Probably a really dumb question, but I have to speak up!

[ChevyBaby]

I've had my Nikon D3000 for about 6 months now but one of the luxuries I have at uni is that we have a 'store' whereby a technician loans out equipment for free and I normally just say 'I want a Canon 10D with a zoom lens or a wide angle lens'

This situation has got me confused with the whole 'numbers' aspect of lenses, if you get what i mean? I wa snever taught it and i've never known where to start trying to find out what means what.

I want a wide angle lens for my Nikon but I'm now in a rutt where i don't understand how the number relate to the lenses.

For example, i call a 50mm lens a standard lens. So what am i looking for in a wide angle lens? So confused and embarrassed

 

[Heck]

Below 50mm you start into the "wide" range. 35mm is like normal wide. 24mm very wide and 18 is ultra wide. Now you got to remember the effects of the lens is different on full frame sensors vs crop sensors.

 

[Bitter Jeweler]

This was a 4mm wide angle lens...

Cropped, on a full frame sensor.

 

[Derrel]

Here you go: Camera Lenses from Nikon

This site might be of some use to you.

 

[tirediron]

50mm is considered a normal lens on a full-frame camera because it most closely approximates the view of the human eye. On an APS-C cameara (crop sensor) this becomes a 35mm and on a 4/3 camera a 25mm. Numbers above these are telephoto lenses and below are wide-angle lenses.

Zoom lenses with a range between 30ish mm and 80ish mm are considered "normal" zooms, while zooms from >70mm are telephoto or long zooms and those below ~35mm are wide zooms. When you get below 20mm you're generally considered to be in the ultra-wide category.

 

[ChevyBaby]

i feel so much better now! thank goodness, im starting to understand - thanks for the help already guys! xx

 

[ChevyBaby]

Haha wow, after reading this - Heck made it incredibly simple so i've given you a giant thankyou, expect a muffin basket in the post too lol - i thought i'd go search for a 10-20 lens. £600. Ouch!

 

[PhotoXopher]

This was a 4mm wide angle lens...

Cropped, on a full frame sensor.

That is one of the coolest photos I've ever seen!

 

[gsgary]

why not look at secondhand, i have bought loads from this shop mail order and they have been great Nikon Auto Focus - Aperture Photographic Tel. 020 7242 8681
it could be near to you

 

[bazooka]

Oh, wow, I thought that was a painting. :thumbup:

 

[Studio7Four]

Let's see if I can get this in before someone types up a better answer...

When describing a lens, there are two numbers (or sets of numbers) to consider. You'll generally see a lens described as a "50mm f/1.8", or a "28-135mm f/3.5-5.6". The first number(s), with the [mm] units, is the focal length. The simple answer to your question is that the lower the number here the wider the angle. A focal length of 14mm is going to be wider than your 50mm, a focal length of 135 is going to be narrower (more zoomed in) than your 50mm.

Here's a (very) simplified exercise to illustrate the effects of focal length (the actual internals of a lens assembly are much more complex, but this is a valid simplification). In simple terms, light enters through the aperture (an opening of a given size) and gets bent by the lens so that the light converges to focus at your sensor/film. Take a piece of paper and draw a dot on it - this represents where the light is focusing. Now draw a line coming out from this point - this represents the "boresight", or the line between the focus and the central point of your image. The further down this line, the farther away the object. Next, draw a line perpendicular to your boresight line at, say, 14mm from your focus (make this line equally long on each side of the boresight line, say 5mm per side). This line represents your aperture. Now draw a line from your focus point to each end of this aperture line, and extend these lines well beyond the aperture. This triangle defines your field of view.

Now do the same thing, using an aperture of the same size but at a different distance from the focus (at 50mm for example). You'll see that the angle of the triangle you just drew as your field of view is narrower than for your 14mm version. Voila - wide angle versus narrow, illustrated. (Yes, this is an extremely simplified model useful just for illustrating the effect of focal distance versus field of view.)

