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by Russell McMahon

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2
votes
4answers
123 views

Should lenses of equal quality for smaller sensors be cheaper?

In theory do we expect lenses of identical specs and quality to be cheaper when designed for smaller sensors? My expectation is that the answer is yes, because all of the things that lenses struggle ...
2
votes
3answers
185 views

Variable focal length for macro lenses?

True macro lenses come in fixed focal length. Are there any macro lensens which have variable focal lengths? And please explain why yes or why not?
3
votes
3answers
188 views

Differences between canon 17-85mm and 18-55mm

I was given a 450d with a canon 17-85mm lens, it has USM and image stabilzing. It has always seemed okay to me but after a few years i have decided to upgrade to the 700d, which has now come with a ...
0
votes
2answers
194 views

What kind of lens are used in mobile phones?

Usually what kind of lens are used in mobile phones. I mean of the types similar to convex, concave etc.. Are they fixed focal length usually? How do we get the focal length of camera from digital ...
2
votes
4answers
2k views

What is the difference between Nikkor D type and G type lenses?

I recently bought a Nikon D5100. And along with this camera, I got the AF-S DX NIKKOR 18-55mm f/3.5-5.6G VR lens as kit. It's "G" type lens, right? One of my friend suggested to buy a 50mm f/1.8D ...
5
votes
1answer
785 views

What makes the Zeiss Otus 1.4/55 so special?

The new Zeiss Otus 55mm f/1.4 is nearly $4000. With faster lenses from Canon (50mm f/1.2L) with autofocus, why is the zeiss lens more than twice that of the Canon counterpart?
4
votes
1answer
451 views

Why is anamorphic bokeh oval shaped?

I understand that an anamorphic lens "stretches" an image when it is recorded, but when it's played back, it's "un-stretched" so that it looks normal. But with images shot with anamorphic lenses, ...
3
votes
3answers
805 views

What is the relationship between “macro” and “telephoto” lenses? [duplicate]

Can anyone explain the difference between "macro" and "telephoto"? I know that a macro lens will give you a magnification of 1:1 but how does it differ from a telephoto lens?
7
votes
2answers
928 views

Which Zeiss lenses are actually made in Germany?

Recently, I used a Zeiss Makro-Planar T* 2/100 ZE only to find a big "Made in Japan" marking on it. Which of their lenses are made in Germany, and does it matter if it's made there vs. Japan?
12
votes
6answers
728 views

What lens characteristics contribute to attractive lens flare?

Some lenses give really harsh and unwanted flares. Some gives beautiful flares that add depth to an image. What's the science behind this?
4
votes
2answers
330 views

What are the theoretical minimum and maximum apertures?

Is there such a thing as a maximum aperture that a lens can be open to? What about a minimum aperture that it can be closed to? Do these concepts even make any sense? Is there a lens with the ...
2
votes
3answers
311 views

Are polarizing filters as useful on normal lenses as they are on wide-angle lenses?

I have seen people using Polarizing filters on many wide angle lenses. Is it worth using a Polarizing Filter on a 40mm 2.8f STM Pancake lens or any other prime lens?
2
votes
1answer
145 views

Canon 40mm STM - The focus cannot be adjusted in manual mode

I bought a new Canon 40mm STM lens and in the Lens Manual it says The focus cannot be adjusted in manual mode. Does it mean that its harmful to rotate the focus ring when the focusing mode is ...
5
votes
2answers
278 views

Why aren't more lenses white?

So high end Canon lenses are white. This is to reduce heat, correct? If so why is this something that only appears in really high end Canon lenses. I wouldn't think that painting a lens white ...
2
votes
4answers
746 views

When should I turn off image stabilization? [duplicate]

I've read a bunch of the questions here about image stabilization, but I don't see any concrete examples/proof or references with regards to the benefits of turning off image stabilization. I've got ...
8
votes
3answers
594 views

Why are Zeiss lenses heavier and larger for Canon EF than Nikon F mounts?

We recently acquired specifications for all DSLR lenses by Carl Zeiss and almost always the Canon EF-mount version is larger and heavier than the Nikon F-mount version. The difference ranges from ...
5
votes
1answer
375 views

Why are so many kit-lenses parfocal if it's an expensive feature?

