As of April 2020, SIGMA offers two mirrorless-exclusive zoom lenses, the 14-24mm F2.8 DG DN | Art and the 24-70mm F2.8 DG DN Art lenses. Additionally, many DSLR zoom lenses can be adapted to L-mount and Sony E-Mount cameras. Learn much more about which SIGMA lenses fit which camera systems here.

Since 2018, Tom’s main camera has been the Sony RX10 IV (price at Amazon) (37 oz, 25x zoom) — the world’s most versatile midsize camera for on-the-go photographers — read my RX10 IV review.

Digitalzoom

This is how it works, and this is how it is. On the shorter end of the focal lengths, it usually feels like APS-C is losing some of the wide-angle capabilities. But lenses like the pair of 10-20mm DC zooms and the 8-16mm F4.5-5.6 ultrawide zooms offer APS-C photographers incredibly wide fields of view that equate to the widest rectilinear fields of view for full-frame ultrawides.

Many SIGMA zoom lenses offer a macro capture mode at the longest focal length at magnification ratios between one-third and one-half life sized reproduction. When a SIGMA zoom lens has “MACRO” in the official name, it means that it has a maximum magnification ratio of 1:3 or greater. This means that at the closest focusing distance, a one inch object will be rendered as one-third of an inch (.333 inches) on the sensor. (In the metric system, one centimeter equals 10 millimeters, so a one centimeter object is drawn across 3.3mms on the sensor.)

Don’t ever use the tripod socket in the base of your camera when paired with a lens that has a tripod collar. You can stress the lens and camera mounts, and while the center of gravity is under the tripod collar mounting point, this can lead to a tripod crashing over!

Despite advanced circuitry, cameras are not smart enough to know which subjects are supposed to be white, black, or midtone in brightness. By default, all cameras underexpose scenes where white tones (such as snow) predominate, and overexpose highlights in scenes where black tones predominate. IMPORTANT TIP: To correctly expose for all tones, you need to lock exposure upon a perceived midtone (such as a gray card; or on a line halfway between light and shadow) in the same light as your framed subject.

Zoom lenses always feature two focal lengths in the name which indicate the shortest and longest focal lengths in relation to the 35mm/full-frame sensor. To determine the overall zoom ratio of the lens, simply divide the longest focal length by the shortest. For example, the SIGMA 18-35mm F1.8 DC HSM | Art and the 8-16mm F3.5-4.5 are both examples of 2x zoom lenses: 35 divided by 16 equals 1.95, and 16 divided by 8 equals 2. (It is common practice to round to the nearest whole number or major fraction.)

Despite its tinier but denser photosite buckets (also called sensels or pixel wells for catching light photons), the 36MP Sony Alpha A7R beats the dynamic range of 12MP Sony Alpha A7S in a normalized comparison of raw files (see dpreview article). While both cameras spread their photosites across the same surface area of a full-frame sensor, the 36MP A7R trumps the 12MP A7S for exposure latitude flexibility in raw post-processing at ISO 100 through 6400. Overall image quality of the 12MP A7S doesn’t beat the A7R until ISO 12,800 and higher (but only in the shadows through midtones under low-light conditions). Sony A7S is better for low-light videographers, whereas A7R is better for low-light landscape photographers who value high resolution and dynamic range.

In principle, you might expect a slightly sharper image on an APS-C sensor when using the sweet spot of a lens designed for a full frame (which has a larger imaging circle), but results actually vary, especially when using older film-optimized lenses. In fact, a lens which is designed and optimized specially “for digital, for APS-C” can equal or exceed the quality of an equivalent full-frame lens on the same sensor, while also reducing bulk and weight (as in the Sony E-mount example further below).

