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An optical 'zoom' or 'variable focal length' lens is one that has a range of focal lengths at which it can operate. "Digital zoom" is a technology which simulates optical zoom by cropping the image.

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37
votes
12answers
3k views

Is digital zoom really useful?

I've always wondered what is the use of digital zoom, apart from viewing the subject clearly on the LCD display. We can take a photo with the optical zoom and crop the photo to the desired region of ...
35
votes
5answers
94k 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 ...
25
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 ...
20
votes
4answers
3k views

What is focal length and how does it affect my photos?

What is focal-length? Are focal-length and zoom synonymous? How does the focal length of a photo affect it?
17
votes
11answers
7k views

What is the best lens for taking photos of birds?

I was using a Panasonic Lumix, now I finally got a Canon EOS 60D, but I was used to that 18x zoom that my old camera has, because you can't get too close from the birds to take pictures, since they ...
17
votes
4answers
2k views

Fast prime vs. expensive zoom for indoor sports photograhy?

I plan to try shooting my kids' indoor activities (Tae Kwon Do and Figure Skating). I can get pretty close to the action for TKD, and I have access to ice/board level positions for shooting at the ...
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?
15
votes
5answers
2k views

Why choose an 80-200mm over an 18-200mm lens?

Being a beginner, I can't see why I must choose an 80-200 over an 18-200. Are there scenarios where an 80-200 would be preferable over an 18-200? I will be buying a D7000 soon and am looking at ...
15
votes
6answers
610 views

Overlapping vs. Complementary lenses

I'd like to know if anyone has any advice or experience they can share about using a pair of zoom lenses that have overlapping focal lengths; or a pair of zoom lenses that have adjacent focal lengths. ...
15
votes
8answers
948 views

Would a prime be redundant with a fast zoom?

Now that I am finally getting a fast zoom (Tamron 17-50mm 2.8) I've been considering a fast prime to go with it, specifically a Sigma 50mm 1.4. Despite its shortcomings, it still does really nice ...
14
votes
4answers
3k views

Why push/pull zoom is not widespread?

The Canon EF 100-400mm f/4.5-5.6 L IS USM has a push/pull zoom mechanism instead of a zoom ring. Other lenses, like the Nikon 80-200mm f/2.8 AF released in 1988 use this type of zoom too, but the ...
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?
13
votes
5answers
1k views

Why do we talk about focal-length when frame sizes are different?

I keep seeing people talking about focal-length of lenses without saying how large the frame is. Is there a more sensible way to talk about how much a lens “zooms”? (I have seen so many adverts ...
13
votes
4answers
4k views

How does changing focal length affect depth of field?

I'm curious about how my "area of acceptable focus" changes when the focal length of the lens I'm using changes as I zoom (or switch lenses). In particular, I'd like to know how the front & back ...
13
votes
2answers
4k views

What differences between point and shoot zoom versus DSLR zoom cause the price disparity?

I'm just getting into the world of photography, stepping up from a point-and-shoot. I've just purchased a Nikon D3100 and it should be here in a couple of days. I've done lots of research, but ...
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 ...
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 ...
11
votes
5answers
801 views

Why are 50mm no longer the default kit lens for prosumer SLRs?

Every time someone asks me for a kit recommendation I point them towards some sort of prime lens with a standard focal length. Similarly, almost anyone I talk to about the ideal budget kit swears that ...
11
votes
3answers
9k 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 ...
11
votes
4answers
800 views

Other than speed and weight, what advantages might a prime lens have over a zoom at the same focal length?

At the same focal length, apart from speed and maybe weight, what other advantages does a prime lens like the 50mm have over a zoom lens like the 24 - 70mm? To put it better, If I set my 24-70mm lens ...
11
votes
4answers
9k views

What's the advantage of buying a fixed 50mm f/1.8 lens when my camera has an 18-55mm zoom lens?

