Teleconverters are a powerful yet often overlooked tool in underwater photography, particularly in the realm of macro and supermacro imaging. Every serious photographer can benefit from understanding and using a teleconverter. This section will explore what a teleconverter is, the types available, the reasons for using one, and the types of lenses that pair best with them. Port configurations, lighting tips, and brand recommendations will also be discussed.
What is a Teleconverter?
A teleconverter is a compact optical device placed between your camera body and your lens. Its primary function is to magnify the central portion of the image, effectively increasing the focal length and allowing you to get closer to your subject without physically moving. This magnification is particularly useful for photographing small marine life where getting close might disturb the subject or be physically impossible due to terrain or depth limitations.
Types of Teleconverters
Teleconverters come in various magnification levels. The most common types are 1.4x, 1.5x, 1.7x, and 2.0x. A 1.4x teleconverter increases the focal length by 40%, while a 2.0x teleconverter doubles it. These devices reduce the amount of light reaching the sensor, which may affect autofocus speed and image brightness, so selecting the right teleconverter is crucial. Photographers frequently choose models like the Kenko Teleplus Pro 300 1.4x or the Tamron SP AF Pro 1.4x, both of which offer reliable autofocus and optical performance.
Visual Comparison With and Without Teleconverter
Consider a Nikon 60mm lens shooting at 1:1 magnification. Without a teleconverter, you get a standard macro image. When you add a 1.4x teleconverter, the image appears significantly closer without changing your physical distance to the subject. This allows for enhanced detail and composition flexibility.
Why Use a Teleconverter?
The primary reason to use a teleconverter in underwater photography is to achieve supermacro capabilities. If your lens already shoots 1:1 macro, a teleconverter allows you to go beyond that, capturing intricate details of tiny subjects like nudibranchs, shrimp, and fish larvae. For terrestrial photography, teleconverters are often used with fast lenses (f/2.8 or f/4) to photograph birds, wildlife, or sports from a distance. Underwater, this concept translates to photographing shy or small animals without having to physically close in.
Underwater Photography Examples
Examples from the field showcase the power of teleconverters. A juvenile fish in Bali, a frogfish in Anilao, or gorgonian polyps off Catalina Island—all photographed with a 60mm lens and a 1.4x teleconverter—demonstrate how much detail and closeness can be achieved. These photos reveal textures and expressions often missed with standard macro lenses.
Choosing Between 60mm and 100/105mm Lenses
Most underwater photographers favor the 60mm lens combined with a 1.4x teleconverter. Olympus DSLR users often use the 50mm lens instead. While it is technically possible to use a teleconverter with a 100mm or 105mm lens, it’s less common due to the increased water column you shoot through, which can degrade image clarity. However, this setup may still be useful for photographing particularly wary subjects like gobies or garden eels from a distance.
Teleconverters and Wide-Angle or Fisheye Lenses
Some photographers experiment with teleconverters on wide-angle lenses such as the Nikon 10.5mm or Tokina 10-17mm fisheye. However, this is generally discouraged. The introduction of the Tokina fisheye lens makes this pairing largely unnecessary. Additionally, mounting a teleconverter on a fisheye lens often requires a custom zoom ring and a port extension of about 20mm. For those wanting mid-range zoom functionality underwater, lenses like the Sigma 17-70mm are better suited than trying to modify a fisheye setup.
Port Considerations
When using a 60mm lens with a 1.4x teleconverter, most photographers find it fits well within the same port designed for a 105mm lens. This is not a strict rule, but it tends to work efficiently in practice. Ensuring proper fit minimizes vignetting and optical distortion, maintaining sharpness across the frame.
Lighting Considerations
Lighting becomes especially critical in supermacro photography. With increased magnification, you get physically closer to the subject, reducing the working distance for strobes. Experimenting with front, side, and backlighting can yield varied and dynamic results. In close-range photography, backscatter is less of a problem, so you can bring your strobes close to the port and illuminate fine textures. Front lighting often works well with supermacro setups.
Importance of a Focus Light
Autofocus performance generally slows down when using a teleconverter. This is due to the light loss and the increased focal length. A high-quality focus light helps your camera lock focus more easily. Interestingly, many photographers report that using a 60mm lens with a 1.4x teleconverter provides faster focus than using a 105mm lens alone, though it still requires practice and patience to achieve critical sharpness.
