Shadowy Daisy

Shadowy Daisy
by damned-truths

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21

The twisting motions you apply to focus and zoom rings are converted to forward and backward movement by helical threads and tracks cut into the barrels inside the lens. This photo shows an example of the threads that do the focusing duties in a partially-disassembled Nikkor prime: Note the tracks cut into the inner barrel and the metal rails in the outer ...


20

There have been stories for years of mail order (and now online) retailers that pull a scam that goes something like this: You respond to an ad for an insanely low price on a lens. They accept your order and bill your credit card. A few days later they contact you to say the exact lens is out of stock, but they will sell you the upgraded version for only $$...


18

The focal length/speed is only one factor in the retail price of the lens. Other goodies like construction (metal vs. plastic), image stabilization (and other automation in general) and vintage can easily add (or remove) a zero. The two lenses in the question are very different products. The 2.8G is a newer product and lacks an aperture ring - the diaphragm ...


9

A simple lens (like the lens in a pair of glasses) forms an image at a distance of f behind the lens for an object at infinity (where f is the focal length). The same lens will form an image at 2f behind the lens for an object 2f in front of the lens. This will achieve 1:1 magnification, i.e. the definition of macro. Thus any single element lens is a macro ...


7

The "elements" and the "blades" are two completely different things. An "element" is a single piece of glass in the lens. Most of what's shown on the diagram are the lens elements. Some elements are colored pink, to indicate that their shape is aspherical. Other elements are colored blue, to indicate that they are made of a special type of glass. Others are ...


5

For the most part, there is no way to predetermine the quality of a lens's bokeh simply by looking at its construction, and even if you look at sample images you may be flummoxed, because the quality of the bokeh can change with the aperture setting as well as with the subject and background distances. For example, the whole "number of blades" thing where ...


5

The AF-S 28-70/2.8D f/2.8 has been out of production since 2007. It's an older version of the lens that's more or less be replaced by the newer 24-70. Nearly every lens that's been superseded tends to cost less than newer replacement models, especially if found used (when it was brand new in 2002, the 28-70/2.8 cost $1400, which if you cost adjust, comes in ...


5

AFAIK the 28-70 isn't being produced anymore since 2008-ish? So if you are buying a new one today chances are it's been in somebody's warehouse for at least 6 years burning a hole in their pocket. The new version also allegedly boasts a better nano-coating on the front element. Not sure what else might be making up for the price difference.


5

According to a related discussion on dpreview: A lens can be made physically shorter than its focal length by the use of additional lens elements called a telephoto group. According to the Wikipedia page for Telephoto lens: The basic construction of a telephoto lens consists of front lens elements that, as a group, have a positive focus. The focal ...


5

It is not just the barrels of high quality lenses. The light boxes of the top tier cameras from both Canon and Nikon are now made of engineering grade composites (i.e. plastic). This includes models such as the 1D X and D4. Why? Because those materials can be engineered to be stronger, lighter, and less sensitive to expansion/contraction with changes in ...


5

Never heard of that. While disproving it 100% is impossible, I would be extremely doubtful if Canon make lesser L-lenses. Most likely you are dealing with a shady vendor and you should avoid them. The difference between local and imported versions is usually in the scope of the warranty and documentation language. Know that an import version is local ...


4

The edge of the blade may reflect light. Such internal reflection is certainly to small to produce visible flare but may introduce some kind of blur. Rounding the blades will reduces this parasit reflection. As these reflection may possibly show-up in the bockeh it may be slightly improved. Diffraction will be not be directly affected. I don't know if ...


2

Part of it is due to the grease on the moving parts, yes. On my Canon 70-200mm f/2.8L, I can feel the notches in the gearing. I think plastic parts have more "give" and also wear down slightly to give a smoother feel.


2

Nikon made two versions of the old 70-300. One had a plastic mount, the other metal. However these were not produced at the same time - one version replaced the other at some point. I have never, ever heard of a manufacturer offering a metal mount as an upgradeable option. Definitely smells like scam.


1

Arrangement of optical elements, level of correction for abberations such as Secondary Color / Chromatic Abberation and Spherical Abberation, shape of the aperture diaphram, a narrower-than-ideal lens barrel which partially occludes the exit pupil, as inkista says your chosen aperture and shooting distance. There are any number of factors which determine the ...


1

I think it's folly to select a lens based on sharpness rather than focal length. First pick a focal length that works for you. Then find a lens with that focal length. The other way is just putting the cart in a different field from the horse, never mind in front of it. Likewise even after you select a focal length sharpness is not even the second ...


1

Generally, if you're talking about across-the-frame, has the higher line on MTF charts, test-chart type sharpness, then telephotos and primes will tend to beat out wider lenses and zooms--particularly in the corners. That doesn't mean you can't find individual cases where that doesn't hold true (e.g., Canon's EF 70-200 f/2.8L IS USM II can pretty much hold ...


1

You surely need to look at some actual lens tests for the specific lenses of interest, like http://www.photozone.de/ Not sure it is a meaningful question, for example, a telephoto magnifies the subject, and makes detail much more obvious (85mm shows 3.5x larger than 24mm), when it may be too tiny to see in a wide angle. But it is not the same view, at ...


1

What is difficult is to build a zoom that can maintain a constant aperture as low as 2.8 along the entire zoom range. Those lens has the characteristics that you can shoot at 70mm or 200mm at f/2.8. To be able to do this make a lens expensive. Check for example cheaper lens from Nikon. You will see that changing focal lens (zooming) will change the minimum ...


1

Making a lens shorter than a simple lens is exactly what the term telephoto means. Telephoto groupings basically act kind of like a magnifying glass, making the field of view close faster than would happen with a simple lens system. Traditional telephoto lenses still required a fair bit of space and lots of lenses to operate, but newer things like ...


1

I doubt there is much you can personally do about it without risking the warranty on the lens. If your other lenses from the same manufacturer don't have that problem, I'd suggest calling up their customer service and asking about it. Chances are they can help you more than we can in terms of if this is normal and what the best way to get it serviced or ...


1

The "import" you are referring to is also termed "Grey Market". The products marked as "USA" and "Import" are most often identical. In the case of Canon "L" series lenses both will be "Made in Japan" If not then there is a problem: "On the back of Canon lenses is a six-digit code, which indicates where the lens was manufactured and when.Example of a ...



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