Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-17-2019, 09:48 AM   #91
Pentaxian




Join Date: Oct 2010
Photos: Gallery | Albums
Posts: 3,956
QuoteOriginally posted by 5r82 Quote
I'm not sure if anyone mentioned it already but the existing DA HD 55-300 f4-5.8 screw drive is almost full frame. There is slight vignetting though. Some of it can can be corrected. It vignettes the most without possibility to correct somewhere in the 100mm range, I don't remember. I use this lens on K-1 and it can make good photos. I assume Ricoh will do small mods to this lens optical design and with new motor it will work well. I hope it is PLM. But even DC motor and it will be Ok. Great travel lens with 28-105 if it is on par with this lens optically.
Umm, no. Small tweak is not going to work. I have DA 55-300 WR and I have used it also with K-1. It is usable from 55-70 and from 130-250 ish. But edges are far from being good(it is good enough). I'm sure that it is going to be more than just little adjustment. If you want corner to corner sharpness with 55-300+K-1 in FF mode, it won't do that at any focal lenght that. you want to crop a bit. I have DFA*70-200 and I would not go back.

05-18-2019, 10:40 AM   #92
Pentaxian
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 33,042
QuoteOriginally posted by repaap Quote
Umm, no. Small tweak is not going to work. I have DA 55-300 WR and I have used it also with K-1. It is usable from 55-70 and from 130-250 ish. But edges are far from being good(it is good enough). I'm sure that it is going to be more than just little adjustment. If you want corner to corner sharpness with 55-300+K-1 in FF mode, it won't do that at any focal lenght that. you want to crop a bit. I have DFA*70-200 and I would not go back.
I'm not sure modifying existing designs is even a thing. Each element requires a certain amount of space based on it's diameter. Start increasing the size of the elements and everything else is going out of whack. It's probably better to start from scratch in many circumstances.
05-18-2019, 10:48 AM   #93
Pentaxian




Join Date: Oct 2010
Photos: Gallery | Albums
Posts: 3,956
QuoteOriginally posted by normhead Quote
I'm not sure modifying existing designs is even a thing. Each element requires a certain amount of space based on it's diameter. Start increasing the size of the elements and everything else is going out of whack. It's probably better to start from scratch in many circumstances.
I do agree even if it is going tobe consumer lens, it needs to be good. just like 28-105.
05-18-2019, 01:21 PM - 3 Likes   #94
Site Supporter
Site Supporter




Join Date: Mar 2009
Location: Gladys, Virginia
Photos: Gallery
Posts: 19,929
QuoteOriginally posted by normhead Quote
I'm not sure modifying existing designs is even a thing. Each element requires a certain amount of space based on it's diameter. Start increasing the size of the elements and everything else is going out of whack. It's probably better to start from scratch in many circumstances.
I'm always amused by how simple a thing people think lens design is. "A simple tweak" is never just that simple. It's more akin to taking your vehicle to the dealer and asking if they can install a bigger windshield. The reality is that the lens body, motor and all the parts have to work together to produce good results. It isn't really the optical design part that takes so much time -- more the part where they figure out the engineering and manufacturing portions of it, turn out a few lenses and tweak the process a little more.

That doesn't mean that Pentax isn't going to come out with a 70-300 variable aperture zoom, but I doubt they will use an existing APS-C lens as a starting place.

