath]

Can't speak to your choices of low light wide zooms, but get the 50 anyway. You'll never get more value for $100.

[Bunch]

Based on...?
A lot of what I have seen is talk of "pixie dust" (placebo) but when it comes to actual photos, they look pretty similar.

That's fair. I did make a cavalier assumption based on pics I've seen so far, and the fact that it's a limited lens vs a non limited with a larger zoom range. The 20-40 has a pretty large sample size here on the forum of great photos. The 16-85 sample size isn't as big, but the recent photos posted are quite good, and certainly blow away the 18-135.

[longbow]

I've had both since March. They're good WR DC lenses, with similar IQ, one is smaller & lighter the other more range. Though the 20-40 is a "faster" lens, in reality I've had to usually stop mine down further than the 16-85 to get the same sharpness. The 16-85 is very good wide open.

That said, if I had to choose only one, it would be the 16-85. Most of my use is outdoors in the woods, with the 20-40 I struggle with it being either too short or not wide enough, the 16-85 being more useful for my needs. There are times though the 20-40 is nice to have because of it's weight & size.

Again, both are good, just come down to your needs.

[GaryH]

I have had both for awhile. I actualy them both on a trip to Italy in June. I wanted to maintain Zoom versatility while having prime like performance and better low light ability of the 20-40. It is a hard decision but the decision gets harder when you have lots of lenses with overlapping ranges........

[biz-engineer]

When based on the type of photography we want to do , the decision between a 20-40, 16-85 or prime is easy. For landscape and archi, 16-85 preferred. 20-40 is not worth because if we use a 30mm or 35mm prime, moving back or forth a few steps we can frame the same as with a 20-40, with the advantage that a 35mm prime can be faster and sharper. So, I'd suggest to select either a 16-85 or a 35mm prime or both, depending if the purpose of the lens. The 20-40 ltd appeal is more about lust than anything else: the pleasure of having an limited style lens, built with aluminum and nice finish. Always remember than a good image is more about framing, composition, colors and light, independent from the lens, but very much related to focal length, point of view, and seeing of the photographer.

[Conqueror]

I've had both since March. They're good WR DC lenses, with similar IQ, one is smaller & lighter the other more range. Though the 20-40 is a "faster" lens, in reality I've had to usually stop mine down further than the 16-85 to get the same sharpness. The 16-85 is very good wide open.

That said, if I had to choose only one, it would be the 16-85. Most of my use is outdoors in the woods, with the 20-40 I struggle with it being either too short or not wide enough, the 16-85 being more useful for my needs. There are times though the 20-40 is nice to have because of it's weight & size.

Again, both are good, just come down to your needs.

Apart from size/weight does the 20-40 hold any advantage in your opinion then?

[ChristianRock]

When based on the type of photography we want to do , the decision between a 20-40, 16-85 or prime is easy. For landscape and archi, 16-85 preferred. 20-40 is not worth because if we use a 30mm or 35mm prime, moving back or forth a few steps we can frame the same as with a 20-40, with the advantage that a 35mm prime can be faster and sharper. So, I'd suggest to select either a 16-85 or a 35mm prime or both, depending if the purpose of the lens. The 20-40 ltd appeal is more about lust than anything else: the pleasure of having an limited style lens, built with aluminum and nice finish. Always remember than a good image is more about framing, composition, colors and light, independent from the lens, but very much related to focal length, point of view, and seeing of the photographer.

As someone who shoots with a 35mm lens a lot, I find that it is not true that you can always back off until you get what you would get with a 20mm lens. 20mm is considerably wider than 35mm. Especially indoors, but outdoors as well, especially in streets. Even my 28mm is quite long indoor sometimes. A 24mm lens can be used for most situations (on APS-C), but not a 35mm. 20mm is good for pretty much everything, unless you really want that ultrawide look (I don't find need to go wider than my 19-35 but that's just me).

Also, I'm not sure the DA 35 2.4 is sharper than the 20-40 at 35mm in comparable apertures, and the DA 20-40 pictures that I have seen certainly look a bit nicer. Not that the DA 35 2.4 is a bad lens - I love mine.

It would be helpful to find out what else the OP has and what kind of pictures he takes.

[longbow]

Apart from size/weight does the 20-40 hold any advantage in your opinion then?

Not really, but weight & size can be a big advantage at times, which is why I'm keeping mine.

[dcpropilot]

The 20-40 kicks butt, get it. 4 primes in one. WR, DC motor, metal. Awesome IQ.

[Nick Siebers]

What dcpropilot said. I have no experience (yet) with the 16-85, but the 20-40 is very nice.