louparker Loc: Scottsdale, AZ

Thanks for the info. I am still wondering if there is any difference in quality between the Pentax/Tamron 18-250 and the later Pentax/Tamron 18-270 -- anyone have any comments? Also, is there any difference in quality between the Pentax/Tamron 18-250/270 and the Sigma 18-300?

Chris T Loc: from England across the pond to New England

Lou - Tamron discontinued the 18-250 when it introduced the 18-270. That should tell you something. The Pentax 18-270 is said to be better than the Tamron, but the Tamron 18-270 is a very good lens, IMHO. The Sigma 18-300 is said to be a better lens than the Tamron 16-300, but on a par - IQ-wise, with the 18-400. Of the Third Party Super-Zooms, the ONLY one available in Pentax Mount is the Sigma 18-300

Some of these links may help you with all this …

18-270 Pentax - a proprietary superzoom!!! ... Is it worth the money? https://www.uglyhedgehog.com/t-577822-1.html

18-300 Sigma - Vignette King, or a Superb Lens, and, at a bargain price!!!!
https://www.uglyhedgehog.com/t-577539-1.html

16-300 Tamron - is this a versatile lens, or - a waste of money?
https://www.uglyhedgehog.com/t-577358-1.html

18-400 Tamron - a Crowning Achievement, or just another so-so-sooperzoom???
https://www.uglyhedgehog.com/t-577815-1.html

Sigma 50-500 OS HSM APO - the perfect SuperZoom, or no?
https://www.uglyhedgehog.com/t-576754-1.html

GENorkus Loc: Washington Twp, Michigan

How about a guessful thought?

It is excepted that Tamron made a version as required by Pentax. Now consider this.

Just like most other lens manufacturers, the 1st release of a lens goes to where they can make the most return on their dollar. Being that Canon and Nikon lead the consumer, that is what they build for and those have in-lens stabilization units.

So my guess would be that Tamron just turned off the stabilizer for the Pentax version they sell.

Anyone who has purchased from a major company who does assembly or tool and die manufacturer knows that company needs to break down their construction line for the other order.

(I'm guessing here!)

When Pentax wanted a lens, it didn't need a stabilizer in the lens. Pentax was probably charged a bit more to permanently mount the stabilizer part. Also to add better weatherproofing of course.

Having a permanent grouping of lenses will alow a much better optical performance than a lense with a stabilizer wigiling all the time. Even when its turned off, it could be off at a different angle. That might explain why the Pentax version got a better rating than the Tamron version.

You wanted a comment. That's also why I really don't care for the in-lens stabilization system.

New subject:
Nikon got smart with their new mirrorless camera. Canon is also soon to join the ranks of in-body stabilization. They probably want their versions of Pixel shift, Astro photography and just a plain better stab unit. I'm sure they realised in-lens stabilization just don't cut it.

Does that tell you something?

Chris T Loc: from England across the pond to New England

GE … what this tells me is you didn't know the Pentax 18-270 is not - in any way - weatherized!!!!!

I think Canon introduced DPAF - which, in a sense - IS Pixel-Shift. And, yes, the follow-up to the EOS R - IS supposed to have 5-way IBIS - a first for Canon. Sooner or later, tho' all cameras will have 5-axis IBIS.

GENorkus Loc: Washington Twp, Michigan

You're correct about not knowing the 18-270 was not weatherized. I should have looked it up to find out.

About the DPAF, That stands for Dual Pixel Auto Focus. I don't really think it can be related to Pixel Shift technology which is actually recording the image in a "more correct" color at the sensor not the action of focusing it for the lens.

I'll just leave it as, "I'm happy with Pentax stuff!"

Chris T Loc: from England across the pond to New England

That's okay, GE ….

Thanks for the explanation of the difference between DPAF and Pixel-Shift …

Yes - I'm pretty happy with Pentax stuff, too - I have the 6x7, and the K-50 - both very fine cameras …

Jim70 Loc: Delaware

I started out as an Olympus (OM-10) user but when that equipment was stolen by some dirt bag, switched to Nikon. Been shooting Nikon for about 40 years but recently just bought a Pentax ME SE. I'm still running the first roll of HP5 through it to check for light leaks, etc. but I have to admit, going back to an aperture priority, semi-manual camera has been a lot of fun.

I was always envious of those with Pentax cameras, now I GOT ONE OF MY VERY OWN!

bdelaney

I use my ASAHI lenses on my Nikon DSLRs and they are still my favorite lenses. (quality adapters are a must) I am sure there are lot's of reasons why the new lenses are better or the old lenses don't work properly but the bottom line is when I shoot with these lenses there is just something nicer about the images. I would not part with them, EVER!

Chris T Loc: from England across the pond to New England

Congrats, Jim!!!! … Enjoy it!!!!