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Saturday, July 7, 2012

Professional DSLR Buying Guide!

Step 1DSLR Buying Guide - Basics

Introduction

Digital SLR cameras are quite different from fixed-lens digital cameras. The main advantages of a digital SLR camera are: less image noise at high-sensitivities, interchangeable lenses, a reflex viewfinder and much faster speed of operation. Note that only the reflex viewfinder is truly a property unique to DSLRs. For an in-depth look at the differences between these two types of cameras read our article The Digital SLR Difference.
Nikon D300SToday's digital SLR cameras all have interchangeable lenses. While this provides great flexibility, choosing the right lens or sdt of lenses can be more difficult than choosing the right DSLR. Most autofocus lenses as well as some not-too-old manual focus film SLR lenses can be used on a DSLR but usually show a different angle-of-view.
Note that there currently exists several interchangeable lens cameras which do not a have reflex viewfinder. Instead, they use their rear LCD for framing, an EVF or an accessory optical tunnel viewfinder which must be matched to a specific lens' field of view. These produce some high quality images, very similar to entry-level DSLRs, in a smaller package but without the speed of operation that most DSLRs achieve. These cameras are known as SLD or ILC.

Top 10 DSLR Things To Know

  • 1Digital SLR cameras are defined by their reflex viewfinder and DSLRs are the most efficient when using it. Recent DSLRs feature live-view which enables the rear LCD to show an approximation of the scene. Currently, live-view either means slow autofocus or a cropped preview and is rarely WYSIWYG.
  • 2A DSLR viewfinder sees through the lens. It is easy to judge focus - but not exposure - through it. You can't see how bright or dark a picture will come out before taking it.
  • 3Optical zoom depends on the attached lens. It makes no sense to specify optical zoom when describing a digital SLR camera. Lenses which do not zoom are called prime lenses.
  • 4A DSLR's focal-length multiplier is determined by the size of its image sensor. The angle-of-view of a lens mounted on a particular camera is calculated using the focal-length-multiplier.
  • 5The connector between an SLR camera and a lens is called a mount. Only SLR cameras and lenses with the same mount-type can be attached to each other.
  • 6SLR lenses are zoomed and manually focused by hand. This is faster, more precise and much more responsive than typical electronic zooms.
  • 7All DSLR cameras have full manual controls, manual focusing, custom white balance, high-ISO sensitivities, a hot-shoe for an external flash and can produce RAW images.
  • 8Available apertures are limited by the attached lens. Available shutter speeds are determined by the camera.
  • 9DSLRs started recording video at the end of 2008. Capabilities are improving but only a handful can focus continuously while filming.
  • 10Battery life on a DSLR is significantly longer than most fixed-lens digital cameras unless live-view is used, since the LCD consumes a lot of power and the sensor needs to be constantly active.




Advantages

Image quality produced by a DSLR is higher than most fixed-lens digital camera although it is strongly affected by the choice of lens. A combination of low image noise and high retention of details, particularly at higher ISO settings, places DSLR ahead of fixed-lens. DSLRs can also capture more dynamic range than the vast majority of fixed-lens cameras. However, both types of cameras are equally capable in terms of color, white-balance and exposure.
The most significant performance advantage of a DSLR is in terms of speed. Compared to fixed-lens cameras, a DSLR focuses faster and shoots faster for longer. Most other timings are noticeably faster too, including the shot-to-shot delay and startup time.

Focusing speed is important when capturing a moving subject. The faster a camera can focus, the faster it will take a picture. Shot-to-shot times and burst speed are generally faster at maximum resolution on a DSLR, but there are much faster CMOS-based fixed lens cameras now. Burst-mode is mostly used in action and fashion photography where capturing a precise moment is paramount. Not only do DSLRs shoot faster, they also take more shots in a single burst at constant speed. This increases the chances of capturing a decisive moment.

Disadvantages

DSLR cameras, like everything else, have issues proper to them. The two main issues are price and sensor dust. Even the cheapest DSLR is priced above nearly all fixed-lens digital cameras when one or more lens is included.
Sensor dust is simply dust that enters into a digital SLR while the lens is being changed. One way to minimize it is to buy a single versatile lens and leave it permanently on. Most recent DSLRs also incorporate a mechanism designed to shake-off sensor dust. This reduces the problem but does not eliminate it.
Minor issues of DSLR cameras include the limited live-view functionality, shutter-sound and relative bulk. One cannot always preview how a picture will be exposed. Instead, metering and experience must be relied upon. DSLR cameras have a much louder shutter sound than fixed-lens digital cameras, this can be disruptive in quiet environments or when discretion is required. Finally, one cannot underestimate the impact of camera size. As a general rule, the larger the camera, the less pictures one takes.

