Teleconverters, Filters, and Lens Accessories

Teleconverters extend lens reach affordably, filters serve specialized purposes when used judiciously, and protective accessories help preserve expensive optics. Understanding when and how to use these accessories—and when to avoid them—helps photographers maximize lens performance while protecting their investments.

Introduction

The thousands of dollars invested in quality lenses deserve protection and augmentation through carefully chosen accessories. However, the camera industry has long promoted accessories that photographers don’t actually need, convincing many to attach “protective” filters that degrade image quality or to carry equipment that adds weight and bulk without meaningful benefits. The key to accessories is selectivity—choosing only those that genuinely enhance capabilities or provide protection in situations where risks justify the cost and inconvenience. Teleconverters represent the most valuable lens accessory for bird photographers, effectively multiplying focal length at modest cost and minimal image quality loss when paired with appropriate lenses. Filters serve legitimate purposes in specific situations but should otherwise stay in camera bags rather than degrading image quality on lens front elements. Lens hoods protect against both physical damage and optical flare. Extension tubes enable close focusing when needed. Protective sleeves cushion expensive glass against the inevitable bumps and scrapes of field work. Understanding which accessories genuinely benefit bird photography, how to use them effectively, and which to avoid entirely helps photographers build efficient, effective lens systems without accumulating unnecessary gear that adds expense and complexity without commensurate value.

Teleconverters: Extending Reach

Teleconverters are short optical devices that mount between camera bodies and primary lenses to increase overall magnification. They represent essential additions to bird photographers’ kits, providing increased reach at relatively modest cost with acceptable image quality compromises when used with appropriate lenses.

1.4x and 2x teleconverters by Canon and Nikon.

How Teleconverters Work

A teleconverter contains glass elements that magnify the image projected by the primary lens before it reaches the camera sensor. Common teleconverter magnifications are 1.4x and 2x. A 1.4x teleconverter increases focal length by 40 percent—a 500mm lens becomes 700mm, a 600mm becomes 840mm. A 2x teleconverter doubles focal length—a 500mm becomes 1000mm, a 600mm becomes 1200mm.

However, teleconverters also reduce the amount of light reaching the sensor. A 1.4x teleconverter costs approximately one stop of light (actually about 1.3 stops, but marketed as 1 stop), while a 2x teleconverter costs two stops. A 600mm f/4 with a 1.4x teleconverter becomes an 840mm f/5.6; the same lens with a 2x becomes a 1200mm f/8.

Image Quality Considerations

Teleconverters add glass elements between subject and sensor, inevitably causing some image quality degradation. However, modern teleconverters from Canon and Nikon are exceptionally well-made, and the quality loss when paired with premium telephoto lenses is minimal.

The 1.4x teleconverter paired with professional super-telephoto lenses produces images that are extremely close to the lens’s native performance. Most photographers cannot detect meaningful differences in sharpness, contrast, or color accuracy between native focal length and images shot with a 1.4x teleconverter on lenses like the Canon or Nikon 500mm or 600mm f/4. For practical purposes, the combination delivers professional-quality results with minimal compromise.

The 2x teleconverter causes more noticeable degradation. Images show slightly reduced sharpness, slightly lower contrast, and somewhat more chromatic aberration compared to native focal length. However, the quality remains quite good when used with premium telephotos. Professional publications regularly use images shot with 2x teleconverters on professional lenses—if the subject matter justifies publication, the slight quality reduction is accepted as worthwhile for the doubled reach.

Lens Compatibility

Not all lenses work well with teleconverters. Manufacturers design teleconverters specifically for certain lens types, and performance varies enormously depending on the primary lens.

Professional super-telephoto lenses—500mm, 600mm, and 800mm primes from Canon and Nikon—are specifically designed to work well with teleconverters and represent the ideal use case. These combinations deliver excellent results that justify the light loss and modest quality reduction.

Many other lenses also perform well with teleconverters, sometimes surprisingly so. The Canon 70-200mm f/2.8 paired with a 1.4x teleconverter becomes a 98-280mm f/4, and the combination produces very good results despite the lens not being a super-telephoto prime. Photographers should experiment with their lenses and teleconverters to discover which combinations work well.

