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A photographic lens is used to focus the light onto film or a digital sensor. Many cameras have interchangeable lens systems, allowing the photographer to choose the type of lens to use.

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46
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5answers
10k views

What is “angle of view” in photography?

I read on the Lens Buying Guide @ neocamera: Focal-length determines the angle-of-view seen through a lens for a given sensor-size. With a full-frame sensor a lens gives the same angle-of-view ...
65
votes
10answers
3k views

How much do lens lineups vary across DSLR platforms?

I was reading this question and recalled how often I hear the advice "choose your lenses and then choose the body that matches" in the context of deciding on a camera platform ...
34
votes
5answers
84k views

How do I convert lens focal length (mm) to x-times optical zoom?

What is the rule to convert the 'mm' notation to the 'optical zoom' notation? I searched a bit and found this one: optical zoom = maximum focal length / minimum focal length For example a 18-55mm ...
120
votes
3answers
39k views

What do all those cryptic number and letter codes in a lens name mean?

Then looking at a lens name there is a lot of acronyms in the name describing it's features (often specific to the manufacturer). Examples, Nikon: Nikon AF-S DX 16-85mm VR f/3.5-5.6G IF-ED Nikon ...
17
votes
6answers
2k views

Can a smaller sensor's “crop factor” be used to calculate the exact increase in depth of field?

If APS-C and similar crop-sensor digital cameras have a focal length multiplying effect such that a 50mm lens has an apparent focal length closer to the field of view of an 80mm on a full frame ...
33
votes
10answers
8k views

Which focal-length lens is usually used for portrait photography, and why?

What focal length or range of focal lengths are usually used for portraits? What is used by professionals? Why would one select a certain focal length? What are the advantages and disadvantages of ...
28
votes
12answers
7k views

Should I buy a camera with kit lens, or body plus lens separately?

I am planning to buy a DSLR soon. Before I zero in on the model, I want to know whether it is advisable to buy a kit (body + 18-55 lens) or not? OR should I go for the camera-body and the lens ...
24
votes
15answers
14k views

What lenses would best comprise a travel photography kit?

On a crop sensor camera, e.g. Canon EOS 7D, what would be the best kit to travel with around Europe for a few weeks? My shooting style will focus on landscape, architecture, and general travel shots ...
27
votes
4answers
11k views

What is a macro lens?

I've read a few threads on here that mention some elementary descriptions of macro lenses and found some marketing fluff in the box for my Canon about them as well, but being a complete novice I was ...
23
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 ...
34
votes
9answers
7k views

Why do people recommend 50mm or other prime lenses as starting lenses for learning photography?

I've seen quite a few people recommend the 50mm prime lenses, in particular the sub-$100 50mm/f1.8, as a starting lens for photographers (especially because they're likely to be using cameras with ...
47
votes
10answers
3k views

Is it lenses which make your photographs, not camera bodies?

I read somewhere on this site itself that you should spend more on your lenses and less on your camera bodies. Is it a myth or a fact that mostly it is the lenses which make your photographs not the ...
56
votes
10answers
5k views

Are there any downsides to using a good-quality UV filter?

Are there any real downsides to using a UV filter? I know that a poor quality UV filter can effect image quality ... but, assuming I use a good quality UV filter, will that actually be an issue? Is ...
25
votes
4answers
4k views

How do you find out the “sweet spot” of a lens?

I've tried googling this, but have never found a satisfactory answer. I've heard the term "sweet spot" thrown around by some photographers to mean the f-stop of a lens which results in the highest ...
11
votes
7answers
1k views

Lens upgrade paths (sub $1000) for the EF-S 18-55mm IS kit lens for Canon APS-C cameras

This is somewhat a follow-up to my earlier question on the limitations of the kit lens. I have browsed through quite a lot of sites including this one for user opinions & reviews of different ...
26
votes
3answers
3k views

How can I test a new lens to make sure it is operating correctly?

How can I test a new lens to make sure it is operating correctly? I found two similar questions with answers specific to things such as sharpness and focus, but I want to cover any and all possible ...
50
votes
6answers
7k views

Why are wide-angle lenses so much more expensive?

