[filoxophy]

Perusing the past few pages of this thread reminds me why I unsubscribed a while ago...

[Nicolas06]

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

[cali92rs]

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.

[IchabodCrane]

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.

[stevebrot]

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

[philbaum]

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.

So overall, body size or weight is not an à 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.

[RonHendriks1966]

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.

[monochrome]

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.

[aurele]

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 !

[Nicolas06]

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).

[Nicolas06]

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.

That's not how I feel. I would really want a 28mm as I think 35mm is just too narrow. We have 35mm because it was already here for FF, not as a APSC design. 28 seems like a very interresting focal lens. Sigma 30mm seems to be very popular, and show that you can have dedicated focal lens APSC design in this range. The reason I don't have a modern Pentax 28mm is pentax doesn't sell it. The reason I don't have a modern 24mm is also Pentax doesn't sell it.

For events, 24-70 & 28-75 transtandard are really interresting on APSC (more than on FF). The crop factor make them more interresting as for even you don't need to go much wider than 24mm anyway but on the opposite the 70mm with crop factor give you much more reach and portraiture possibilities.

Many use 70-200 on APSC and add even a TC. This give you equivalent of 150-420mm f/4 lens. Something very expensive and even more bulky on FF.

There sense to have many more focal lenses for prime and zooms to better fit each need. It is just one has to take into factor cost into it.

[Uluru]

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 ...

Frank Lumo is right, but our thinking about implementation of the FF is wrong. We wait for something else to happen because we think 'something else' invisible to us causes the delay.

Yet in reality, only thing Ricoh needs to do now is to equip one K-mount camera with a 36MP FF sensor, and let the users decide what to do with it. 36MP FF will allow some ~15 MP in APS-C crop mode, so users of the DA lenses can be happy as well — its like having a K5IIs together with an FF.

Having an FF camera and also some DA lenses is like having two amazing cameras in one. And who wants to go for the FF lenses, let him do that too. Lots of Tamron and Sigma lenses cover the FF, at least 6 or 7 current Pentax lenses can fit the bill as well. So the FF tech is not an obstacle at all. The obstacle is something else.

This is a matter of a pragmatic approach of the brand owner — how far Ricoh is willing to imagine, see possibilities, inform and excite its audience. Can they do the above? Yes.

But will they do that? I don't think their imagination stretches that far. Ricoh imposes pragmatic problems, one after another, and as a consequence the audience — in lack of brand owner's vision — suddenly 'sees' "explanations" for such problems. It's a sad life in a Shakespearean existential "to be or not to be" loop — too afraid to live, too scared to die.

[Cynog Ap Brychan]

Focal lengths like 28mm and 135mm are oddballs on APS-C,

I'm curious. 28mm gives a FF equivalent FL of 42 mm - close to the diagonal of 35mm film (hence the Pentax FA 43mm Ltd) and 135 is just over 200 mm a popular focal length in FF. So, why are these oddball?

[GlassJunkie]

Actually he's quite correct. His physics and math are sound.

In any cost study there are impericals (cost to make, design, ship). Pricing studies involve elasticity. For those that are involved in manufacturing, we work with these outside physics.

I agree with some of Lumos physical math.... HOWEVER...

The following are not supported by conventional methodology and are in fact Lumo's opinions:

1,1 "So overall, body size or weight is not an à 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." Not supported any quantitative data., or even qualitative user analysis.. Opinion or supposition

1.1 " Full frame SLR cameras will soon be sub $ 2,000 items and absolutely rule the enthusiast SLR market." Absolutely NO quantitative customer / market support. No behavioral analysis, No focus group scoring. Pure opinion and supposition. IMHO

"In theory, pixels < 1 µm are doable if diffraction-limited (sharp) <F/1.2 lenses can be made. In practice though, full frame cameras have a resolution advantage over APSC cameras." On pixels < 1µm, yes. On "in practice FF has resolution advantage" ? Really? Not true... a 24mpFF does NOT deliver the same resolution of a 24mp APSc on a pixel density/given area basis. There ARE however (per Lumo's analysis) IQ tradeoffs in the corners due to APSC lens image circle size than a FF lens on an APSC does not have.

"It is a myth that APSC cameras crop the "sweet spot" from the center of full frame lenses. Such myths can arise when comparing non-equivalent cameras … (cf. [camera equivalence §4.2.2] for further detail). Correct...



1.3.2 Overall, equivalent full frame lenses deliver better image quality. Or at a given image quality, they are cheaper (like in consumer grade full frame lens vs. professional grade APSC lens). In a vacuum, yes, but this does not consider the rest of the system, hence the argument is non-sequitur to the overall premise. Poorly built case... There are many variables like cross-pixel "crosstalk" which can effect "quality" significantly and he has totally discounted algoritmic effectiveness of the processor. IMHO



1.3.1 " An image downsampled from a higher resolution to a destination resolution will look sharper than one captured at that resolution, everything else being equal." Correct



1.3.1.2 "And the cost of a hole is … zero, nothing, nada. This is an extreme example which illustrates that lens cost decreases and ultimatively vanishes as the sensor size increases, for any given predefined image quality." An absurd statement. It has nothing to do with a price/IQ/ customer cost effectiveness curve used to actually sell something. Purely abstract analysis. IMHO



1.3.3 "My personal opinion is that the accuracy of focus (both automatic and manual) is the strongest single argument in favour of full frame over APSC." Stated as opinion, not supported in analysis I have ever used in product design or manufacturing. IMHO


1.6 "Another example where bigger may mean cheaper." Not supported by ABC allocations in materials, conversion, margining of componentry, R&D allocations. Assumed economy of scale? Not stated by any manufacturing cost methodology... Pure opinion. IMHO



2.1 " This means the market must have moved away from its point of equilibrium. Sensor sizes have been kept smaller than technically appropriate, possibly to protect good margins in a growing and prospering market. Such a state of any system is known as supercritical: any small perturbation may suffice to throw it back into a state of equilibrium." Markets are not ideal systems. They do not always behave rationally, logically,and the effects of emotion, ergonomics, user acceptance (in this case of the imaging system, output media, and human perception of the value and quality of the output, delivered medium, and imaging system) have been totally discounted in this analysis. Questionably relevant in 2012, less in '13, not at all in '14. Apart from some areas of solid theoretical physics, the "Value of FF over APSc" on both quantitative and qualitative bases was not established. Nice opinion piece though... IMHO



ANY production engineer, product developer, activity based cost trained manufacturing manager, marketing executive that I know (and I have been) would put his analysis in the "fun to talk about" His snippets have some validity, and some arguments are supported, but the outcome is clearly not supported, logically , mathematically, or in any actionable fashion. His reasoning works for him, and others, I am sure, not for me.


And for Cali92rs, I have a graduate engineering degree, graduate work in R&D management, operations research, materials engineering, process engineering, market research, and have run multi-billion dollar manufacturing and automated production operations. Real world and the math tools... A "Doctorate" is Not required to make a sound argument,,... Logic, process, sound analytics, and in this case an understanding of how markets and the human element work are.

[PJ1]

The same reason why Pentax doesn't have a MILC with a aps-c sensor yet

I thought the K-01 was a Pentax aps-c sensor MILC. They've had it already! (Or maybe I only think my K-01 is a Pentax.)