However, some combinations don’t work at all. Budget zoom lenses, slower telephotos, and certain optical designs may not physically accept teleconverters (manufacturers often include protruding rear elements that prevent mounting), or they may produce such poor results that the combination is unusable. Additionally, the light loss from teleconverters may push maximum apertures into ranges where camera autofocus systems struggle or refuse to operate—many cameras won’t autofocus at f/8 or slower, making 2x teleconverters problematic with f/4 lenses on those bodies.

The 1.4x as Standard Equipment

For bird photographers using professional super-telephoto lenses, the 1.4x teleconverter should be considered standard equipment rather than optional. The combination of minimal quality loss, useful reach extension, and modest light cost makes the 1.4x teleconverter valuable in many situations.

Many bird photographers keep 1.4x teleconverters attached to their super-telephotos as default configuration, removing them only when the extra stop of light is needed or when subjects are close enough that the added reach isn’t beneficial. A 600mm with a 1.4x teleconverter (840mm effective) provides ideal reach for many small bird species while maintaining f/5.6 maximum aperture—slower than native f/4 but still fast enough for strong autofocus performance and adequate light in most conditions.

The 2x for Maximum Reach

The 2x teleconverter serves more specialized purposes. The two-stop light loss reduces a 600mm f/4 to 1200mm f/8—an aperture where many camera autofocus systems struggle and where shutter speeds must be quite fast to compensate for the extreme focal length’s magnification of camera shake.

However, when conditions are right—good light, calm air, solid support—the 2x teleconverter enables photography that would otherwise be impossible. The ability to turn a 500mm into 1000mm or a 600mm into 1200mm allows frame-filling portraits of very distant birds or extremely small subjects. Despite the reduced sharpness compared to native focal length, the images are publishable quality when technique is good and conditions favorable.

Professional photographers regularly use 2x teleconverters on premium telephotos and accept the quality compromises for the reach they provide. The slight softness matters far less than whether the subject fills the frame adequately—a slightly soft but well-composed image of a distant warbler is infinitely more valuable than a tack-sharp image where the bird occupies only a tiny portion of the frame.

Practical Teleconverter Use

In the field, many bird photographers carry both 1.4x and 2x teleconverters, choosing based on conditions and subjects. When photographing from a blind where birds approach predictably at known distances, they might shoot at native focal length or with a 1.4x. When working distant shorebirds across mudflats, they might add a 2x for maximum reach despite the quality trade-off.

Changing teleconverters in the field requires care. The process exposes both lens and camera sensor to dust, so it should be done in protected locations when possible and with attention to keeping everything clean. Some photographers dedicate separate camera bodies to different configurations—one body with lens at native focal length, another with a 1.4x attached—avoiding field changes entirely.

Filters: Selective Application

The first principle of filters is straightforward: if a filter isn’t serving a specific purpose, it shouldn’t be on the lens. Despite camera salespeople having long promoted the idea of permanent “protective” filters, placing even high-quality glass in front of expensive, precisely engineered lenses degrades image quality unnecessarily.

The Protective Filter Myth

Camera retailers often suggest attaching UV or “protective” filters to lenses permanently to prevent scratches on front elements. This advice is problematic for several reasons.

First, it places an additional piece of glass—often of mediocre quality if buyers choose inexpensive filters—in front of optics that may have cost thousands of dollars and contain a dozen or more precision elements. Even high-quality filters degrade image quality measurably, reducing contrast, increasing the potential for flare, and introducing additional surfaces that can show reflections or artifacts.

Second, in decades of field use, most photographers never put significant scratches on lens front elements. Lenses are remarkably durable. Minor marks on front elements rarely affect image quality anyway—small scratches or dust on the front element are so far out of focus relative to the image plane that they’re essentially invisible in photographs.

If a filter were truly protecting the lens from damage, that would suggest using the lens in conditions where serious damage is likely—in which case, why use expensive equipment in those conditions at all? The handful of situations where front element damage is genuinely likely (sandstorms, sea spray, fireworks debris) can be addressed with temporary protective measures rather than permanent filter mounting.

Filters That Serve Purposes

While protective filters are generally unnecessary, several filter types serve legitimate purposes in specific bird photography situations:

Graduated Neutral Density Filters: A graduated neutral density filter (split ND) features neutral density filtration on one portion—typically half—while the other half remains clear. A gradation zone between the two halves can be hard-edged (transitioning quickly) or soft-edged (transitioning gradually).

