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Forum: Lens Clubs 11-25-2016, 02:29 PM  
Post your HD PENTAX-D FA 150-450mm F4.5-5.6 ED DC AW pictures!
Posted By maucard
Replies: 2,373
Views: 332,045
Thank you John (and also to Jim, if his reply was directed to me). Given that you liked them, I add other two images of the same subjects shot (as the previous images) with the 150-450 @ 450. The first with k3 at 3200 iso f5.6, the 2nd with k1 at 500 iso at f6.3, both cropped.
Forum: Lens Clubs 11-24-2016, 12:20 PM  
Post your HD PENTAX-D FA 150-450mm F4.5-5.6 ED DC AW pictures!
Posted By maucard
Replies: 2,373
Views: 332,045
Some shots taken with 150-450 and K1 (n.3 and n.4) or K3 (n.1, n. 2, n. 5). All of them are cropped. Very satisfacted with the lens. :)
Forum: Pentax SLR Lens Discussion 09-28-2016, 03:02 PM  
Pentax HD FA 15-30mm F2.8 and 24-70 F2.8 vs. "same" Tamron lenses.
Posted By maucard
Replies: 21
Views: 5,584
Thank you Clackers. Ok... so, the copy-to-copy variation can be an explanation, but if you look to the above cited reviews the differences seem quite huge and in the same directions for the two couples of lenses (both Pentax lenses are more even in wide-open performance, both are more aberration-prone than Tamrons), so it does not seem (albeit it cannot be excluded) the result of a random variation in lens quality. As you said, the glasses used in the Pentax version of the lenses are different, so (perhaps, but I'm not an expert in the field) it is possible that the exact quality and type of the used glasses may produce quite different performance on a same lens design, and that Pentax engeneers chosen the type of glasses used for these Pentax lenses in order to maximize the uniformity of performance (at the expense of a worse control of optical aberrations)...

---------- Post added 09-28-16 at 03:16 PM ----------



I agree with you, Na Horuk, these are all additional good explanations for a different performance of lenses having a same lens design. Hence, we may conclude that (this is my point) for what we know these lenses are not simply "Pentax rebranded Tamron lenses" (as often they are referred in the web forums) but Pentax manufactured lenses wich, albeit sharing a same basic optical design with the Tamrons, could have (for what we know) a quite different optical performance.
Forum: Pentax SLR Lens Discussion 09-28-2016, 02:15 PM  
Pentax HD FA 15-30mm F2.8 and 24-70 F2.8 vs. "same" Tamron lenses.
Posted By maucard
Replies: 21
Views: 5,584
I just noticed that the lens performance tests on the ephotozine web site show very different results for the supposed Pentax/Tamron siblings: (1) Pentax HD FA 15-30 F2.8 vs. Tamron SP 15-30 F2.8, and (2) Pentax HD FA 24-70 F.2.8 vs. Tamron SP 24-70 F2.8. In both cases, the Pentax lens seems to have a much more even performance than the Tamron equivalent, with small difference between center and border also at f 2.8; on the other side, the Pentax lenses show a more than double amount of chromatic aberration with respect to the Tamrons... Here are the links:

HD PENTAX-D FA 15-30mm F2.8 ED SDM WR Review
Tamron SP 15-30mm f/2.8 Di VC USD Review
Pentax HD Pentax-D FA 24-70mm f/2.8 ED SDM WR Review
Tamron SP 24-70mm f/2.8 VC USD Lens Review

Of course the differences may be explained by errors made during in the procedure of the lens performance tests, but... what do you think, is it possible that the Pentax/Tamron siblings are not siblings indeed? Would it be possible, for example, that the optical design is the same (Tamron in origin) but slightly modified by Pentax for its own Tamron-derived lenses?

Maurizio
Forum: Pentax SLR Lens Discussion 03-30-2016, 02:08 PM  
500mm f4.5 Pentax K issue
Posted By maucard
Replies: 12
Views: 1,100
The small wheel on the lens, near the k mount, should be turned clockwise as much as possible, with some strength.
Forum: Welcomes and Introductions 02-25-2016, 02:09 PM  
Greetings to all Pentaxians
Posted By maucard
Replies: 8
Views: 507
Thank you all for the friendly welcome! And, surely Steve, I will upload some photos on the site soon. :-)
Forum: Welcomes and Introductions 02-24-2016, 04:58 PM  
Greetings to all Pentaxians
Posted By maucard
Replies: 8
Views: 507
Thank you Dave. Let's say that I had so many years (since the "aborted" MzD, about 16 years ago) to prepare myself to invest in a Pentax digital full frame!


p.s. nice shots on your web site
Forum: Pentax News and Rumors 02-24-2016, 02:47 PM  
CP+ Interview Question Suggestions
Posted By maucard
Replies: 127
Views: 14,072
Adam, my request for Pentax/Ricoh managers would be to extend the in-camera corrections for the Pentax lenses of the pre-digital era. By now, they implemented these corrections just for some FA or Limited lenses, but probably it would not been so costly to add corrections also for many other lenses. Why not all the FA lenses? And the F lenses? I would suggest that also for the lenses that are not recognized as specific Pentax lenses by the camera (this occur of course for K and M lenses, but probably also for F lenses), it would be possible to assign specific in camera corrections, "manually" selected by the user. The function can be implemented as for the choice of the focal length when you mount a K or M or A lens. For example: you mount a manual focus lens, the display will ask (just as it works now) to select the focal, you will say (for example) 200, the display will ask: do you want select an in camera correction for Pentax lenses (Y/N ). If yes, you will be asked to select among corrections for the Pentax A 200 f2.8, M 200 f4, K200 f4, or other Pentax 200 manual focus lenses...
Forum: Welcomes and Introductions 02-24-2016, 02:17 PM  
Greetings to all Pentaxians
Posted By maucard
Replies: 8
Views: 507
Hi all,
that's my first post, but this nice forum is very familiar to me, I often used to follow the forum discussions without posting, just to see what is boiling in the pentaxian water. I love landscape and nature photography, and my start in 1988 was with my dad's K1000. After that, MZ5, MZs, 645, 67II, some initial resistance to entering into digital, but then istDS, K5, K3 and now.... Ok, as probably many of you, I'm quite impatient to use FA and K lenses on the K1 !

Friendly greetings to Adam and to al forum members!

Maurizio
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