What is it about wide-angle lenses that makes them so much more expensive than an equivalent-quality tele or prime lens? Take the Canon EF-S 10-22mm USM, for example. RRP is nearly £1,000! Are they ...
21
votes
9answers
2k views

How to choose a lens for my first DSLR?

I am considering buying my first DSLR. How do I know whether I need a 18-200 lens, 17-85, or 18-55? Or something else?
16
votes
5answers
5k views

What focal length gives a “normal” field-of-view on APS-C cameras?

I wish to purchase a "standard angle-of-view" prime lens for my Canon Rebel, which has an APS-C sized sensor. Various articles note that the popular "nifty 50mm" lenses are a little too much of a ...
18
votes
6answers
2k views

What are the limitations of a typical kit lens as a general purpose lens?

I have a Canon EOS 550d with the 18-55mm IS kit lens. I have done quite a bit of shooting with it over the last few months (portraits, nature, night shots etc), and find the image quality to be pretty ...
12
votes
4answers
3k views

What is a normal lens?

I've heard people call 50mm lenses "normal lenses". For a lens to be considered normal, does it have to be exactly 50mm or is there some leeway? Does the normal focal length depend on crop factor of ...
37
votes
8answers
6k views

Why is the 50mm prime lens the most standard?

Seems that most photographers choose the 50mm as their prime lens (at least from what I've read). I'm looking at getting a prime lens for my Nikon D3000 and the cost difference between the 35mm 1.8 ...
13
votes
3answers
475 views

What is Chromatic Aberration?

What is Chromatic Aberration? Is it a physical part of the lens, or just an optical illusion?
16
votes
4answers
3k views

What is a “fast” lens?

I've been reading lots of camera reviews lately and have ran across several references to "fast" lenses. What exactly is a fast lens and what are its advantages compared to other lenses?
36
votes
4answers
2k views

Should I get DX for my APS-C camera, or FX lenses in case I upgrade to full-frame in the future?

I recently bought a Nikon D90 camera body, which has a "DX" APS-C-sized sensor.. Within the same budget, should I go with DX lenses or should I get full frame lenses in case I upgrade to a full frame ...
18
votes
4answers
9k views

How do camera body motors compare to in-lens motors for focusing?

What is the difference between using a motor on the camera body and the motor built into lenses? Aside from how both compare in terms of speed, what differences would I notice if I use a body with a ...
16
votes
13answers
3k views

What is a good two lens “starter kit”?

A friend of mine is buying his first DSLR. He's chosen an entry-level Canon model, and wants to know which lens he should go for. My advice is to go for a good 70mm prime and an 18-200mm. The former ...
18
votes
5answers
2k views

Is it worth it to have the 50mm f/1.8 Canon lens?

Is it really useful to have a fast prime lens for portrait photography, considering a low budget? If it is, what about the Canon EF 50mm F1.8 II? I have an entry level 18-55mm lens and a Canon 20D. ...
6
votes
7answers
5k views

How can I visualize or simulate the effect of different focal lengths?

I have seen many camera review sites illustrate the effect of using different focal lengths on the same photograph using frames. There are also similar illustrations to compare different sensors (full ...
10
votes
3answers
7k views

Why prefer the 18-55mm and 55-250mm lenses vs 18-200mm?

There seems to be a preference for to have the 18 mm - 55 mm 55 mm - 250 mm lenses, but no mention of why they're better than a single 18-200mm. Could someone please explain why the two separate ...
1
vote
2answers
3k views

Canon 75-300mm f4-5.6 USM or 55-250mm f4-5.6 IS lens?

I am getting a deal on a Canon T3 cam with 18-55mm kit lens and I have choice of one extra lens: 75-300mm f4-5.6 and 55-250mm f4-5.6. I generally like to shoot street, abstract and nature photos and ...
60
votes
11answers
22k views

Is there a noticeable difference between 1.8 and 1.4 prime lenses?

I have been shopping around for a prime lens for my Nikon D50. I noticed that the 1.8 is hundreds of dollars cheaper than the 1.4 AF-S. What will I gain for that cost difference? Is it really ...
21
votes
5answers
5k views

How to capture the scene exactly as my eyes can see?

