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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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1answer
3k views

What are Barrel and Pincushion distortion and how are they corrected?

I have some questions regarding Barrel distortion and pincushion distortion. Since they are related I have put them in single post. I am aware that barrel distortion occurs more in wide-angle ...
9
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3answers
2k views

Why is the Nikon 70-300mm f/4.5-5.6G ED IF AF-S VR twice as costly as Nikon 55-300mm f/4.5-5.6G ED VR AF-S DX?

The Nikon 70-300mm f/4.5-5.6G ED IF AF-S VR is almost twice as costly as Nikon 55-300mm f/4.5-5.6G ED VR AF-S DX. Why is that so? The only difference I see is the internal Focus. If that ignored are ...
8
votes
3answers
460 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 ...
8
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2answers
314 views

Are there any downsides in using 2x extenders?

What are the negatives with using teleconverters?
7
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5answers
738 views

Why not have the diaphragm in camera body instead of the lens?

Why is the diaphragm to control the amount of light entering the camera typically in the lens and not the camera body itself?
7
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1answer
1k views

What are the differences between two generations of Canon EF-S 55-250mm f4-5.6 IS?

I was going to buy Canon EF-S 55-250mm f4-5.6 IS lens from eBay. But I saw there is a another lens available as MK II with same focal lengths. I googled to find difference between above lenses, but ...
6
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4answers
8k views

Canon kit with standard EF-S 18-55mm IS or 18-135mm IS?

I'm going to order a new Canon 550d in a kit with a lens. I'm fairly new to SLR photography which means I have not much knowledge about the difference between lenses. There is an offer for a Canon ...
5
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2answers
1k views

Is it normal for focal length to change while focusing?

When I change the focus distance on my Pentax 55-300mm lens, the focal length appears to change. More specifically, the lens appears to zoom in as I focus towards the minimum focusing distance. This ...
5
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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 ...
4
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1answer
3k views

Can I use the lens from Canon AE-1 on a Canon EOS 60D, with an adaptor maybe?

I have a Canon AE-1 (film) and I bought a digital slr camera Canon EOS 60D. I have lenses from the AE-1 camera, but I don't know if there are some adaptors to use so they fit in the 60D camera... any ...
4
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4answers
2k views

When would one choose a 50mm f/1.4 over 85mm f/1.8 (or vice versa) for portraits?

Say you are using a crop body, and you have both 50mm/1.4 USM and 85mm/1.8 USM lens in your bag. Now, you want to take a portrait where there is adequate light and space, and you have decided to take ...
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5answers
2k views

Is an EF 50mm f/1.4 the same as 50mm with an EF-S lens on a Canon 550D?

I have a Canon 550D with the standard 18-55mm kit lens. The 550D has a 1.6× crop factor. My question is very simple but whenever I've asked before (Yahoo Answers) I always got overly-complicated ...
3
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4answers
8k views

How needed is the Image Stabilization on the Canon 70-200 f2.8 L USM lens?

I just picked up photography a few months ago as a hobby (not planning to go professional at all), but will be getting good gear and glass over time. Right now I have a T3i, which I'm considering ...
2
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1answer
270 views

What is the largest aperture on a commercially available lens? [duplicate]

Out of pure curiosity, what is the largest aperture, or lowest f-stop, a commercially available lens has. I have seen the 50mm prime lens from canon with 1.2, but not lower than that. What are the ...
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vote
1answer
408 views

Size of the entrance pupil vs size of the aperture

I understand that the entrance pupil is the image of the aperture as seen from the front of the lens. However, is the size of the entrance pupil the same as the size of the effective aperture? In ...
0
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2answers
1k views

How does focal length relate to macro magnification? [duplicate]

I'm new to photography and would like to know a little more about zoom lens, The main thing I wonder about is this, I have a Fujifilm S4000 camera that claims to have 30x magnification. The new ...
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3answers
3k views

70-200mm lens: Canon or Sigma? f/2.8 or f/4?

