It's a bird

by Vian Esterhuizen

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11

It's most likely a commercial decision based upon cost and performance. Let's take your prime at f/1.2 example. Canon makes a number of 50mm lenses. The EF 50mm f/1.8 II is about $100. It has 6 elements in 5 groups, 5 aperture blades and a plastic barrel. It takes a 52mm filter and weighs 130g. The EF 50mm f/1.4 USM is about $350. It has 7 elements in 6 ...


8

The 1200mm lens you cite is something of an aberration, since it's built-to-order, not a general-market lens — see Why are some big telephoto lenses so expensive compared to telescopes? and Why are some lenses so expensive?. But the general rule holds true: lenses for DSLRs and most mirrorless cameras are gigantic compared to those in superzoom cameras. ...


6

The 50mm f/2.5 Compact Macro lens is not a "true" macro lens. It does not magnify 1:1 (i.e., 1:1 means that the size of the image on the sensor is the same as the actual size of the object); it only magnifies 1:2.5. So, it doesn't let you get as close as a true macro lens like the EF 100mm f/2.8L IS USM Macro. In addition, the design's a lot older. It was ...


5

The lenses in mobile phones are typically made from molded plastic elements rather than ground glass elements, and these are in optically inferior to glass in general (higher dispersion, lower refractive indices). However molded elements have a big advantage in that they can be made into absolutely any shape, whereas glass is very difficult to grind into ...


4

Not including a DOF scale can make the lens barrel smaller and allows the use of different focusing mechanisms such as linear motors instead of the traditional helicoid (which is where the DOF scale used to be printed). It is less important to have the scale as you can get instant feedback on what is and isn't in focus with a digital camera, and differences ...


4

You want to contact Sigma and find out if they'll still rechip the lens. Given the age of the lens and the fact that you're not the original owner, they may not be able to rechip it, or might charge for it, but it's worth a shot--the worst they can do is say no. Third party lens makers typically reverse engineer the electronic communication between the ...


4

It reminds me of one of my FD mount lenses where you pull\push to adjust focal length, rotate to adjust focus, and then there is the aperture ring for...well adjusting the aperture. I don't quite understand what you mean when you say 'swipe' through the aperture settings. It is a variable aperture so, when it is at 205mm it has an aperture of 4.8 as ...


4

No. There are several problems here. This lens looks a lot like the Senko 50mm f/0.95, i.e., it is a C-mount lens for 1" format video. This lens vignettes even on micro four-thirds (2x crop). There's no way the image circle will cover an APS-C or full-frame camera, and the registration distance is much much smaller than that of Nikon F. In order to get the ...


3

No, because the register (distance from the mounting flange of the lens to the sensor plane) is quite short.


3

This is a swirl-y bokeh, an often desirable flaw commonly found in some vintage lenses and lenses. There are some lenses known for this this characteristic, most notably the soviet made Zenit Helios 40-2 85mm F1.5 which is still being manufactured. You can find this lens on ebay for ~$600. If you are adventures enough you can convert the Cyclop night vision ...


3

This photo is taken with a petzval lens which corrects all aberrations decently except for, well, petzval aka field curvature. Because the edges are in focus at a further distance, the blur is smaller there. Because the lens is fairly highly vignetted, the lens also effectively has a larger f number towards the edges, again reducing the blur. The result ...


3

The main difference between a DSLR and a mobile phone camera is not the lens, but the sensor. The sensor in a typical consumer DSLR is around about 24 x 16 mm, but that in a typical smartphone (the iPhone 6) is around 4.8 x 3.6 mm - or in other words, the DSLR sensor is around 22 times larger than that in a smartphone. As Matt has answered, the lenses in a ...


3

There's an obvious difference between "good" and "great" glass at 20mp, surely it's even more obvious at 50mp. The problem is regarding resolution as some binary thing—it resolves or it doesn't. The reality is that contrast at a given resolution is what really matters. The point at which it goes from 10% MTF* to 0% MTF—extinction resolution or maximum ...


3

First, a word about what depth-of-field is and is not: In a way, depth-of-field is an illusion. There is only one plane of focus. Everything in front of or behind the point of focus is out of focus to one degree or another. What we call DoF is the area where things look, to our eyes, like they are in focus. This is based on the ability of the ...