What settings of my DSLR camera will emulate the scene exactly as I can see through my naked eyes? I think it's not possible to get the contrast and colors exactly as my eyes can see, and it may vary ...
17
votes
2answers
857 views

How do lens lineups vary across Mirrorless camera systems?

We often hear advice like ""choose your lenses and then choose the body that matches". We have great information on DSLR systems at How much do lens lineups vary across DSLR platforms?, but what about ...
9
votes
6answers
10k views

What is a good general purpose lens for Canon?

As an upgrade from kit lens 18-55mm, which would be a better general purpose lens? Obviously there is no "best" option, as everyone has a different budget and style, but what are the best options ...
21
votes
3answers
5k views

What is 'freelensing'?

I've recently heard about a photographic technique called 'freelensing.' How do I go about 'freelensing,' and what can I do with the technique?
15
votes
6answers
23k views

How do I find the right size of filters for a lens?

I was looking to get a circular polarizing filter and an UV filter for my Canon 550D, 18-135mm lens. When I checked online I found these filters came in different sizes, like 62mm, 67mm, 72mm, 77mm. ...
15
votes
6answers
5k views

How does background blur (bokeh) relate to sensor size?

This is a somewhat theoretical question. Suppose I first take a photo of a subject using a full frame sensor DSLR, with a given lens (say 50mm prime lens at f/3.5). Now suppose I exchange the camera ...
14
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?
14
votes
6answers
2k views

Is a UV Filter required/recommended for lens protection?

Is it still required/highly recommended that I buy a UV or similar filter to 'protect' the front element of my lens? I ask because this advice has been around for 30 years and you would think that ...
5
votes
4answers
1k views

What are the tradeoffs when replacing two zoom lenses with a superzoom?

I have two lens currently for my camera. An AF-S DX VR NIKKOR 18-55mm f/3.5-5.6G (kit lens) and a AF-S DX VR Zoom-NIKKOR 55-200mm f/4-5.6G IF-ED lens. I have found that there are cases when the ...
34
votes
5answers
6k views

What should one look for when buying a used lens?

When buying a used lens, what should the buyer check? Other than looking for obvious physical damage on the outside of the lens, what else should be inspected to identify the condition or quality of ...
52
votes
8answers
3k views

Why do some lenses cost 10 times as much when the specs are very close?

For example, a Canon 50mm f/1.8 lens is about US$110, while another Canon 50mm f/1.2 lens is about 14 times as expensive, at about $1450. Is the 1.8 or 1.2 the main reason for the price difference? ...
14
votes
10answers
27k views

Which prime lens for Pentax?

My girlfriend is buying a Pentax K-5 (I already have a Pentax DSLR so we thought it made sense for us to be able to share lenses), and she's not sure about which lens to get with it, so I've been ...
17
votes
2answers
6k views

What is T-number / T-stop?

Usually, when discussing aperture of a lens, F-stop and F-number are used for quantifying. But some photographers, and especially videographers, also mention T-stop. The concept and numbering used ...
32
votes
8answers
4k views

Do I really need a fast 50mm lens?

Everyone I speak to says that a 50mm lens is the best and beats them all as an all-rounder. I was wondering whether to get myself a decent, fast 50mm as well. However I'm still not 100% sure whether I ...
16
votes
6answers
2k views

Which scenarios are better shot with a prime lens versus zoom lens or macro lens?

What scenarios are better shot with a prime lens? A zoom lens? A macro lens?
19
votes
4answers
747 views

What should I consider when purchasing a macro lens?

What should I be aware of when buying a macro lens (other than that it will fit my camera)? What features should I look for? What specs should I pay close attention to? What factors affect macro ...
14
votes
8answers
6k views

Is it a wise-decision to buy full-frame lenses for use on an APS-C body?

I have a Canon 550D which I've been using for around a year now. I really love it and have learned a great deal with this and the 18 - 135mm kit lens. But now with experience I feel the need to get ...
8
votes
4answers
860 views

Why buy an intentionally soft lens?

While reading some reviews of older lenses, I keep reading "It's soft wide open, but that's not always a problem with portraits." Over my rather short time in photography thus far, I've come to ...