Rough guide to glass, Starting off lenses

Mellor

Right, so the lens is a very important piece of kit. It controls the properties of a range of factors. Angle of view, F stop, amount and quaility of light, basically what the camera sees.
So as a beginner, I could do with a few pointers to clear the water. These should also help other beginners about. The following is my limited knowledge of lens, if anyone could correct my errors, expand on points and/or answers questions it would help.

The "Kit" Lens.
Alot of cameras come with a similar kit lens. Most of the lower entry level camera (400D, D40) have a similar lens. In the range of 17-55mm f4.8-5.6
This is going to be a general multi-purpose lens suitable for a wide range of shots.

The "nifty fifty"
This is a popular lens it appears. As a prime (fixed) lens it can go to a lower reletive appeature size. Down to sub 2 is standard, some going to 1.2 or 1.4
This results in faster and/or better quaility (ie lower iso) images to be shot. Useful in low light situation (gig photography) and moving objects (sports photography).
But, what kind of zoom factor does a 50mm prime have on a DSLR? I ask because I am aware that on a DSLR a lens lens acts as if it has a longer focal length due to the crop factor. The sensor is nearly always smaller than 35mm film so it "sees less", this results in the image appearing zoomed/cropped.
So depending on the focal lenght multiplier in the DSLR a 50mm amy act as a 65-80mm, is this right?

The fish eye
Fish eye shots, are quite unique, warped a twisted but used right they can look well. Obviously the best way to achieve this is through a FE lens, but are fish eye attachments any good?
What sort of an effect would a fish eye attachment have on say a kit lens, or a 50mm

Fajitas!

Thread stuck, feel free to offer your own opinions, advice, and experiences

Borderfox

Probably the best lens to get after the kit lens and the "nifty fifty" 50mm f1.8 is the Sigma 70-300 APO. Super telephoto to start off with and can be put to a lot of uses including daylight sports and nature (birds/wildlife) also has a basic macro function which can get nice shots out of..pretty cheap aswell starting around €150 on the net rising to €200 in Dublin

Sample shot from the Sigma 70-300 APO

Borderfox

Nifty Fifty when shot at f1.8 makes the subject in focus but the background out of focus and is useful for backgrounds with lots of distractions in them, I would only use a dedicated Fisheye lens to achieve the effect as there is so much distortion that the lens needs to control it and not an add on.

Mellor

Zoom Lens Sample
The following images are taken from the same spot with various focal lengths. Each is shot at f4


28mm


50mm


70mm


210mm

Borderfox

50mm


500mm

PeakOutput

this is exactly the info i was looking for

so with the sigma 70-300 you can get from mellors 3rd pick to even more zoom than his 4th pic but not as much as borders 2nd pic? is that basically it?

Fajitas!

Exactly!

Borderfox

Thats it in a nutshell. A 50-500mm Zoom is 10x and a 70-300 is approx 4.5x divide the left into the right to find out how many X it is, although dont rely on it for making decisions regarding image quality.

Borderfox

Heres an example of the 50mm f1.8 (Nifty Fifty) This was shot at f1.8 and as you can see the boy is in focus but everything else around him front and back is out of focus.

PeakOutput

doe anyone want to explain the f part now?

pete4130

f numbers relate to the size of the aperture the lens is using (how big the hole is in the lens that lets the light through!) Smaller f numbers such as f1.4 or f1.8 are large apertures/holes. Larger numbers such as f11 or f16 or f22 are smaller apertures/holes (its confusing as the smaller number means a bigger hole!). Wider/bigger apertures/holes allow more light into the lens so you can get faster shutter speeds. Same priciple as your pupil getting bigger in dark situations to let more light in and allow you to see better.

If you go to this link its got a good diagramatic of f numbers and their related apertures:

http://members.shaw.ca/davempicklyk/apertures_50mm1.8.jpg

pete4130

Fisheye lenses are good fun lens offering 180 degree field of view, but a little bit expensive for a lens you may not find a use for everyday. The are very wide and get alot in. If you have one, Don't be afraid to get very close to subjects when photographing them and expect anything close to the corner of the frame to get very distorted at close distances. You can get cheaper alternatives such as screw-on fisheye adators that screw onto the front of your existing kit lens. These screw-on adapters generally don't offer the same quality as dedicated fisheye lenses.

