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09-10-2015, 06:49 AM   #16
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QuoteOriginally posted by Edgar_in_Indy Quote
Maybe it's also due to the increasing resolution of digital cameras, and people's tendency to pixel peep.
That is right. fast lenses use to be "dreamy" when wide open. Good ones are sharp in the center and resolution does not have to be very good in corners when wide open, even shooting with film. Who need corner sharpness if you shoot f1.4? Best sharpness usually comes at F 5.6-8.
But now, people like to "test" lenses on 36mp sensor, because testing is free. So new lenses have to be sharp from F 1.4, which means a lot more glasses to adjust all kinds of aberrations. The result is what we see, monsters.

09-10-2015, 07:01 AM   #17
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The only lens I need to be pin-sharp wall-to-wall is my 35mm Macro. Everything else is allowed to be imperfect at the edges. Except maybe if I get a DA15/4.0; then I want the edges to be as good as the centre.

QuoteOriginally posted by grahame Quote
But now, people like to "test" lenses on 36mp sensor, because testing is free. So new lenses have to be sharp from F 1.4, which means a lot more glasses to adjust all kinds of aberrations. The result is what we see, monsters.
Yes, because there are people out there who judge lenses solely on the test charts and lab ratings and don't pay attention to what's out there in the field, but who have attained positions from which they can influence the purchasing habits of others - and lens makers, who want to sell lenses, are to a certain extent obliged to service this driving force. I accept and agree that the only honest way to compare two lenses against each other is with charts etc, but you HAVE to be able to interpret the results in the context of what you're using it for. It's no use having a lens that can give you some absurd number of line pairs/mm constant across the frame if it's too awkward, heavy or expensive for the market you've pitched it at, and that's before we get to reliability and QC issues.

Eventually we're going to get to a megapixel level that no affordable lens will be able to live up to (if we're not already there). Then what?
09-10-2015, 07:33 AM   #18
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Yes. They are getting larger. Look at the 28-45 for the 645. I'm sure folks will be shocked by the size and weight of the coming D-FA* 24-70/2.8.
09-10-2015, 08:07 AM   #19
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QuoteOriginally posted by Dijker_t Quote
Fully agree on that!
Lenses have to be bigger if they are faster since the amount of light that is collected by a particular lens is proportional to the surface area of the aperture. A 200mm f/4 only needs a surface area of 50mm, but a 200mm f/2 needs a surface area of 100mm. People now desire faster lenses for go with better sensors, the need to blur the background with smaller sensors, etc. This means lenses that are faster and, therefore, larger in size.

With wider angle lenses the difference isn’t as much simply due to the math. The difference in surface area between a 50mm f/2 and f/1.4 isn’t all that much, but there are other issues making the lenses larger and heavier. The difference in surface area between a 400mm f/5.6 and f/2.8 is significant, and I imagine it is more difficult to manufacture within proper tolerances!

Wide angle lenses are also larger if faster even if the surface area math indicated there shouldn’t be much difference in size. There are other things to consider like controlling aberrations due to the wider focusing area, the disproportionate size of the front lens as it relates to the distance from the diaphragm, etc.

The more stuff packed into a lens, that heavier it will be. That is why I like the IS in the camera, the way PENTAX does it.

A f/1.4 “normal” lens that is soft at f/1.4, but sharp at f/2 is a waste of money compared to purchasing a sharp f/2. Making the faster lens sharp wide open may mean more glass, making the lens heavier and longer.

I hope I have the above right. If not, someone correct me and I'll edit my comments.

09-10-2015, 08:40 AM   #20
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QuoteOriginally posted by pathdoc Quote
Eventually we're going to get to a megapixel level that no affordable lens will be able to live up to (if we're not already there). Then what?

I only wish, when camera maker producing such cameras, they still make some camera that has lower resolution, so we can buy and use.
To be honest, I still don't get it why so many people want to buy 36 or even higher megapixel cameras. Some commercial photographers need high MP, but 95% regular users, including professional photographers, don't really need that high number. Well, this topic has been discussed for many years, and I never won.

