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08-15-2014, 06:56 PM   #766
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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   #767
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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   #768
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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....
08-15-2014, 08:09 PM   #769
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Perusing the past few pages of this thread reminds me why I unsubscribed a while ago...

08-15-2014, 08:09 PM   #770
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QuoteOriginally posted by stevebrot Quote
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
Thoses 2 are not a 70-200. I was specifically speaking of the 70-200. And it was part of the response saying that sigma doesn't sell only cheap lenses
08-15-2014, 08:10 PM   #771
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QuoteOriginally posted by GlassJunkie Quote
I saw the PPS. It's got to be real...

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



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...
Unless you are Doctor GlassJunkie and you can refute the mathematics of someone who has a PhD in Physics, I think you should play in the shallow end.
08-15-2014, 08:14 PM   #772
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QuoteOriginally posted by stevebrot Quote
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

Since this thread has already gone seriously OT, I don't feel bad asking you your impressions of the Sigma 17-70.
08-15-2014, 09:22 PM   #773
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QuoteOriginally posted by IchabodCrane Quote
Since this thread has already gone seriously OT, I don't feel bad asking you your impressions of the Sigma 17-70.
I have had it since April and so far I am very impressed. I have posted a comprehensive review:

Sigma 17-70mm F2.8-4 DC Macro HSM (Contemporary) Lens Reviews - Sigma Lenses - Pentax Lens Review Database


Steve

P.S. I very seldom rate a lens higher than 8

08-15-2014, 09:29 PM   #774
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There's a huge huge difference between theoretical physics and engineering, i.e. designing an applied solution that actually realizes the extremely idealized advantages that Falk purports to demonstrate, which in practice are likely to be of far less importance than he claims them to be. As a point of illustration, I have a close family friend who is a PhD in theoretical physics from MIT (and a former NASA/JPL employee), as well as a close family member who was a long-time engineer in the nuclear industry. It's always interesting to hear their discussions regarding the theoretical performance of various processes, and how dramatically lower the yield in practice is. An order of magnitude less is not uncommon.

Further, the projections he makes regarding future consumer behavior based upon a cost/"image quality" analysis are patently ridiculous, and ignore the actual reasons why consumers choose the cameras they do and how they actually use them. For the vast quantity of camera buyers, even most serious ones, image quality is already "good enough," and factors like portability, ruggedness, useability, and bottom line cost for a given purpose are much more important than maximum image quality across all effective lens lengths and apertures. Sure, there will always be a small amount of gearheads who will want to push the envelope on image quality enough to ignore the rapidly diminishing returns that sensor upgrades provide (yes, that final 5% increase in image quality, if there is even a way to really quantify something so subjective, might be cheaper on FF, but ultimately, it is still only a 5% increase), but to suggest that all DSLRs will eventually be replaced by medium format mirrorless is ludicrous, since the lenses, even with shorter registration distances, will need to be dramatically larger to achieve similar focal lengths equivalencies, and the buying public has repeatedly demonstrated its preference for more features in smaller and cheaper packages. Why do you think that even the new, cheaper Canikon FFs are still handily outsold by APS bodies, even among pros (Canon 7d, anyone?)? Real people have set budgets and limited needs, and choose their cameras accordingly.

Turning back to the subject at hand, like it or not, Pentax, since even before the Hoya years, has decided that cost and features were going to be their selling points for their camera bodies, with image quality (despite wringing best-in-class quality out of APS-C sensors) and lens selection being secondary. And what will drive them into the FF market will not necessarily even be the desire to build a camera that produces superior images to current offerings. Rather it will simply be to be seen as a first-tier camera maker on par with the big boys and will probably be minimally, if at all, profitable for the foreseeable future. Production of the body will be the cheap part, since it will likely re-use most of the K3 platform. But the sunk costs for engineering new FF lenses with new focal systems, sealing, etc. won't be cheap, and they are going to have to be amortized over a very small amount of units. But hey, if that's what it takes to survive as a camera brand, then that's jsut the cost of doing business.


QuoteOriginally posted by cali92rs Quote
Unless you are Doctor GlassJunkie and you can refute the mathematics of someone who has a PhD in Physics, I think you should play in the shallow end.
08-15-2014, 10:26 PM   #775
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QuoteOriginally posted by ElJamoquio Quote
Actually he's quite correct. His physics and math are sound.
I suspect his physics and math are sound, but i think some of his assumptions are incorrect or unmentioned.