Step 2DSLR Buying Guide - Choosing

Sensor Size

DSLR models can have different sensor sizes. The FLM or focal-length-multiplier indicates the proportion of the sensor in relation to 35mm film. The larger the FLM, the smaller the sensor, and vice-versa. A full-frame sensor has the same size as a 35mm film and therefore its FLM is 1. The most common FLMs are 1.5, 1.6 and 2. Here are the important consequences of sensor size:
  • Larger sensors produce images with less noise and higher dynamic range compared to smaller sensors of the same resolution.
  • Larger sensor require larger lenses and are more sensitive to lens defects.
  • Larger sensors show less depth of field at a fixed aperture.
  • The angle-of-view of a lens is proportional to the sensor size. The effective focal-length of a lens is equal to the actual focal length multiplied by the FLM.
  • Lenses are designed with a minimum FLM. So, a full-frame lens is designed for a FLM of 1 and can be used on smaller sensors, like those with a FLM of 1.5. The converse is not true.

Anti-Shake and Stabilization

Anti-Shake MechanismTwo mechanisms exist for reducing camera shake due to slow shutter-speeds and long focal lengths. One way is to incorporate stabilization into the camera body. This way was pioneered by Konica-Minolta and works by moving the sensor to compensate for camera movements. It was originally called Anti-Shake. Sony, who purchased the technology, calls it Super-Steady-Shot. Pentax now has similar technology which it callsShake-Reduction. Olympus calls this iS for image stabilization. Other manufacturers embed stabilization in select lenses by moving an internal lens element, this is called Optical-Stabilization. Canon labels its stabilized lenses with IS and Nikon uses the VR label.
Anti-Shake and Optical-Stabilization appear to be equally effective and allow 2 to 3 extra stops of hand-holding ability. In other words, shutter-speeds can be 4 to 8 times slower than without stabilization. The difference between these two mechanisms is:
  • Body-based stabilization applies to all lenses and its cost is incurred once per camera.
  • Optical stabilization is only available on selected lenses and its cost is incurred once for each such lens.
 

Lens Mounts

A lens mount has 2 purposes. It connects and enables communication between a camera body and its lens. Since physical connections have seldom changed, most lenses can be physically connected to a body with the right type of mount. As lenses were modernized, new features were added to newer lenses and mounts. The consequence of this is that most older lenses can mount on cameras from their manufacturer but not all such lenses fully function on DSLR cameras.
The greatest differentiating factor among DSLR cameras is the lens mount because it gives access to a specific line-up of lenses from the camera manufacturer. Certain third-parties make lenses in multiple lens mounts which generally differ specificationwise and qualitywise from camera manufacturers' line-ups. Lenses made for small sensors are smaller, lighter and possibly cheaper than equivalent lenses for large sensors.

Lens Types

A lens which cannot be zoomed is called a prime lens. Lenses which can be zoomed are called zoom-lenses. Zoom-lenses may be quite versatile for framing but prime lenses commonly have several advantages: lighter weight, wider maximum aperture and smaller size. Their reputation for higher image quality is being disputed.
Lenses have a maximum aperture which frequently depends on its focal length. A wider maximum aperture means that less light is needed and depth-of-field is shallower. When a lens is labeled with two aperture values, one is the maximum aperture at the shortest focal length and the other is the maximum aperture at the longest focal length. When a lens is labeled with only one aperture value, it means that the maximum aperture is the same across all focal lengths. Most new lenses are auto-focus lenses, as opposed to manual-focus lenses which must be focused manually. A lens which can focus closer than a regular one is labeled as a macro-lens.
Like cameras, lenses come in different qualities that cannot be deduced from their specifications alone. Manufacturers each have designations for lenses of various qualities. Lens quality determines its potential sharpness, resolution, contrast and aberrations. Lens quality can strongly influences focus speeds when they include a focus-motor. Canon lenses having a quick and quiet focusing system are labeled USM, Pentax labels those SDM, Nikon calls those as AF-S and Sony calls them SSM.
TIP Read the Lens Buying Guide for more information about understanding and choosing lenses.




