What is a compact DSLR and how does it differ from a “regular” DSLR? (And what does DSLR mean?)
Compact DSLRs and “regular” or full-size DSLRs are the Digital counterparts of traditional 35mm film cameras, specifically Single Lens Reflex cameras. Single lens reflex cameras allow you to view the scene through the camera’s lens via a mirror and prism system, i.e., a reflex viewing system. DSLR is an abbreviation of digital single lens reflex.
The difference between regular―or full-size DSLRs―and compact DSLRs has more to do with the size of the imaging sensor than the size of the camera, although compact DSLRs are invariably physically smaller than full-size DSLRs, hence the nomenclature, "compact." Full-size (or full-frame) DSLRs contain imaging sensors that approximate the size of a standard 35mm negative or slide, which is 24 x 36mm.
Compact DSLRs contain imaging sensors that are about 50% smaller (23.6 x 15.8mm) than a standard 35mm film frame. The exceptions to this rule are compact DSLRs from Canon, which are about 60% smaller (22.3 x 14.9mm) than a standard 35mm frame (and no, the 10% difference in the physical size of the sensor does not measurably affect the image quality, as any camera reviewer and Canon owner will readily affirm).
What is a "lens magnification factor" and what does that mean in terms of choosing a lens for my camera?
Because the imaging sensors in compact DSLRs are 50% (or 60% for Canon) smaller than full-size imaging sensors, the field of coverage of standard 35mm lenses is correspondingly 50% (or 60%) less. In other words, the resulting images look “more telephoto.”
The formula for figuring out the focal-length equivalency of a 35mm-format lens used with an APS-C format sensor is as follows: multiply the focal length of the lens by 1.5, or in the case of Canon compact DSLRs, 1.6.
As an example, a 50mm “normal” lens used on a compact DSLR records a field of view (FOV) comparable to the FOV of a 75mm (or 80mm) lens, which effectively turns it into a short telephoto lens. Similarly, wide-angle lenses become less wide, i.e., a 20mm lens records the FOV of a 30mm (or 32mm) lens and a 28mm lens effectively becomes a closer-to-normal 42mm (or 44.8mm) lens. Telephoto lenses are equally affected. A 200mm lens effectively becomes the equivalent of a 300mm (or 320mm) lens and a 300mm lens effectively becomes a 450mm (or 480mm) lens, etc.
How many megapixels are enough?
This is a loaded question, and the straight, honest answer is that the most basic compact DSLRs―which contain 10MP imaging sensors―pack enough resolving power to produce lovely 16 x 20” color or black-and-white prints from sharp, properly exposed image files. Everything after that is pure gravy.
Some compact DSLRs capture JPEGs and RAW files. How important are RAW files?
A sharp, properly exposed JPEG captured with a compact DSLR can produce excellent imagery. The limitations of JPEGs is that JPEGs only retain data based on whatever presets you program the camera to capture, i.e., white balance, exposure, tone and contrast settings, etc.
RAW files, which are also called digital negatives, contain all of the exposure data, and all of the exposure settings are established when the RAW file is processed post capture, creating a new image, which if properly processed can contain more detail and better overall image quality than a JPEG. The RAW file remains as is, and can be reprocessed an infinite number of times.
Click image above to view screen shot.
Do compact DSLRs come with a lens or do you have to purchase a lens separately?
It depends on the make and model. Some compact (and full-size) DSLRs are offered either as body only or with a “kit” lens. The kit lens is almost always a zoom lens with a wide-angle to short or mid-range telephoto focal range, usually in the equivalent range of what would be a 28 to 90mm or 105mm lens on a full-frame camera.
Some compact DSLRs are also available as two-lens kits containing a wide-to-short telephoto lens (described above) and a longer zoom, most commonly a lens in the 55-200mm zoom range. Between the wide-to-short tele zoom and the longer kit zoom, you’re pretty well covered from an equivalent focal range of about 28 to 300mm.
Do compact DSLRs use the same lenses as full-size DSLRs?
Yes, and with few, if any, exceptions almost all currently manufactured lenses are designed to cover full-frame (24 x 36mm) image fields. And this would apply to most full-frame lenses made within the past decade. Just remember to take the magnification factor (1.5x or 1.6x) into consideration when selecting focal lengths for any particular scenario.
If I buy a lens made specifically for a compact DSLR can I also use it on a full-size DSLR?
As a general rule, no, because:
- The image field of lenses designed to cover the field of coverage of an APS-C format sensor falls short of the corners of a 24 x 36mm (full-frame) image area.
- The lens and camera mounts of most compact (APS-C format) DSLRs and lenses differ from the lens and camera mounts of full-frame DSLRs made by the same manufacturers.
The exceptions to the above generalities are some of the pro-level DSLRs that can accept and detect smaller-format lenses and automatically mask off the “dead areas” that lie outside of the APS-C image area in the viewfinder as well as on the image sensor, making it possible to shoot APS-C format images on full-frame DSLRs.