Shooting Techniques for Better Results
There are several techniques to make the most of your teleconverter setup. It’s best to use a prime macro lens with a maximum aperture of f/2.8 or f/4. Continuous focus mode allows the camera to adjust focus without needing to lock before taking the shot. This can be particularly helpful when working with moving marine life. Shifting the focus point within your camera also helps isolate the exact spot of interest, like an eye or a unique pattern on the subject.
Practical Applications
With a 60mm lens and a 1.4x teleconverter, you can successfully photograph skittish fish, tiny nudibranchs, and other small creatures. This setup is popular among macro photographers in places like Southern California, especially when visibility is limited. The combination provides versatility without the bulk or complexity of switching to different lenses underwater.
Technical Considerations for Canon and Nikon Users
Canon 60mm lenses typically require a 12mm extension tube to function properly with a teleconverter. Nikon users should note that the newer AF-S 60mm lens does not work with teleconverters, while the older version does. It is possible that using an extension tube with the newer Nikon model could resolve this limitation, but testing is required.
Alternative Tools for Supermacro Photography
While teleconverters are highly effective, they are not the only option. Diopters—especially wet diopters—are also widely used in underwater macro and supermacro photography. Some photographers use both tools, depending on the subject and the dive conditions. Diopters have the advantage of being easier to mount or remove during a dive, adding flexibility to your shooting style.
Real-World Experiences with Teleconverters
Photographers who frequently shoot supermacro underwater often develop specific habits and preferences around teleconverter use. After enough dives, the equipment becomes second nature, and positioning, strobe control, and subject approach become instinctive. It is through repetitive real-world practice that the nuances of teleconverter performance become clear. When paired correctly with a camera body and lens, a 1.4x teleconverter can consistently produce sharp, high-magnification images with minimal distortion or color fringing.
In locations like Anilao in the Philippines or Catalina Island in California, visibility and subject size can vary greatly. Many macro photographers find that a 60mm macro lens with a 1.4x teleconverter strikes the right balance between versatility and image detail. Whether shooting nudibranchs, pygmy seahorses, or flatworms, this combination offers consistent results with minimal gear adjustments.
Compatibility Across Brands
The most popular brands producing high-quality teleconverters include Kenko, Tamron, Canon, and Nikon. Each has specific compatibility limitations depending on the lens model and camera body.
Kenko’s Teleplus Pro 300 1.4x is favored by many macro photographers because it is compatible with a variety of lenses, even those that may not officially support teleconverters. It maintains autofocus capability, which is essential for underwater photography where manual adjustments can be cumbersome.
Tamron also manufactures 1.4x teleconverters that are optically similar to Kenko’s but may have different cosmetic appearances. Nikon and Canon also produce their own branded teleconverters. These often provide slightly better optical alignment with their native lenses but are typically more restrictive in terms of compatibility. Nikon’s teleconverters, for instance, work best with specific telephoto lenses and often do not support 60mm macros or third-party options.
Challenges with Autofocus Performance
One of the most common issues with using teleconverters is a reduction in autofocus speed and reliability. This is because teleconverters reduce the amount of light that reaches the camera’s sensor, usually by one stop for a 1.4x converter. The lower light levels can make it more difficult for autofocus systems to lock onto fine details, especially in low-visibility underwater environments.
To overcome this, experienced divers use high-output focus lights positioned near the subject. These lights help maintain consistent brightness and contrast, giving the camera a better chance of locking focus quickly. When paired with fast lenses—those with a wide maximum aperture like f/2.8 or f/4—the autofocus system performs significantly better.
Tips for Achieving Sharp Focus
Achieving sharp focus with a teleconverter requires patience and practice. Here are several strategies that have proven effective for underwater macro work:
Use continuous autofocus mode to allow for minor focus adjustments without requiring the camera to lock before each shot.
Move the focus point manually to align with the subject’s most important feature, such as the eye of a fish or the rhinophores of a nudibranch.
Rock gently back and forth in the water to fine-tune your distance to the subject. Often, tiny movements of just a few millimeters can bring the image into sharp focus.
Take multiple shots at slightly different distances and review them during your surface interval to better understand where sharpness peaks.