---------- Post added 09-10-15 at 10:54 AM ----------

QuoteOriginally posted by quant2325 Quote
A f/1.4 “normal” lens that is soft at f/1.4, but sharp at f/2 is a waste of money compared to purchasing a sharp f/2.
It really depends what you want: A faster 1.4 lens has good enough center resolution and low line counts in the corner can give you: 1) brighter viewfinder 2) shallow DOV 3) faster shutter speed 4) creamer bokeh. 2&4 helps emphasizing the subject.

If these are not what you want, and you want corner to corner sharpness, F2 lenses makes great sense. That is why members here might have >10 50mm lenses. You pick the one can get the job done.

But my point is: in reality, I never found I need corner sharpness when I shoot F 1.4 or 1.8. In most case, item in the corner of a frame is not on the focal plane, unless it is a macro photograph. Macro lenses are so expensive for good reasons: good corner to corner sharpness, and flat focal plane.
09-10-2015, 08:56 AM   #21
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QuoteOriginally posted by Nick Siebers Quote
My hunch is that the various mirrorless options are drawing away the people who value compactness, leaving the SLR makers trying to "swing for the fences" and greenlighting big heavy optical designs they never would have in the past ....
Now that the various mirrorless brands have succeeded in crowding the very market they fabricated, they are also coming out with bigger and heavier native lenses, and bodies too.
09-10-2015, 09:13 AM   #22
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QuoteOriginally posted by quant2325 Quote
A f/1.4 “normal” lens that is soft at f/1.4, but sharp at f/2 is a waste of money compared to purchasing a sharp f/2. Making the faster lens sharp wide open may mean more glass, making the lens heavier and longer.
My experience with the Pentax 50/1.4s would dispute that. Even if f/1.4 isn't "sharp", one can still take some interesting pictures that the f/2 lens wouldn't produce. I accept your point, though, that if you only shoot a fast lens stopped down,and you could have gotten a slower lens that would perform as well, the speed is not needed.
09-10-2015, 09:14 AM   #23
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QuoteOriginally posted by Tanzer Quote
Now that the various mirrorless brands have succeeded in crowding the very market they fabricated, they are also coming out with bigger and heavier native lenses, and bodies too.
I would point out that they also continue to produce very small bodies and lenses. I think with the larger mirrorless cameras, it's a case of covering all the bases for potential customers, since some people actually prefer the ergonomics of larger camera equipment.

There were also small options in 35mm film days, but these days technology improvements mean you don't have to compromise as much with small cameras/lenses.

09-10-2015, 01:20 PM   #24
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Relatively fast lenses from the 1970s like the 50mm f/1.4 and the 75-150 f/4 were still at 49mm for filter size which would be considered amazing today. They were metal barrels and MF, of course. Even so, relatively small, plastic barrel screw-drive lenses such as the 28-70 f/4 (52mm filter) existed in the early FA days, but the build was low quality. Given the Ltd. line, I think in-lens motors are a major contributing factor. In-lens motors (DC) that don't tend to fail might need to be a bit larger yet. Canon and Nikon require ILIS, and that takes a bit extra space. We see more WR and * quality lenses requiring a bit more bulk. Many small factors add up to a lot more bulk.