According to this answer, parfocal lenses (lenses that can zoom in/out without losing focus) are relatively rare and more expensive. However, the original poster's kit-lens is parfocal. ...
2
votes
2answers
891 views

Why are large aperture lenses so expensive? [duplicate]

Why are lenses with very large apertures so expensive? For example, generally speaking, there is a significant price difference between a f/1.8, f/1.4 and f/1.2 lens of the same focal length. Doesn't ...
5
votes
0answers
48 views

How does lens design affect the richness of color reproduction? [duplicate]

Comparing a kit zoom lens to a faster, 20-year-old prime it seems like the old lens produces richer, warmer color. I've noticed the same kind of comparisons elsewhere. What is the lens actually doing? ...
11
votes
6answers
1k views

Do lenses lose sharpness when they age?

I was reading this answer where it mentions, "..it's a lens that can lose sharpness as it ages.." and was wondering if this is true and if yes, true for all lenses. Reasons as to why this happens and ...
1
vote
1answer
130 views

Is the size of the rear opening of a lens related to image quality?

I purchased a Sony NEX F3, and it came with a 16mm lens and a 18-55mm lens. It seems to me that the 18-55mm lens produces better picture. Does the bigger lens opening in the 18-55mm lens produce ...
2
votes
3answers
417 views

What are the difficulties with making a 10mm-300mm zoom lens?

I'd like to have a comprehensive explanation why such a lens doesn't make 'sense', whether economically, technically, ergonomically, etc. Please support each reason with some details so I can learn ...
19
votes
3answers
1k views

Is it physically possible to build a long zoom (17-300 mm for example) at an aperture value of around 1.4 or 1.2?

I'm curious if the physics allow a company to build such a lens of course with good IQ, minimal color aberration, maximum sharpness, and little to none lens vignetting or edge softness
4
votes
2answers
648 views

Are all DSLR lenses made of glass?

This question is about lenses to "big" DSLRs, not system or compact cameras with interchangeable lens. Are all lenses made of glass in DSLR? And if not, is there a notable difference between: kit ...
3
votes
2answers
2k views

What does “Flat Field Focus” mean?

Looking at lenses, specifically sigma macro lenses, I noticed that it had a ""Flat Field" front lens element". What does this mean? And how is it different to the norm?
1
vote
1answer
1k views

What are screw drive lenses?

Are lenses known as screw drivers actually available?If so what are their features and why are they called so.Name some of the lens and their manufactures.
9
votes
3answers
644 views

Why are 50mm Lenses Cheaper?

There is no doubt that 50mm lenses, if all other variables are held equal, will beat any other lens when it comes to value for price (lower f/number). I want to know why. Possible theories I have ...
4
votes
1answer
240 views

What is meant by 'centering quality'?

I'm reading lens reviews and I have encountered the term 'centering quality' a few times (e.g. http://www.photozone.de/sony_nex/720-sony50f18nex?start=1). What does this term mean? What are the ...
12
votes
1answer
590 views

How does a macro lens focus so close?

How does a macro lens focus so closely and how is the system different to that of a non-macro lens?
13
votes
2answers
1k views

Retrofocus lens? What's that?

I saw that in Why do some people prefer 50mm to 35mm prime lenses? , in @MattGrum's answer: ... The 50mm is a simpler design compared to the retrofocus 35mm ... What's retrofocus?
-1
votes
1answer
346 views

Below which focal length are lenses considered to be wide angle?

Focal length is the only factor that decides whether a lens is described as being normal or wide angle. Below which focal length are lenses considered to be wide angle? Is this focal length the same ...
22
votes
2answers
2k views

What characteristics make a lens good or bad?

When reading lens reviews on the Internet, I often find subjective statements about the image quality that a lens produces, such as "good contrast" or "sharp". The problem is that I don't think I am ...
7
votes
3answers
809 views

What are ED elements?

I find that some lenses are indicated with the letters "ED", referring to some special type of lens element. What are ED elements, and what advantages do they bring? Note that this question isn't ...
1
vote
3answers
261 views

Do lenses need to be made with more precision for Hasselblad's 60MPix camera?