During the past decade, the 16-megapixel sensor and performance of the early models of Olympus M1 (Mark I, introduced in 2013) and M10 (I-III) paled in comparison to the 24-megapixel sensor APS-C systems that I used from 2012-2016 (on Sony A6300 and predecessor NEX-7, using Sony 18-200mm lens, 11x). Consider a Micro Four Thirds system with interchangeable lenses such as the Panasonic GX80 (2016). For the GX80’s weight and expense class, the Sony A6400 or A6300 cameras provide more for the money — 45% larger light-gathering sensor (APS-C), generally better quality images (24MP vs 16MP), better viewfinder, excellent hybrid focus system, and longer battery life (400 versus 290 shots per charge), at a similar weight.

Constant-Aperture zoom lenses keep the same maximum aperture throughout the entire focal range. So, for example, the 120-300mm F2.8 EX DG OS HSM | Sports and the 24-105mm F4 DG OS HSM | Art are both constant aperture zoom lenses. The key advantage of constant aperture zoom lenses is that you do not lose any light-gathering power as the focal length increases. This is helpful in challenging lighting situations, where the extra F-stops allow for faster shutter speeds. Autofocus operations inside a camera’s body also depend on the amount of light coming through the lens.

Zoom lenses also come in two main varieties: constant-aperture and variable-aperture. Each type has its strengths and purposes, depending on what is most critical to the photographer. When you look at the name of a zoom lens, if there is only a single aperture given, this is a constant aperture zoom lens. If there are two F-stops named with a dash in between, this is a variable aperture zoom lens.

Since 2016, a 1-inch Type sensor size has optimized the portability of sharp travel cameras (recommended here). In comparison, cameras using larger APS-C sensors require heftier 11x to 19x optical zoom lenses which struggle to sharpen the edges of the frame. With a sensor smaller than APS-C, Micro Four Thirds systems have lagged behind the competition for sharp images from a generous zoom range in a compact package. Cameras using full-frame sensors restrict zoom range or overburden travelers. Sensors smaller than “1-inch” size can support super zoom ranges but worsen image quality, especially in dim light. Smartphones compensate for tiny cameras via computational power and instantly-shareable images, but can fumble in dim light or telephoto reach.

Landscape photographers often prefer to capture a deep depth of field, which can be achieved with both small and large sensor cameras. Optimal edge-to-edge sharpness usually occurs when stopping down the aperture once or twice from brightest opening, such as between f/4 to f/5.6 on 1-inch Type sensor, or between f/5.6 to f/8 on APS-C or full-frame (which also helps diminish chromatic aberrations). Stopping down further with f/numbers larger than this increases depth of field, but worsens diffraction through the smaller pupil opening (such as at f/11-f/16 on 1″ sensor or f/22 on APS-C), noticeably softening detail. Fast, high-quality lenses on full-frame sensors may be sharpest at two to three stops down from brightest aperture — check your lens on review charts. Avoid f/16, f/22, and f/32 on most cameras, unless you don’t mind the extra fuzziness.

When using camera raw file format, to maximize dynamic range of brightness values from bright to dark, use base ISO (around ISO 100 or 200 in most digital still cameras), rather than higher ISO settings, which amplify noise (blotchiness at the pixel level, most-visibly in shadows). However, using the latest full-frame sensors at high ISO values 6400+ can capture unprecedentedly low noise and open new possibilities for dim-light action photography at hand-held shutter speeds, indoors or at night.

Answering the question: “Which zoom lens is right for me?” depends on your photographic intentions. A single zoom lens such as the 18-250mm can cover wide-angle to telephoto, plus macro in a single lens, when traveling light with maximum versatility is the demand. Or a zoom lens like the 120-300mm F2.8 DG OS HSM can offer telephoto prime performance with the added benefit of a zoom range, along with the ultimate in lens customization when paired with the SIGMA-exclusive USB Dock and SIGMA Optimization Pro. The SIGMA 18-35mm F1.8 DC HSM is the world’s first F1.8 zoom lens for APS-C DSLRs and offers image quality that surpasses top-shelf prime lenses in independent lab testing. The pair of SIGMA 150-600mm F5-6.3 DG OS HSM zoom lenses offers incredible full-frame telephoto zoom range in two different designs, with optical stabilization. The SIGMA 17-50mm F2.8 EX DC (OS)* HSM and the 17-70 F2.8-4.0 DC MACRO (OS)* HSM | Contemporary are both fantastic standard zoom upgrades that blow away the standard kit lens that ships with so many DSLRs.

