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Of and relating to the specifics of lens construction and manufacture.

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5
votes
2answers
825 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 ...
8
votes
1answer
298 views

How are ‘stills’ lenses calibrated differently to ‘motion picture’ lenses?

I was watching this promo video about the new Sony PMW-F3 and one of the DOPs mentioned that stills and motion picture lenses are calibrated differently. This is around the 4 minute mark in the video. ...
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
3answers
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 ...
23
votes
5answers
3k views

What is special about lenses with f-number < 1?

Talking about fast lenses, Wikipedia mentions Nikon TV-Nikkor 35mm f/0.9-Fastest Nikon lens ever made Why don't, for example, f/0.5 lenses exist? Is there some special construction that comes ...
7
votes
3answers
668 views

Fast telephoto primes for APS-C mounts — would they make any sense?

I can see the benefit of designing and manufacturing a wide-angle lens specifically for APS-C sized sensors instead of full-frame sensors: you will get smaller, lighter, and cheaper lenses. But is it ...
12
votes
3answers
14k 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
479 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: … ...
2
votes
2answers
86 views

Resources for learning about digital cameras technical design?

I would like to learn more about the design of digital cameras in general, and DSLR in particular, from optics to sensors to mounts. Do you know any up-to-date resources (other than Wikipedia) where ...
2
votes
1answer
438 views

Relay lens for beam splitter

I have the setup that is shown in this figure. The view is from the top. I have a beam splitter which splits the light that is collected from a SLR lens. To be able to focus the light I have a ...
10
votes
1answer
418 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 ...
19
votes
4answers
10k views

Why is the aperture ring removed from new Nikon lenses?

Maybe I'm wrong, but I notice that Nikon's newer lenses don't have an aperture ring. For example, an older AF 35 mm f/2D is now replaced by AF-S DX 35 mm f/1.8G, or AF 50 mm f/1.8D is replaced by a ...
14
votes
5answers
4k views

What's the difference between the Canon and Nikon lenses mounts?

I was wondering what, if any, are the technical differences between the two mounting systems. Does one auto focus faster? Can one hold more weight? Things along those lines that make them different. ...
31
votes
5answers
5k views

How do constant aperture lenses work?

Cheaper zoom lenses usually are faster at the wide end and slower at the long end (for example, the $150 Canon EF-S 18-55mm f/3.5-5.6). More expensive constant-aperture zoom lenses have the same ...
11
votes
3answers
985 views

What effect does the lens hood have on pictures and how does its shape impact that? [duplicate]

I have a Sigma 50mm lens f1.4 and it has a lens hood that has a sine wave shape going around the perimeter of the lens. I imagine this particular shape is useful for getting a particular effect and ...
12
votes
8answers
3k views

Will using a lens at max aperture (“wide open”) result in poor images?

I’m looking to add a second lens to my kit lens I got with my Nikon d7000. I have read several reviews on both the 35 and 50 mm lenses made by Nikon in particular that said using either lens at the ...
7
votes
7answers
1k views

How come there are no 24-70mm f/2.8 lenses with image stabilization?

There definitely aren't any Canon or Nikon lenses. I also have not seen any third party lenses. I can think of two reasons for this: There is some technical limitation (which I tend to doubt since ...
12
votes
4answers
899 views

How close can a lens focus?

From my understanding, if you want to do some macro photography it is better to have a lens that can focus when it is really close to the subject. Sometimes people buy extension tubes to help them ...
-5
votes
5answers
4k views

How can I get bokeh with an aperture of 3.5 as my max?

I am trying to get DOF portraits of my daughter with my Nikon d7000, as per my previous post. I have zoomed in to 100mm or so and tried to get a large aperture but as I zoom, the camera decreases f# ...
5
votes
7answers
6k views

Does the Nikkor 50mm f/1.4g perform better than the f/1.8d?

Looking into these two lenses, I'm getting the impression that for my Nikon D-90 with DX camera sensor that the f/1.8d would waste light that is cropped by the sensor whereas the f/1.4g would not as ...
13
votes
5answers
554 views

Why don't today's lenses come with a polarizer by default?

As I am now looking for a decent polarizer for my 18-105mm and 50mm (Nikon D80) I realized how important they are for outdoor photography. So why aren't they directly hard-mounted on every modern ...
11
votes
4answers
2k views

Lens “family” names - what do they mean and should I care?

Some lens manufacturers have special names for their lens designs/families. Just to name a few: Leica - Summar/Summarit/Summilux, Elmar/Elmarit, Noctilux Carl Zeiss - Planar, Tessar, Sonnar, ...
27
votes
2answers
3k views

What is a pancake lens?

I've read about a "pancake lens" but don't really understand what that means. What the pros and cons of having a pancake vs. another type of lens? I'm thinking of getting a Panasonic Lumix DMC-GF1 ...
21
votes
0answers
574 views

Is Image Stabilization better in the lens or the body? [duplicate]

Possible Duplicate: What is the difference between in-lens image stabilizing and in-sensor image stabilizing? Some DSLR manufacturers have image stabilization (IS) in the body of their ...
12
votes
4answers
4k views

How can a lens like a 18-55mm have more than one focal length?

How can a lens have a range of focal lengths? Shouldn't it be a single number? Isn't focal length supposed to be fixed for a lens of a particular shape and geometry? What am I missing? How many ...