The second number, the f/#, is basically an indication of how large an aperture the lens can produce. Think of this like a fraction - because the actual number is on the bottom, the smaller the number the larger the fraction (1/2 is larger than 1/4), so the larger the aperture. Your film or digital sensor is a light collector much like a bucket is a water collector...to get a properly exposed image you have to collect a certain amount of light (fill the bucket). Imagine you had a collection bucket (your sensor) hanging below a huge water reservoir (the world outside your camera). Drill a hole in the reservoir and let the water drain into your bucket. The larger the hole you drill the faster your bucket will fill (the quicker you can collect a good image). This is why large aperture lenses (low f/#) are called "faster" lenses. A 50mm f/1.4 lens is going to have a larger maximum aperture (you can always stop it down) than a 50mm f/1.8 lens.

Sorry if this is dumbing it down too much, but I hope it helped grasp the concepts...

 

[ChevyBaby]

Let's see if I can get this in before someone types up a better answer...

When describing a lens, there are two numbers (or sets of numbers) to consider. You'll generally see a lens described as a "50mm f/1.8", or a "28-135mm f/3.5-5.6". The first number(s), with the [mm] units, is the focal length. The simple answer to your question is that the lower the number here the wider the angle. A focal length of 14mm is going to be wider than your 50mm, a focal length of 135 is going to be narrower (more zoomed in) than your 50mm.

Here's a (very) simplified exercise to illustrate the effects of focal length (the actual internals of a lens assembly are much more complex, but this is a valid simplification). In simple terms, light enters through the aperture (an opening of a given size) and gets bent by the lens so that the light converges to focus at your sensor/film. Take a piece of paper and draw a dot on it - this represents where the light is focusing. Now draw a line coming out from this point - this represents the "boresight", or the line between the focus and the central point of your image. The further down this line, the farther away the object. Next, draw a line perpendicular to your boresight line at, say, 14mm from your focus (make this line equally long on each side of the boresight line, say 5mm per side). This line represents your aperture. Now draw a line from your focus point to each end of this aperture line, and extend these lines well beyond the aperture. This triangle defines your field of view.

Now do the same thing, using an aperture of the same size but at a different distance from the focus (at 50mm for example). You'll see that the angle of the triangle you just drew as your field of view is narrower than for your 14mm version. Voila - wide angle versus narrow, illustrated. (Yes, this is an extremely simplified model useful just for illustrating the effect of focal distance versus field of view.)

The second number, the f/#, is basically an indication of how large an aperture the lens can produce. Think of this like a fraction - because the actual number is on the bottom, the smaller the number the larger the fraction (1/2 is larger than 1/4), so the larger the aperture. Your film or digital sensor is a light collector much like a bucket is a water collector...to get a properly exposed image you have to collect a certain amount of light (fill the bucket). Imagine you had a collection bucket (your sensor) hanging below a huge water reservoir (the world outside your camera). Drill a hole in the reservoir and let the water drain into your bucket. The larger the hole you drill the faster your bucket will fill (the quicker you can collect a good image). This is why large aperture lenses (low f/#) are called "faster" lenses. A 50mm f/1.4 lens is going to have a larger maximum aperture (you can always stop it down) than a 50mm f/1.8 lens.

Sorry if this is dumbing it down too much, but I hope it helped grasp the concepts...

:bolded: lol, you don't know me. Nothing is too dumbed down for me, thanks so much for the in depthness! Love it!

And Thanks Gary, that's near me, that's really bloody helpful! Feel much beter now

 

[clanthar]

50mm is considered a normal lens on a full-frame camera because it most closely approximates the view of the human eye.

It's actually a little more complicated than that. The normal lens for any camera is typically calculated by measuring the diagonal of the film format and rounding off. So for example a Hasselblad negative measures 76mm on the diagonal and the normal lens is typically an 80mm.

Human vision is complex; human peripheral vision is very wide and human "concentrated" vision is circumstantially variable. So it's hard to pin down just what constitutes the view of the human eye. It is a common understanding that camera normal lenses are "close" to human vision. That begs the question "close" in what manner? Does the human eye have an angle of view?