What about using a lens designed to cover a full-size DSLR on a compact DSLR?
With almost all lenses made within the last decade, this should not be a problem. Just remember to keep the magnification factor in mind when considering your choice of focal length.
Are lenses that are designed for full-size (24 x 36mm) DSLRs sharper than lenses designed for use with compact DSLRs when used on compact DSLRs?
Technically speaking, a lens designed specifically for use on an APS-C format DSLR should produce sharper imagery than an equivalent focal length lens designed to cover a full-frame imaging sensor. This is because lenses are designed to resolve “X” amount of data (usually defined in terms of “lines per inch”), based on the surface area of their intended imaging format.
Therefore, based on the above scenario, when using a 50mm full-frame lens on an APS-C format DSLR, you’re not making full use of the resolving power of the lens compared to the resolving power of a 50mm lens designed to resolve the same detail onto a smaller image area.
But, depending on a number of variables including the real resolving powers of each particular lens and camera sensor, the differences may or may not be detectable, most notably in images taken for Web-only usage or smaller print sizes.
Many entry-level DSLRs can shoot video. What’s the difference between 720p and 1080p video?
The terms 720p and 1080p have to do with resolution. Video captured as 720p produces video imagery measuring 1280 x 720 pixels. Higher-res 1080p video signals measure 1920 x 1080 pixels. HD TVs are available in both 720p and 1080i formats, and both will play back video in either format by internally “up-converting” or “down-converting” the original signal to match the broadcast format. Although the native recorded format usually displays the best image quality, up-converting or down-converting the incoming signal to match the broadcast signal works quite well for all but the fussiest HD TV viewers.
Why do I need Scene and Exposure modes?
Scene and Exposure modes help fine-tune the act of snap shooting. As an example, “Snow” mode adjusts the exposure and color-balance settings to compensate for the bright reflective qualities and excessive bluish tint common to snow scenes. Similarly, “Fireworks” mode boosts the ISO sensitivity of the camera’s imaging sensor while slowing down the shutter long enough to record the color trails of the fireworks. Other common Scene Modes include Sunset, Sepia, Black and White (Monotone), Foliage, Portrait, Pets and Landscape.
Are accessories interchangeable between compact DSLRs and full-size DSLRs?
With the exception of batteries, battery grips and the occasional remote-control device or cable, most accessories should be compatible across the same or similar-generation DSLR product lines from any given manufacturer.
What accessories should I consider purchasing to go along with my compact DSLR?
Additional items worth considering to go along with your DSLR include the following:
1. Memory Cards At the very least, you should always have a minimum of 1GB of memory in your camera and more if you plan on shooting JPEG+RAW stills and HD video. If you think you're going to shoot video and/or RAW+JPEG stills, both of which gobble memory like there’s no tomorrow, you should double, triple or quadruple that number, depending on how far you plan on being from a laptop or other data-downloading device. Always buy a faster memory card than you think you need, because sooner or later, you’ll probably need it.
Always buy better memory cards than you think you’ll need.
Avoid memory cards with prices that are “too good to be true,” because they usually are, especially if you’re depending on great results when taking pictures of special occasions or when traveling to once-in-a-lifetime locales.
While point-and-shoot digicams do not require the same performance levels as pro-quality DSLRs, the memory card you purchase today will most likely be usable in the next camera you buy, and maybe even in the camera you buy after that. Consider purchasing a higher-performance card than your current camera requires, because your next camera will almost certainly require higher performance levels than the camera you purchase today, which will more than justify the few extra dollars you spend for a better card today.
2. Spare Battery Always carry at least one spare, especially if you plan on shooting in colder environments where low double-digit and single-digit readings can quickly neuter a freshly charged battery well before its intended time. (20 minutes to a half hour in a warm pocket is usually enough to jumpstart it while you shoot with the spare.)
3. Battery Grip The benefits of using a battery grip include a secondary shutter release and camera control dial for (comfortably) adjusting exposures and firing the shutter when holding the camera in a vertical position.
Photographers with larger hands also like using battery grips because they afford them something “meatier” to hold on to when shooting and more importantly, a place to rest the two fingers that always seem to end up hanging there with nothing to do.
Lastly, battery grips hold a second battery, which essentially doubles the number of exposures you can fire off before having to recharge them or simply call it a day. Some battery grips also offer the option of using standard AA batteries, which can be a lifesaver if you’ve exhausted your lithium-ion batteries and there are still another 45 minutes of pretty light in the western skies.
4. External Flash Even though all compact DSLRs contain built-in flashes, their abilities are mostly limited to smaller, informal “party shots” and outdoor fill flash. External, shoe-mounted flashguns, a.k.a. Speedlites, Speedlights, etc., feature anywhere from two to four times the power output along with the ability to soften shadows by bouncing the light from low ceilings and adjacent walls, as opposed to the dead-on, flash-in-the-puss look of pop-up flashes.
