Tag Archives: Camera lens

Buying Lenses – a quick guide…

Buying lenses

Buying lenses is not as straight forward as it seems. There is a lot to consider.

Critical features to consider when buying lenses

The key to buying lenses is knowing what you want to achieve with your purchase. It is also important to have a clear idea of your budget. However, there are a whole range of other things that have an impact too.

There are a wide range of photographic lenses to buy for most cameras. Each has their own characteristics. A lens can easily cost more than your camera. Take care with your choice. The wrong decision can leave you with a lens that is not suitable to your interest.

Getting started on buying lenses

First of all sit down and write down all the reasons you want a lens. Also, write down all the possible things against buying lenses (of any sort) at this time. Try to convince yourself you really don’t need to buy. In most cases of purchase-fever the buyer gets things they don’t want. So, when spending lots of money you should be careful. Buying lenses is a big investment. If you make the right choice then your purchase may last you through a number of camera bodies. So think carefully and make the right decision up front. That way your money will not be wasted.

I have purchased about thirty lenses over the years. Of those, five were bad purchases. Four were impulse buys – not suited to my needs. In another case, a hasty decision meant I bought a poor quality lens. From this experience I have compiled the list below to help you when buying lenses in future.

Some of the basics for buying lenses

1. Focal Length:

  • a. Measured in millimeters.
  • b. Smaller Focal lengths provide wider angles of view.
  • c. Longer focal lengths show less of the scene and tend to magnify the view.
  • d. Distortion may be found at the extremes of focal length.

2. Aperture:

  • a. Measured in f stops (eg.f2.8 [wide open] f5.6 , f16 [small aperture]).
  • b. Wide aperture lets in most light – faster shutter speeds possible (eg. F2.8).
  • c. Small aperture lets in less light – requires longer shutter opening (eg. F22).
  • d. Wide aperture provides short depth of field.
  • e. Smaller apertures gives sharpness throughout the depth of the picture.
  • f. Zooms – Aperture size gets smaller with increase in focal length.

3. Stabilisation:

  • a. Slow shutter speeds mean more chance of camera movement, which makes blur.
  • b. Stabilised lenses typically give one or two f stops smaller aperture without more blur; the stabilisation compensates for movement.
  • c. Cost is higher if the lens is stabilised.
  • d. Canon = IS (image stabilisation); Nikon = VR (vibration reduction); Sigma = OS (optical
    stabilisation); etc…
  • e. Stabilisation may be in the camera rather than the lens.
General considerations when buying lenses

1. Optical characteristics

  • a. Glass optical quality varies with the production process and ingredients.
  • b. More lens elements/groups reduces light able to pass through the lens.
  • c. High quality optical glass does not reduce light as much as cheap glass.
  • d. Each manufacturer has a specific type of glass for higher quality lenses.
  • e. Optical aberrations come from low quality optical glass.
  • f. Lens optical coatings reduce aberrations and flare.
  • g. Distortions are caused by specific groupings of lenses.

2. Motors/drives:

  • a. Used to drive the aperture control; stabilisation and auto-focus.
  • b. Sometimes noisy – not desirable for wildlife shots.
  • c. Adds a lot of weight to the lens.
  • d. Not necessary on manual-focus prime lenses.
  • e. Some cameras have them only for auto-focus.
  • f. Older lens models have slower, sometimes heavier, often noisier motors.

3. Weight:

  • a. Often forgotten attribute. If you can’t carry it, then it’s no good for you!
  • b. Weight often increases with wider apertures – fast lenses may be too heavy for you.
  • c. Weight will tend to increase the amount of hand-shake movement.
  • d. Stabilisation motors put a lot of weight on the lens too.

4. Sensor optimisation

  • a. Lens focal lengths are usually stated for full-frame cameras (quoted for 35mm sensors).
    But…
  • b. A cropped sensor will still have the same focal length lenses as a full-frame, but image size will multiply it by the crop factor. (See: crop factor).
    So,
  • c. Cropped sensors increase the lenses’ magnification. Eg. Canon APS-C lenses are optimised for the Canon cropped sensor. The crop factor is 1.6. So a 100mm lens on a Canon 450D is actually equivalent to a 160mm focal length on a canon full frame camera like the 5D.
  • d. Different crop factors apply to different manufacturers and cameras.
  • e. Some optimised lenses will not fit different sensor sized cameras – APS-C – check the fit and crop size in the specification for the lens.
More specific issues affecting you when buying lenses

1. Zoom vs. Prime

  • a. Zoom lenses give you a variable focal length; you control magnification.
  • b. Prime lenses have fixed focal length. Move nearer/further to change the angle of view.
  • c. Zooms give you focal control over the framed view.
  • d. Primes tend to be higher quality lenses, sharper, faster (wider apertures).
  • e. Primes more compositionally challenging.
  • f. Primes – colours and exposure control more realistic.