Depth of Field Considerations
As magnification increases, the depth of field becomes narrower. When using a 60mm lens with a 1.4x teleconverter, depth of field is already tight at f/8 or f/11. Many photographers shoot at apertures of f/16 to f/25 to maximize the in-focus area. However, these smaller apertures require more light, so strobe positioning and power output become even more critical.
Balancing depth of field with available light and strobe efficiency is a constant consideration. If you over-light the subject or cause backscatter, detail can be lost. Under-lighting may result in noisy or underexposed images. Finding this balance requires experience and sometimes multiple attempts on the same subject.
Best Subjects for Teleconverter Use
Teleconverters are most effective with small, cooperative subjects that don’t move quickly or flee when approached. Ideal subjects include:
Nudibranchs
Shrimp and crabs
Flatworms
Goby fish
Juvenile frogfish
Pygmy seahorses
These creatures often reside in crevices or on surfaces where they remain still long enough for careful focusing and composition. Their small size and detailed textures make them ideal candidates for supermacro imaging.
Environmental Factors Affecting Performance
Water clarity, available light, and current strength all influence the effectiveness of a teleconverter setup. In murky water, the loss of contrast can make focusing more difficult, especially with a slower lens. Strong currents can make it hard to maintain the ideal working distance, leading to blurred images due to movement. In low-light conditions, slower shutter speeds may be required, increasing the chances of motion blur unless strobes are precisely timed.
To maximize success, shoot early in the dive when you're fresh and visibility is likely at its best. Choose dive sites known for still water and abundant macro life. When conditions are not ideal, consider switching to a different lens or shooting technique.
Composition and Framing
The tighter field of view created by a teleconverter challenges your framing skills. There is little room for error, and you may find parts of the subject unexpectedly cut off. Pre-visualize your composition and take a few test shots to adjust your framing. Move slowly and deliberately to avoid scaring your subject away.
Because of the increased magnification, small changes in camera angle or lighting can dramatically affect the final image. Spend time analyzing how different strobe positions change the appearance of shadows, highlights, and color. Even rotating your camera slightly or adjusting the tilt can produce a significantly different visual effect.
Troubleshooting Common Problems
Several common issues can arise when using a teleconverter underwater. Each has a practical solution.
Problem: Autofocus hunting in low light.
Solution: Use a high-powered focus light with a wide beam pattern and switch to manual focus if necessary.
Problem: Vignetting at the corners.
Solution: Ensure your port and lens alignment are correct. Use a longer port extension if needed.
Problem: Excessive backscatter.
Solution: Pull strobes farther from the port and angle them outward to avoid lighting particles in front of the lens.
Problem: Inconsistent sharpness.
Solution: Stabilize your body and camera, increase shutter speed, and review images for focus point accuracy.
Building Muscle Memory
Like any specialized skill, using a teleconverter effectively requires repetition. After several dives, you’ll develop an internal understanding of optimal working distances, lighting angles, and camera settings. Over time, you’ll find it easier to anticipate how a subject will appear at higher magnification and how to adjust your equipment accordingly.
Many professional photographers note that after a few months of regular use, their teleconverter setup becomes their preferred gear for macro dives. It offers creative control and the ability to capture images that few others attempt due to the technical challenge.
Teleconverters extend your creative range underwater, enabling supermacro images without requiring a full gear overhaul. With the right lens pairing, careful focus technique, and environmental awareness, you can consistently capture high-detail shots that reveal the intricate beauty of underwater life. While they introduce some optical and lighting challenges, the rewards are substantial for photographers willing to invest the time to learn.
Combining Teleconverters and Diopters for Supermacro Magnification
Advanced underwater photographers often seek to push magnification beyond the limits of what a single accessory can achieve. Combining a teleconverter with a diopter is one such approach. Diopters, whether dry (attached before a dive) or wet (mounted during the dive), add another layer of magnification. When used together with a teleconverter, the results can be astonishing—achieving image reproduction ratios far beyond 1:1, capturing microscopic textures, or isolating fine details such as the eyes of a nudibranch or the legs of a tiny crustacean.
However, combining the two also compounds optical and lighting challenges. The depth of field narrows further, often to less than a millimeter. Lighting becomes more directional and susceptible to blocked strobes or internal lens reflections. Focusing becomes more sensitive to camera shake and subject movement.
