[miriya]

Pentax DA 17-70mm f/4 SDM Lens Review

Digital Camera Review's 17-70/4 lens review posted.

It looks really bad at all edges, unacceptable.

Its so horrible!

I doubt lens was bad copy, that used to review.

[k100d]

must be a bad sample
this comparison is much better DA17-70 side by side with Sigma 17-70: Pentax SLR Talk Forum: Digital Photography Review

[roentarre]

Mmmm, that does look a little bad in the corners. So it is really the luck of the draw

[thePiRaTE!!]

I might question a little the corner tests as the image at wide angle bends away, as though it may not have been a flat target, but the 70mm seems flat enough. Rather drastic change between f8 and f16 in sharpness where I wouldn't normally expect that - I suspect how precise the focus hit the target at f8.

Still, the distortion in the brick wall shot at 17mm was ... terrible. Sharpness overall is suspect. One might hope that if this will be another 16-50 lottery that for the test copies at least they would be proofed for things like that.

Don't count me as a doom and gloomer, I love my K20 but I have no confidence in the made in Vietnam era lenses - design or build - further highlighted in the following exerpt from the above:

"What I'm less thrilled about, though, is the focusing ring: our test unit's focus control was plenty smooth, but with poorly damped, hard stops at both ends. Even less appealing to many will be the fact that the ring requires so little resistance to adjust that it barely holds focus if the camera is shaken, and that total travel from minimum focus to infinity is a paltry 45 degrees."

I know most will probably never take the wheel as far as focusing is concerned with it being an SDM lens, and for the masses, perhaps this lens will suffice but it certainly doesn't inspire.

Hopefully the 60-250 is better, I wonder if the DA* get any preferencial handling in the plant or if it just boils down to better internals but with the same lottery construction?

[wlachan]

The results from the "page of text" seem OOF. Even the worst lens I have ever used cannot be that bad. As to edge/corner performance, 2D test is not a good indication how good it performs in real world. Afterall, it is not a flat field macro lens. It also doesn't tell whether the lens suffered from misalignment which would impact the sharpness severely.

[clawhammer]

Honestly, that distortion isn't too troubling when considering what I'd want to use this lens for-- walk-around 'party' lens that I use for shooting shots of my nieces and nephews at family functions, etc. For wide angle/architectural use, get a super-wide like the 12-24, 14, or sigma 10-20.

I really hope they got a bad sample, however, because the telephoto-length page test is alarming. If it was OOF, I could see how you could get sharp images only at f/16, as the DOF increases. Another possibility is that they were focused at absolute shortest focal distance, and is not a good performer at that length. If you read the manuals for the 18-55 and 16-45, they caution you about using the lens within those focusing distances. As I can't find anywhere on their site their methods for testing, I'd take this review with a grain of salt.

[frank]

must be a bad sample
this comparison is much better DA17-70 side by side with Sigma 17-70: Pentax SLR Talk Forum: Digital Photography Review

I don't know. My own comparison shows that the Sigma 1770 wins almost in every aspect

[falconeye]

Digital Camera Review's 17-70/4 lens review posted.

Good to see samples. Chasseur d'Images gave it a good rating except at 70mm where it said it lacks sharpness. From the samples shown here, I would say the same applies to 17mm edges.

Altogether, I put it in one bin with 18-55 and 50-200mm, i.e., lenses to avoid if you want to outperform an excellent P&S.

Pentax DA 17-70mm f/4 SDM Lens Review

Digital Camera Review's 17-70/4 lens review posted.

It looks really bad at all edges, unacceptable.

Its so horrible!

I doubt lens was bad copy, that used to review.

must be a bad sample
this comparison is much better DA17-70 side by side with Sigma 17-70: Pentax SLR Talk Forum: Digital Photography Review

Mmmm, that does look a little bad in the corners. So it is really the luck of the draw

After all, is this Photography or Gambling??? My money is hard to earn to bet on lenses quality!!

[Spongefingers]

If I was looking for a new zoom like this, I'd be suspicious. I would have to test one out for myself if at all possible.
I think I'd stick with my 18-55 for now...

[Prairie Dog]

I "adopted" the Pentax 17-70mm as soon as they became available, actually, only a couple of weeks after purchasing the Pentax 16-45mm, too. I love 'em both and really like the 17-70mm better, though; focusing is awesome and it's sharp too. I did not try either before I purchased, just ordered on-line and was delighted with both.

[kevinf7]

Just an update to this thread which I stumbled upon in Google. Regarding the review: Pentax DA 17-70mm f/4 SDM Lens Review

I found my copy which I received a few weeks ago (Oct 2011) behaving exactly like how it was described in the review. It was soft wide open and not particularly sharp especially at the longer focal lengths (50-70). It was better only at the wider angles and when stopped down a bit. Overall I was not satisfied with the sharpness and have since returned the lens.

I dont know if my copy was a bad one (maybe not given the above article). Out of curiosity do any other 17-70 owners also experience the same IQ results as those shown in the article?

[rawr]

Out of curiosity do any other 17-70 owners also experience the same IQ results as those shown in the article?

Just FYI, there is a whole lens section in this forum where you'd get better results for your question,
Pentax SLR Lens Discussion - PentaxForums.com

In the lens review area that lens doesn't rate as excellent:
Pentax-DA 17-70mm F4 AL [IF] SDM Reviews - DA Zoom Lenses - Pentax Lens Reviews & Lens Database

Some external reviews of this lens say it's OK, but not great. Edge softness is one thing these two reviews note:
Pentax SMC DA 17-70mm f/4 AL [IF] SDM - Review / Test Report

Pentax smc DA 17-70 mm f/4.0 AL [IF] SDM review - Introduction - Lenstip.com

But interestingly, the SLRGEAR review finds good sharpness from f4 onwards, with no problems of edge softness, and concludes:
"In short, very good performance for sharpness, to the point that any degradation in image quality will most likely be a result of the presence of chromatic aberration or corner shading."

Pentax Lens: Zooms - Pentax 17-70mm f/4 AL IF SDM SMC DA (Tested) - SLRgear.com!

So yes, sample variation is something to be aware of with this lens and lenses in general.

[gazonk]

Photozone was very positive, though: Pentax SMC DA 17-70mm f/4 AL [IF] SDM - Review / Test Report - "undoubtedly the most desirable standard zoom lens in the current Pentax lens lineup"

[bwDraco]

Another possibility is that they were focused at absolute shortest focal distance, and is not a good performer at that length. If you read the manuals for the 18-55 and 16-45, they caution you about using the lens within those focusing distances.

My 18-55 only shows obvious problems at the macro range at the 18mm end. The corners are soft, apparently due to field curvature, but the lens is reasonably sharp in any other use case, even wide open.

--DragonLord