Prime lens

Jack Howard is a lifelong photographer and author of two editions of the how-to book, Practical HDRI. Based in Central Jersey, Jack's go-to photography spots are backroads and beaches of his home state. He loves to travel far and wide with his wife and daughter, visiting national parks, museums, tropical islands and more along the way.

Wide lens

So, you can have a wide to short telephoto zoom lens with a higher overall zoom ratio than a telephoto to super telephoto zoom lens. For example, the 24-105mm F4 DG OS HSM | Art is a 4.3x zoom, while the huge 300-800mm F5.6 EX DG HSM lens is a 2.6x zoom lens, and the SIGMA 18-300mm F3.5-6.3 DC MACRO OS HSM | Contemporary is a wide to telephoto zoom lens with a very high zoom ratio. (We’ll let you do the math on this one!)

Zoom lens construction technology has come a very long way over the past forty years. And while it is still very typical for many zoom lenses to have some degree of field distortion at one end or the other of the zoom range as well as some slight vignetting at times, the overall image quality straight from the sensor of a modern zoom lens flat-out blows away the results of lenses from a few generations back.

Read this pointed perspective on how far image quality has progressed from early DSLR to 2014 smartphone cameras. Historically, evocative images can certainly be captured regardless of camera size or modernity. But for a given year of technological advance, tiny-sensor cameras can have severe limitations compared to physically larger cameras in terms of print enlargement, autofocus speed, blurred performance in dim/indoor light, and so forth. That being said, the “best” travel camera is the one that you are willing to carry.

Cameras rarely capture pictures the way we perceive. Think of all those shots where the sky is too bright or the foreground is too dark, losing crucial detail — irrecoverably in a lossy JPEG file. Reshooting to adjust the exposure is often helpful, but usually isn’t enough to properly portray the range of light from dark to bright. We must compensate through editing to restore images to what our eyes saw in the field.

For a given field of view, cameras with larger sensors can achieve a shallower depth of field than smaller sensors, a feature which movie makers and portrait photographers like to use for blurring the background (at brightest aperture setting, smallest F number value) to draw more attention to the focused subject. Conversely, smaller-sensor cameras like the Sony RX10 III and RX100 III tend to be much better at capturing close-focus (macro) shots with great depth of field (especially at wide angle), at ISO up to 800. But the macro advantages of small-sensor cameras can diminish in dim light or when shooting at ISO higher than 800.

Using HDR (High Dynamic Range) imaging lets any size of sensor greatly increase an image’s dynamic range by combining multiple exposures — as done in modern smartphones, camera firmware, or PC imaging apps. On cameras larger than smartphones, HDR techniques are usually unnecessary due to the great dynamic range of a single raw file from 1″-Type BSI or APS-C sensors, or larger.

Zoom lenses are designed to offer the photographer a great deal of flexibility in composition and framing without ever having to change lenses, or even physical position, for that matter. All it takes is a quick twist of the zoom ring and the composition can go from the shortest focal distance to the longest for a very different take of the scene presented before your lens. And many SIGMA zoom lenses offer true macro capture at the telephoto end, for close-up capture of tiny objects, adding to the overall versatility.

Without the help of a flash on nearby subjects, night and dim indoor photography is best with a full-frame sensor to gather more light with less noise. Low-noise night photography is usually best shot on a tripod at slow shutter speeds in raw format between ISO 100 and 800 (or as high as 1600-3200 on the latest large sensors). The latest top smartphones have made impressive leaps in automatic night modes.