To mitigate these challenges, experienced divers often pre-visualize shots before entering the water and configure their gear with precision. Extension rings are used to accommodate the increased physical length of the lens-teleconverter-diopter assembly. Ports are adjusted to reduce vignetting and maintain sharp corners. And strobes are angled creatively to maintain even illumination across highly magnified subjects.
Case Study: Dive Log from Anilao, Philippines
The reef systems around Anilao are a hotspot for supermacro photographers. One dive log entry illustrates the typical experience of an advanced macro dive using a Nikon 60mm lens, a 1.4x teleconverter, and a +10 wet diopter.
Dive Site: Secret Bay
Depth: 8–15 meters
Visibility: 10 meters
Camera: Nikon D7100 with Nikon 60mm f/2.8 macro lens
Accessories: Kenko 1.4x teleconverter, SubSee +10 diopter
Lighting: Dual strobes with snoots, continuous video focus light
Subject 1: Shrimp on a bubble coral. The shrimp’s eyes were barely 2mm across. Focusing required carefully rocking the camera and using back-button focus. Lighting was accomplished by angling the strobes to sidelight the coral structure.
Subject 2: Nudibranch (Chromodoris willani). Focused on the rhinophores at f/22. The depth of field was extremely thin, and only one or two shots out of 20 achieved tack-sharp focus at the correct spot.
Subject 3: Skeleton shrimp. Due to its transparent body, proper lighting was essential to make it stand out from the background. Backlighting combined with high contrast post-processing helped isolate the subject.
These dive log entries highlight both the technical challenges and the creative rewards of using teleconverters in combination with diopters. Success depends on methodical shooting, precise strobe placement, and patience.
Port and Extension Ring Adjustments for Advanced Setups
Using teleconverters often requires adjusting your port system. A teleconverter adds physical length to the camera-lens assembly, and failing to account for this can cause vignetting, corner softness, or even internal port contact.
To accommodate this, underwater photographers use extension rings or port spacers that maintain the correct distance from the lens front element to the port dome or flat surface. The goal is to preserve the lens’s optical path and allow enough space for internal focusing mechanisms.
A typical example involves using a 60mm macro lens with a 1.4x teleconverter. If your housing uses a flat macro port originally sized for the 60mm lens, you may need to add a 20mm extension ring to accommodate the longer setup. However, exact spacing depends on the housing brand and the lens barrel’s movement when focusing. Many users report success fitting this combination inside a port originally built for the 105mm macro lens.
The same care applies when using diopters. Some wet diopters require a flat front port for proper optical alignment. If the diopter housing is too close to the lens, image sharpness degrades at the corners. Proper distance and alignment are key.
Extreme Environments: Cold Water Macro with Teleconverters
Shooting in cold water adds another layer of complexity to supermacro photography. In locations like British Columbia or Norway, macro subjects abound—such as hooded nudibranchs, crinoid shrimp, or skeleton shrimp. However, cold water conditions present specific obstacles: heavy exposure gear, reduced dexterity, and darker ambient lighting.
When using a teleconverter in these environments, proper buoyancy and stability become even more important. Thick gloves can make it difficult to manipulate dials or buttons. In such cases, back-button focus or even manual pre-focusing at a fixed distance may be preferable.
Due to lower visibility and colder temperatures, photographers often use stronger focus lights and brighter strobes. Additionally, the color temperature of the lighting may need to be adjusted to account for the blue-green hues of colder water. Shooters often prefer high-powered strobes with wide beam angles and adjustable output to illuminate fine details in dim environments.
Exposure settings also need careful balancing. ISO may need to be raised slightly (e.g., from 100 to 400) to allow for smaller apertures without excessively long shutter speeds. Still, noise control is crucial for maintaining image quality at high magnifications.
Custom Strobe Modifications for Supermacro Work
Lighting plays a defining role in supermacro photography. With a teleconverter reducing light and working distances being incredibly small, positioning the strobes becomes a delicate process. Some photographers use snoots—tubed extensions that narrow the strobe beam to a focused point—to direct light precisely onto the subject.
For even finer control, users may modify their strobes with diffusers or barn doors. These allow better management of shadow edges and prevent unwanted reflections or backscatter. Some even 3D-print their custom strobe accessories to suit specific subject types.