There are mainly 2 types of fisheye lenses.

A Circular fisheye lens which sees 180 degrees in every direction, resulting in a black circle of vignetting on the image.

A Rectangular fisheye lens sees 180 degrees diagonally across the image and don't have the black vignetting around the image.

Here are some examples of Rectangular fisheye shots I've taken.

Mellor

Any opinions on fisheye attachments?

Borderfox

our survey says XXX I wouldnt be really gone on anything that going to add distortion except for a lens that has it built in..

Fajitas!

I think the general word on them is... They're sh*te... They reduce the quality of your glass, are only effective at certain focal lenghts, and the fisheye effect is very rarely what it's supposed to be...

And they reduce the quality of the glass!

pete4130

Attachments onto lenses to make them "fisheye" are generally cheap to buy, resulting in poor quality, lots of distortion, really soft at the edges, you lose a stop or two more light than normal and usually have a nasty colour cast in the image. Because they have no petal hood and cheaply made they are really prone to light bouncing around inside the fisheye attachment with flare appearing all over an image thats been shot with the fisheye attachments.
I'd advise not to touch them if you can help it and save some money to get a proper fisheye!

elven

Or have the faults as an endearing quality and get a fisheye holga

Mellor

Any of the other basic lens on included, Macro anyone?

Stephen

For ultra wide angle fun on cameras with APS-C sensors, I can't recommend the Sigma 10-20 highly enough.

Borderfox

I would second that Stephen, the Sigma is a fantastic lens and can get some unique shots

Borderfox

If you want to try macro you can use the filters that basically magnify the image by an x factor or you can use extension tubes on eg. a 50mm f1.8 which can give great images. These work by moving the lens further away from the body so it can focus closer than it does normally. Another way is to use a reversing ring to basically turn the lens around the opposite direction on the camera body. Lastly you can use a dedicated macro lens, I use a Canon 100mm macro lens and the shots from it are superb, sigma make a comparable version with also excellent results. Below are two examples from the Canon 100mm f2.8 macro shot handheld with flash.



100% crop

Mellor

Stephen wrote: »

For ultra wide angle fun on cameras with APS-C sensors, I can't recommend the Sigma 10-20 highly enough.

Chicago is a nice city I must say. At least I think it Chi town there

Mellor

Borderfox wrote: »

If you want to try macro you can use the filters that basically magnify the image by an x factor or you can use extension tubes on eg. a 50mm f1.8 which can give great images. These work by moving the lens further away from the body so it can focus closer than it does normally. Another way is to use a reversing ring to basically turn the lens around the opposite direction on the camera body. Lastly you can use a dedicated macro lens,

I have wondered how various shots compare, ie:
Macro lens vrs reversing ring vrs extender tube fast lens combo vrs filter

Borderfox

I would think that the dedicated macro lens would when properly set up outperform all other methods as most of the other methods would in some way effect the image quality (very slightly)

Thirdfox

Mellor wrote: »

Chicago is a nice city I must say. At least I think it Chi town there

He he - you mean Shanghai is a nice city?

The face of China is changing at a really rapid rate (too fast for some people )

Stephen

Yup, its Shanghai

Mellor

Thirdfox wrote: »

He he - you mean Shanghai is a nice city?

The face of China is changing at a really rapid rate (too fast for some people )

Sorry my comments were in relation to a building in the background, its almost copied from chicago, nearly expected the hancock to be there too, I did notice the writing to the right, couldn't of narrowed it to shanghai though

Thirdfox

Mellor wrote: »

Sorry my comments were in relation to a building in the background, its almost copied from chicago, nearly expected the hancock to be there too, I did notice the writing to the right, couldn't of narrowed it to shanghai though

Wasn't trying to be negative about your post at all so absolutely no need to say sorry.

I thought it was Beijing at first - all these cosmopolitan cities start looking awfully similar after a while.

Great photo though Stephen!

