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08-15-2014, 12:35 PM   #736
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QuoteOriginally posted by patarok Quote
SIGMA UK website says...

Sigma Interchangeable lenses for SLR/ DSLR Cameras converted to any of the following mounts; Sigma, Sony, Nikon, Pentax, Canon
120-300mm F2.8 DG OS HSM | S Cost of Conversion Mount Service 280

i would say just call them by phone and ask.

It also say in the FAQ:

QuoteQuote:
Q2: Are all the Sigma lenses supported by this service?

A2: Only Sigma lenses from our Global Vision product lines (Contemporary, Art and Sports) will be eligible.



Q3: Can I request to convert to any mount of my choice?

A3: Yes, as long as the lens in the requested mount has been released by SIGMA as a product.
In other words, the lens has to be available in the mount you are requesting already.

08-15-2014, 12:50 PM   #737
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QuoteOriginally posted by philbaum Quote
T........ Thats what Pentax should focus on -no pun intended- lenses - make fast focusing lenses and a few fast exposure ones to confuse the critics. Lenses, lenses and more lenses.
My sentiments exactly - high quality lenses with large apertures with fast focus motors for the existing product line. You cannot be all things to all people. Be the best apc-s camera available with the best lenses.
08-15-2014, 03:37 PM   #738
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QuoteOriginally posted by monochrome Quote
FF = Bigger, heavier, faster lenses.
APSc = Smaller, lighter, more elegant, slower lenses.
Please don't perpetuate this myth.

If you compare lenses with the same light gathering capability then very often there is no difference with respect to size and weight. Only an apples to oranges comparison concludes that APS-C lenses are smaller and lighter.

In particular APS-C in conjunction with K-mount (a full frame mount) struggles to realise any size advantages.

Beyond a certain level of image quality, an FF system actually also becomes the cheaper choice.
08-15-2014, 03:40 PM   #739
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QuoteOriginally posted by Class A Quote
Please don't perpetuate this myth.

If you compare lenses with the same light gathering capability then very often there is no difference with respect to size and weight. Only an apples to oranges comparison concludes that APS-C lenses are smaller and lighter.

In particular APS-C in conjunction with K-mount (a full frame mount) struggles to realise any size advantages.

Beyond a certain level of image quality, an FF system actually also becomes the cheaper choice.
APS-C digital was developed in accordance with the original APS film system. While the system failed for film the entire reason why it was developed was smaller sizes and lower cost.

In other words cheaper is relative.

08-15-2014, 03:41 PM - 1 Like   #740
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QuoteOriginally posted by Class A Quote
Please don't perpetuate this myth.

If you compare lenses with the same light gathering capability then very often there is no difference with respect to size and weight. Only an apples to oranges comparison concludes that APS-C lenses are smaller and lighter.

In particular APS-C in conjunction with K-mount (a full frame mount) struggles to realise any size advantages.

Beyond a certain level of image quality, an FF system actually also becomes the cheaper choice.

He said that APS-C was slower, so I think it's a fair comment.

For the same equivalent speed, FF is usually a hair smaller. But he's stated he's not comparing the same lenses, and he has a point. There's no commonly available 23mm F/6 for full frame, for instance. A lot of people shoot at F/6 or smaller most of the time, and they don't want to carry around an F/4 lens... or in this case, the slowest common lens I'm aware of for 24mm is F/2.8!
08-15-2014, 03:44 PM - 1 Like   #741
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QuoteOriginally posted by RonHendriks1966 Quote
Problem is that Pentaxian's simply don't buy the expensive lenses from Sigma in large enough quantities. They just sell some cheap zoom's, 18-200 and 18-250 in larger amounts.
I think they also buy more expensive lenses where Pentax doesn't really have an alternative like 18-35 f/1.8, 85 f/1.4, 30 f/1.4, 35 f/1.4 but also 150-500 & 50-500.

