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08-11-2010, 02:03 PM   #76
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I been using the TAMRON 1.4X Pz-AF MC4 for a few years now with all my lenses and It works about as good as can be expected from a TC on fast lenses, I doubt very much if Pentax can better it or the Sigma version or it would have been released back when it was set to be. But if they can you can expect it will cost more than $500.


Last edited by Fl_Gulfer; 08-11-2010 at 08:19 PM.
08-11-2010, 02:31 PM   #77
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2.0, $350 ($500 if it rates a 10 on pentaxforums - I'll pay for quality), 60-250 and 300mm
08-11-2010, 02:34 PM   #78
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QuoteOriginally posted by zackspeed Quote
My question is,how much may it cost,would you prefer the 1,4x or the 2,0x version?
I ask because,Pentax Japan is asking if there is any interest for the converter.
It seems that Pentax have no idea that we wanna have one!
But they could/would bring one.
So,i told my Pentaxians that there are lots of user wich want order one,if itīs available.
In september i am at Photokina in colonia/germany.
Have a meeting with my Pentaxians for try the new Bodys and other stuff.
I will bring them all informations and ideas about the converter.
Not only my person will buy one and would pay for great quality.
So,if you are thinking itīs a good idea tell what you think about the converter.
In best hope,Andy
I badly need a Pentax 1.4 SDM converter for my DA* 60-250mm f/4 and am willing to pay up to $250 for Pentax's best glass such as they put in the rear converter-A 1.4 X-L. I would also use it on a Pentax DA* 400mm f/4 prime if they ever get around to producing one.
08-11-2010, 11:39 PM   #79
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No TC, more MP.
16MP is a start.

With 16MP and a 1.4x equivalent crop, I'd still have 7MP of quality that no optical 1.4x TC will ever achieve. That's still plenty of resolution for most applications.


Last edited by Class A; 08-13-2010 at 02:43 PM.
08-11-2010, 11:41 PM   #80
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QuoteOriginally posted by fredok1 Quote
I badly need a Pentax 1.4 SDM converter for my DA* 60-250mm f/4 and am willing to pay up to $250 for Pentax's best glass such as they put in the rear converter-A 1.4 X-L. I would also use it on a Pentax DA* 400mm f/4 prime if they ever get around to producing one.
As much of my hobby is surf and wildlife shots I'm tongueing for a minimum 400 f5.6 DA prime plus 1.4x and 1.7x telecons. Would cover most of my needs unless I needed a dedicated Swarovski telescope for ultra long range.

Otherwise the kit primes (18-55 AL II and 50-200 are fine at respective ranges of 25-50 and 75-180). BTW I've shot some killer ones in good light on an older Sigma 28-80 (since published in book format).
08-12-2010, 12:20 AM   #81
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Before one buys a TC one have to be sure that the lens it is to be used upon out resolves the sensor by at least as much as the TC will magnify the picture, otherwise you might as well crop. And with the ever increasing MP count I think the TC's days are numbered.
08-12-2010, 02:45 AM   #82
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QuoteOriginally posted by Gimbal Quote
otherwise you might as well crop. And with the ever increasing MP count I think the TC's days are numbered.
And what with focusing :?:
AF sensors are not infinite small points and on the other hand - cannot be made bigger - in certain situations, one could want to see cropped (teleconverted) image in viewfinder
08-12-2010, 03:41 AM   #83
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QuoteOriginally posted by Gimbal Quote
Before one buys a TC one have to be sure that the lens it is to be used upon out resolves the sensor by at least as much as the TC will magnify the picture, otherwise you might as well crop. And with the ever increasing MP count I think the TC's days are numbered.
Yes, especially if your subject is moving fast, cropping have the advantage to allow to subject to be off-center. But this have the limit to increase perceived noise...

08-12-2010, 03:42 AM   #84
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QuoteOriginally posted by opiszon Quote
And what with focusing :?:
AF sensors are not infinite small points and on the other hand - cannot be made bigger - in certain situations, one could want to see cropped (teleconverted) image in viewfinder
Don't go injecting logic into this now my boy.
08-12-2010, 08:07 AM   #85
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QuoteOriginally posted by oneill Quote
As a long lens wildlife shooter, FA*600F4.0, DA#300F4.0 etc, any converter longer than a 1.4x does not make much sense to me due to the extra stop of light loss. Sigma already make an excellent screw drive 1.4x converter that I occationaly use on my 600, although I would prefer a Pentax one, but at this point I would be much more interested in an SDM converter.