Focal-Length

Lenses must be primarily chosen by their angle-of-view on a particular DSLR. Commonly, the 35mm equivalent focal-length is used instead. In 35mm terms:
  • A 50mm lens is considered normal because its shows perspective similar to the perception of a single human eye.
  • 35 to 70mm lenses are considered standard. They are used for general purpose photography and snapshots.
  • Lenses longer than 70mm are considered telephoto.
  • Lenses longer than 250mm are considered ultra-telephoto.
  • Lenses shorter than 35mm are considered wide-angle.
  • Lenses shorter than 24mm are considered ultra-wide angle and show pronounced perspective distortion. Much shorter lenses are mostly fisheye lenses.
  • Portraits are often taken around 105mm, since it produces a pleasing perspective.
To decide what lenses are needed:
  1. Select a range of useful focal-lengths and divide by the camera's focal-length-multiplier.
  2. Divide the maximum by the minimum focal-length to determine the optical zoom.
  3. If the optical zoom is higher than 15X, then more than one lens will be required.
  4. If the optical zoom is higher than 6X, it may be possible to get a single lens but such a lens typically compromises on image quality.
  5. A single zoom or several prime lens can be chosen when a short range is required.
  6. Select one or more lenses to closely match the desired range. Additional requirements such as maximum aperture and minimum focus distance can be considered here to make a final decision.

Step 3DSLR Buying Guide - Models

DSLR Categories

There are fewer models of DSLRs than other types of digital cameras. However, their feature set is often quite similar, particularly among models of a given manufacturer. DSLRs are considered to have the highest image quality among digital cameras. The models that are Full-Frame have an advantage over cropped-sensor models and from those, Four-Thirds models are at a slight disadvantage.
DSLRs are usually grouped into broad categories with unclear distinctions such as Professional, Semi-Professional, Advanced Enthusiast and Entry-Level. Note that for a given sensor size, there is virtually no image quality difference between an entry-level and a professional model, provided they were produced with similarly advanced technology. This means that the year of introduction of a DSLR has more impact on image quality than its category. Below DSLR models are placed into categories based on features intended for advanced users:
  • Entry-Level: The simplest DSLRs in terms of features. Generally smaller and lighter.
  • Advanced: Designed for advanced use. Must have dual control-dials and a greater number of buttons for efficient use.
  • Semi-Professional: Tougher advanced models with weather-sealing for use in adverse conditions.
  • Professional: Tough, weather-sealed models with a 100% Viewfinder for precise framing.
This wide column shows cropped-sensor DSLRs and the narrow column on the right shows full-frame models.