But the 70-200 is on pentax roadmap and there already 50-135 that is lighter and smaller and better suited range for APSC (at least for some practices) and there already also the 60-250 that is only f/4 but offer a wider focal range with a fantastic optical quality. If you want a 70-200, there also the cheap tamron that is good, focus on shorter distance and is very popular.

Sigma only get the one with enough money that need fast focussing for sport. They may even loose that soon. So they stop it.

The Sigma 70macro is surrounded too by DFA50 macro, DFA100 macro, DA35 macro and for thoses on a budget tamron 90 macro. This doesn't let that much market possibility to sigma.
08-15-2014, 03:54 PM   #742
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QuoteOriginally posted by stevebrot Quote
Yep, and Sigma support for Sony Alpha is pretty spotty. I think their willingness to support a mount is a question of expense to bring to market as balanced against potential sales. Nikon makes the cut while #3 (Sony) and Pentax often don't.
Which is why Sony bought into Tamron. I think the possibility exists for Ricoh to make a similar deal, but not with Sigma. Sigma is privately owned.

I'm pretty sure the partnership with Tokina ended when Hoya sold Pentax to Ricoh.
08-15-2014, 04:11 PM   #743
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QuoteOriginally posted by Class A Quote
Please don't perpetuate this myth.

If you compare lenses with the same light gathering capability then very often there is no difference with respect to size and weight. Only an apples to oranges comparison concludes that APS-C lenses are smaller and lighter.

In particular APS-C in conjunction with K-mount (a full frame mount) struggles to realise any size advantages.

Beyond a certain level of image quality, an FF system actually also becomes the cheaper choice.
Myth or not, Pentax intentionally markets their prime APSc lenses as small, light, (slower) elegant lenses. If they do the same with any forthcoming FF lenses then that's the distinguishing factor!! But if they don't produce f/2.8 zooms and an f/2 wide the howls on this Forum will be joined by Cerberus at his gates.

However, I'm not sharpening any axes - if I'm incorrect in physics it's OK to correct me. I'm just thinking marketing.


Last edited by monochrome; 08-15-2014 at 04:16 PM.
08-15-2014, 04:14 PM   #744
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QuoteOriginally posted by boriscleto Quote
Which is why Sony bought into Tamron. I think the possibility exists for Ricoh to make a similar deal, but not with Sigma. Sigma is privately owned.

I'm pretty sure the partnership with Tokina ended when Hoya sold Pentax to Ricoh.
Fuji makes lenses for Hasselblad and all of the Sony professional broadcast TV lenses. The X-mount lenses are very impressive. If Pentax works with anyone I would pick either Fuji or Olympus.
08-15-2014, 04:46 PM   #745
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Gee, I thought you were fibbing, until...

QuoteOriginally posted by Deedee Quote
Come on people testing those Pentax cameras - Leak some damn photos under other pseudo names. Next we will have news about "Leaked images"!

Lets do it!

P.S. I am testing a full frame Pentax K-1 with ISO 300,000 and Leaf Shutter. It also has the "Movie Button" and "Swivel Screen". Camera has NFC/wifi/blue tooth. 51 AF points with 39 Cross type AF points. 11 Frames per second. Camera will be launched with a K-mount converter for full frame lenses (So people who don't want to get rid of their vintage glass can use the new system WITHOUT Vignetting). Flash Sync speed of 1/500. Processor SAFOX XXX AFZ M D N TLD module. 30 Mega Pixels. Built in Full-Tether using USB 3.0 / HDMI and Wifi with native support to Lightroom and Adobe Camera Raw.

P.P.S The camera will be designed to take X-Ray of previous dead presidents and their ghosts.
I saw the PPS. It's got to be real...

---------- Post added 08-15-14 at 07:54 PM ----------

QuoteOriginally posted by Class A Quote
Please don't perpetuate this myth.

If you compare lenses with the same light gathering capability then very often there is no difference with respect to size and weight. Only an apples to oranges comparison concludes that APS-C lenses are smaller and lighter.

In particular APS-C in conjunction with K-mount (a full frame mount) struggles to realise any size advantages.

