Evaluate how well a Lens meets your needs and compares to competing products
If you've completed step one you've identified what you need in a lens and you've learned about the different features of lenses. While you were doing your research, you probably started the process of determining which features - and thus which type of lens - will best meet your needs. Now you are going to continue that process, but in greater detail.
In this step you will
evaluate the lenses available on the market to determine how well they meet your personal needs and establish, by a process of elimination, an initial short-list of contenders. Then you will compare these short-listed lenses to find out which ones stand out from the competition.
Evaluate how well a Lens meet your needs
Your priority at this point in your evaluation is to find the available lenses in the market that best meet your needs. You can save a lot of time during this activity by quickly eliminating any lenses that are unsuitable because they don't meet your key requirements. For example, if you have a limited budget for this purchase then you can ignore any lenses that clearly exceed your price limit.
Your choice of lenses is virtually limitless. Cameras offer a choice of a fixed unchangeable lens or a changeable lens mount. If the camera you purchase does not allow the lens to be replaced, you will need to purchase a camera capable of capturing the images you want with the pre-installed lens.
Cameras such as single lens reflex (SLR), medium and large format cameras allow for lens changes to suit the operator's needs. The range of lenses obtainable for these cameras presents an unlimited vista of photographic opportunities.
Lenses are divided at the most basic level into manual and auto-focus types. Auto-lenses automatically handle all the picture-taking chores. The manual types allow the operator to input focus and aperture size.
Tip:
Always ask your salesman if the camera you are considering, whether it is a film or digital model, has a lens changing capability.
The focal length is the distance between the center of the lens itself and the film or image capture surface. Focus determines the clarity or sharpness of the image. Special effects can be used by varying the focus process. The focal length of a lens is denoted in millimeters (mm). Focal lengths range from less than 17 mm (very close-up) to well over 1200mm (extreme long distance).
Aperture size is determined by an internal diaphragm device which controls the amount of light entering the camera. Literally, it is a hole through which the light enters the camera and is adjustable for size. The aperture is normally denoted by an f/ (known as an f-stop) number such as f/4 or f/16.
Tip:
Aperture sizes are confusing in that the smaller the stated aperture size - e.g. f/4, f/1.2, etc is ideal for portraiture - the larger the amount of light the aperture actually allows to enter the camera. The larger numbers such as f/16, f/22, etc are ideal for landscape as smaller amounts of light will enter the camera.
Apertures are often referred to as having a slow to fast speeds. This refers to the fact that the larger the aperture opening (the lower the f/ number) the more light is allowed into the image capturing chamber. The larger and quicker the volume of light allowed, the faster the image can be recorded, hence, a “faster” lens.
The combination of focal length and aperture size are the primary determinates of the lens price. The more difficult the focal length is to produce and the larger the aperture size will be, the more expensive the resulting lens. Other features such as quality, extra elements in the lens, and special purpose lenses will also add expense.
Selecting the correct lens for your purpose will depend upon your image needs. Close-up, sporting events, landscaping, wildlife photography and many more types of photography all are improved when the correct lens is selected. The focal length of the lens is the primary determining factor in the selection process. Aperture size ranges are available to suit your needs for each focal length category.
Tip:
A “normal” lens is the best over-all lens available as well as the most popular. A 50 to 55 mm lens capable of up to an f/1.8 aperture size will perform well for most general photographic situations.
Lens focal lengths fall into one of several categories. A normal lens is so-called because the image seen through the viewfinder is basically the same as seen through the naked eye. A normal lens is of a fixed focal length around 50 mm. A wide-angle lens provides a larger depth of range making them ideal for large group focus.
A fish-eye lens captures a 180 degree angle of view and sometimes even more. It is an extreme lens providing an unusual perspective for special effects and purposes. Some fish-eye lenses are capable of providing a near circular image. These lenses have a unique landscape image recording capability.
Telephoto lenses can “reach-out” and capture distance subjects. A moderate telephoto lens of 85 to130 mm has a range of capabilities from portraiture to landscape photography. A medium telephoto lens of 135 to 300 mm is considered a middle-distance capability. Sporting events and subjects in the near-distance are captured by these lenses. A medium telephoto lens is heavy, but unlike its cousin the super-telephoto lens, can be used to good effect without a tripod.
The super telephoto lens is a specialized instrument. It is normally very heavy and when attached to the camera the system should be supported by a tripod to assure image clarity. These lenses are available from 400mm to over 1200 mm. Capable of capturing extra long distant subjects they are used for a huge range of special purposes. A high-quality 400 mm lens with a variable aperture is a near-perfect instrument to capture wildlife pictures.
A macro lens which can be of virtually any focal length varies from other lenses in that they are capable of being focused to an extremely close range. Macro lenses are capable of capturing minute subjects in a frame-filling image.
Zoom lenses provide a range of adjustable focal lengths. Various lenses have unique ranges such as 17 to 35 mm, 55 to 130 mm, or longer lengths of 300 to 400 mm. These lenses offer the ability to quickly capture images at various distances by a simple adjustment without changing the lens. Zoom lenses are extremely useful, but limited in generally having a slower aperture speed and are often quite heavy.