The best thing that Pentax could do for me would be a prime DA#400F4.0 which is an excellent avian "flight" lens. I have considered buying the Canon one and a body to go with it, but I hate using two different bodies in the field much less two different makes.

Murray
PENTAX Photo Gallery: Artist Bio - Murray O'Neill
I too am on the fence about switching over to Canon. I would prefer to stick with Pentax if only they would produce a DA* 400mm f/4. But I would also want a 1.4 TC to go along with the prime. Not sure how much longer I can wait on Pentax.
08-12-2010, 05:49 PM   #86
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I'd like a weather resistant SDM+screw-drive teleconverter for sure.
08-12-2010, 06:14 PM   #87
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I would buy both, but the 2x would be my first choice.
08-13-2010, 12:42 AM   #88
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1.4, $275usd, da*60-250
08-18-2010, 07:34 AM   #89
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Hi There,

Can't we conclude that there is a general interest for TC?
- But reading the whole thread from the start and having done some search on internet outside this forum as well, I still don't know which tele converters there actually are on the market that would work like a newbie like me wants to see.

Pentax should have a general idea of which lenses they sold in which quantities. And if they are a bit smarter they should also be able to make estimations on the amount of non-Pentax glass in the market.
The next marketing step would be to find out which tele converters would make sense for how many people, which will of course depend on the selection of lenses people have. And that estimate the chance they could sell one for which price.

Summarized: I doubt this forum is a typical population of pentax users...
  • Most people by camera with 1-2 kit lenses, they won't pay enough money for a quality teleconverter.
  • Still many people buy 1, 2 or maximum of 3 special lenses, probably mainly the typical primes (for macro vs tele) and fast still reasonable affordable tele zooms.
    • Give the price & weight of the "extreme" tele lenses, you can assume this group has not such lens (and is part of next group)
    • How many fast glasses does Pentax have?
      • 16-50 mm F2.8, TC doesn't make much sense, those customers already have something > 100 long for sure
      • 50-135 mm F2.8, YES TC makes sense, Pentax know how many they sold
      • Shorter primes, only if << 200 USD and good IQ, but it will hurt sales of other primes --> No go
      • 100 mm F2.8, YES TC makes sense, Pentax know how many they sold
      • 55 mm F1.4, YES TC makes sense, Pentax know how many they sold (but it might impact 100 mm F2.8 sales...
      • Note that all YESes are WR lenses, TC should be WR as well!!!
  • Some people buy even more lenses, including extreme tele lenses. Given the small quantity of this group, Pentax can focus on the extreme lenses only (others fall in previous group) and they know exactly how many of these lensed they sold. Based on lens specs and lens line up it should not be difficult to determine if 1.4-5x, 1.7x or 2x makes any sense (for which lens) and what would add the biggest value. Because market is smaller and develop cost for sure not lower the price might be higher to ensure an interesting return on investment.
My impression is that it will be interesting to release a TC if they can sell it for ~300 USD (that is with acceptable margin, so driven by their costs to make them) and works for 50-135 mm, 100 mm and most other popular primes OR for 150-200 USD if one works only on 50-135 mm and another for again 150-200 USD on the 100 mm.
For the more extreme lenses I think the equation is even easier to make.

But to help me, which Sigma teleconverters will work with DA* 50-135 mm F2.8 lens?
  • On Sigma site I can only see compatibility with Sigma lenses
  • If IQ still OK then I would prefer 2x (because it is more that 2x zoom lens)
  • Works then means Auto focus, Aperture control, Exposure metering?
  • In-Body Image Stabilization for zoom lenses with tele converter (and correct info in RAW&JPG) would be good sales argument as well (should be feasible with body firmware update)
And would the Pentax 1.7 teleconverter work on the DA* 50-135 mm F2.8 or should I go for the 1.4/1.7 S or L?
  • Same one also on 100 mm F2.8 and 55 mm F1.4? (I think/hope so)
  • and also same or differnet one on DA and FA limitted primes? (I think/hope so)
  • and on Sigma 30 or 50 mm F1.4? (of course with Pentax mounting, I totally don't know, but guess the Sigma should of course work)
Full functionaly and commonality (with full functionality on all) will for sure help sales of TC's!!!

For non-Pentax lenses on Pentax bodies a TC will have more value if it re-anables out focus and aperture control, that would be realy sweet. Can it also be done for lenses with non-Pentax mounting?

Best regards,

Joep

PS: Sorry for long story, I am just curious if same TC would "properly" work with 50-135 mm as well as Pentax and Sigma primes.
08-18-2010, 04:44 PM   #90
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You may have forgotten about the mother of all TC threads ever...

-> https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/19694-tamron-t...rter-pics.html
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