Smartphones can have even tinier sensors, such as 1/3.0″ Type (4.8 mm x 3.6 mm) in Apple iPhone versions 5S through 8. Remarkably, top smartphone cameras have improved miniature sensors to the point where citizen journalists can capture newsworthy photos with image quality good enough for fast sharing and quick international publication. The latest Google Pixel, Samsung Galaxy, and Apple iPhones include great cameras, especially the pro models. My former Samsung Note5 smartphone (same camera as in S6 & S7 with 1/2.6″ sensor) captures sunny 16-megapixel images sufficient to make a sharp 18-inch print, virtually indistinguishable from that taken by a larger camera.

Compared to APS-C, the step up to full-frame-sensor cameras costs extra, adds bulk, and is only needed if you regularly shoot in dim light higher than ISO 6400 (such as for indoor action), or specialize in night photography, or often print images larger than 2 or 3 feet in size (to be viewed closer than their longest dimension by critically sharp eyes). But there’s no need to go overboard. Let’s put this in perspective: huge effective billboards can be printed from small 3-megapixel cameras (read my article).

But this smaller sensor also means their is an apparent gain in focal length on the longer side of the zoom range. This means that a 200mm focal length on an APS-C DSLR is more like a 300mm field of view and a 500mm focal length is like 750mm on a full-frame camera. For wildlife photographers, this sensor factor can make distant animals bigger in the frame. And when it comes to full-frame lenses on APS-C DSLRs, the smaller image circle means that the image is captured with incredible sharpness from the center section of the lens.

Which SIGMA zoom lenses are right for you depends on your photographic intentions, budgets, and overall size constraints. In this article, we are going to explore many facets of zoom lenses for digital photography and explain the terminology, key features and benefits of the different types of zoom lens. We’re also going to showcase images made with a variety of SIGMA zoom lenses to illustrate key concepts.

I have them all: A7r mk I, A6100, LS100, RX 100V, Iphone Pro Max, Samsung S22 Ultra. The old saying still applies, it’s whatever you have with you. Professionals- full frame and medium format all the way. Travel/Portability? For video, the S22 is the best. For photos, the S22 Ultra has 100mp mode and 40mp selfie mode. It didn’t take any more room in my travels. I went to Paris for 2 weeks last December and didn’t miss a shot. The biggest advantage is being able to share the photos immediately and the zoom. I agree, even though the RX100 has better image quality, the zoom of the LS100 makes it ultimately more useful. I did a test recently at an indoor concert from the balcony. The LS100 is better in zoomed far in low light than the S22 and the 1 inch sensor is much smoother when pixel peeping. I may consider supplementing the S22 when travelling. No camera needs to be the jack of all trades. The A6100 comes close, “larger” sensor and excellent video. The A7r has the best sensor. But adding a huge lens isn’t an option for travel or anything for that matter. I may pair it with the FE 28 F2 to simulate having a Leica Q. Because I purchased each of these cameras for $500 or under, I can afford to keep them all and use them on rotation. None of the newer cameras make any sense to me anymore. On a side note, the S22 Ultra is getting better all the time. After taking a photo or video, the media is processed by AI, eliminating many photo limitations like blown out skies, underexposed faces, lack of contrast, low light noise to some extent. Night modes can use multiple exposures to minimize noise and increase sensitivity. If a camera can incorporate those AI features, then there will be a next generation of cameras. (in body vignette removal and dispersion reduction already exists so I know it’s possible)

Panasonic and OM SYSTEM (formerly called Olympus) make excellent Micro Four Thirds sensor systems, which unfortunately haven’t kept up with rival travel cameras from 2012 through 2023.

In 2018, the best & brightest pocketable zoom camera was the Sony Cyber-shot DSC-RX100 VI (at Amazon) (11 oz, 8x zoom 24–200mm f/2.8-4.5) — my favorite backpacking camera. Upgrading to Sony RX100 VII (2019) focuses even faster. Read my RX100M6 review.