A popular configuration is to place one strobe in a forward-angled position to light the foreground and another strobe angled behind or above the subject to create separation from the background. This three-dimensional effect highlights subject textures and avoids a flat look, especially when magnification exaggerates every surface detail.
Teleconverter Use in Blackwater Photography
Blackwater diving—night diving in open water to photograph planktonic and pelagic life—is an emerging genre where supermacro setups thrive. In these conditions, subjects are often smaller than a fingernail and move unpredictably.
A teleconverter becomes invaluable when photographing larval fish, juvenile cephalopods, or microscopic jellyfish. With the right configuration, you can isolate the subject from the inky blackness, using backlighting and tele-macro magnification to produce striking, ethereal images.
Stabilization is particularly important. Photographers often hold their breath during the shot or use laser pointer guides to maintain focus distance. Because subjects drift in the current and move quickly, focus tracking is nearly impossible. Instead, most use manual focus, setting a fixed distance and waiting for the subject to enter the frame.
Due to light absorption, strobes must be placed very close and aimed precisely. Some shooters even use constant-on video lights instead of strobes to avoid lag and to track moving subjects more easily. The combination of high magnification and a completely black background makes the subject pop in ways that are impossible in reef environments.
Subject Behavior and Teleconverter Timing
Understanding animal behavior is as critical as technical setup. Supermacro success depends heavily on your ability to predict when and how subjects move. This helps with composition, focus, and timing the shot.
Subjects like shrimp or nudibranchs move slowly, which allows for more control. Gobies or blennies, however, dart quickly between coral heads. Using a teleconverter in these cases requires extreme patience. Position your body and camera in advance, pre-focus on a likely path, and wait.
The best teleconverter opportunities often come at the end of a dive, when you’re already familiar with the site layout and have spotted ideal subjects. By spending more time with fewer subjects, you increase the chances of capturing memorable images.
Pre-Dive Equipment Checklist
Before entering the water, conduct a full gear check to ensure your teleconverter setup is functioning properly. Here’s a checklist commonly used by professional photographers:
Inspect the teleconverter for any internal dust or smudges on the glass.
Mount the teleconverter securely and verify the camera recognizes it.
Check that autofocus is working properly with the specific lens setup.
Ensure all housing seals are clean and secure, especially around port extensions.
Test your strobe firing and focus light before submerging.
Review your dive plan to choose subjects suitable for supermacro.
Backup diopters or extension rings can also be packed in the gear bag in case field adjustments are necessary. Having the right spare tools allows for gear changes even on a boat or beach setup.
Optical Quality: What to Expect and How to Maximize It
Although teleconverters introduce additional glass elements, a well-matched setup maintains high optical quality. Avoid pairing teleconverters with zoom lenses or slow lenses, which tend to degrade image clarity. Prime macro lenses with large apertures and high sharpness ratings yield the best results.
Post-processing can also help. Slight adjustments to contrast, sharpness, and clarity in editing software can bring out the detail captured at high magnification. Cropping is often minimal, as the teleconverter brings the subject frame-filling already.
To retain maximum quality:
Shoot at low ISO whenever possible.
Use sharp apertures—typically around f/8 to f/22, depending on the lens.
Avoid extreme edge composition, where distortion is more likely.
Keep your subject as parallel to the lens as possible to maintain focus across the surface.
Advanced use of teleconverters opens up a new realm in underwater photography, where subjects once too small to photograph now become artistic possibilities. Through smart configuration, proper lighting, and behavioral understanding, the tool becomes more than an accessory—it becomes a gateway to capturing the underwater world’s tiniest, most captivating details. While the learning curve is steep, the creative reward and uniqueness of images are unmatched.
Wildlife Photography with Teleconverters
Wildlife photography often involves capturing elusive animals from a distance, where approaching the subject closely is either impossible or would disrupt natural behavior. Teleconverters are a popular solution in this genre, allowing photographers to significantly extend their lenses’ reach without investing in extremely long and expensive prime lenses.
For example, a 600mm lens coupled with a 1.4x teleconverter becomes an 840mm lens. This added focal length proves especially useful for photographing birds, which are often small, fast-moving, and sensitive to human presence. The reach allows for tight framing and detailed shots while maintaining a respectful and non-intrusive distance.