2. Why you want this lens…
Make sure you know why you are buying lenses. Consider these points below:

Fisheye lenses (8 – 18mm on cropped sensor; 14 – 18 mm on full frame)

  • Introduces central focus with peripheral distortion.
  • Highly creative focus provides extreme visual views drawing the eye to the centre.
  • Used primarily for highlighting specific subjects or attributes of the scene.
  • Ideal (according to some) for full-frame sensor work for portraits.

Zoom lenses (long focal lengths 50 to 600mm)

  • Sometimes dubious quality in some parts of the zoom.
  • Flexible for many purposes, but especially wildlife photography at longer focal lengths.
  • Ideal for getting ‘into’ the shot.
  • Creativity related to the placement of the subject in the frame; angle of view variable.
  • Extreme zooms (350 – 800mm zoom ranges)(Very long range lenses greater than 800mm available).
  • Extreme expense – (expect cost around £5,000 for the 800mm sort of focal length).
  • Excellent for specialist wildlife and long range work.
  • Angle of view very limited at extreme end.
  • Very heavy – absolutely requires tripod for longest ranges.
  • Really only supportable for specialist work (professional wildlife photographer).
  • Cheaper to hire for the odd trip.
  • Macro (from around 35mm to 200 mm) (sometimes achieved using extension tubes).
  • Used to get close-up shots of very small subjects.
  • Focal length is artificially extended to magnify for close-up work – aim to get 1:1 or larger result.
  • Can be used for longer views; tends to be at restricted apertures for non-macro work.
  • Great for magnification shots.
  • Great creativity scope.
  • Tilt and Shift.
  • Specialist – for control of where to place sharpness in the depth of field OR how to deal with
    converging parallels (lines in the road or converging verticals in buildings).

Wide angle lenses (16 – 24 mm on cropped sensor) (24 – 35 mm on full frame sensor)

  • Used for getting wide views of the subject; sweeping view across a scene.
  • Some optical distortion at the very wide end accentuates central subjects.
  • Tend to be used by landscapers; often capable of very small apertures (f22 – f36).
  • Standard zoom lenses (35mm to 200mm of varying focal lengths).
  • Provide great flexibility because can change from wide angle to magnification.
  • Quality often highly price dependent.
  • Optical quality variable with change in focal length.
  • Very long focal lengths often have high f-stops (eg. F5.6).

Standard prime lens (50mm)

  • Sees approximately what the human eye sees (full-frame sensor cameras).
  • Slightly wide angle for cropped sensors.
  • Usually good low light performance because of aperture size is usually wide.
  • Approx.. 80mm for cropped sensors – good for portraits.
  • Creativity allows for the same flexibility that the eye sees.
  • Controlled angle of view is determined by photographers position (no zoom control).
  • Standard prime lens (80mm).
Ultimately it is about image quality

When you are buying lenses consider what you are going to get. If you buy a cheap lens you will get a poor picture.

Most modern camera bodies are going to produce pretty good pictures. But if you stick a poor quality, budget lens on a camera it will give you a poor result. A top quality lens will serve you for many years. It will swap between bodies of the same manufacturer. It will produce quality pictures from your body.

On the other hand a poor quality cheap lens will degrade the ability of the camera body. Which will devalue your overall investment. It is pointless upgrading a body to a higher specifications if your lenses are not up to the same performance standard. Buying lenses is about setting your aspirations. Buying lenses of poor quality is about limiting your potential, for now and for years to come.

Buying lenses – checking the various options

The sheer number of lenses available is daunting. Try starting with a lens finder. This great Lens finder on Amazon.co.uk makes buying easier.
Note:
USA users may not be able to get the above “Lens finder on Amazon.co.uk” link. See below…
Link version for USA users: Amazon.com Lens Finder
Please report problems with these links.