Most cheaper compact cameras have smaller but noisier sensors such as 1/2.3″ Type (6.17 x 4.56 mm) — tiny enough to miniaturize a superzoom lens, but poor for capturing dim light or for enlarging prints much beyond 12-18 inches.

And when you add in the ease of use and accuracy of lens profile corrections that are bundled in most RAW conversion software programs such as the Adobe Camera Raw Engine that is the heart of Lightroom and Bridge/Photoshop toning, many of the historical disputes about prime lenses being the unsurpassed imaging kings don’t resound so absolutely any more.

A bulkier DSLR-style camera with APS-C sensor may attract traditionalists wanting a legacy optical viewfinder, improved night photography, and a bounty of lens choices:

Since the release of Panasonic ZS100 in 2016 and Sony RX100 VI in 2018, publishable image quality can now come from pocketsize cameras having versatile 10x or 8x zooms. Capturing 20 high-quality megapixels, both the Panasonic ZS100 and superior Sony RX100 version VI rival the daylight image quality of all of my camera systems used over 34 years until 2012 — beating my cameras up to 4 times heavier, up to 11x zoom range, up to 12 megapixels, shot at base ISO 100.

Optical lens

Yearly advances of 2014-16 put the sweet spot for serious travel cameras between 1”-Type and APS-C size sensors. Then from 2016-2022, camera designs using 1”-Type sensors surpassed the portability of APS-C models for capturing publishable images within a wider zoom range.

Many SIGMA zoom lenses feature an Optical Stabilizer, which is a floating lens group that counteracts slight camera movement during image capture—these lenses all have OS in the official lens name.  The Optical Stabilizer acts like an invisible tripod, minimizing slight camera movements during longer exposures.

For a given year of technological advance, a camera with physically bigger sensor area tends to capture better image quality by gathering more light, but at the cost of larger-diameter, bulkier lenses. Recent digital sensor advances have shrunk cameras and increased optical zoom ranges while preserving image quality. The top smartphone cameras can potentially make good 18-inch prints and share publishable pictures. Clearly, an evocative image can be created with any decent camera in the hands of a skilled or lucky photographer. For my nature-travel publishing, I prefer a midsized camera with 1-inch Type sensor for superior optical zoom range, good performance in dim light, and sharp prints:

Both lenses are optimized for digital, yet the APS-C lens is much lighter weight and performs equal to or better than the full-frame lens. Side-by-side comparisons and also DxOMark tests on a Sony A6000 camera show that while they are about equally sharp, the Sony 24-240 has more distortion, vignetting and chromatic aberration than the 18-200mm.

Of course, as you zoom in or out and recompose, the overall feel of the image can change dramatically, as a lens goes from a wide field of view to standard, or a standard field of view to super telephoto.

Whichever type of zoom lens it is, the SIGMA lens designers strive to create the best possible lens, incorporating aspherical, SLD and FLD elements as necessary to best transmit the scene to sensor. The optimum optical formula varies depending on the focal lengths, and the goal is to always design the best-performing lens possible within the design parameters.

zoomlens中文

Zoom is also commonly confused with how close a lens can bring a subject. The zoom number, like, only shows the range from the widest to narrowest angle of view for that lens. Zoom is a good indicator of flexibility, then, but not how close you can get with that lens. For that, you need the focal length, like m, 1m, etc. In point-and-shoot cameras, it s more common for manufacturers to advertise the zoom rating of a lens (,, etc.), whereas DSLR and mirrorless lenses will be advertised by their focal length range (18-m, 24-1m, etc.). If a lens has a single focal length number, e.g. m, it is a prime lens and doesn t zoom at all, but generally offers superior sharpness, depth of field control, and light-gathering ability.