I was thinking of buying a Canon EF 70-200m f2.8 mk1 (I would love to buy mk2 but here's a noticable difference in price, at least in my country), but after awhile I came to the conclusion that this ...
0
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3answers
1k views

Should I choose the AF Nikkor 50mm f/1.4D or AF-S DX 35mm f/1.8G?

I have D5000 DX body and planning to buy a fast lens. I'm stuck on choosing between "AF NIKKOR 50mm f/1.4D" and "AF-S DX NIKKOR 35mm f/1.8G". I was quite leaning towards 50mm f/1.4D, as I had plans ...
40
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11answers
4k views

Should I keep Image Stabilization (IS) off when I do not actually need it?

I own a Canon 7D and a EF-S 15-85 IS lens and I keep the image stabilization turned on all the time. Recently, an experienced photographer told me that this is a huge mistake because it reduces image ...
18
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5answers
916 views

Why do two lenses with the same F-number give different amount of light?

Why do the following two lenses provide different amount of light? In both images we have fixed focusing distance, distance to the object, ISO, shutter speed and F-number.
31
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7answers
1k views

Do good lenses really last a lifetime?

I’ve heard people say “a good lens will last a lifetime” many times. Is this actually true of modern lenses? More specifically, will a good lens be usable for a lifetime? With an inexpensive adapter, ...
30
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3answers
13k 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 ...
31
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7answers
14k views

What can a fisheye lens be useful for?

I have a variety of lenses in my camera kit. One that I do not have, and has me curious, is a fisheye lens. I mostly understand what it does: it captures an image with distortion similar to what you ...
27
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3answers
2k views

What does a hexagonal sun tell us about the camera lens/sensor?

In this picture, we see that the sun comes out as a hexagon. I am sure it is not arbitrary. What does the hexagon tell us about the instrument that captured the image?
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7answers
1k views

Tips for shooting in an aquarium?

What would be your advises when taking shoot in an aquarium? What are your preferred lenses? How do you deal with the low light? What about the aquarium glass which bring some deformation? The fact ...
13
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8answers
394 views

A website that can help me in choice of new lens?

Is there any website that can help me to choose the best lens? I would like to find a website where I can specify a range of minimum focus distance, a range of maximum focus distance, range of ...
13
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3answers
2k views

Do you have advice for buying my first lens after kit 18-55mm (sub-$300)?

I’m looking to buy my first lens beyond the kit 18-55mm for my Pentax K-x. As a student my budget limits me to around a sub $300 offering. I am new to photography, and so I have a hard time answering ...
12
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4answers
1k views

Sigma 10-20mm f5.6 alternatives?

I've been wanting to add a wide angle lens to my collection for a while now. Sigma 10-20mm f5.6 looks good. I was looking at it about 2 years ago. I was wondering if there have been newer wide angle ...
11
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9answers
2k views

Galapagos vacation — what photo gear should I take?

Soon I'm off to the Galapagos Islands. I have to admit I've been spending a lot of hours talking to people and reading reviews, and that has left me very confused choosing the correct gear for my ...
10
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8answers
3k views

For greater telephoto range, should I use 70-200mm + teleconverter or a longer zoom lens?

Right now, I have a Nikon 18-200mm f/3.5-f/5.6 VR lens. I like it, but want more telephoto range and would also like to be able to use faster shutter speeds. I am interested in the 70-200mm f/2.8, but ...
25
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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 ...
22
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4answers
1k views

Do the Lightroom lens correction tools make good lenses less important?

Lightroom has Lens Correction tools such as Distortion, Vignetting, Chromatic Abberation, etc. depending on the brand and model of lens. Due to this feature, is it less relevant what the distortion ...
22
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7answers
2k views

Why do some lenses cost so much?

Something that confuses me is why there is some lenses that cost so much. For example the only difference that I see between the two lenses is the aperture: f/2.8 vs f/4. Canon EF 70-200mm f/2.8L II ...
20
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6answers
1k views

How long should a lens last?