If you are buying lenses enter the important factors for your lens choice. It returns a list of the lenses to suit that purpose. I find this an invaluable tool for helping to me to find a range of lenses from which to make my ideal purchase.

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Damon Guy (Netkonnexion) - Author of Buying Lenses

Damon Guy (Netkonnexion)

Damon is a writer-photographer and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photogs.
See also: Editors ‘Bio’.
By Damon Guy see his profile on Google+.

Ten simple ideas to improve your photography (and a fun quiz)

Ten Tips

Ten Tips and 12 fun quiz questions.

Simple things help you…

We should all take a step back and think about the basics sometimes. It helps us remember essential techniques and keeps us on our toes. Here are the basics with some fun quiz questions too.

The simplest techniques in photography are often the most important ones. In this post we make sure we don’t forget them…

10 essential things to know; 12 fun quiz questions
  1. Not knowing your camera: This is really bad news. If you are hoping to improve your photography make sure you learn what every lump, bump, dial, screen, lens and twiddly bit does. Read your manual regularly. Practice with each function until you have got it right. Then practice it in the dark so you can do a night shoot.
    Quiz Question 1: How many lenses are there on a camera? Answers at the end!
  2. Poor stance: Most people when starting photography don’t realise that the way they stand and hold the camera creates all sorts of problems and poor performance. If you are a keen photographer a good stance can contribute to improved sharpness (hand-held shots), better focus, more steady hand and better shot timing. Learn to stand properly right at the start and you will save yourself lots of re-training time later.
    Quiz Question 2: At what point in the breath cycle is it best to take your shot?
  3. Not using a tripod: classic mistake. Tripods save you lots of time and give you pin sharp photographs. They give you an opportunity to set your camera up properly and ensures that your are ready for your shot.
    Quiz Question 3: A monopod has one leg, a tripod has three legs. What is, and how might you use, a bipod?
  4. Not giving the camera time to focus: When you press the shutter button halfway down it causes the auto-focus to cut in which focuses the camera. But if you punch straight through that to the shot the focus has not had time to do the full focus. This normally happens on the first focus attempt when the focus is right off. After that the lens in nearly focused and will adjust more quickly. So don’t make your first focus attempt too close to the shot or it will be blurred.
    Quiz Question 4: Why do you have two rings on a modern auto-focus/zooming photographic lens? What do you call each of them?
  5. Taking pictures against a bright light? Cameras don’t like very bright lights. Especially if there are also very dark spots nearby. Shooting indoors while looking at a window out to a bright sky will cause a strong white spot. This is very distracting and draws the eye away from the subject. Not good. There are Light and Lighting resource pages on Photokonnexion for you to learn more.
    Quiz Question 5: How many stops of light can healthy human eyes see (20:20 vision)? How many can the camera (rough generalisation) cope with?
  6. Relying on flash (especially pop-up flash): Pop up light has a very small concentrated source. It discolours faces, washes out colours, creates harsh, sharp-lined shadows and is badly placed (too close to the optical axis) creating nasty highlights on faces. Try to use natural light more. It is much more forgiving and does not produce such harsh shadows most of the time.
    Quiz Question 6: What is often the result of using pop-up flash with respect to two parts of the face?
  7. Dead centre subject: If you put the subject of your picture in the centre it will usually be boring. If you off-set your subject the eye will be looking to see why the symmetry is broken. That keeps the eye hunting around the screen. Learn about the “Rule of thirds” and other Composition principles. That will help you make the shot more compelling to the eye.
    Quiz Question 7: What type of compositional perspective would you be working with if you want to promote a three dimensional feel to your picture composition?
  8. Horizon control: Make sure your horizon is level, especially if it is a seascape. If you leave it on an angle the picture will be ruined because it will look like the sea is sliding off the page! Horizons also induce mid-picture viewer-stupor. Make a decision. Either shoot for the sky in which case place the horizon in the bottom third of the picture. Or, shoot for the ground in which case the horizon goes in the top third of the picture. An off-set horizon is more dynamic and keeps the viewers eye moving.
    Quiz Question 8: If your main choice is to shoot for the sky, where would you take your exposure from? (Where would you point your viewfinder focus point?) a. The sky? b. The ground?
    Quiz Question 9: Describe autofocus hunting and why it happens?
  9. Simplify, simplify, simplify: The most effective way to show a subject to your viewer is to de-clutter the picture. Take out of your composition everything that is nothing to do with the subject. The more you make the viewers eye go to the subject the more effective your shot will be.
    Did I mention that you should simplify your shot?
    Quiz Question 10: What is it called when you paint out something from your picture in post processing to simplify a shot?
    By the way, did I mention that you should work really hard to simplify your shots?
  10. Go manual: Auto-modes on your camera are really best guesses about what the manufacturer thinks will be suitable for the average shots most snappers will take. Buy you are a keen photographer. To get the camera to do exactly what you want, and to make discerning choices about your images you should work on improving your manual control. Your understanding of photographic principles will improve, your skill at exposure will improve and you will find yourself making informed choices about how you want your picture to come out. You will turn from a snapper into a photographer.
    Quiz Question 11: What does the ISO control do? a. Adjust the sensitivity of the digital image sensor or b. Change the aperture size?
    Quiz Question 12: Does ‘shutter speed’ or ‘aperture’ control movement blur?
Answers to quiz questions
  • Quiz Question Answer 1: I am talking about any camera that has a lens, not just DSLRs. the number of lenses is a matter of variation. If you are discussing photographic lenses then only that one will count (but read on). Some people think of each glass element in the photographic lens as an independent lens. Technically that is not true. They are optical lenses or glass elements, not photographic lenses. However, if the photographic lens (and elements if you included those) were all you counted you would be wrong. Here is a short list of Possible lenses on a camera of any sort…