2

I think there are two very basic reasons why DoF scales are no longer put on lenses: zoom and autofocus. Zoom lenses would have to have dynamic DoF scales that would change for whatever focal length is set on the lens. While maybe this could be done with, say, eink or lcd displays, it's something that's never really been put on lenses before. But the more ...


2

The Canon lens has focal length of 1200mm and maximum aperture of f/5.6, whereas the Nikon lens has a focal length (at the long end) of 357mm and maximum aperture of f/6.5. So the Canon lens is longer and has a faster aperture, which requires a larger front element, 214mm vs 55mm. This is a substantial difference and makes the Canon larger, heavier and more ...


2

The problem you are experiencing is due to the way third party lens makers usually design their lenses to be compatible with cameras made by someone else: they reverse engineer them to work on the existing offerings of the camera maker at the time they design the lens. If the manufacturer later updates their system the original manufacturers have access to ...


1

The image brightness will be the same. The entrance pupil size does not matter for image brightness - what matters is only the F number (or more accurately, T number which is equal to the true f number divided by the square root of the transmission.) In a bit more detail: If you fix your field of view at 100deg and vary the sensor size, the focal length ...


1

Another difference is that the 50mm isn't a true macro lens since it doesn't let you reach a 1:1 scale. The 100mm can also be used as a short telephoto but otherwise, you might be better off getting a Canon EF-s 60mm f2.8.


1

Sigma 18-35mm f/1.8 DC HSM A Is a lens that I do not own. I thought that it fits your requirements rather well, hence I suggest looking into it. It is wide angle and very fast. How fast are your subjects relative to you? If you are on the same boat, you should be fine. I mention that because sometimes Sigma lenses have trouble with autofocus. You should ...


1

Aperture is a bit of a misnomer; a hold-over from simpler times and simpler lens designs. What matters is the entrance pupil, or the apparent size of the aperture as viewed through the front (business end) of the lens. With a simple lens design (a double-Gauss or Tessar, for instance), the physical aperture and the entrance pupil are approximately the same ...


1

You should create your own custom profiles for the inverted lenses.


1

From what I've researched the only real difference is how close you have to be to your object to take the pictures. It's true that the 100mm lens lets you shoot from twice the distance as the 50mm lens and get a similar composition. That's because the angle of view for a 50mm lens is twice that of a 100mm lens. But the composition won't be exactly the ...


1

I have that camera. My top lens choice for that camera is the pancake 20mm. It's the only lens that I always take with me and spends most time on the camera. It's such a fast lens, so sharp, and I've not felt limited by the focal length very much. One example of a situation where this focal length is limiting is when visiting a zoo, you can't get in ...


1

It sounds like you might have damaged the 18-55 lens by twisting on the "wide angle" lens when your 18-55mm lens was set to autofocus. The force of twisting the screw-on "wide angle' adapter onto your lens with the focus motor connected may have damaged your lens' focus motor to the point it can no longer focus on distant objects when the wide angle lens is ...


1

Your lens is damaged. One of your images (shown below) exhibits an abnormal amount of spherical aberration. It is not the kind of softness you would get when out of focus. Also, notice that the bricks on the left side are significantly softer than the right side, which indicates decentering. Both of these indicate that one or more lens elements have been ...


1

Smaller format lenses are eased by having lower maximum image heights and smaller fields of view at the same focal length. Each aberration has explicit field dependencies which describe the rate at which they grow. For the following equations, y is the ray height at the lens and h is image height. Spherical Aberration varies by y3. Coma varies by y2h. ...


1

For Canon, the EF-S was designed to precicely scale down the geometry of EF by the crop factor. SO, the EF-S 17-55 f/2.8 gets its design kick-started by shrinking down the existing design for ... well, they don't make a EF 27-88, so not the clearest example. But I have read that some designs are scaled down. IAC, the rather large 17-55 is 1.6× smaller ...


1

Remember, Nikon 70-300 (1.5x costlier than the 55-300 option) is also a FX lens and hence it can be treated as future investment. Tomorrow, when you invest in a FX body like D750 or D810, you can easily use 70-300 but not the 55-300 or 55-200 I have both the Nikon versions, the 55-200 and 70-300, and so can stress upon the fact that VR is a must when it ...


1

You will get this message if the lens barrel is locked; push the lock/unlock button on the lens. Then extend the lens a bit, and that might take care of the problem---at least it did for me!



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