Consider the Sony RX10M4 camera — to emulate that 25x zoom range with Micro 4/3 lenses is a heavier and pricier proposition, debatably without a commensurate gain in image quality. For example, consider the following high-quality 69+ ounce system with two lenses covering 24-800mm equivalent zoom range mounted on a Micro Four Thirds sensor:

Fresnel lens

For improving image quality, the quality and diameter of the lens can rival the importance of having a physically larger sensor area. Prime (non-zoom) lenses usually are sharpest for larger prints, but zoom lenses are more versatile and recommended for travelers.

For greatest editing flexibility, rather than shooting JPEG format, serious photographers should record and edit images in raw format, which is supported in advanced cameras (but often not in small-sensor devices). Editing raw format fully recovers badly-exposed images − allowing you to “point and shoot” more freely than with JPEG. Even so, I carefully shoot to expose each histogram to the far right while avoiding truncation of highlights, in order to capture the highest signal-to-noise ratio in each scene. Try to stay close to base ISO 100 or 200. I typically first shoot a test shot on automatic Aperture-preferred priority, inspect the histogram, check any blinking highlight warnings, then compensate subsequent shots using Manual Exposure (or temporary Exposure Lock grabbed from the scene). Tonal editing of JPEGs can quickly truncate color channels or accumulate round-off errors, often making the image appear pasty, pixelated, or posterized. White Balance (Color Balance) is easily adjustable after shooting raw files, but tonal editing often skews colors oddly in JPEG. 12-bit Raw format has 16 times the tonal editing headroom and color accuracy compared to JPEG (which has only 8 bits per pixel per red, green, or blue color channel). In their favor, automatic point-and-shoot JPEG camera exposure modes get smarter every year, making advanced larger cameras less necessary for many people.

One type of zoom lens is not “better” than the other in an absolute sense—each type of zoom lens has its appeal for different types of photographers and applications, depending on budget, weight considerations, and other variables.

I have regularly upgraded my digital cameras every 2 to 5 years because the latest devices keep beating older models. Since 2016, 1″-Type sensors optimize the bulk of serious travel cameras, as in the following which capture excellent dynamic range (bright to dark) with exceptionally fast autofocus.

Telephoto lens

For a given year of technological advance, cameras with larger sensors typically capture a wider dynamic range of brightness values from bright to dark per image than smaller sensors, with less noise. In 2016, Sony’s 1″-Type backside illumination (BSI) sensors capture sufficient dynamic range for my publishing needs.

How can we distinguish the image quality captured by different cameras? Images are best compared at a normalized pixel level (with fine detail examined on a monitor as if printed with equal overall image size) after shooting side-by-side in the field with comparable lens and shutter speed settings. Consider two sibling full-frame-sensor cameras:

Many of the larger SIGMA lenses ship with tripod collars. These tripod collars are paired with the lens because the tripod collar indicates where the center of gravity of the lens and camera resides. If you’ve got a lens that includes a tripod collar, you should always use this for mounting to a tripod, monopod, or other quarter-twenty threaded stabilizing accessory.

However, constant-aperture zoom lenses are limited in total zoom range: the 24-105mm F4 DG OS HSM | Art is the highest zoom ratio constant-aperture zoom lens in our catalog. And the demands of optical physics require a lot of big glass to make constant-aperture zooms, especially for the full-frame image circle.

With early DSLR cameras, many photographers were concerned about the loss of image quality or resolution by using a digital sensor with a light-gathering area smaller than 35mm film. However, for my publishing needs, APS-C-size sensor improvements easily surpassed my scanning of 35mm film by 2009.

In my field tests, the sharpness of Sony’s high-quality SEL1670Z 3x zoom f/4 lens on A6300 is only about 5% better than Sony RX10 III f/2.4-4 in bright light in the wider half of its 24-105mm equivalent range, but no better in dim light. I expect that RX10’s catch-up in quality under dim light is due to superior light sensitivity of BSI sensor plus larger lens diameter gathering more light, 72mm versus 55mm.

