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02-08-2016, 11:20 AM   #91
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QuoteOriginally posted by Simen1 Quote
Even though very mm counts a lot in the wide angle range, the zoom ratio is only 1,45. That is so little I would rather have a prime and crop the little difference if necessary. A 10mm f/2,0 or so.
If you have a small zoom ratio, thus high image quality, and the difference between 11 and 16 mm is quite considerable due to the wide-angle aspect, then why would you want a prime?

Plus, there is no prime. I would've already bought one of the Samyang primes if they had something genuinely UWA that takes filters, but for Pentax the only UWA Samyang lens that takes filters is the 16 mm f/2, and that's just not wide enough.

02-08-2016, 12:30 PM   #92
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QuoteOriginally posted by awaldram Quote
I see no reason the same does not apply to a High Definition coating and would like to see the cast of the 24-70 I suspect it is Tamron's coating
I find plenty of reasons to reject "it is Tamron's coating" hypothesis, not least of which is what Ricoh's U.S. site explains in regards to the DFA 24-70:

QuoteQuote:
The lens is treated with high-grade, multi-layer HD Coating.* Compared with conventional multi-layer coatings, this PENTAX-original coating assures higher light transmittance and less reflection to deliver bright, high-contrast images free of flare and ghost images, even under demanding lighting conditions such as backlight.
Nor do I believe any coherent reason to believe that SMC refers to "any multi coated process." The old K-Mount Takumars lacked the SMC coatings, but it is thought that some of them may have been multi-coated. SMC does not equal just any multi-coating. It is a unique Pentax developed and patented technology.
02-08-2016, 01:08 PM   #93
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02-09-2016, 07:33 AM   #94
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QuoteOriginally posted by northcoastgreg Quote
I find plenty of reasons to reject "it is Tamron's coating" hypothesis, not least of which is what Ricoh's U.S. site explains in regards to the DFA 24-70:



Nor do I believe any coherent reason to believe that SMC refers to "any multi coated process." The old K-Mount Takumars lacked the SMC coatings, but it is thought that some of them may have been multi-coated. SMC does not equal just any multi-coating. It is a unique Pentax developed and patented technology.
Such passion for Pentax consumer coatings .!!

Pentax 'superior' coatings have been since 1997
Ghostless first used in the 43 limited
and Aerobrite as used in the da* lens
PENTAX Lens Technology / Lenses / Products | RICOH IMAGING

7layer .998 light transference might have been unique and patentable in 1971 but please its cheap and common as muck today .... You'll not find a modern lens that isn't superior to the original Pentax 1971 coatings and that includes the like of the da 18-55 SMC. !!

There is no written evidence that teh Pentax da 18-250 SMC has Tarmon coatings other than its color cast matches all Tamron lens and is different from all Pentax made SMC lens.

To me that pretty conclusive evidence.
How Lens Coating Works
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/138601-pent...8-250-a-2.html

As to the 24-70 coating Pentax say

HD Coating to improve image description *2
The lens is treated with high-grade, multi-layer HD Coating.* Compared with conventional multi-layer coatings, this PENTAX-original coating assures higher light transmittance and less reflection to deliver bright, high-contrast images free of flare and ghost images, even under demanding lighting conditions such as backlight. *2:HD stands for High Definition.

Notice the hyphen between PENTAX-original ?? this means any coating Pentax defines as High |definition is a HD coating , Also they say "higher light transmittance and less reflection" but neglect to say compared to what ?

It doesn't mean it not a great lens but the rose coloured specs do not make it look better

See what an owner says about the coatings and behavior (someone not trying to sell you one)
https://www.pentaxforums.com/lensreviews/hd-pentax-d-fa-24-70mm-f28-ed-sdm-wr.html


Last edited by awaldram; 02-09-2016 at 07:45 AM.
02-09-2016, 11:23 AM   #95
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QuoteOriginally posted by lytrytyr Quote
With modern wide angles, which have to be big anyway,
there's no real advantage to having a prime.

Your crop would be equivalent to a loss of resolution
which a zoom would enable you to keep.

I love primes myself,
but have come to appreciate the 08 wide zoom on the Q system.
I don't speak of the 08 wide zoom for the Q, I don't know it and it is surely light.

For APSC, still, on most occasion I have DA15... That quite small, light and un-obtrusive. It accept filter and is extremely resistant to flare and contrastty in difficult lighting conditons.

You even don't think of it, you can just add the lens in the bag, just in case because it doesn't take that much space or weight.

I would not do the same with a 8-16, 10-20 or 12-24...

Would say that everybody has his own pratice
02-09-2016, 05:55 PM - 1 Like   #96
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QuoteOriginally posted by Nicolas06 Quote
You even don't think of it, you can just add the lens in the bag, just in case because it doesn't take that much space or weight. I would not do the same with a 8-16, 10-20 or 12-24...
no kidding:

02-09-2016, 07:25 PM   #97
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QuoteOriginally posted by SpecialK Quote
I can use the Tokina from 15-17 on FF - yay.
The DA10-17 is fine from about 14mm too.
02-09-2016, 11:48 PM   #98
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QuoteOriginally posted by Digitalis Quote
no kidding:
And when in the bag, you don't have to mess with the DA15 hood that is retracted inside the lens !

Weight wise, the sigma is 2.6 time heavier

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