Split ND filters address high-contrast scenes where one portion is significantly brighter than another—most commonly, bright skies above darker landscapes. By positioning the neutral density portion over the bright sky, the filter reduces the brightness difference, preventing either blown-out skies or underexposed foregrounds.

Adding a graduated neutral density filter in front of my lens let me darken the sky, which otherwise would have appeared white, by two stops for this photo of a newly hatched Glaucous Gull chick in Alaska. 35mm, 1/125 second at f/11, ISO 200

For bird photography, split ND filters occasionally help when photographing birds in dramatic landscape contexts where sky brightness would otherwise dominate exposure. A two-stop split ND filter represents the most useful strength for these applications. The gradation should be positioned carefully, using the depth-of-field preview function to visualize exactly where the transition falls.

However, most bird photography doesn’t benefit from split ND filters—the situations where they’re valuable are relatively rare and specialized. Many photographers prefer to address high-contrast scenes through post-processing rather than in-camera filtration, as modern RAW files offer substantial latitude for balancing bright and dark areas.

Two-stop graduated neutral density filter mounted on a wide-angle lens

Polarizing Filters: A polarizing filter reduces reflected light and glare, deepening blue skies and reducing sheen from vegetation or water surfaces. The filter must be rotated to find the angle where it achieves maximum effect, and the degree of polarization varies depending on the angle relative to the sun.

For bird photographers, polarizers occasionally prove useful when photographing landscapes and habitat images, removing unwanted reflections from water or reducing the glossy appearance of wet vegetation. The effect can make images appear cleaner and more saturated.

However, polarizers come with significant costs. They reduce light by one to two stops, requiring either slower shutter speeds or higher ISOs to compensate. They can create uneven polarization effects in wide-angle shots, with some portions of sky appearing much darker than others. And for direct bird photography, the situations where polarization helps are relatively uncommon.

Neutral Density Filters: A neutral density (ND) filter reduces the amount of light passing through without changing the character or color of that light. ND filters come in various strengths, each reducing light by a specific number of stops, or in variable ND designs that offer adjustable light reduction.

For bird photography, ND filters have very limited application. They’re occasionally useful when incorporating motion blur into images—perhaps blurring wing motion while keeping the bird’s body sharp, or showing water movement around a bird—but there’s typically too much light for the slow shutter speeds required. Adding an ND filter enables those creative techniques.

However, these applications are quite specialized. Most bird photographers rarely use ND filters, as the situations where they’re beneficial are uncommon. Videographers use ND filters more frequently to achieve specific shutter speeds while maintaining wide apertures, but for still photography, ND filters remain specialty tools.

Filter Quality Matters

When filters are used, quality is essential. Cheap filters with poor optical quality will degrade images significantly, potentially eliminating the benefits the filter was meant to provide. Trusted filter manufacturers include B+W, Tiffen, Hoya, and Singh-Ray. These companies produce filters with high-quality glass, precision coatings, and proper manufacturing standards that minimize image degradation.

Filters come in different mounting systems. Screw-on filters attach directly to lens front threads and come in various diameters matching different lenses. Drop-in filters slide into special holders in the rear of super-telephoto lenses. Rectangular gel filters insert into holder systems that attach to lens fronts. For most bird photographers, screw-on filters for mid-range lenses and drop-in filters for super-telephotos represent the most practical options.

Photographers with multiple lenses sharing the same filter thread diameter need only one set of filters, making screw-on filters economical. Common filter sizes include 77mm for many telephotos and 52mm for drop-in systems on super-telephotos.

Lens Hoods

Lens hoods—rigid plastic or occasionally metal accessories that attach to the front of lenses—serve two important functions and should generally remain in place during shooting.

Optical Benefits

The primary purpose of lens hoods is shading front lens elements from direct or oblique light that might cause optical distortions. Light striking the front element at extreme angles can create ghosting (repeated images of bright light sources) or flaring (a milky haze that reduces contrast across the entire image). Lens hoods reduce these problems by blocking light from reaching the front element except through the intended optical path.

Even expensive, well-coated lenses can suffer from flare and ghosting under certain lighting conditions. Hoods provide inexpensive, effective protection against these issues.