Stephen

There's a bunch more here: http://flickr.com/photos/shanafin/sets/72157602607163510/
About half of them were taken with the 10-20.

viking

I found this website from Canon very useful when trying to understand the basics:

http://web.canon.jp/imaging/enjoydslr/index.html

Its seems a little slow for me since I last looked at it but its quite good.

sineadw

On tubes versus dedicated macro - obviously the tubes save a fortune (especially if you get a loan of them ) but the major major drawback for me is you're completely limited to macro - you can't focus any further than a few inches when they're on, which means you might miss shots with changing lenses (has happened to me..). The 100 macro makes a lovely portrait lens too. I want one

Here's one I took with the macro tubes on and the 50mm..



100% crop (I think..)

Stephen

^^^ That 100% crop is brilliant, I love the way you can see the texture of the fly's eyes. At least, that's what I think they are
How far away would the camera have been from the fly when you took that?

sineadw

a few inches at most stephen. He was really really teensy. I love the back hairs - very fetching

440Hz

Borderfox wrote: »

Now that's what I call a fisheye!! Nice one

Mellor

Sorry, but what does 100% crop mean?

pete4130

A 100% crop is where you DON'T downsize the image and show a small portion (a crop) of the image at its full size (100%). A 100% crop allows you to see how sharp the image is at its full size, so you can see if a lens is sharp or not.

As they say on Blue Peter, here's one I prepared earlier....
This image was shot on a Sigma 50-150mm lens @ 150mm, f2.8 & at the closest focussing distance possible (1m). This was pushing the lens to its extents, in regards to the extreme focal length in its range, it's widest aperture and it's closest focussing distance. These are all things where sharpness & image quality can be at their worst, so combining all 3 together is somewhat a test in the worst circumstances.



- In the first image you can see the whole image, but it has been downsized so it can be easily seen on a web page to about 1000 pixels wide. NOTE: the area in the bottom corner of the first image marked by a rectangle, this is the area I will show as a small portion (a crop) of the image at its full size (100%) in the 2nd image

Thirdfox

^ Hey Pete - glad to see you sold it. Didn't know you were shooting with a D3! Very clean 1600 iso image

pete4130

Thirdfox wrote: »

^ Hey Pete - glad to see you sold it. Didn't know you were shooting with a D3! Very clean 1600 iso image

I'm insulted......its 2000 ISO! Yeah hopefully its sold. I'll be happy when I have the cash in my hand! The D3 is incredbile. It feels like cheating. Minimal post processing, most shots are almost right straight from camera :eek:

Thirdfox

pete4130 wrote: »

I'm insulted......its 2000 ISO!

Opanda says differently

[Image]
Make = NIKON CORPORATION
Model = NIKON D3
Orientation = top/left
X Resolution = 0.03
Y Resolution = 0.03
Resolution Unit = inch
Software = Adobe Photoshop CS2 Macintosh
Date Time = 2008-01-13 15:19:49
White Point = [313/1000, 329/1000]
Primary Chromaticities = [64/100, 33/100, 21/100, 71/100, 15/100, 6/100]
YCbCr Coefficients = 299/1000, 587/1000, 114/1000
YCbCr Positioning = co-sited
Exif IFD Pointer = Offset: 364
GPS Info IFD Pointer = Offset: 1040

[Camera]
Exposure Time = 1/160"
F Number = F2.8
Exposure Program = Aperture priority
ISO Speed Ratings = 1600
Exif Version = Version 2.21
Date Time Original = 2008-01-13 15:08:53
Date Time Digitized = 2008-01-13 15:08:53
Components Configuration = YCbcr
Compressed Bits Per Pixel = 4
Exposure Bias Value = ±0EV
Max Aperture Value = F2.83
Metering Mode = Pattern
Light Source = Cloudy weather
Flash = Off
Focal Length = 150mm
User Comment =
Subsec Time = 0.22"
Subsec Time Original = 0.22"
Subsec Time Digitized = 0.22"
Flashpix Version = Version 1.0
Color Space = Uncalibrated
Exif Image Width = 800
Exif Image Height = 531
Interoperability IFD Pointer = Offset: 1008
Sensing Method = One-chip color area sensor
File Source = DSC
Scene Type = A directly photographed image
CFA Pattern = [R,G],
[G,B]
Custom Rendered = Normal process
Exposure Mode = Auto exposure
White Balance = Manual white balance
Digital Zoom Ratio = 1.53x
Focal Length In 35mm Film = 225mm
Scene Capture Type = Normal
Gain Control = High gain up
Contrast = Normal
Saturation = Normal
Sharpness = Normal
Subject Distance Range = unknown
Gamma = 2.2

pete4130

OK, I'm wrong! I did shoot some at ISO 2000 when I was taking them I thought?

