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53

Yes. There is development in four areas: computer design, material science, features, and finally a category I'm going to call "not better just different". Computer Design Lens design has always been a mix of art and science. In the first part of the previous century, art was clearly primary (even for scientific lens designers). Now, lens design software ...


44

There are many characteristics which make better lenses better. The basic goal of a lens is to render an ideal replica of the framed scene, but because of the limitations of the real world, that's physically difficult. Lenses inevitably introduce optical artifacts not present in the scene itself. So, an important aspect is minimization of artifacts. Good ...


30

Theoretically one can do anything. It just takes more glass — and correspondingly, size, weight, and cost. A 300mm f/1.2 lens would need an apparent aperture of 250mm — which is almost 10 inches in diameter. And for extra complication, that needs to project an image circle which fits through the lens mount, which is probably around 2 inches. So that's a ...


27

A polarizer cuts out light — about one and a half to two stops, give or take. Additionally, one does not always want the effect. In wide angle shots, it can make skies look distinctively uneven. So, it makes sense to not include them by default. B+W and Hoya are good brands. It's worth spending a bit more a well-made one with good coatings.


27

Broadly speaking wide aperture lenses are easier to design the longer the focal length. The reason that you don't see any 400mm f/1.4 lenses is due to manufacturing difficulties, e.g. keeping dispersion low while producing elements of the size required for such apertures. It's worth restating that the designation f/1.4 means that the size of the aperture ...


27

There is no simple relationship between the physical length of the lens and its focal length. For example, a retrofocus wide angle is generally longer than its focal length, while a telephoto lens is shorter than its focal length. Inside a zoom, you have several lens groups that move independently. The focal length of the zoom depends on the relative ...


24

Pancake lens is a lens which is designed to be physically very thin and compact, relatively pocketable when combined with a slim body. Current pancakes have fixed focal length, from moderate wide to moderate telephoto, they're usually relatively slow for a prime lens (f2.8 and slower) although exceptions exist. Pancake lenses don't alter the image in any ...


22

It's now more common to control aperture through the camera. The mechanical aperture ring adds cost, mechanical complexity which can lead to equipment breaking, and it can be confusing to users (if it's set to something other than the smallest aperture many cameras will give a confusing error on a lot of modes). It also prevents Nikon from putting a seal ...


21

I think manufacturers list the number of elements it just so you know how much effort they put into a lens! There's no simple answer to whether more of fewer elements is preferable. More elements generally means greater correction for distortion, chromatic aberration etc. however this extra correction might be necessary due to the design or the performance ...


20

A range of focal lengths indicates a zoom lens. There are two major classes of lenses. Primes, or primary lenses, have a single focal length. They tend to be higher quality, as there can be fewer lens elements, and fewer moving element groups. One exception to this rule is super telephoto prime lenses, particularly faster lenses (f/2.8), which are some of ...


20

The wider a maximum aperture, the more prevalent optical aberrations will tend to be (given a "simple" lens.) Wide aperture lenses become increasingly difficult to manufacture at reasonable cost, as you have to put more effort into correcting those optical aberrations. Additional lens elements are necessary to mitigate chromatic aberration (which can become ...


19

Fundamentally a telephoto design is used to make a lens body shorter than it's focal length, for practical reasons [what if your 18-300 ultrazoom was actually 30cm long?], a retrofocus design is the opposite, and makes a lens longer  than it's focal length in order to leave space for the mirror on an SLR. You can tell if your lens is a retrofocus or ...


18

The Nikon mount is far older than the Canon one. Nikon have updated their old (OLD!) manual focus lens mount continously, adding new mechanical and electronic connections to it over the years to support new features. Canon started with a blank sheet of paper on their EOS mount in the late eighties and did not even try to maintain backwards compatibility. The ...


18

The short answer is because it is cheaper to manufacture such lenses. The longer the lens and the wider the aperture, the larger the optical elements in the lens - thus larger the expense to produce them. A lens like 70-200/2.8 must have a front optical element of 200mm/2.8=72mm, which is quite a chunk of glass. On the other hand, the 70-300/4-5.6 needs to ...


17

The reason for using a hood is to block light rays from elements outside of the actual frame (stray light) to enter into the lens and degrade the image quality (lowering contrast). Effectively, it "shades" the lens from these rays. Since a sensor is rectangular, valid light rays that fall on the corners arrive from angles larger than light rays that fall on ...


16

Given that you have explicitly disqualified fungus and dust inside the lens, then the answer is no. A lens will not "naturally" lose sharpness with age. Glass is glass. It is a fixed medium, and assuming a 100 year old lens is in good condition without any extraneous wear and tear like fungus, dust, or a strong enough jolt to misalign one of the internal ...


15

I'm reading your question is basically "what do they do in a more expensive lens to make it better?" There are a number of things. Quite a bit is simple mechanics: more expensive lenses get better quality assurance, so you have a lot better assurance that the individual lens you get actually performs as well as the design was intended to. Second, is pretty ...


14

You can't zoom to f/3.5 at 100mm on your lens, your lens will do at best f/5.6 at 105mm. You can however get a shallow DOF effect quite easily, for example by shooting at f/5.6 at 105mm, with your subject quite close (say 6ft) and you background say 10ft behind the subject. See this set of photos I took with a Nikon D70 (much older predecessor to the ...


14

Speaking from the world of amateur astronomy, there's quite a bit of development happening with lenses. Eyepieces and objectives are all using new, exotic glass and computing resources to design well-corrected refractive devices. New glass mixes don't come along very often and the proper effort to better mate the shapes and characteristics still requires ...


14

I'd expect that virtually all lens design and analysis these days is done with optical design software like Zemax or Code V. Unfortunately, these products are priced for people and companies that make a (substantial) living working in the field. However, I have come across an optical design tool for Windows called OSLO that offers a free version with ...


14

You ask whether a lens can lose sharpness over time, but then go on to say: Please note, I am not talking about general wear and tear, or dust inside the lenses, nor am I talking about fungus in the lens. Which are exactly the reasons lenses lose sharpness over time. So the answer is no - once you exclude all the factors which causes lenses to lose ...


14

It just means you push / pull the front of the lens to zoom, rather than twisting a zoom ring. The mechanism is simpler to design/manufacturer but is less precise and has a reputation for sucking dust into the lens due to the large change in volume when zooming.


13

Minimum focusing distance is useful to know, but it is only indirectly related to how much the lens will magnify an image. More to the point is the maximum magnification. This figure is often available (see here for an example) and is typically reported in two ways: in a form like "0.2x", which means an object can be reproduced at 0.2 times life size on ...


13

This is called Minimum Focusing Distance. It is measured from the film/sensor plane. Usually it's printed on the lens ( next to a flower icon ).


13

Lenses faster than f/1.0 exist but the prices skyrocket once you get below 1.0 as you're close to the limit of how far glass can actually bend incoming light! Tolerances become very tight and manufacture is expensive. The limit is around f/0.5 for glass (which has a refractive index of 1.5) to go faster you'd need to use a more exotic material such as quartz ...



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