Physical Protection

Perhaps more importantly for practical field use, lens hoods protect front elements from physical contact. A lens hood takes the impact when lenses bump against tripod legs, branches, rocks, or the ground during inevitable stumbles and mishaps. Many lenses have been saved from scratched or damaged front elements because the hood absorbed impacts.

For expensive super-telephoto lenses, the protective value of hoods is substantial. The alternative—exposing the front element directly to field hazards—is unnecessarily risky.

When to Remove Hoods

In high winds, lens hoods can catch air and cause vibrations that degrade image sharpness. When shooting in strong, gusty conditions, particularly with long lenses on tripods, removing hoods sometimes improves results. However, these situations are relatively uncommon, and the default should be keeping hoods attached.

Extension Tubes

Extension tubes are short tubes without glass elements that mount between camera bodies and lenses to reduce minimum focusing distance, allowing closer work than lenses can normally achieve.

How Extension Tubes Work

Lenses are designed to focus from infinity down to some minimum distance—perhaps 15 feet for a super-telephoto, closer for shorter lenses. Extension tubes change the lens-to-sensor distance, shifting the focus range. A lens that normally focuses no closer than 15 feet might focus down to 8 feet with an extension tube, allowing much tighter framing of subjects at close range.

However, extension tubes also eliminate the ability to focus at infinity. With the tube attached, focusing range shifts from some close minimum to some intermediate maximum—perhaps 8-20 feet. Subjects beyond that range cannot be focused.

Applications in Bird Photography

Extension tubes serve specialized purposes in bird photography. They’re occasionally necessary for extreme close-ups with long telephoto lenses—tight portraits of larger birds at very close range, or photographing nests and eggs in research contexts.

However, recent generation super-telephoto lenses from Canon and Nikon focus much closer than older designs, reducing the need for extension tubes. A modern 600mm might focus down to 14-15 feet, close enough for most bird photography applications without accessories. Extension tubes have become less essential than they once were.

Photographers working with older lenses that have longer minimum focusing distances, or those who regularly shoot extreme close-ups with telephotos, might find extension tubes valuable to keep available. For most bird photographers, they’re optional accessories that see occasional specialized use rather than regular equipment.

Lens Protection and Cases

Protecting expensive lenses from the inevitable bumps, scrapes, and weather exposure of field work justifies modest investments in protective accessories.

Neoprene Lens Covers

Neoprene lens covers—protective sleeves that wrap around lens barrels—provide cushioning against minor impacts while making lenses less visually conspicuous and more comfortable to handle in extreme temperatures.

LensCoat produces the most popular covers, offering options in various colors and camouflage patterns for nearly every major lens. The covers attach with hook-and-loop fasteners, allowing easy installation and removal. They provide access to all lens controls and windows while protecting the barrel.

Beyond physical protection, these covers offer unexpected benefits. Photographers worry less about minor bumps and scrapes when lenses are covered, reducing stress when working in rough field conditions. The covers also reduce glare from white lens barrels, potentially making photographers less conspicuous to birds.

Some camouflage patterns help lenses blend into environments when shooting from blinds or in situations where human presence might disturb birds. And in extreme cold, neoprene provides some insulation, making lenses slightly more comfortable to handle with bare or gloved hands.

Rigid Lens Protectors

Tragopan manufactures CamShell rigid lens protectors that provide superior protection compared to neoprene sleeves. These hard-shell cases surround lenses while still allowing operation of all controls. They’re more expensive and bulkier than neoprene options but offer far better impact protection.

For photographers who work in particularly demanding conditions—rocky terrain, dense brush, or situations where lens impacts are likely—rigid protectors justify their costs. For most bird photographers, neoprene sleeves provide adequate protection at lower cost and bulk.

Lens Cases and Bags

When transporting lenses separately from camera bags, dedicated lens cases provide protection. Most lenses ship with their own cases, and these generally serve well for storage and transport. Long lens bags designed for super-telephotos offer shoulder straps and padding, making them practical for carrying lenses to and from vehicles or between locations.

However, many photographers find dedicated lens bags redundant once lenses are in camera backpacks or other primary carrying systems. The cases serve well for storage of lenses not currently in use but see less field application than might be expected.