[LowVoltage]

The second image, which I'm guessing is supposed to correspond to the the 18-70mm lens, is somewhat similar in its construction to the elements/groupings in the existing Pentax 17-70mm lens, if Bojidar Dimitrov's K-mount data base is anything to go by. Curiously, the patented lens states a dynamic maximum aperture. On the other hand, the first patent illustration has far fewer elements, but I can't imagine a simpler design would match to the constant aperture lens. Do we know, definitively, which illustration goes with which designation?

[Barry Pearson]

I see a diagram for 15-45/2.8-3.5 lens too.

DA Limited Zoom?

The roadmap shows the line for the DA Zoom Limited starting higher than 20mm and stopping short of 40mm.

More like about 24mm - 38mm.

[Uluru]

There were maaany lens patents before. Some were really exciting. And we have not seen a single one of them made into a real product. So yes, where is damned 23mm/2.5?
Patents often means filling the patent office with papers and signatures, users with great expectations.
And that's all about it.

[cali92rs]

There were maaany lens patents before. Some were really exciting. And we have not seen a single one of them made into a real product. So yes, where is damned 23mm/2.5?
Patents often means filling the patent office with papers and signatures, users with great expectations.
And that's all about it.

Unfortunately I agree. Most of the time they are filed to keep competitors from using the same formula. Only if they feel its marketable and worth their time/money/effort will they actually produce it. Heck they may even sell it or license it to a competitor and collect royalties. We do that all the time in the aerospace industry.

[monochrome]

Unfortunately I agree. Most of the time they are filed to keep competitors from using the same formula. Only if they feel its marketable and worth their time/money/effort will they actually produce it. Heck they may even sell it or license it to a competitor and collect royalties. We do that all the time in the aerospace industry.

Apparnetly the OLD Pentax did that for years.with the SMC coating application process. Accoring to Asahi Optical Historical Club (article in Spotmatic Magazine) AOC received license fees from nearly every lens maker.

[tigrebleu]

16-70/4 is probably a replacement for DA 17-70/4, and might be WR and use DC motor.
18-70/4-6 sound like a new kit lens with WR and hopefully with DC motor too.

I see a diagram for 15-45/2.8-3.5 lens too.


Agree, 25-350 seems odd for a APS-C lens, and would make more sense for FF.

I agree, Fogel. The DA17-70mm could use a WR version. However, maybe Ricoh fears such a lens might end up competing with the DA*16-50mm, so they could decide to not make it WR...

Same goes for the 18-70mm lens being a kit lens.

Also, the DA16-45mm is in need of a replacement (it was discontinued after all), so a WR version with a new optical formula to avoid the darn wide-angle softness in the corners (thanks to a wobbling lens) would be welcome, hence the possible 15-45mm lens. If that one is WR and F/2.8-3.5, it will replace my old 16-45mm in a no time.

[haaldemir]

16-70 ? Before shared da*16-85. Now changed?

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[builttospill]

I'd be very interested in a 16-70 f/4 that's WR with a DC focus motor.

The old DA 17-70 f/4 is in dire need of an upgrade.

Reading a statement like this makes me wonder if you've even owned the DA 17-70. It's not an old lens, and it's optics are incredible. There are other lenses being discussed in this thread which may be in dire need of an upgrade, such as the discontinued DA 16-45 or FA 20-35.

If you mean SDM itself is in dire need of an upgrade, then I'll agree with you. But then 17-70 is just one of many SDM lenses, and it's one of the newer SDM lenses at that.

[VisualDarkness]

16-70 ? Before shared da*16-85. Now changed?

Nobody ever said that a 16-85 was coming, the roadmap is merely estimates.

[Barry Pearson]

Reading a statement like this makes me wonder if you've even owned the DA 17-70. It's not an old lens, and it's optics are incredible. There are other lenses being discussed in this thread which may be in dire need of an upgrade, such as the discontinued DA 16-45 or FA 20-35.

If you mean SDM itself is in dire need of an upgrade, then I'll agree with you. But then 17-70 is just one of many SDM lenses, and it's one of the newer SDM lenses at that.

The DA 17-70mm f/4 is my main studio lens, and on the rare occasions when I have just one lens it is likely to be the one.

But I would like a WR version. It has a seal between the lens and the camera, but it isn't otherwise WR. In fact I would like it to be AW.

[philbaum]

Reading a statement like this makes me wonder if you've even owned the DA 17-70. It's not an old lens, and it's optics are incredible. There are other lenses being discussed in this thread which may be in dire need of an upgrade, such as the discontinued DA 16-45 or FA 20-35.

If you mean SDM itself is in dire need of an upgrade, then I'll agree with you. But then 17-70 is just one of many SDM lenses, and it's one of the newer SDM lenses at that.

That kinda stuck in my craw too. The DA17-70 renders very nicely, and quiet with the sdm. I have the Tamron 28-75 f2.8, and choose to use the 17-70 more often, except when i need that f2.8. I think the lens money could be used for higher priority design work

[thibs]

Also, the DA16-45mm is in need of a replacement (it was discontinued after all), so a WR version with a new optical formula to avoid the darn wide-angle softness in the corners (thanks to a wobbling lens) would be welcome, hence the possible 15-45mm lens. If that one is WR and F/2.8-3.5, it will replace my old 16-45mm in a no time.

The 16-45 replacement is the 17-70.

[ogl]

I think patents means nothing in this case. There a lot of patents, but only 1% of patents became the real lenses.
The meaning of patents is to protect intellectual property and to declare any special (even very small) innovation.
The patents could be intermediate during creation of real optical diagram (design) for real lens.

[Barry Pearson]

The 16-45 replacement is the 17-70.

Yes - I gave my DA 16-45mm to a relative when I bought the DA 17-70mm. The latter has been a much more useful lens.

(I have the DA 12-24mm, so that extra millimeter at the wide end of the DA 16-45mm wasn't important to me).

[cbope]

Reading a statement like this makes me wonder if you've even owned the DA 17-70. It's not an old lens, and it's optics are incredible. There are other lenses being discussed in this thread which may be in dire need of an upgrade, such as the discontinued DA 16-45 or FA 20-35.

If you mean SDM itself is in dire need of an upgrade, then I'll agree with you. But then 17-70 is just one of many SDM lenses, and it's one of the newer SDM lenses at that.

You're correct, and my reason for staying away from the DA 17-70 f/4 comes from a couple comments (copied from PF lens review of this lens):

"The Pentax lens is a different matter. Sadly, we must report that hunting occurred frequently with our test sample. Good lighting conditions were not a problem, but as soon as light levels started to fall, hunting problems began occurring. Problematic conditions included contrasty subjects in well-lit rooms, focus charts, and low-contrast subjects under sunlight. Hunting occurred more often when the center focus point was selected. When using the focus test chart, closing the selected aperture surprisingly increased the occurrence of hunting. This last observation leads us to believe that the issue is electronic and not optical."

And this:

"Because of the Pentax lens’s hunting problems, we feel the Sigma lenses are a better choice."

Now, of course this could be sample variation and PF just got a bad copy. It also comes down somewhat to price. The Sigma EX 17-50 f/2.8 is down to 399€ after the recent price drops while the DA 17-70 f/4 is 576€ (about the same price as the Sigma was originally). The price gap is negotiable, and I wouldn't hesitate to go for the Pentax if it's as good optically as the Sigma EX and doesn't have focusing issues on a K-5.

Although the Sigma gets a point for the extra stop of speed, the DA gets a point for longer reach, so in my book they balance out, assuming the optical and AF performance are similar. Anyone who has owned both lenses care to comment, assuming price is not a deciding factor? Which lens would you go for?