However, field performance can vary depending on several factors such as light, autofocus capabilities of the camera body, and the subject’s behavior. In good lighting conditions, especially with high-end cameras, teleconverters perform excellently. But in low light, autofocus may become sluggish or even non-functional with certain combinations, particularly with 2.0x converters.
Sports Photography and Fast Action
Sports photography also benefits from teleconverters, especially when shooting events in large stadiums or racetracks where physical proximity to the subject is limited. With a 1.4x or even 2.0x converter, photographers can effectively cover the entire field or track while remaining stationary in the press area.
Autofocus speed and accuracy are critical in sports. Top-tier camera bodies like Canon’s R3, Sony’s A1, or Nikon’s Z9 handle teleconverters well, retaining reliable tracking and focus even at extended focal lengths. However, even the best setups may see a slight drop in focusing speed and hit rate when using a 2.0x teleconverter, particularly under challenging lighting or fast movement.
Shutter speed becomes another critical factor. As the aperture decreases with the teleconverter, the photographer may need to increase ISO to maintain a fast shutter, which introduces noise. Thus, balancing ISO, shutter speed, and aperture becomes essential in these dynamic environments.
Macro and Close-Up Work
Although teleconverters are more commonly associated with long-distance shooting, some macro photographers also use them creatively. When added to a macro lens, a teleconverter increases the lens's effective focal length while preserving its minimum focusing distance. This results in increased magnification and working distance.
For instance, using a 100mm macro lens with a 2.0x teleconverter gives an effective focal length of 200mm. This enables the photographer to achieve a 2:1 magnification ratio without needing to get extremely close to the subject—beneficial when shooting insects or skittish small animals.
One trade-off in macro use is the drop in sharpness and contrast, especially with higher-magnification setups. But for photographers comfortable with focus stacking and careful post-processing, the added magnification may be worth the compromise.
Astrophotography and Distant Landscapes
Astrophotographers and landscape shooters focused on distant mountain peaks, moon shots, or planetary imaging may consider teleconverters for boosting focal length. When used with high-quality, long prime lenses and stable tripods, teleconverters can help capture crater details on the moon or compress distant mountain layers into dramatic compositions.
Still, the weaknesses of teleconverters—such as optical degradation and increased susceptibility to atmospheric distortion—are particularly noticeable in these contexts. Slight imperfections or heat haze become more apparent at long focal lengths. Therefore, the best results usually come from 1.4x converters with top-tier glass and optimal atmospheric conditions.
Compatibility and Brand-Specific Performance
Canon's teleconverters, such as the Extender EF 1.4x III and Extender RF 2x, are optimized for specific L-series lenses. Compatibility is excellent with most super-telephoto primes, and autofocus remains usable on compatible bodies even with the 2x extender.
Canon’s RF system shows noticeable improvements in communication between lens, converter, and camera body, allowing better autofocus performance and image stabilization. That said, not all RF lenses support teleconverters due to design limitations like rear element positioning and physical clearance.
Nikon Teleconverters
Nikon’s Z-series teleconverters—the TC-1.4x and TC-2.0x—offer solid performance with native Z-mount super-telephoto lenses such as the Z 400mm f/2.8. These converters are designed to maintain weather sealing and AF speed when used with high-end mirrorless bodies like the Z9.
In the F-mount system, Nikon’s AF-S teleconverters (such as the TC-14E III) perform reliably when paired with pro-level lenses. However, AF can struggle with third-party lenses or slower zooms, and compatibility is more limited than in the Z-mount lineup.
Sony Teleconverters
Sony offers 1.4x and 2.0x converters that work primarily with G Master telephoto primes. The FE 400mm f/2.8 and FE 600mm f/4 are commonly used with these extenders. Autofocus speed and tracking accuracy remain relatively strong, particularly on the Alpha 1 or A9 series.
Because Sony’s system is heavily reliant on in-lens and in-body communication, their teleconverters are optimized for native glass only. Attempting to use them with adapted or third-party lenses typically results in non-functionality or severe autofocus issues.
Third-Party Brands
Teleconverters from third-party manufacturers such as Sigma, Tamron, and Kenko offer more affordable options but with trade-offs in optical performance and compatibility. Sigma’s Global Vision line teleconverters (like the TC-1401 and TC-2001) perform reasonably well with certain Sigma Art and Sports series lenses.
