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04-02-2014, 08:25 AM   #691
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QuoteOriginally posted by Aristophanes Quote
personally I think one of the reasons why Sigma is releasing this lens is it complements video DSLR work very well. It's something of a monster sizewise.
I guess it's panfocal with a completely silent AF then? I haven't ever seen one in person.
But that would make it even more desirable... Sigma really hit the jackpot with this lens, I think.

04-02-2014, 08:48 AM - 1 Like   #692
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QuoteOriginally posted by Pål Jensen Quote
To put things in perspective the Sigma weigths only 100g (not noticable) less than a set of the Pentax HD 15 Limited, 20-40 Limited, and the HD 55-300; a setup that covers almost everything anyone could want focal lenght wise...
Okay...Those lenses average out to f/4, why should they be compared to an f/1.8 constant zoom?
While we're at it, we might as well compare it to a DA 18-250, at only 455g it is 310g lighter than an 18-35 and covers almost everything anyone could want focal length wise, and you don't have to bother changing lenses! Buy one of those wide-angle filter things for the front of the lens and you've got your DA 15 too!

Fast high-quality zoom lenses for an SLR generally tend to be large and heavy, there's no way around it.
04-02-2014, 08:48 AM - 1 Like   #693
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to put in perspective this lens cover the most used focal...27-50....all at 1,8 aperture and with tack sharpness from edge to edge even at 1,8.

the pentax lenses from 15 and 20-40...are not sharp edge to edge not even close at f5,6...they cost a lot of money,, they are slow as hell, from one to two stop the sigma, their af is slower and not silent.....and the cost of sigma is less than pentax 20-40....
04-02-2014, 09:54 AM - 2 Likes   #694
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QuoteOriginally posted by Mock Quote
Buy one of those wide-angle filter things for the front of the lens and you've got your DA 15 too!
Sure, add a coke bottle and you've got your DA*300 too!

04-02-2014, 10:07 AM - 1 Like   #695
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QuoteOriginally posted by jonny1986 Quote
to put in perspective this lens cover the most used focal...27-50....all at 1,8 aperture and with tack sharpness from edge to edge even at 1,8
But with an extremely shallow DOF at 1.8, even as a crop lens. A lot of tha sharpness appears to be wasted at 1.8. At 10 ft. @ 28mm/1.8 its hyper focal is only 2.8ft. Except for brick walls, how many subjects are that constrained? Keep in mind that high ISO options and PP has obviated the need for a lot of fast glass under most subject matter conditions. One can make a valid argument there is an aesthetic overuse of fast glass today with a gigantic "me too" mimicry. If faster is better why is the Canon f/4 "L" glass so popular with pros and prosumers and sells like gangbusters? Fast glass operates at a very small margin of both sales and aesthetics.

It also has AF concerns at such a shallow DOF something noted for all fast glass especially using PDAF. Just goes with the design. It is a massive, 2xFL lens at over 900g, so, like all designs has compromises. It's 40% costlier and heavier than a Tamron 17-50/2.8, with ~40% less reach combining both ends. That's the premium for 1.3 more stops. No free lunch.

What gets me is the massive weight of the thing at a time when all market activity is pointing to smaller and lighter driving the bulk of sales both in bodies and lenses. There a substantial number of DSLR photographers would would never buy this lens based on its size alone. It's kind of like making a Corvette during an energy crisis.
04-02-2014, 10:35 AM   #696
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QuoteOriginally posted by Aristophanes Quote
It's kind of like making a Corvette during an energy crisis.
Sigma, or any company for that matter, makes production decisions based on profit. Apparently the demand is so great here that they don't have time yet to produce them for Pentax. The Corvette has been in constant production for many years and through may energy crises. Why? Because there are buyers.
Remember Pet Rocks? There has never been a single product, of any kind on the market that somebody couldn't make a case against, but no company with competent leadership would ever choose to not produce anything, regardless of its characteristics if it is sufficiently profitable.
04-02-2014, 10:36 AM   #697
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QuoteOriginally posted by Aristophanes Quote
If faster is better why is the Canon f/4 "L" glass so popular with pros and prosumers and sells like gangbusters? Fast glass operates at a very small margin of both sales and aesthetics.
Well... I'm going to disagree with you there. The trio of Canon L f/2.8 zooms has been called the Holy Trinity for a long time. The f/4 trio is the "Baby Trinity". The consensus is that you get the f/4 if you can't afford the f/2.8. Canon shooters seem very concerned with status and perception - I'm not saying this is right, as the f4 lenses can deliver results that sometimes are just as good, and they're much more portable - well, to me they're still huge... I'm sure there are exceptions that value portability over speed. But most people want the fast glass. Kind of like most people who want to be considered "pros" want the full frame sensor

QuoteOriginally posted by Aristophanes Quote
It's kind of like making a Corvette during an energy crisis.
Like buying a Corvette when gas prices are high, yeah, in a way it is.
A fun fact: during the latest recession, Ferrari has sold more cars per year than at any time in history.
When you gotta have that fast car, you gotta have that fast car*.

(* replace car with glass )
04-02-2014, 10:59 AM   #698
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QuoteOriginally posted by Parallax Quote
Sigma, or any company for that matter, makes production decisions based on profit. Apparently the demand is so great here that they don't have time yet to produce them for Pentax. The Corvette has been in constant production for many years and through may energy crises. Why? Because there are buyers.
Remember Pet Rocks? There has never been a single product, of any kind on the market that somebody couldn't make a case against, but no company with competent leadership would ever choose to not produce anything, regardless of its characteristics if it is sufficiently profitable.
Corvetee sales have been steadily declining for decades, as have almost al larger sports cars:

Chevrolet's 2015 Z06 could be the last new Corvette ? ever | Digital Trends

Companies make decisions based on market risk in the analysis that there *may* be profit. Profit is not known until after capital is expended and repaid.