Most top-tier flashguns also feature “zoom heads,” which automatically adjust the spread of light to complement the angle of view of the focal length of your lens. There are also numerous light-shaping tools, i.e., softboxes, diffusers, snoots, etc., designed to shape the light to match your needs.
Other tools one should consider when purchasing a flashgun are TTL off-camera flash cords, which allow you to move the flash up to an arm’s length off-center of your subject to “model” the light. Many flashguns also allow for wireless remote flash using built-in or plug-in accessory triggering devices.
Additional considerations you should address when shopping for a compact DSLR:
1. How does the camera feel and function? Specs and “expert reviews” aside, how the camera feels in your hand, how intuitive the menus and controls are to you in your hands, and the brightness and ease of viewing in the camera’s viewfinder, are all factors that will help you decide which camera is the best camera for you.
2. Are you already vested in lenses from a previous camera system? While this should not be a prime motivator when it comes to buying a camera that fits your particular current needs, it is definitely part of the equation. If, for example, you own or have easy access to older Minolta AF lenses, be advised they are perfectly compatible with all current Sony Alpha DSLRs. Similarly, almost all Pentax lenses―including older manual-focus lenses dating back to the 1960’s can be used with all current Pentax DSLRs directly or via adapters. Although manual-focus lenses remain manual focus and you are limited in terms of shooting modes and almost all forms of data transfer, the lenses work―dust reduction and all.
3. Does the compact DSLR you are considering also capture video? In addition to stills, most compact DSLRs also capture 720p or 1080p HD video. If you’re interested in motion pictures, this should certainly be taken into consideration.
And don’t forget about a good bag to go along with your new camera system.
Quick Comparison Guide fo Consumer (Entry-Level), Prosumer, & Pro DSLRs
|Consumer DSLRs||Prosumer DSLRs||Pro DSLRs|
|Sensor Size||APS-C||APS-C, Full Frame||APS-H, Full Frame|
|Construction||Polycarbonate||Metal Alloy / Polycarbonate||Metal Alloy (some polycarbonate)|
|Viewfinder Coverage (approx.)||95% to 97%||95% to 100%||98% to 100%|
|Prism Finder||Pentamirror (almost always)||Pentamirror or Pentaprism||Pentaprism|
|Longest Shutter Speeds||Up to 30 seconds + Bulb||Up to 30 seconds + Bulb||Up to 30 seconds + Bulb|
|Highest Shutter Speeds||1/2000 to 1/4000||1/4000 to 1/8000||1/8000|
|Maximum Frames per Second||Up to 4.5 fps||Up to 7 fps||Up to 10 fps|
|Flash-Sync Range (approx.)||1/125 to 1/200||1/160 to 1/250||1/250 to 1/320|
|External (PC) Flash Sync||Seldom||Usually||Always|
|In-Camera Flash Bracketing||No (or seldom)||Depends on Model||Yes|
|Dual Memory Card Slots||No||Depends on Model||Yes|
|Dual Image Processors||No||No||Depends on Model|
|Stereo Mic Outlets||Depends on Model||Depends on Model||All Video-enabled models|
|Stereo Audio||Depends on Model||Depends on Model||Yes|
|APS-C Lens Support||APS-C only||Depends on Model||Depends on Model|
|Optional Battery Grips||Depends on Model||Yes||Built-in (almost always)|
|HD Video Quality||720p / 1080p||720p and/or 1080p||720p and/or 1080p|
|Depth-of-Field Preview Button||Seldom||Depends on Model||Yes|
|Interchangeable Focusing Screens||No||Depends on Model||Yes|
|FireWire Connectivity||No||Rarely||Most Likely|
- Entry-level DSLRs contain APS-C format imaging sensors, which are approximately 50% smaller than a “full-frame” 35mm (24 x 36mm) negative or slide. The exceptions are compact DSLRs manufactured by Canon, which contain imaging sensors that are 60% (1.6x) smaller than full-frame images.
- When considering lenses, you must factor in the field of view of the smaller sensor size compared to the field of view afforded by the same lens with a full-frame DSLR by multiplying the focal length by 1.5 (or 1.6 for Canon).
- The pixel count of the imaging sensor should not be your prime consideration because the smallest APS-C sensors, which contain about 10 megapixels, contain more than enough resolving power to produce high-quality prints up to 16 x 20” or more, and far more resolution than needed for Web use.
- Most compact DSLRs are available with or without a kit lens, which is usually a zoom lens with an equivalent focal range of a 28-90mm lens on a full-frame 35mm camera.
- Lenses made for full-frame (D)SLRs work perfectly fine with compact (APS-C format) DSLRs, but lenses designed for use with compact DSLRs only work with select full-frame DSLRs.
- In addition to stills, most compact DSLRs can also capture 720p or 1080p HD video.
- With the exception of batteries (occasionally) and battery grips (always), most concurrent DSLRs can share accessories including flashguns, cords and remotes (sometimes), etc.
- You should always carry a spare battery and memory cards.