I've got a Nikon D3100 with an 18-55mm zoom lens. I'm keen to experiment with some other lenses and a friend of mine recently reccommended I purchase a fixed 50mm f/1.8 lens as he said it's good for ...
11
votes
6answers
352 views

On smaller prints, will a high-quality zoom lens provide near equal image quality compared to primes?

Let's say I shoot with Canon EF 35mm f/1.4L, Canon EF 50mm f/1.4, and a Canon EF 85mm f/1.8. Can these 3 primes be replaced with a Canon EF 24-70mm f/2.8 for the convenience of not needing to change ...
11
votes
4answers
1k views

Is it problematic to mount a Canon EF 100-400mm f/4.5-5.6L lens on Rebel XSi (450D) body?

I have a Canon Rebel XSi (450D) and I'm going on a two week trip to Argentina and Patagonia where I want to try some wildlife photography. I have the kit 55-250 f/4.5-5.6 lens which I like, but I ...
11
votes
2answers
1k views

Does a greater optical zoom range on a lens mean less image quality?

I have read that big optical zooms of let's say 10X do not produce excellent image quality. Is this true even nowadays, as there have been many technological improvements in this area? For example, ...
10
votes
5answers
952 views

Why do fixed lens cameras have a motorized zoom while interchangeable lens cameras don't?

I would like to know why motorized zoom (controlled by a W/T lever) is always on fixed-lens cameras and never on interchangeable lens cameras.
10
votes
5answers
981 views

What are the pros and cons of non-extending zoom lenses?

Apart from the obvious benefit of not changing the center of gravity, what are the technical pros and cons of zoom lenses that do not change "physical length" when changing the focal length? For ...
10
votes
4answers
289 views

What are important considerations when purchasing a zoom lens?

What should I be aware of when buying a zoom lens (other than that it will fit my camera)? What specs should I pay close attention to?
10
votes
2answers
416 views

Max aperture on zoom lenses - stepwise or linear?

When zooming with lenses without a fixed max aperture, the change in aperture* that the camera displays is stepwise, usually in steps of thirds. But, is the max aperture really the same all the way as ...
9
votes
2answers
4k views

What is the meaning of W and T on a camera's zoom buttons?

On every conventional digital camera (excluding the models with detachable lenses), there are buttons to zoom in and out with W side and T side. When you press W, the lens zooms out. The lens zooms ...
9
votes
7answers
438 views

Should I postpone buying a zoom lens until I've learned to zoom with my feet?

After several years of shooting with my point-and-shoot, I upgraded to an NEX-5R, with two prime lenses — a 35mm f/1.8 and a 19mm f/2.8. I don't have a zoom lens, not even the kit lens. I've been ...
9
votes
4answers
589 views

What is the technical name for a zoom lens which has a fixed maximum aperture?

What is the technical name for a lens which has the same maximum aperture throughout the entire zoom range?
9
votes
4answers
850 views

Is it the same if you take a picture by setting 50mm in a 18-55mm lens and by using a 50mm prime lens?

Is it the same if you take a picture setting 50mm with a 18-55mm lens and a 50mm f/1.8 prime lens? Assuming that ISO, aperture, and shutter speed are the same, will both the lens give same results? I ...
9
votes
4answers
473 views

Why are some zoom lenses “soft” at either end of the focal length range?

As one reads about zoom lenses, a relatively common comment that comes up in reviews of some lenses (especially lower-priced lenses) is that the lens is not as sharp ("soft") at one or both ends of ...
8
votes
4answers
6k views

What does 'how much zoom' mean?

I have Canon 18-135 and 70-300 zoom lenses. People ask me how much zoom my camera supports. What am I supposed to tell them? "135 ÷ 18 = 7.5" and "300 ÷ 70 = 4.2"?
8
votes
7answers
8k views

How do I get the best results for sports with a 70-200mm f/2.8?

Can anyone help? I am using a nikon d7000 for sports photography. My husband kindly bought me a sigma 70-200mm telephoto lens 2.8 as I shoot a lot of low light indoor sports. I have only just started ...
8
votes
3answers
685 views

What is a pump zoom lens?