Entry-Level

Advanced

  • Canon 60Da

    18 MP, 5.3 FPS, ISO 100-12800
    •  

  • Canon 60D

    18 MP, 5.3 FPS, ISO 100-12800
    •  

  • Olympus E-30

    12 MP, 5.0 FPS, ISO 100-3200, Built-In Stabilization
    •  

  • Nikon D90

    12 MP, 4.5 FPS, ISO 100-6400
    •  

  • Canon 50D

    15 MP, 6.3 FPS, ISO 100-12800
    •  

  • Sony A700

    12 MP, 5.0 FPS, ISO 100-6400, Built-In Stabilization
    •  
 

Semi-Professional

  • Sigma SD1

    15 MP, 5.0 FPS, ISO 100-6400
    •  

  • Pentax K20D

    15 MP, 3.0 FPS, ISO 100-6400, Built-In Stabilization
    •  

  • Pentax K10D

    10 MP, 3.0 FPS, ISO 100-1600, Built-In Stabilization
    •  

Professional

  • Pentax K-5

    16 MP, 7.0 FPS, ISO 80-51200, Built-In Stabilization, Automatic Horizon Correction
    •  

  • Nikon D7000

    16 MP, 6.0 FPS, ISO 100-25600
    •  

  • Olympus E-5

    12 MP, 5.0 FPS, ISO 100-6400, Built-In Stabilization
    •  

  • Canon 1D Mark IV

    16 MP, 10.0 FPS, ISO 50-102400
    •  

  • Canon 7D

    18 MP, 8.0 FPS, ISO 100-12800
    •  

  • Nikon D300S

    12 MP, 7.0 FPS, ISO 100-6400
    •  

  • Pentax K-7

    15 MP, 5.2 FPS, ISO 100-6400, Built-In Stabilization, Automatic Horizon Correction
    •  

  • Olympus E-3

    10 MP, 5.0 FPS, ISO 100-3200, Built-In Stabilization
    •  

  • Nikon D300

    12 MP, 6.0 FPS, ISO 100-6400
    •  

Step 2DSLR Buying

General Points - For All Digital Cameras

Fuji Finepix F80 EXR RedBuying a digital camera is the final and easiest step. The key to buying the right digital camera is to choose before buying. Settling on one or a few models before buying is critical as there is little chance of finding out accurate information at the last minute. With that in mind, here are 6 points to consider when buying a digital camera:
  • Choose first: Find out before hand which model or models have the right features, performance and image quality for your needs. That is what theGeneral Digital Camera Buying Guide and DSLR Buying Guide are about.
  • Don't rush yourself: Make sure that you have time to learn the new camera before using it for something important. This is very important when going an vacations where you may not have access to information and service for your new digital camera.
  • Don't be rushed by others: Getting the wrong camera can causes a lot of frustrations. Never buy a camera because that model is in stock instead of a model you really wanted. Same thing for specials, you can choosewhere to buy depending on price and specials but not what to buy.
  • Sales people are there to help... themselves: They have different strategies for doing that but do not expect to find out which one. Your best defense is knowledge and to stand your ground. The best sales people will sell you a camera that suits your needs to increase your satisfaction with the store for future business. Even so, it is difficult for someone to understand your needs well enough in a few minutes. There is conflict of interest when they cannot obtain the ideal camera for you.
  • Complete the camera: You need more than just the camera itself. Cameras which use AA batteries rarely come with rechargeables or a charger. Not all AA batteries are the same, so be careful what you buy. If you do not have already the right type of memory card, get a reputable brand in a reasonable size. Here is a hint: Good cards are backed by a lifetime warranty. Fast cards are recommended for video recording and long continuous shooting.
  • Accessorize slowly: It's a good idea to get familiar with a camera before adding to it. Also, if for some reason the camera is not right, then there are less things to return. Some things such as cleaning-fluids, brushes and adhesive protection can't be returned.



Lens Considerations - For DSLR Cameras

Pentax FA 77mm F1.8 LensBuying a DSLR requires thinking about lenses. To get started, you only need one. Buyers may already have compaitble lenses, either from a previous DSLR or from a compatible film SLR. Remember that the field-of-view may change and that some bodies do not support autofocus on all lenses, even if the mount is the same. Lenses are an integral part of a DSLR system, here are 4 important points to know:
  • Choose first: Yes, again. Read the Lens Selection feature article for detailed information. Most importantly, consider your needs in terms of focal-length, aperture, number of lenses and weight. Then, buy the most important of those lenses. Buy more only if you are quite certain it is the right thing.
  • Avoid the kit lens: Most entry level to mid-range DSLR are available as body-only or with a kit-lens. There arereasons why kit lenses are practically given away. Some stores may offer a bundle instead where they sell a body-only DSLR with a lens at a discounted price. These are usually worth the money if the lens sold matches your needs.
  • Strategize: There multiple ways to get all the lenses you need. The most cost effective is to decide on a set of lenses and buy them in order of importance, as budget permits. Another way is to buy a lens with the intention of replacing it with one or more better lenses. With optics it is quite feasible because lenses often keep their value rather well.
  • Do you want a filter with that? Maybe, but not always. It is common to sell a cheap UV-Filter for protection, but be aware that these degrade image quality to a certain degree. The best is to use one for emminent danger like salt-water, sand and perhaps a case of chronic clumsiness. Higher quality filters exist for more frequent use. As for other filter types, consider the thread-size of all lenses you want. It can be extremely costly to get certain filters for all sizes so cost-savings can be made by buying filters in a large size (77m or 86mm) and using step-up rings to adapt them. The catch is that step-up rings usually prevent using a lens-hood.

Where To Buy

Online stores for digital cameras are extremely common. Prices vary and so does their honesty and reliability. There are many reputable places as well.
US, Canadian and International visitors can get their digital cameras from B&H Photo, either online or at their physical store in New York City.
 
Adorama, located in NY city, offers a huge variety of digital cameras, lenses and accessories. The accept orders from the US, Canada and several other countries.

Where Not To Buy

Shady places with ridiculously low prices. Their sales department usually contacts you to confirm your order telling you that everything is an extra, including items that come in the original box. Getting customer service or reimbusment is usually a long and painful process. When in doubt, check several merchant ratings such as Reseller Ratings before ordering anything.
See Camera Confidential for a fun read.


Ref:neocamera
Posted by Than Han at 9:56 PM
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