    There may be others.

  • Quiz Question Answer 2: You should take a shot at the full inhale point or full exhale point before inhaling or exhaling in the next part of the cycle. You can choose which is best for you. All you do is delay the next part of the cycle while you take a shot. This is the point in the breath cycle when there is least movement of the shoulders/chest. Read more about it in Simple tips for a good stance
  • Quiz Question Answer 3: A bipod is photographically uncommon. Understandably, it has two legs. Find out more here… Definition: Bipod
  • Quiz Question Answer 4: The two rings on an auto-focussing photographic lens allow one ring to focus the image – the focus ring. The other ring is for zooming the lens. The latter changes the focal length and is called the focal length ring.
  • Quiz Question Answer 5: Human eyes can see about 18 to 20 stops of light when healthy. However, by contrast the best commercially available cameras have to operate with a dynamic range of 8 to 12 stops of light. Research is pushing the boundaries but there is still a big gap to meet the dynamic range of the human eye (in 2013).
  • Quiz Question Answer 6: Pop-up flash is very likely to cause red-eye.
  • Quiz Question Answer 7: To make things look three dimensional in your image you should be working with three point perspective. Look for lines in your image that promote cube-like structures. For example buildings, walls and other objects with lines and shapes that have a solid feel in real life. This will trick the eye into believing that there is a solid object in the picture. Read: Simple ideas about perspective in photography and: Definition: Perspective
  • Quiz Question Answer 8: If you shoot for the sky you will need to be taking your exposure from the sky as that is the brightest point. This will leave the ground darker in your exposure than you would see it with your eye. You can use one of a number of techniques to correct that later.
  • Quiz Question 9: Auto-focus hunting is when the auto-focus in the lens cannot focus and will keep going up and down the focus range trying to get a focus. This is a common problem at night, in darker conditions, low contrast conditions and clear or totally grey skies. You can read more about it in: Auto-focus ‘Hunting’ Definition: Hunting, Auto-focus

  • Quiz Question 10: when you paint out something from your picture in post processing to simplify a shot? You normally use a cloning tool. You can find out more in: Definition: Cloning; To Clone; Cloned; Clone Tool.
  • Quiz Question 11: What does the ISO control do? It adjusts the sensitivity of the digital image sensor allowing you to work in bright light (low ISO setting) or low light (high ISO setting). There is an article on ISO here: ISO.

  • Quiz Question 12: Shutter speed controls movement blur. Aperture controls blur (bokeh) created by the loss of sharpness outside the zone of acceptable sharpness. This is traditionally known as the depth of field. More reading on: Definition: Exposure and related to aperture: Definition: f number.

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By Damon Guy (author and Photokonnexion editor)

Damon Guy - Netkonnexion

Damon Guy (Netkonnexion)

Damon is a writer-photog and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photogs.
See also: Editors ‘Bio’.
By Damon Guy see his profile on Google+.