pete4130

PeakOutput wrote: »

doe anyone want to explain the f part now?

pete4130 wrote: »

f numbers relate to the size of the aperture the lens is using (how big the hole is in the lens that lets the light through!) Smaller f numbers such as f1.4 or f1.8 are large apertures/holes. Larger numbers such as f11 or f16 or f22 are smaller apertures/holes (its confusing as the smaller number means a bigger hole!). Wider/bigger apertures/holes allow more light into the lens so you can get faster shutter speeds. Same priciple as your pupil getting bigger in dark situations to let more light in and allow you to see better.

If you go to this link its got a good diagramatic of f numbers and their related apertures:

http://members.shaw.ca/davempicklyk/apertures_50mm1.8.jpg

I thought I'd expand on my explaination and show some images that show the optical differences the f numbers make to photographs.

The first image was shot as f2.8 (large aperture/wide hole) and shows a small Depth of Field (DoF), which means a small, select part of the image is in focus.
Everything in front and behind the focal point being out of focus, more so the further away from the focal point it is. One common use for small DoF is in portraiture to make the subject stand out form the background.
You can see signs of vignetting in the first photo (darkness at the corners of the photo) when shooting at wider apertures/smaller holes.


The second image is the exact same photo except taken at f22 (small aperture/small hole) and shows a large Depth of Field, which means all or almost all of the photograph is in focus. One common use for a large DoF is in landscape photography to make everythign from the foreground to the horizon be sharp and in focus.

Roen

Can't remember who the OP of this was but Tamron do a nice little interactive gadget that shows you FL and aperture relationships

Clicketh here!

Mellor

The OP was me, I knew about FL and RA, was intended as a rought guide for other new users, sucess if you ask me

PixelTrawler

Had a google around for 50MM f1.8 lens - can you point out the one you were talking about at the start of this thread...

Stephen

Are you a Nikon or Canon user? Or something else?

pete4130

Here's the Canon Version:

http://www.canon.co.uk/For_Home/Product_Finder/Cameras/EF_Lenses/Fixed_Focal_Length/EF_50mm_f18II/index.asp

and here's the Nikon version:

http://www.europe-nikon.com/product/en_GB/products/broad/403/overview.html

Sigma do there own version but its very espensive for some reason?

You can get a 1.4 version in the nikon which is 3x the price, but made from a metal rather than plastic, although the 1.8 has been reputed to have better image quality. The question to ask is if the extra 1/2 stop of light is worth an extra €200-€300?
Canon do 2 other versions, a 1.4 & a 1.2 version....obvisouly more expensive than the 1.8.

PixelTrawler

Forgot the mention Im a canon user - cheers guys

Mellor

I have the canon 1.8, great little lens.

I read recently that Stanley Kubrick shot a section of a movie with a f/0.75 lens:eek::eek:
The fastest in history. Was used for a scene lit only be a few candles.

jackdaw

OK 2 q's:

1.
So is a fixed 50mm f1.8 a good investment ?

why not just use my kit lens (18-55) at 50 ?

is the crucial advantage here the f 1.8 value ?

2.
but im confused , an example photo above of a boy on a horse
shows everything behind the kid and horse blurred, but i thought you needed
a high f value (like f11) for this effect ?

bovril

jackdaw wrote: »

OK 2 q's:

1.
So is a fixed 50mm f1.8 a good investment ?

why not just use my kit lens (18-55) at 50 ?

is the crucial advantage here the f 1.8 value ?

2.
but im confused , an example photo above of a boy on a horse
shows everything behind the kid and horse blurred, but i thought you needed
a high f value (like f11) for this effect ?

1. the 50mm 1.8 will be sharper than your kit lens at 50mm and the 1.8 will mean you can shoot in lower light conditions.

2. A low f number 1.8 means a wider aperture and therefore a blurry background. F11 will have your image sharp from front to back (or at least the majority of your picture depending on the distance of the objects). It's a hard idea to get your head around and can be seen easier with a lens that has a wider aperture than 4.0. The easiest way to get your head around it is to play around with your camera on Av when you get it.