Pentax will need to find more to distinguish itself against Canon and Nikon in the FF battle. When you consider that Pentax is the only IBIS among the three, and in a good position with relatively small FF prime lenses, the way of taking advantage of these differences should involve development of smaller zooms (both in terms of range and aperture size). While the 20-40 Ltd. hinted at that, its crop range, relative IQ, and variable aperture did not impress all that successfully with the apparent intended audience (and it isn't a FF lens). Rather than duplicate higher end f/2.8 zooms offered by the other brands, scaling down good zooms to f/3.5 or even f/4 constant aperture would put Pentax in an interesting class sized between the major FF dSLRs and the better mirrorless offerings. Where you need shallow DoF, the primes allow for it and tend to give a better bokeh - even in the modern zoom designs.
09-10-2015, 02:10 PM   #25
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has anyone here ripped apart an SDM lens? I'm curious how much of the bulk is due to the glass, and how much due to the SDM motor etc. Pentax has proven that you can have sharp, fast lenses that retain a small size (FA/DA limited primes for example), but those used the screwdrive for AF. Obviously the more you want a lens to do... the bigger it's going to get (sharp image through a wide zoom range; fast, constant aperture; fast, silent built-in AF) My Dad was over the other night, and hefted my daughter's k20D with the DA*16-50 on it and immediately commented on how huge the lens was.... I was thinking to myself "it's smaller than the 50-135 that's on it's way here..."
09-10-2015, 02:56 PM   #26
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To each one his own. Some situations and some users need fast glass, that is close to perfection from it's widest aperture, some people do not need it. I hate sweeping generalizations. I prefer to keep the ISO as low as possible on my K-3, despite the fact that I can process images in a way to minimize the consequences of High ISO. I frequently shoot landscapes at widest possible aperture in the late evening, early morning, especially if I am travelling somewhere and cannot bring the tripod with me. This is just one of the situations, where a combination of a uniform sharpness across the frame and light gathering capabilities are needed.
I am shooting a concert in a really dark rock club. I obviously need a fast shutter speed. I normally use 1/100 or 1/125. To maintain correct exposure with an F2.8 I need to use ISO 6400 or even 12800. At F1.8 I can use ISO 3200 to 6400. I normally underexpose and compensate for that in the post processing. I am already pushing the limits of K-3. For that kind of footage I need flexibility i.e. a zoom lens. 16-50 is an F2.8 lens which is already considered bulky by some users. It's performance wide open leaves to be desired, especially at the long end. I opt for Sigma 18-35 which is also an F1.8 lens. Optical qualities of this lens are outstanding, but they come at the price of size and weight (not a problem for me). Why would I want to have a portrait of the musician on stage which has much of the details and colours lost to High ISO and acceptably sharp only in the centre, leaving the other parts of body and instrument blurred ?
If you, as a user, have not encountered a situation where a big, heavy yet optically excellent lens will drastically improve your results, it does not mean that such situations do not exist. Do not get me wrong, I have nothing against compact lenses, but there are situations where I am ready to sacrifice the size for performance and I don't see that as a problem. A matter or preferences and necessity.
09-10-2015, 03:24 PM   #27
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I can see the situations where a faster zoom is very helpful, and also understand some users, particularly some professional shooters don't mind carrying big, heavy and expensive gear with them for the best IQ they can get.

But I still think most people don't need a super fast zoom lens that has corner to corner sharpness at largest aperture, which camera/lens makes are trying to make us believe we all need.
For example, when shooting concert in a really dark environment, I believe only the performers have light on them and the background is much much darker, usually. A fast lens has sharp center is good enough for that. corners are black or just have some light spots. We don't need good solution here.

same for shooting wide open for landscapes in low light: I guess most of these photos were taken at wide end, and in most case the upper corners are just sky with good color, and lower corners are dark ground. Most of these photos are good because of composing and color, not for its details in the corners.

Don't get me wrong, I think lenses that are sharp at largest aperture is useful and valuable, I just hope camera/lens makers don't forget the other side: sometime we need smaller lens even it is not optically perfect when wide-open.
09-10-2015, 03:33 PM   #28
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Lenses are getting bigger due to the demands of better sensors and the expectation from customers due to pixel peeping. If you want compact in the future stick to APS or smaller...
09-10-2015, 03:38 PM   #29
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QuoteOriginally posted by hks_kansei Quote
In short, companies realised people were buying SLRs for reasons other than the size, and probably figured it's not worth spending time making a camera compact if people dont care.

There's also likely a bit of marketing there, since many people (then and now) think bigger cameras = more professional.
Sorry, but people do care. I am continually reading about a sustained migration to smaller and / or lighter offerings as picture quality improves for smaller sensors and associated lenses. Apart from pixel peepers, top end enthusiasts and professionals there is only so much quality and versitilty needed. With a growing grey (older) market where weight is becoming more of a consideration plus a younger market that knows the quality that lightweight compacts and phones are now giving plus a growing acceptance of electronic viewfinders, I think that the (D)SLR will, in the long (perhaps even mid term)term, increasingly be looked on as a specialists tool (a bit like film medium format cameras) and not one for most amateurs unless it can match its competitors for size, weight etc. Only once that is done I think the rate of migration will start to slow.
09-10-2015, 04:05 PM   #30
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I have 90 lenses, but only two full frame lenses that have the same FL and f-stop opening.

The old one is my Super Takumar 35mm f2.0 and the newer one is an FA 35mm f2.0.

The new one is tiny the old one is huge.
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