QuoteQuote:
So overall, body size or weight is not an priori argument against full frame. However, there is still a market niche for smaller propositions. Many people though can live with a camera the size of a D800 just fine
A. Even if people "can live with a camera the size of a D800 just fine", the fact of the matter is, they are choosing not to. Many people are buying m4/3, many are buying RX100s with 1" square sensors, many millions more are choosing to be satisfied with smart phone cameras. I've read several posts from folks who formerly had FF cameras, who have switched to smaller formats. Many travelers, including hikers who have to carry their sleeping bags and tents on this backs, are choosing to carry smaller cameras, lenses and tripods - go figure.

B. Falk talks about the possibility that FF camera sizes can be reduced in size. He fails to mention the bloated nature of today's high quality VR equipped, FF zoom lenses. Not only bloated in size but in weight. It figures that lenses that need to cover a larger sensor size also need to be larger in diameter to suit the optics. Again, more weight for folks hiking, who choose to shoot wildlife and need longer telescopic lenses.

I'm not saying that FF bodies and lenses are bad, its that there are pros and cons to any choice. If you don't believe me, just look at the marketplace. FF DSLRs are still less than 9% of the DSLR market. Sure price is a part of that market share. But size and weight of the FF combo is also a part of it. Nikon has made a huge investment in FF technology, but yet Wall Street is not confident in their decision.

By Falk's article, we should all be throwing our aps cameras in the ditch and buying the nearest FF camera. That article is 2 years old and it still hasn't happened. The article makes a good point, its just not comprehensive from a business point of view.
08-16-2014, 01:36 AM - 1 Like   #776
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Well if you want something smaller. There are trade-offs. So 70-200mm/f2.8 needs a 77mm ring on front, but if you are willing to go with 70-200mm/f3.2 then you are good to go with a 67mm ring. You can't have it all!! You can fit a FF sensor inside Q, but you can't put SR inside. So there is a minimum where you have to deal with. No idea where it stops, but a FF sensor with SR can fit inside K-3, maybe just a different internal electronic design is neede to fit the rest inside.
08-16-2014, 01:47 AM   #777
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QuoteOriginally posted by dcshooter Quote
But the sunk costs for engineering new FF lenses with new focal systems, sealing, etc. won't be cheap, and they are going to have to be amortized over a very small amount of units. But hey, if that's what it takes to survive as a camera brand, then that's jsut the cost of doing business.
Fortunately those lenses can be sold to consumers who own only an APSc dSLR.
08-16-2014, 02:02 AM   #778
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QuoteOriginally posted by RonHendriks1966 Quote
Well if you want something smaller. There are trade-offs. So 70-200mm/f2.8 needs a 77mm ring on front, but if you are willing to go with 70-200mm/f3.2 then you are good to go with a 67mm ring. You can't have it all!! .
i have to admit that if i can get a good 70-200 with AF under 1kg i would take it, not mater if it's say f4 !
08-16-2014, 03:40 AM   #779
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QuoteOriginally posted by aurele Quote
i have to admit that if i can get a good 70-200 with AF under 1kg i would take it, not mater if it's say f4 !
Closest is 60-250 f/4 for 1040g or 70-200 f/2.8 tamron for 1150g...

Or 50-135 f/2.8 for 685g. I choosed this one (and still think it is too heavy/big).
08-16-2014, 04:34 AM   #780
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To some extent, yes.

However a large part of Lumo's analysis hinges on the fact that a FF can go wider, with a faster aperture, cheaper than can an APS-C, which is something pretty much everyone knows already. The problem is that the ratio of size between an APS-C and 35mm sensor is such that there are not neat correspondences between many of the common/useful focal lengths - e.g. to acheive a 50mm equivalent, you need a 33mm lens. Yeah, a 35mm is pretty close (and in fact, the 35mm 2.8 is my most commonly-used DA lens), but lenses optimized for the APS-C sensor will likely be the preferable choice for APS-C only consumers, since those will still be cheaper and more suitable for the cameras they own. That's why Nikon maintains separate lines of DX and FX lenses. Focal lengths like 28mm and 135mm are oddballs on APS-C, which is why you don't tend to see them in Pentax's DA lineup, and probably won't be big sellers except for FF shooters if re-introduced. Likewise, given the built-in width advantages of FF sensors, things like walk-around zooms are likely to be designed with long-end reach in mind rather than maximum short-end width, meaning that APS-C shooters will still have a strong incentive to opt for DA lenses with ranges more suitable for their sensor size.

Then, of course, there is also the very real question of whether Pentax will be able to develop a useful IBIS system for a FF sensor. If not, any new high-end FF lenses (particularly zooms) will undoubtedly include optical stabilization, substantially increasing their size and weight, thus making them less attractive to APS-C owners who bought into Pentax exactly for the compactness of its packages.

QuoteOriginally posted by monochrome Quote
Fortunately those lenses can be sold to consumers who own only an APSc dSLR.
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