[David L]

In preparation for K-1, I need help to decide which 24-70mm f2.8 lens to buy. The Sigma 24-70 lens is much cheaper - available new from Walmat online store for USD820 (sigma 24-70mm pentax - Walmart.com), and I can find an used copy online even cheaper. Is the IQ from DFA 24-70 (based on Tamron) much better than the Sigma? Your advice is much appreciated.

[12345]

Atleast the DFA would be weathersealed even if nothing else is better.

[VoiceOfReason]

I have the Sigma. It is fast focusing, sharp, and silent, but not WR. I got mine used for 375 AUD.

[kenspo]

It is two different prices and two different worlds. If you can afford it, the Pentax one is a no-brainer.

[Winder]

In preparation for K-1, I need help to decide which 24-70mm f2.8 lens to buy. The Sigma 24-70 lens is much cheaper - available new from Walmat online store for USD820 (sigma 24-70mm pentax - Walmart.com), and I can find an used copy online even cheaper. Is the IQ from DFA 24-70 (based on Tamron) much better than the Sigma? Your advice is much appreciated.

The Sigma is probably going to be replaced by the new Sigma 24-70 F/2.8 which they just filed a patent for. The older Sigma is probably going to get pretty cheap, but there probably wont be a K-mount version of the new Sigma 24-70 F/2.8 for several years. I looked at the older Sigma several times and never could find a copy that gave me consistent focus accuracy on my K-5 (what I had at that time). The Tamron/Pentax 24-70 is a much better lens. I just hope that the Pentax version is made a little better than the Tamron version.

http://photorumors.com/2016/03/28/sigma-filed-a-patent-for-a-24-70mm-f2-8-dg-os-hsm-art-lens/

[Rondec]

The Pentax DFA 24-70 is a very nice lens, quite sturdy and sharp -- bokeh looks a little nicer to my eye than the Sigma bokeh (still has some donuts in spots). I did review it in the lens reviews. I haven't used the Sigma, but have viewed photos. If you are considering full frame, then I would lean stronger towards the Pentax. If you are using them on APS-C, they would both be adequate.

(looking at the Sigma 24-70 reviews on the forum, I am convinced that one of them is actually a review of the 18-35 f1.8, otherwise the comment "sharp at f2" makes no sense).

[Blacknight659]

If you have the money... get the Pentax.

1) It will probably work better
2) WR
3) Will Sigma support the older lens? Will they make the new version in K mount?
4) Ultimate compatibility / Future proof

If the 16-50mm SDM didn't have the issues it had, I would have went with it over the 17-50 Sigma. I love the Sigma cost, and in the case of this lens it provides better reliability. BUT, I would go with brand name every time I could Unless money is truly an issue. If that is the case then get what you need to get the job done.

I am saving up for the 24-70 Pentax btw.

[nomadkng]

I once owned the Sigma 24-70, in fact over about 5 years I owned 2 different versions.

The past tense is telling. I found alternatives that were much better.

The Sigma is a decent mid-level lens in terms of image quality and performance. It's a step up from the Sigma 17-70 and was my logical progression. However it has a very limited bandwidth of useable apertures, about f4.5-f8. Above f8 it really started to suffer from diffraction on my k20and later k5iis. Wide open it would make a great portrait lens, especially at 70mm.

The semi-macro feature was handy until I could afford true 1:1 marcos, and then it was left in the dust.

I now own the Sigma 24-60, which I like much better than the 24-70, but I'm worried it's flare issues (which is standard equipment on a sigma lens) will limit it's use.

I have not used the new HSM version of the Sigma 24-70, but MTF charts alone tell me it's got about the same level of performance.

If my 24-60 just won't get it done, often enough, I'm going to end up with the Pentax 24-70, if nothing else because it handles the sun in frame very well.

This is a long winded way of saying, go with the Pentax 24-70 from the start, unless your budget (or significant other) just absolutely says "No."

[DogLover]

I've had the Sigma (newest, HSM version) for several years now. My feelings about it are pretty much the same as they have been for other Sigmas I have owned. It's a fine lens, I just find Sigma rendering to be a bit more "clinical" than Pentax rendering. I use mine almost exclusively for event photography, at which it excels. It's a fast focuser and I've had no trouble at all with focus accuracy on my K-3. There is no "pixie dust" in there, to be sure, but it's a sharp, solid lens for it's intended purpose. I'm positive that I will not trade it for the Pentax unless the cost difference becomes nominal, and that day may never come, which is fine.

I might add that the only Sigmas I've used that don't render in what I am calling a "clinical" manner are the discontinued 30/1.4 and my 100-300/4, which I would have to be really desperate to ever sell.

[kenspo]

I'm positive that I will not trade it for the Pentax unless the cost difference becomes nominal, and that day may never come, which is fine.

Well..I have used both much..have you? The quality is like night and day, so of course the price will have a difference. The Sigma one is ok, but slower in focus and not as sharp. But good enough for most "every day photographers", for pros, not so much!

[David L]

Thanks to you all for your valuable advice...I'll start to save money for a DFA 24-70!
Cheers
David

[kenspo]

Good choice