After test trials in 2016, I switched from APS-C to the 20MP 1-inch-sensor Sony RX10M3, which more than doubled my optical zoom to 25x, while equaling or improving overall image quality from edge-to-edge. Upgrading to Sony RX10M4 in 2018 strengthened the deal by speeding autofocus. This sharp 24-600mm f/2.4-4 zoom camera system weighing just 37 ounces has been a game-changer for hiking and general travel photography. Caveat: although it’s one of the most versatile cameras ever invented, Sony RX10M4 isn’t necessarily the most optimal for night photography, wedding photography, or certain other specialties that don’t require a large zoom range.

Editor’s Note: This piece was originally published in 2014. In April 2020, it was revised to include updated product information and links, mirrorless zoom lens information etc.

Theoretically, new full-frame lenses “designed for digital” (using image-space telecentric design) may perform better on a digital sensor than would older lenses designed for film:

For photographers who want to shoot wide-open in manual exposure mode, this also means you won’t be underexposing your shots as you zoom out, since the F-stop remains constant. Same goes for off-camera strobes—there doesn’t need to be any adjustments as you zoom to recompose with a constant aperture zoom lens.

Smartphone tips: To better isolate subjects at a distance, update your model with a bigger telephoto camera, such as on the latest iPhone Pro Max or Pro models. Better yet, Samsung Galaxy S22 Ultra and S23 Ultra include an impressive 10x optical zoom, which works great, Tom can attest! A 2x power tele on a smartphone resembles the field of view of a 50mm-equivalent lens, 3x resembles 75mm, and the extremely useful 10x resembles 260mm. Tiny subjects can be enlarged biggest at close focus using the telephoto lens (like a macro lens). Avoid the digital zoom on smartphones, which records extra pixels without adding quality — instead, move closer before shooting, or crop at editing time.

In my side-by-side field tests, the sharp, bright 25x zoom of Sony RX10 III (read my version IV review) resoundingly beats the resolution of 11x SEL18200 lens on APS-C Sony A6300 at 90+ mm equivalent telephoto, even as high as ISO 6400. (Wider angle zoom settings show little quality difference.) Apparently RX10’s faster f/2.4-4 lens plus backside illumination (BSI) technology magically compensate for the sensor size difference, 1″-Type versus APS-C. Like most APS-C-sensor cameras in 2016, A6300 lacks BSI. Surprisingly little noise affects RX10’s image quality at high ISO 6400 in dim light. Its larger lens diameter gathering more light also helps in this comparison (72mm filter size of RX10 III versus 67mm SEL18200 on A6300).

For tonal editing, camera raw file format allows 16 times more leeway than default JPEG files. Tom highly recommends recording and editing images using your advanced camera’s raw file format (except in smartphones, where the default HDR-generated JPEG files may make raw irrelevant). Editing raw format can magically recover several stops of highlight and shadow detail which would be lost (truncated) in JPEG file format (if overexposed or underexposed).

Although I prefer the above portable all-in-one solutions for travel convenience, a top APS-C-sensor camera (such as Sony A6300) lets you interchange lenses and capture less noise in dim light at ISO 3200+ sensitivity.

* Crop Factor: Note that a “full frame 35mm” sensor/film size (about 36 x 24 mm) is a common standard for comparison, having a diagonal field of view crop factor of 1.0. The debatable term crop factor comes from an attempt by 35mm-film users to understand how much the angle of view of their existing full-frame lenses would narrow (increase in telephoto power) when mounted on digital SLR (DSLR) cameras which had sensor sizes (such as APS-C) which are smaller than 35mm.

SIGMA offers many zoom lenses designed specifically for APS-C DSLRs. These lenses for the smaller image circle are designated with DC in the official name. And every DG lens for full-frame cameras will mount on the APS-C DSLRs in that same mount, too.  All SIGMA lens focal lengths are given in relation to the full-frame size, whether it’s a DG or DC lens, so whenever a lens is mounted on an APS-C sensor camera, it is necessary to take the sensor size into account and adjust the apparent focal length and field of view accordingly. For most APS-C DSLRs, it is a 1.5x factor, so the SIGMA 10-20mm F3.5 EX DC HSM lens equates to a 15-30mm F3.5 zoom lens.  (10 x 1.5 = 15) – (20 x 1.5 = 30).