04-02-2014, 11:10 AM   #699
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QuoteOriginally posted by jonny1986 Quote
the pentax lens from 20-40...are not sharp edge to edge not even close at f5,6.
35 lp/mm, according to the second graph here:

Test Pentax HD DA 20-40 mm f/2.8-4.0 ED Limited DC WR - Rozdzielczo
04-02-2014, 11:18 AM   #700
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QuoteOriginally posted by ChristianRock Quote
Well... I'm going to disagree with you there. The trio of Canon L f/2.8 zooms has been called the Holy Trinity for a long time. The f/4 trio is the "Baby Trinity". The consensus is that you get the f/4 if you can't afford the f/2.8. Canon shooters seem very concerned with status and perception - I'm not saying this is right, as the f4 lenses can deliver results that sometimes are just as good, and they're much more portable - well, to me they're still huge... I'm sure there are exceptions that value portability over speed. But most people want the fast glass.
Right, but the market economy has always been that you get the zooms for practicality based on affordability. f/2.8 for those who can afford it, the "baby L's" for those who cannot, or for whom the size/weight factor renders f/2.8 oversize.

The "fast glass", in part because of the limited aesthetics of the super-shalow DOF, was usually a prime because that is the more economical choice. So you buy the "baby L's" and a couple fast primes because the need for the 1.8 DOF shallowness is there in far shooting fewer situations. Much more affordable.

The Sigma tries to make the fast glass the normal zoom, but the size and weight premium is substantial. It will sell OK in the way that a muscle car still sells OK (see prior post), but its size/weight keeps it away from the substantial majority of the market. What you "want" and what you can reasonably and regularly carry are flip sides of the same economic coin. The Sigma is a gargantuan lens, heavier than the Canon 24-70/2.8 by over 100g and 211g heavier than the f/4, both of which were considered big glass already, and both of which are FF and have more wide and long reach. And in case anyone hasn't noticed, DSLR and lens sales are dramatically down lately, giving way to smaller systems all around.

What works for Sigma on this lens is it can sell across brands. That alone is probably the only reason why a lens of this girth can succeed. Lenses like this were not made prior because fast very heavy glass sold poorly due to the limited need for both the aesthetic and the weight penalty. What probably makes market sense for Sigma here is the last decade's worth of DSLR installed base in this new, Golden Age, of photography. This lens is not the future almost based solely on its size; it's selling to the past.

I don't think Canon shooters are any more absorbed with status than Pentaxians who tout the FA Limiteds.
04-02-2014, 11:34 AM - 1 Like   #701
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QuoteOriginally posted by Mock Quote
Okay...Those lenses average out to f/4, why should they be compared to an f/1.8 constant zoom? .
I was putting its weight into perspective. I'm perfectly aware that these lenses do not do the same thing.
I was illustrating that this lens is so heavy that you can get a "complete" APS line-up for the same weight.
Theres no free lunch...
04-02-2014, 11:39 AM   #702
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QuoteOriginally posted by Aristophanes Quote
Corvetee sales have been steadily declining for decades, as have almost al larger sports cars:

Chevrolet's 2015 Z06 could be the last new Corvette ? ever | Digital Trends

Companies make decisions based on market risk in the analysis that there *may* be profit. Profit is not known until after capital is expended and repaid.
Thank you, for validating my point. If they are dropping the Corvette, it's because sales are lagging.
QuoteOriginally posted by Pål Jensen Quote
Theres no free lunch...
Exactly!
04-02-2014, 11:45 AM   #703
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QuoteOriginally posted by ChristianRock Quote
A fun fact: during the latest recession, Ferrari has sold more cars per year than at any time in history.
When you gotta have that fast car, you gotta have that fast car*.

(* replace car with glass )
A Ferrari is about performance. Performance in a lens is about optical quality which has nothing to do do with lens speed. A fast lens should be compared to a truck.
04-02-2014, 11:45 AM   #704
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QuoteOriginally posted by ChristianRock Quote
Well... I'm going to disagree with you there. The trio of Canon L f/2.8 zooms has been called the Holy Trinity for a long time. The f/4 trio is the "Baby Trinity". The consensus is that you get the f/4 if you can't afford the f/2.8. Canon shooters seem very concerned with status and perception - I'm not saying this is right, as the f4 lenses can deliver results that sometimes are just as good, and they're much more portable - well, to me they're still huge... I'm sure there are exceptions that value portability over speed. But most people want the fast glass. Kind of like most people who want to be considered "pros" want the full frame sensor

)
Art Wolfe made an excellent argument for why he uses the f4.0 lenses and carries only a few lenses with him. their weight and his age. Pretty sure for him it was not a dollar issue. IMHO he creates great images, been a fan of his work since I first say it in Seattle in 1990.
04-02-2014, 11:49 AM   #705
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QuoteOriginally posted by redrockcoulee Quote
Art Wolfe made an excellent argument for why he uses the f4.0 lenses and carries only a few lenses with him. their weight and his age. Pretty sure for him it was not a dollar issue. IMHO he creates great images, been a fan of his work since I first say it in Seattle in 1990.

These are my reasons too. I really want that 15 Limited, 20-40 Limted and the 55-300 combination. It is an amazing focal lenght range unthinkable at 900grams a few years back.
I've been through that fast lens phase wchich included 300/2.8, 85/1.4 and 135/1.8, 50/1.2 +++ all carried at the same time.
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