One of Hasselblad's cameras has a Double-Full-Frame sensor. Does that mean that the lenses needed for it are incredibly complex to build (to have a sharp, high quality, abberation free image on the ...
11
votes
2answers
2k views

What is the benefit of an internal focus lens?

The "IF" in Pentax DA★ 200mm f/2.8 ED (IF) SDM stands for "Internal Focus". I know what this means: the lens doesn't change in size as I focus. (And it's true; it doesn't.) What's the point of this, ...
6
votes
5answers
1k views

What about lens construction influences bokeh?

I can understand how certain elements of a lens can correct an aberrations or make it sharper - but specifically, how do lens manufacturers influence the bokeh - the quality of the blur? There's a ...
5
votes
2answers
488 views

Why are there no fast APS-C zooms beyond 55mm?

I am looking to add a longer lens to my current zoom (a Tamron 17-50) for my Nikon D300 (but I believe this question is relevant across aps-c lens manufacturers). There is just one currently in ...
8
votes
3answers
428 views

What is the limiting factor in lens construction when it comes to f-stop values?

This widely praised Nikon 105mm macro lens has a maximum f-stop value of 2.8. I've held it in my hands, it's a big lens. Meanwhile, this 50mm Nikon lens can go up to f/1.2, despite being 25% cheaper ...
4
votes
1answer
2k views

How to read a lens spot diagram?

How to read such a lens spot diagram?
24
votes
3answers
2k views

When you zoom in with a lens on an SLR why does the lens go in then out?

I guess this is more a question of optics than photography but I just got an SLR with a basic 18-55 lens. I noticed that when going from 18 to 55 or 55 to 18 the lens physically comes back in and ...
19
votes
3answers
2k views

Why do wide angle prime lenses have relatively small apertures?

I've noticed that many of the wide angle prime lenses (at least for Canon) have somewhat smaller apertures than their normal or telephoto counterparts. E.g. the regular Canon 24mm prime is f/2.8 while ...
50
votes
5answers
1k views

Is there development in the world of lenses?

Now, I'm not an expert, so if this post makes you laugh, you're welcome. Still, as far as I know there are basically two components that determine the potential quality of a camera's photos: Sensor ...
26
votes
3answers
11k views

What does the number of elements and groups in a lens mean?

All lens specifications include a statement of how many elements the lens contains, and in how many groups, for example: Nikon AF-S VR Zoom-NIKKOR 70-300 mm 1:4,5-5,6G: 17 elements in 12 groups (two ...
13
votes
2answers
2k views

Why do zoom lenses and compact cameras have varied maximum aperture across the zoom range?

Why does a camera's maximum (allowed) aperture get smaller when you increase its zoom?
5
votes
2answers
792 views

What's the base f-stop when counting an ideal f-stop for lens?

I've read a lot around this site that an ideal quality of the lens is achieved when using f-stop roughly 2 stops slower than the fastest value of the lens. Firstly, I'm not exactly sure what "2 ...
14
votes
9answers
2k views

Are all kit lenses poor? (And if so, why?)

Kerri Shotts says (emphasis mine): Also, if you already have great glass, there is little reason to get more (unless you need it for a certain reason). E.g., if you have a 70-200 f/4, don't rush ...
7
votes
2answers
3k views

What are the advantages of a lens having a fixed maximum aperture?

What are the advantages of a lens having a Fixed Maximum Aperture? Previous answers have indicated that "pros tend to want constant apertures in zoom lenses". While in general lenses with a fixed ...
11
votes
3answers
11k views

How does a spherical lens differ from an aspherical lens?

Many lenses (like the Pentax DA 15mm f/4 Limited, or the Nikon AF-S 35mm f/1.4G) are described as having "aspherical lens elements". Does this mean that regular lenses are spherical lenses? What's the ...
7
votes
4answers
472 views

Were lenses for film designed to focus different colors at different depths, and what does that mean for digital?

I was reading the book Adobe Photoshop CS5 for Photographers: The Ultimate Workshop by Martin Evening & Jeff Schewe (Focal Press. 2011) and read this paragraph about film lenses and DSLRs: … ...
10
votes
1answer
409 views

Can anyone identify this lens?

I read once, in a book, about a lens that was an "inverse fisheye". Basically a hemispherical mirror mounted at one end of a glass tube. I can't remember what it was called, nor can I find any ...