Dollyzoom

The non-standardized fractional-inch sensor sizing labels such as 1/2.5-inch Type and 1/1.7″ Type confusingly refer to antiquated 1950s-1980s Vidicon video camera tubes. When you see those archaic “inch” size labels, instead look up the actual length and width in millimeters reported in the specifications for each camera:

The archaic inch-sizing of camera light sensors is clarified in the illustration and table below, with relative sizes and millimeters. Legacy sizing labels such as 1/2.5″ Type harken back to antiquated 1950s-1980s Vidicon video camera tubes.

I’ve oft admired the solid quality of recent Micro Four Thirds cameras such as Olympus (rebranded as OM System in 2022) who made my beloved OM-1N film camera back in the 1980s. But Olympus upgrades have come too late for me, such as their sensor improvement from 16 to 20 megapixels (in Olympus M1 Mark II & III in 2016 & 2020, and in M10 Mark IV in 2020). In comparison, the Sony A6xxx camera series is nearly as compact, yet collects more light onto a physically larger 24mp APS-C sensor. Pricing can also be similar comparing APS-C vs 4/3 when shopping for slightly older versions or used gear. And for zoom ranges larger than 8x, the 1″-sensor Sony RX10M4 and RX10M3 cameras beat all comers anywhere near their weight class (37 oz), with a surprisingly sharp 25x zoom system.

This can help keep handheld shots sharp at slower shutter speeds. The general rule of thumb is that OS can help keep images acceptably sharp for a few stops under the reciprocal of the focal length, so, the effective slowest shutter speed for sharp shots will change as you zoom in or out. We take a long look at OS in this companion piece, if you want to learn more about how, when, and why to use OS when it is offered on a lens.

A zoom lens is a type of camera lens that offers the photographer a useful range of different focal lengths in a single lens. This is in comparison to a prime lens, which only offers a single focal length. A zoom lens allows for quick and easy re-framing of a scene while staying in the same physical position. SIGMA offers a wide variety of zoom lenses, ranging from wide-angle zooms, super telephoto zoom lenses, and standard zoom lenses designed for everyday use.

For many photographers first exploring macro capture, this a great way to get comfortable with the nuances of macro photography. At very close focusing distances, all motion is amplified.  For example, a bit of jittery camera movement, and the slight swaying of a flower can mean the difference between having that ladybug perfectly in focus or having the subject drift out of the sharpness zone. Macro takes practice, and if you crave higher magnification than is offered at the far end of a the zoom, SIGMA offers a line of pro-caliber prime macros offer true 1:1 (life-sized) magnification for even more close-up details.

Variable-aperture zoom lenses feature two F-stops in the name, indicating the maximum aperture at the shortest and longest focal distance. This means that the overall light-gathering power of the lens decreases as the focal length increases, leading to slower shutter speeds at longer focal lengths. The benefits of this trade-off include more compact lens designs and higher zoom ratios.

The 120-300mm F2.8 DG OS HSM | Sports is a 2.5x zoom lens and the 70-200mm F2.8 DG OS HSM | Sports is a 2.8 zoom lens. Zoom ratio only relates to the difference between the shortest and longest focal lengths, so the 150-600mm F5-6.3 Contemporary and Sports lenses are 4x zoom lenses, while the 60-600mm F4.5-6.3 DG OS HSM | Sports is a 10x high ratio zoom lens. All three of of these lenses offer the same maximum telephoto focal length, but the 60-600mm offers a much longer zoom range.

Depth of field gets much more shallow as focal distance increases, even as telephoto compression diminishes the apparent relation between distant objects. The same scene can quickly be seen many different ways with a zoom lens. What’s most important is to choose the focal length and depth of field that will best capture what you are trying to say with your image.