However, third-party teleconverters often lack the robust AF support and weather sealing found in first-party options. Users should test these converters with their specific gear combinations before relying on them in critical situations.
Optical Quality and Real-World Image Results
Center and Corner Sharpness
The most noticeable impact of a teleconverter is often in corner sharpness. While center sharpness can remain relatively high with a 1.4x converter, the edges tend to soften more. This is especially true when shooting wide open, so stopping down the aperture slightly—such as from f/5.6 to f/8—can restore some clarity.
With a 2.0x converter, both center and edge sharpness degrade more significantly. This effect is compounded when the base lens isn’t of top-tier quality. High-end primes fare best, maintaining acceptable sharpness, but mid-range zooms may struggle.
Chromatic Aberration and Distortion
Adding more glass to a lens system increases the chance of chromatic aberrations, particularly along high-contrast edges. While modern converters are well-corrected, some color fringing can still appear, especially in lower-quality optics or under harsh light conditions.
Distortion isn’t usually a major issue, but vignetting—darkening at the corners—can be slightly more pronounced, especially at wide apertures or when using filters on the lens.
Contrast and Flare Handling
A drop in contrast is often noted with teleconverters, especially the 2x variants. The increased glass elements can introduce more internal reflections, which reduce micro-contrast and can affect fine detail rendering.
Flare becomes a greater concern when shooting toward bright sources like the sun or stadium lights. Using hoods and avoiding direct light entry can help, but high-end coatings like Canon’s Super Spectra or Nikon’s Nano Crystal are critical in managing these issues.
Bokeh and Depth of Field
Teleconverters impact depth of field by narrowing the maximum aperture. As a result, bokeh—out-of-focus background quality—can change subtly. With a 1.4x converter, the background may still appear smooth, especially on longer focal lengths and wide apertures.
With a 2.0x converter, the decrease in aperture leads to a deeper depth of field, which may result in less background blur. Bokeh highlights may also appear more defined or show slight aberrations, especially with complex aperture shapes or older lens designs.
Best Practices for Using Teleconverters
Use with High-Quality Primes
The best results from teleconverters come when pairing them with high-performance prime lenses. These lenses are optically superior and handle the degradation introduced by teleconverters better than variable aperture zooms.
Photographers using a 300mm or 400mm f/2.8 prime will see less noticeable image quality loss compared to someone using a 70–300mm f/4.5–5.6 zoom. Investing in quality glass is critical when using extenders.
Manual Focus and Live View
When autofocus struggles, especially with 2.0x converters or in low light, switching to manual focus with live view magnification can ensure precise results. This is particularly useful for static subjects or when shooting from a tripod.
Live view can also help detect focus shift or field curvature, enabling better judgment of the focus point and depth of field.
Tripod and Support Systems
Extended focal lengths amplify camera shake, so using a sturdy tripod or monopod becomes essential when working with teleconverters. Even slight vibrations can lead to motion blur, especially when using shutter speeds slower than 1/1000 second at 800mm or beyond.
Tripod collars, gimbal heads, and remote triggers can further enhance stability and help maintain composition while tracking subjects.
In-Camera Corrections and Post-Processing
Modern camera bodies offer lens correction profiles that can mitigate some of the vignetting, distortion, and aberrations introduced by teleconverters. Shooting in RAW and applying lens-specific profiles in post-processing tools like Lightroom or Capture One ensures the best possible final image.
Sharpening, contrast adjustments, and noise reduction may also be necessary to counteract the softness and increased ISO introduced by teleconverter use.
Conclusion
Teleconverters are powerful tools in a photographer’s kit, offering the ability to extend focal lengths and enhance framing possibilities without the cost or bulk of additional lenses. From wildlife and sports to macro and astrophotography, their application is broad, but their effectiveness depends greatly on the underlying optics, camera body compatibility, and shooting conditions.
A 1.4x teleconverter generally provides a strong balance of reach and quality, suitable for most scenarios with minimal compromise. The 2.0x variant offers even greater magnification but comes with more substantial trade-offs in light, sharpness, and autofocus reliability.
Understanding the strengths and limitations of teleconverters enables photographers to make informed decisions about when and how to use them. When paired with high-quality lenses and used thoughtfully, teleconverters can unlock creative potential and extend the photographer’s reach—literally and figuratively—into new visual territories.