Beyond a certain level of image quality, an FF system actually also becomes the cheaper choice.
I am apolitical, but after reading the tripe from LumoLabs, The WhiteHouse should hire him. His math is the worst type of alleged statistical dribbel, he obviously does not have an engineering or operations research degree or training, his hidden "qualifiers" at the end of each section are utter nonsense. He ought to be working on the climate curve, unicorn cloning, or Masters & Johnson's follow up on "Self Help".

Worst case of alleged "quantitatively supported" malpractice I have ever seen...
08-15-2014, 05:31 PM   #746
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Uh Oh. Incoming.
QuoteOriginally posted by GlassJunkie Quote
I am apolitical, but after reading the tripe from LumoLabs, The WhiteHouse should hire him. His math is the worst type of alleged statistical dribbel, he obviously does not have an engineering or operations research degree or training, his hidden "qualifiers" at the end of each section are utter nonsense. He ought to be working on the climate curve, unicorn cloning, or Masters & Johnson's follow up on "Self Help". Worst case of alleged "quantitatively supported" malpractice I have ever seen...
08-15-2014, 06:04 PM   #747
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QuoteOriginally posted by monochrome Quote
Uh Oh. Incoming.
Normally I would send out for popcorn. In this case maybe heading for the basement would be better.....................
08-15-2014, 06:56 PM   #748
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QuoteOriginally posted by GlassJunkie Quote
I am apolitical, but after reading the tripe from LumoLabs, The WhiteHouse should hire him. His math is the worst type of alleged statistical dribbel, he obviously does not have an engineering or operations research degree or training, his hidden "qualifiers" at the end of each section are utter nonsense. He ought to be working on the climate curve, unicorn cloning, or Masters & Johnson's follow up on "Self Help".
Actually he's quite correct. His physics and math are sound.
08-15-2014, 07:26 PM   #749
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QuoteOriginally posted by Nicolas06 Quote
Sigma only get the one with enough money that need fast focussing for sport.
Or the one (like me) that want a higher quality walk-around with a little broader range. I recently bought the Sigma 17-70/2.8-4.0 (C) which, while not expensive, is not exactly cheap either.

I also own the Sigma 50/2.8 EX DG Macro which is neither a sports lens or particularly expensive.


Steve

---------- Post added 08-15-14 at 07:40 PM ----------

QuoteOriginally posted by monochrome Quote
if I'm incorrect in physics it's OK to correct me. I'm just thinking marketing.
Heck, I don't know either way. I do know that bloated size has little to do with APS-C vs. FF. Ditto for wide maximum aperture. My smallest SLR lenses are fast (wider than f/2.8) and made for 35mm film and, no, none are pancakes.

IMHO, the relative slowness of most modern lenses has little to do with lens design or format and everything to do with auto focus. If you make a fast AF lens longer than 35mm for a digital SLR you are going to hear anguished screams regarding AF performance. After all, only the higher end AF systems are able to focus reliably at apertures wider than f/5.6 and even the better systems are limited to f/2.8 and then only for the center region AF points. I also believe that is why the split-image viewfinder is typically not found on AF cameras. Having one shows the hit/miss nature of the AF system.

...end of rant.


Steve

---------- Post added 08-15-14 at 07:45 PM ----------

QuoteOriginally posted by ElJamoquio Quote
Actually he's quite correct. His physics and math are sound.
I don't know what Falk does for a living, but my understanding is that he has a doctoral degree in Physics.


Steve

---------- Post added 08-15-14 at 07:47 PM ----------

QuoteOriginally posted by jatrax Quote
In this case maybe heading for the basement would be better.....................
Aunty Em! Aunty Em!


Steve
08-15-2014, 07:53 PM   #750
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QuoteOriginally posted by ElJamoquio Quote
Actually he's quite correct. His physics and math are sound.
It would seem that you are correct. I checked the Lumo site and this is what I found.. "Falk Lumo has a scientific background holding a Ph.D. in Theoretical Physics."

I've got to guess that his math is sound....
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