There are some special purpose lenses available which purposely distort the image onto the image capturing surface. These lenses are generally used for distinctive creative effects. A shift lens offer unique vistas of buildings and landscapes for limited purposes.
If your camera is not a 35 mm film type camera there are tables which identify the equivalent focal length references as compared to the 35 mm. In addition, digital camera lens and micro-chip technology is evolving so rapidly that focal length (both mechanical and digital adjustable) and traditional aperture size referencing would be nearly unintelligible to the non-technical layman. For these newer digital cameras a “35 mm equivalent” is offered so that you will be able to understand the capability of the camera.
When you were considering your requirements in a lens it's likely that you singled out certain factors such as manual or automatic focus, telephoto, wide angle or special feature, compatibility with existing equipment and cost as being of major significance. As with so many other products, the more features offered, the higher the price.
Buyz123 has created a checklist containing examples of major features; you can work from this checklist when evaluating how well various lenses meet your personal needs:
Features Checklist
Basic Lens Types
Lens Features
- Focal length
- Aperture - slow to fast
- Mirror or reflex lens
- Apochromatic - used to correct color distortion and blurriness
- Image stabilization
Photographic Lens Categories
- Normal - 50 to 55 mm
- Wide angle - Any with 180 degree view
- Moderate telephoto - 85 to 130 mm
- Medium telephoto - 135 to 300 mm
- Super telephoto - 400 to 1200 mm
- Macro - 60 to 300+mm close focusing ability
- Zoom - 70 to 300+ mm
- Special effects - Various, create spherical distortions
- Lens extender - 1.4x and 2.0x
Uses of Lens Filters
- Lens protection
- Color correction
- Special effects
Lens Filter Types
- UV, haze and other protection
- Polarising
- Contrast and color correction
- Digital camera filters
- Color conversion
- Special effects
- Infrared
- Neutral density
Warranty
There are a lot of features listed here, and some of them may not be relevant to your particular requirements. So, work your way through the list and assess how each of these features impact on your lens needs. You can then create a personalized checklist of the features you really require.
Once you have finished evaluating the lenses available for sale in the light of your personal needs and arrived at a short-list of 'possibles' you are ready to progress to the next stage. This involves comparing the lenses one-on-one in order to find those that really stand out.
Evaluate how well a Lens compares with competing Lenses
Comparing the items on your interim short-list, one to another, is an important part of the purchasing process - we all want to buy the best lens we possibly can. So once you have established a short-list that meet your needs it is time to evaluate how well they compare in fine detail. This way you can assemble a select list of lenses that stand out from the crowd.
Questions to ask yourself:
Which lens on my short-list offers the best value for money?
Which of these lenses best meet my needs?
Which has the best warranty?
Which lens is the easiest to use?
Which of the lenses seems of the highest quality?
Which lens do I like best?
By answering these simple questions, you are actually eliminating lenses that aren't absolutely right for you. This is an excellent time - if you haven't done so already - to evaluate how well your short-listed products measure up in the following areas: Physical Quality, Warranty Conditions and Accessories & Extras.
Physical Quality
Regardless of the method you use when purchasing the lens, you need to find an opportunity to examine the product to evaluate how well it is made, and to check that it is truly suitable for you and your purpose. This is the time to examine the quality of the materials, and how well the lens is put together. Check the assembly - is the lens solidly constructed? It's also important to examine the lens from the perspective of ease of use. How easily is the lens prepared for cleaning and maintenance? Are the controls easy to use? Make sure the lens is user-friendly - some lenses look great on paper, but unexpected problems will show up when you finally get your hands on them.
Physical Inspection Checklist:
- Materials - quality, appearance
- Assembly - all parts held together securely, good quality fittings
- Solidly constructed - stable, no loose components
- Proper fit of removable parts - easy to remove and replace, fit snugly
- Controls - visible, easy to use, accessible, clearly labeled
- Size and weight - appropriate for surroundings and purpose
- Appearance - well finished, appropriate color, neat fittings etc
- Easy and comfortable to use
Warranty Conditions
Similar products may be available with significantly different terms and conditions, and you want to get the best deal you can. Parts and labor are often covered under separate warranties, for different time periods; sometimes there can be a significant difference in the warranty offered with one model compared to that offered with the next model up. It is particularly important to investigate any conditions that might void a warranty, such as if you attach the lens to the camera incorrectly.
Warranty Checklist:
- Duration - check the specifics
- Parts, Labor, Mechanical
- Exactly what is covered
- Exactly what is excluded
- Conditions or actions that may void the warranty
Accessories and Extras
When evaluating similar products, it is a good idea to include accessories in your assessment. You need to be clear about exactly what accessories are really necessary, and whether these can be included with the purchase. What other extras are required - do you need a lens carry case, for instance? What about a contract or service plan?
Accessories Checklist:
- Accessories - included or extra cost?
- Upgrades - will the product need upgrades, what are the costs?
- Compatibility issues - will it work with your existing products?
- Contracts or Service Plans - conditions, penalties, costs
- What else will you need to get the most out of your camera lenses?
Once you've worked through the Evaluation step you will have a final short-list of lenses that meet your needs and stand out from competing products on the market. It's time then to move on to the third and final step: Purchase.
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