There are loads of ratings and tests for how long DSLR bodies last, but I have never really seen much that describes the expected lifespan of lenses. Recently, one of my cheap-o lenses (Nikon ...
11
votes
6answers
13k views

What is the difference between a telephoto lens and a zoom lens?

Looking at the product page for Nikon lenses, I notice a distinction between telephoto lens and zoom lens. What is the difference between the two? Why would I want one over the other? I wiki'd ...
13
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5answers
589 views

What are the different focal lengths of macro lenses and their advantages?

I am interested in macro-photography. I see there are macro telephoto (zoom?) lenses (e.g. 200mm), or smaller macro lenses (e.g. 40mm) ... What are the different types of macro lenses and their ...
13
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1answer
438 views

Is dust in a zoom lens a problem which should be addressed?

I have accumulated some amount of dust inside one of my zoom lenses, visible through the front glass. It does not appear to affect picture quality as far as I can tell, but I wonder if this is ...
8
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3answers
232 views

What are the standard tests available to quantify lens parameters?

In some of the questions I have asked here, some of the terms frequently used to describe the difference in image quality between the cheaper lenses and the premium ones have been increased contrast, ...
7
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3answers
1k 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 ...
6
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5answers
10k views

How to reverse the canon 18-55 kit lens to use it as macro?

I have been trying to use my 18-55 kit lens as a macro but have no idea how to go about it. Do I need an adapter to mount the lens reversed on the camera? Also, is it possible to use canon 50mm f/1.8 ...
5
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3answers
1k views

How does using a lens with some focal length on a full frame camera differ from using a lens with “equivalent” focal lens on a crop camera?

As an example, a 35mm lens on a crop body (such as Nikon DX) is said to be "equivalent" to a 50mm lens on a full frame body. Equivalent here means that they will have the same field of view, but what ...
3
votes
4answers
7k views

Why do some people prefer 50mm to 35mm prime lenses, even for a crop sensor?

Comparing the two lenses for an APS-C sensor: EF50mm f/1.8 EF35mm f/2 here Leaving out cost as a factor, EF 35mm has the following advantages: 43 degree while 50mm has 31 degree Its equally ...
18
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6answers
1k views

Maximum lens weight for my camera?

I apologize if this was asked before, but where can i find information about maximum allowed lens weight for my camera? I'm asking because, i have an opportunity to get old Soviet build 80-200mm lens ...
15
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10answers
16k views

What's wrong with the Canon EF-S 15-85mm?

Maybe this question should be on meta. I've just come across the Canon EF-S 15-85mm. It's been available since 2009. I'm just wondering why it has never been mentioned on photo_se_com or any of the ...
13
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6answers
576 views

Does lens speed still increase meaningfully when the physical aperture is larger than the sensor size?

This question came to me this morning, thinking about 50mm lenses. I have the Pentax 50mm f/1.7 (manual) and it's a very nice lens, but would be considered (relatively) slow on 35mm film, and many ...
12
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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 ...
10
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4answers
2k views

What are the best methods for cleaning really dirty lens elements?

I bought old M42 Pentacon 50mm f1.8 lens from a car boot sale. It works but is pretty dirty and it has also dirt inside (no mould/fungus though). Opening the lens is not a problem but I would like to ...
9
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3answers
1k views

What's the term for wide angle lenses with no distortion?

Is there one word to describe the difference between wide angle lenses that have a circular distortion and wide angle lenses that produce images where perspective lines remain straight?
9
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4answers
2k views

EF-S 18-55mm kit vs 10-22mm f/3.5-4.5 for nature photography

I moved from a point and shoot to a DSLR last year and I love to photograph nature in general. I have a T2i/550D with the 18-55mm kit lens and was wondering if I would benefit from the EF-S 10-22mm ...
8
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4answers
3k views

Is it difficult to focus on 1.4F prime lens, and if it is how to counter that?

Does difficulty in focusing have anything to do with 1.4F (Nikon G)? Will it be still difficult if I use manual focus? Is auto focus too slow? Is there a way to counter it? This example photo (from ...