While browsing for cheap second hand lenses I found the Cosina 70-210mm f4.5-5.6. The seller notes that it's a pump zoom. Googling the term does yield some results, but these simply state that a ...
8
votes
3answers
5k views

What is the technical difference between focus and zooming?

This may look like a silly question but I don't know what the difference between zooming and focusing is. Zooming in will usually let me have fewer subjects in the scene while zooming out will allow ...
8
votes
3answers
459 views

Would a fixed or zoom telephoto lens be better for learning?

My daughter has a Nikon D-90 camera body and two prime f1.4 lenses 50mm and 35mm. She is interested in learning more, and I am curious which of a zoom or fixed telephoto lens would help her best? Is ...
8
votes
1answer
549 views

Why is the Canon MP-E 65mm F/2.8 Macro Lens not called a zoom?

The Canon MP-E 65mm works differently than my other macro lenses. Compare: With a standard 35mm macro, I can frame first and then adjust focus which only changes framing very slightly with. With the ...
8
votes
1answer
2k views

Why does the maximum aperture change with focal length? [duplicate]

Possible Duplicate: Why do zoom lenses and compact cameras have varied maximum aperture across the zoom range? It is rather common with zooms that the maximum aperture changes (in fact, ...
7
votes
4answers
1k views

Do I need other camera lenses if I have an 18-200mm or other super-zoom?

I wanted to ask that once you have purchased a lens of say 18-200mm, then is it required to purchase other lenses — say 24-70mm, 24-105mm, 18-105mm, 28-135mm,etc. Does 18-200mm lens satisfy all the ...
7
votes
4answers
1k views

How to take sharp photos while using maximum optical zoom?

When I shoot with high zoom (above 3X on my point-and-shoot camera), the sharpness of the picture seems to come down. Is it a feature of all cameras or is it due to higher sensitivity to camera shakes ...
7
votes
6answers
314 views

Digital zoom versus optical zoom for minimising camera shake

Here's the scenario: every so often our garden plays host to some small deer. Naturally, I try to take pictures of them. From inside the house, I can get a decent shot with full zoom on my camera. ...
7
votes
7answers
2k views

Which lenses are best for macro and for birdwatching (both Canon and Nikon)?

Now I have old Sony A100 DSLR + Minolta AF 24-50/4, Minolta AF 50/1.6, Tokina ATX 80-400/4.5-5.6, ... My camera is old. In near future I am going to buy new DSLR. I think it will be Canon or Nikon. I ...
7
votes
5answers
2k views

How much different are the Tamron 17-50mm f/2.8 stabilized (VC) and non-stabilized versions?

I have seen these 2 lenses being suggested by many people across the site as general purpose zooms and an upgrade to the typical 18-55mm kit lenses. The price difference seems to be around $200 (~INR ...
6
votes
4answers
1k views

Why is my lens only somewhat sharp near the center and very blurry on the edges?

I bought a canon 50-250mm IS lens (for my T1i), maybe two years ago and haven't used it much, but whenever I do, I always regret using it. Pictures are blurry, the depth of field too shallow and so ...
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 ...
6
votes
4answers
711 views

Is depth of field and bokeh influenced by distance to the subject?

I know that the aperture size has a direct effect on the depth of field. However, what about distance to the subject? Let's say I took two pictures, one at 24mm and one at 70mm, using the same lens ...
6
votes
5answers
3k views

Why is my Nikon 18-200 lens not focusing at higher focal lengths?

My Nikon 18-200 lens on a D300 camera will not focus when it is zoomed between 135mm and 200mm. Is there any tips on how to solve this besides handing it in to a photo store?
6
votes
4answers
841 views

Should I get a kit or separate lens for my D7000?

I am set on getting a D7000 and am drooling already to get one. My only hurdle left is to determine whether the kit lens is good or if i should get the body only and put the 300$ difference between ...