What we can do is carry the exercise further to the finished photograph and ask, what lens focal length will render the scene printed with perspective that matches the perspective from the original camera position. To do that we have to know the print size and viewing distance for the print. If you hang a bunch of different size photos on a wall and measure the distance that say a random sample of 10,000 viewers stand to view the photos you'll discover than people on average comfortably stand back from an image about double the long side of the image. So for a 16x20 print they'd stand back 40 inches. Run the math and you'll have the lens focal length that reproduces perspective in the print faithful to the camera position. On a 35mm camera that would be a 75mm lens. Given that and the idea that normal should be what a person would see from behind the camera, there's an argument that normal for a 35mm camera should be 75mm. (The difference between 50mm and 75mm isn't all that much -- so this a bit esoteric).

Take Care,
Joe

 

[ChevyBaby]

50mm is considered a normal lens on a full-frame camera because it most closely approximates the view of the human eye.

It's actually a little more complicated than that. The normal lens for any camera is typically calculated by measuring the diagonal of the film format and rounding off. So for example a Hasselblad negative measures 76mm on the diagonal and the normal lens is typically an 80mm.

Human vision is complex; human peripheral vision is very wide and human "concentrated" vision is circumstantially variable. So it's hard to pin down just what constitutes the view of the human eye. It is a common understanding that camera normal lenses are "close" to human vision. That begs the question "close" in what manner? Does the human eye have an angle of view?

What we can do is carry the exercise further to the finished photograph and ask, what lens focal length will render the scene printed with perspective that matches the perspective from the original camera position. To do that we have to know the print size and viewing distance for the print. If you hang a bunch of different size photos on a wall and measure the distance that say a random sample of 10,000 viewers stand to view the photos you'll discover than people on average comfortably stand back from an image about double the long side of the image. So for a 16x20 print they'd stand back 40 inches. Run the math and you'll have the lens focal length that reproduces perspective in the print faithful to the camera position. On a 35mm camera that would be a 75mm lens. Given that and the idea that normal should be what a person would see from behind the camera, there's an argument that normal for a 35mm camera should be 75mm. (The difference between 50mm and 75mm isn't all that much -- so this a bit esoteric).

Take Care,
Joe

*jaw drops* oh wow [baffled] i'm enjoying learning lol
i'm enlightened because i want a wide angle because i feel like 50mm lens DOESN'T capture what i see, my peripheral vision must be so insane, i wanna stand in the corner of a room and capture everything i see, but when i get my 50mm out, it cuts off so much of what i see!

But at the same time i wanna be able to have people in my image without distorting them and giving them giant noses

 

[clanthar]

i'm enlightened because i want a wide angle because i feel like 50mm lens DOESN'T capture what i see, my peripheral vision must be so insane, i wanna stand in the corner of a room and capture everything i see, but when i get my 50mm out, it cuts off so much of what i see!

But at the same time i wanna be able to have people in my image without distorting them and giving them giant noses

Sounds like you need a wider lens. With all the variable size sensors out there on digital cameras make sure you know what the "normal" starting point is for your camera. In discussions like this it's common to reference the 35mm format as a standard and so 50mm is normal, but for an APS size sensor, 50mm is into the beginning of the telephoto range. 24mm is wide for a 35mm camera, but not for an APS size sensor. You need 14mm with an APS sensor to get that same angle of view.

One of the most exciting aspects of photography is that lenses that extend well beyond the "normal" range (either way) see the world quite differently than we do. We don't have the option of switching our eyes or plugging in zoom eyes. Using wide and/or telephoto lenses allows photographers to explore and render views of our world that we otherwise could never experience.

You used the word "distort" above; don't do it. It confuses what's actually taking place. If you walk up to a friend and place your eyes six inches from their face you'll see a big nose. It's not distortion you're experiencing -- it's only uncommon to your typical experience. Insects don't see the world in the same way that we do. Is their vision then distorted? They out-number us on this planet. A camera can see the world in ways we can't, for example b. jeweler's fisheye shot above. That photo is not a distortion; it's uniquely camera vision and it's very fortunate that we can both experience it and manipulate it as a way to explore our world.

Take Care,
Joe