05-18-2019, 07:54 PM - 2 Likes   #95
Site Supporter
Site Supporter
jatrax's Avatar

Join Date: May 2010
Location: Washington Cascades
Photos: Gallery | Albums
Posts: 11,812
QuoteOriginally posted by Rondec Quote
but I doubt they will use an existing APS-C lens as a starting place.
Despite years of posts stating all Pentax needs to do is tweak an existing design to make it (Choose one: FF, faster, use a new motor, use an in lens motor, take pictures of unicorns) Pentax has in every case I am aware of started from scratch to make a new lens to modern design specs. As you say, tweaking a design that is antiquated and was built using antiquated methods and materials is really a non-starter. Much simpler to just start over and design it to be built on the equipment and with the materials in use today.
05-18-2019, 09:30 PM - 2 Likes   #96
On Hiatus. Back Later.
Loyal Site Supporter
monochrome's Avatar

Join Date: Mar 2008
Location: Flyover Country
Photos: Gallery | Albums
Posts: 24,427
QuoteOriginally posted by jatrax Quote
Despite years of posts stating all Pentax needs to do is tweak an existing design to make it (Choose one: FF, faster, use a new motor, use an in lens motor, take pictures of unicorns) Pentax has in every case I am aware of started from scratch to make a new lens to modern design specs. As you say, tweaking a design that is antiquated and was built using antiquated methods and materials is really a non-starter. Much simpler to just start over and design it to be built on the equipment and with the materials in use today.
I would bet a dime to a dollar the reason Pentax can keep running batches of the FA Limiteds has to do with the comparatively high use of hand work (per the recent video) and thus less dependence on machines that might no longer even exist - and that they continue to run batches of the original lenses because ‘simple’ updates such as weather seals or internal focus motors would be start-from-scratch redesigns, not simple updates (and then they would be new lenses, not the Princesses).

05-20-2019, 03:31 PM - 2 Likes   #97
Site Supporter
Site Supporter




Join Date: Jun 2015
Photos: Gallery | Albums
Posts: 309
QuoteOriginally posted by monochrome Quote
I would bet a dime to a dollar the reason Pentax can keep running batches of the FA Limiteds has to do with the comparatively high use of hand work (per the recent video) and thus less dependence on machines that might no longer even exist - and that they continue to run batches of the original lenses because ‘simple’ updates such as weather seals or internal focus motors would be start-from-scratch redesigns, not simple updates (and then they would be new lenses, not the Princesses).

Limited Lens - until it sees the light
At some point the Princess need to marry a charming Prince and bring us more Prince and Princesses right? Otherwise the line will end!!
05-20-2019, 04:13 PM   #98
On Hiatus. Back Later.
Loyal Site Supporter
monochrome's Avatar

Join Date: Mar 2008
Location: Flyover Country
Photos: Gallery | Albums
Posts: 24,427
QuoteOriginally posted by suraswami Quote
At some point the Princess need to marry a charming Prince and bring us more Prince and Princesses right? Otherwise the line will end!!
I believe one of the long term planning themes is extending the Limited line of lenses. That does not necessarily mean the Princesses will be refreshed. It does mean their design ethic will be extended to other focal lengths.

Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
aperture, asahi, consumer, da, dfa*, f/4, f4, fa, forum, fullframe, lens, lenses, pentax, pentax news, pentax rumors, photography, picture, quality, ranges, review, slr
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: DA and HD DA Primes: DA 50 1.8, DA XS 40mm, HD DA 35mm, DA 21mm, HD DA 15mm Amarony Sold Items 8 02-20-2019 06:21 AM
HD Pentax-D FA* 50/1.4 comparison with Zeiss Milvus 50/1.4 and Sigma 50/1.4 Art Medex Pentax K-1 64 12-14-2018 01:14 PM
For Sale - Sold: DA70,DA*55,16-50/50-135,DA-HD 55-300,DFA*70-200,Tamron28-75,1.4x HD Rear converter Pentax_WA Sold Items 8 05-06-2018 08:08 PM
For Sale - Sold: O-GPS1, 16-50, 50-135, HD 21, FA 50 1.7, A 50 1.4, Tokina 20-35, TC 1.4x, *istDS transam879 Sold Items 13 09-09-2017 11:54 AM
HD 20-40 or HD 21 & HD 35 macro BarryE Pentax SLR Lens Discussion 33 09-03-2017 06:05 AM



All times are GMT -7. The time now is 10:11 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top