Nikon Speedlight
SB-25 TTL AF Speedlight

Four years after debut of the high performance flash, Nikon SB-24, Nikon announced a successor, Nikon SB-25 TTL Speedlight in 1992. This update was essential due to rapid development in both Nikon camera/flash design. It was marketed along with a new generation of Nikon AF SLR camera, Nikon F90 (N90 in US), a high tech AF SLR camera with cross AF sensors, built-in 3.6 fps power drive, improved Matrix metering with 8 segments evaluative system that requires works a new series of AF-Nikkor lenses that has a distance chip embedded in the lense for evaluating light levels and contrast of the subject and based on the distance information to track on moving subject during a shooting sequence.

Among the many innovative features in the camera, there are few areas which directly related to flash photography which called for an update of a new flash unit to support the functions: The F90 was the world's first SLR camera that provides TTL-Multi Sensors (5 segments) evaluative flash metering. The system provides precise light and distance in flash exposure measurement. Further, since beginning with the F90 onwards, many Nikon updated AF SLRs also offer other new camera function in Matrix filled-flash, second curtain sync, preflash Red-Eye reduction and an amazing 1/4000 sec FP fast sync capability. The last few inclusions were not supported in the design of any of the previous Nikon AF speedlights and the SB-25 was specifically introduced to patch what the previous Nikon Speedlight such as SB-24 that cannot offer and aimed to supplement those functions with the new F90 and of cause, all the subsequent Nikon AF bodies introduced at later stage that may provide similar capabilities.
Well, similarly that was how Nikon auto TTL-thrystor evolved all these years - the subsequent Nikon SB-26 TTL AF Speedlight that introduced later in September, 1994 (with the F90x) also incorporates a few additional enhancements (in particular with an interesting built-in wireless slave flash control function for true-cordless single or multiple flash operation). Eventually when AF-Nikon SLRs which has 3D-Matrix Multi-Sensors balance fill-flash function, there was also a need to call for a new flash model to support the 3D-Matrix and that was how both the Nikon SB-27 and Nikon SB-28 speedlights were introduced.
However, Nikon SB-25 Speedlight is versatile enough and has a great backward compatibility with older Nikon SLR models as it can also be used with all Nikon AF SLR cameras without the prescribed new functions. With any Nikon bodies that equipped with more advance functions, such as 3D-Multi-Sensor TTL auto flash, it will/should be working flawlessly with those bodies as well and it can also be used with Nikon standard TTL auto flash, as well as non-TTL automatic flash, as well as full manual control. This very high-spec Nikon TTL auto thyristors unit does not only performs true to its capability, but it has an extremely well-designed physical construction. The entire body structure is very rigid and all operating buttons are hard rubberized-coated, slightly recessed to prevent accidental actuation. Operating logic is well thought out especially in relating to its display system. The LCD panel at the rear section indicates selected distances or ranges, as well as apertures which can be adjusted. Operating status such as type of automatic flash, special flash functions, and zoom head setting are indicated.
This high performance Nikon TTL Speedlight has a guide number of 118 (138 ft at 35mm setting, ISO/ASA100 film). It provides enough raw power to cover for many action-based flash photography and even support working range for stroboscopic effect in repeating flash photography.
With capable Nikon SLR bodies that supports rear curtain synchronization, such as the Nikon F4 Series, F90, F801(s) and F601(s)) available at its time of introduction, the flash allows synchronization with the rear shutter curtain. Similarly, with these mentioned bodies, the power driven motorized zoom head will adjust its focal length in correspondence with the focal length of the lense in use.
One improvement made to the SB-25 is its flash head which has a tilting angle (-7°) which allows the flash extends its TTL filled-flash function in macrophotography. Similar to the previous SB-24, the SB-25's flash head is very versatile and flexible as it can be maneuver by tilting from -7° to +90 >° with click stops; rotates through an arc of 270 °, 90 ° clockwise and 180 ° counterclockwise with click stops.
The LCD is backlit and has a very pleasant indigo colour when it is turn on in the dark. It provides good contrast to read various information and settings even when the ambient light is not ideal.
Naturally, other than permitting high speed FP sync flash, the main additional technical highlights still remain in its newly incorporated features in Red-Eye Reduction and the two Monitor Preflash features with camera models such as F90 and above. With the flash functions of the N90 the SB-25 has two preflash features in a visible pre-flash burst of light which is used for reducing any possible redeye effect and an invisible monitor preflash provides information regarding reflectance of the subject in focus. As many of the keypads, switches and button at its rear control panel are very similar to the previous SB-24 and owners and/or any photographer who may have experience with the SB-24 may find it very easy to navigate the various controls in the SB-25. Below are some of the features found in the SB-25 Speedlight, used them singularly or in combination with the camera types you owned and you may find the SB-25 can be a truly worthy investment with its vast potential help to unleash your creative potential in flash photography.
In a multiple flash photography setup, the complexity of ensuring good, natural looking flash pictures can be very difficult. Nikon designed Speedlight with an array of system flash accessories (TTL sync cords, flash couplers and TTL connections to simplify the entire process.
In operation, Nikon designed the SB-25 simplifies the flash taking process with more assuring results via some new technologies in both camera/flash combinations: i.e. before the main flash fires, imperceptible Monitor Pre-flashes go off to scan the whole scene with the TTL Multi Sensor. The in board computer instantaneously evaluates which areas need what amounts of light; and then the main flash illuminates the scene perfectly. So, this ensures dark areas stay dark, the light areas are rendered with better, more natural colour. On the other hand, the foreground remains balanced with the background. This process ensures the whole scene can be looks more natural without the presence of over dominant flash effect. The breakthrough of these sequence enables a more realistic-looking flash pictures.
Technical Highlights & Main Features at a glance:

The powerful SB-25 has a guide number of 36 (metres) at ISO 100 at its 35mm zoom setting, and 50 (metres) at 85mm. With the F90, it offers such advanced features as Multi-Sensor Balanced Fill-Flash, Red-Eye Reduction and FP High-Speed Sync. Selectable flash modes include TTL mode, non-TTL auto, and manual flash control. For example, FP high-speed sync enables you to capture a sharply focused moving subject with shallow depth of field in fill-flash. Also selectable is a strobo-effect operation in which the flash fires continuously at selected rates. The SB-25 provides autofocus capability in total darkness with any Nikon AF SLR (AF-assist Illuminator). You can rotate and tilt its flash head for bounce flash photography. Flash coverage automatically adjusts for any focal length from 24 to 85mm. This can be increased to that of a 20mm Ultrawideangle lens with the built-in wide flash adapter. Manual control is also possible. For your reference, all basic information related to flash photography is displayed on the flash's LCD panel. There's also a built-in bounce card for the catch-Iight effect.

Finally, the ISO-Standard type accessory shoe on most Nikon SLRs introduced after 1992 offer an extra secure positioning hole which will mate with the flash foot for foolproof mounting system prevents the SB-25 from accidentally slipping off. Overall, this high performance Nikon AF-TTL flash is very usable and has very wide compatibility with Nikon AF SLRs - which makes it a very attractive speedlight to use.
Slow Sync When flash pictures are taken at high shutter speeds in dim light, the background may come out dark. Setting Slow Sync extends the automatically controlled shutter speed range In P and A mode (between 1/250 sec. and 1/60 sec.) down to 30 sec. Now background details jump.
Detailing the FULL LCD display of the Nikon SB-25 speedlight and briefly described its various functions. Reference: The Instruction Manual
Rear-Curtain Sync Nikon Speedlights make it possible to fire the flash just before the shutter curtain closes especially effective at slow shutter speeds. This results in the available light turning into a stream of light following the flash-illuminated subject. When Rear-Curtain Sync is set in the Auto-Multi Program or Aperture-Priority Auto exposure mode, Slow Sync is automatically selected.
Red-Eye Reduction Before the shutter is released and before the TTL Multi Sensor's pre flashes, the SB-25 fires three visible but relatively dim flashes, followed by the main flash which takes the picture. The three dim pre flashes make the subject's eye pupils become smaller, thus reducing the appearance of Red-Eye
FP High-Speed Sync With the Nikon SB-25 Speedlight set at the FP mode, the flash output continues from the start of the shutter curtain opening until it is fully closed, thus allowing flash synchronization with fast shutter speeds from 1/250 to 1/4000 sec. You can capture fill-flash pictures even with film that has a high ISO rating, and still maintain wide aperture settings for expanded control of depth of field. You choose from two levels of flash output. Please note that: Not all Nikon SLRs are equipped with the FP sync feature (F5, F100 and F90(x) series and/or future models).
Repeating Flash This strobo-effect operation is selectable with the Speedlight SB-25, 'In which the flash fires continuously at selected rates, you can choose the length of time between flashes (1Hz to 50 Hz), the number of flashes and flash output amount.
AF-Assist Illuminator Dedicated Nikon Speedlights - the SB-28, SB-27, SB-26 SB-25, SB-23, SB-22 and SB-20 -with autofocus illuminators send an LED-pattemed beam of light to the subject. making it possible to take sharply focused pictures even in total darkness.
Nikon TTL multiple-flash system Choose a combination of Nikon Speedlights: SB-28, SB-27, SB-26, SB-25, SB-24, SB-23, SB-22, SB-20 or even the MF SB-16B, and use them with the TTL remote or TTL multi-flash sync cord. The camera's TTL Multi Sensor system automatically measures and controls the light from all units.
Automatic Balanced Fill-Flash works not only in bright light situations but also in twilight and at night within a controlled shutter speed/aperture range. 5-Segment TTL Multi Sensor In combination with a full fine of Nikon dedicated TTL Speedlights, Any Nikon SLRs that offers such capabilities (see Specification section for reference) can really spark your imagination, illuminating any photographic situation. You can perform automatic balanced fill flash in the TTL mode in any flash shooting situation, assuring a beautiful, naturally balanced exposure for both foreground and background. With any capable Nikon SLRs (see specification section), TTL flash output is controlled by a 5-segment TTL Multi Sensor incorporated in the bottom of the mirror box. Flash output is more precisely monitored and controlled than conventional TTL flash control with its single-segment TTL sensor.
3D Multi-Sensor Balanced Fill-Flash The highest performance possible, 3D Multi-Sensor Flash works with a combination of a Nikon SLR that offers such capability (as a rough guideline, Nikon F90/N90 onwards), a D-type AF Nikkor lens and the SB-25 AF Speedlight. In this flash mode, the SB-25 fires a series of pre-flashes that are detected by a capable Nikon SLR that equipped with such feature; then the TTL Multi Sensors will analyze for brightness and contrast. Moreover, distance information from the D-type AF Nikkor lense in use, along with other exposure control information, is integrated, thus automatically compensating flash output level so that flash output and ambient light are balanced. 3D Multi-Sensor Balanced Fill-Flash can be performed with any metering system. When a capable Nikon SLR model with such capability and a SB-25 are used with a non-D-Type AF or Ai-P Nikkor lens, (non 3D) Multi-Sensor Balanced Fill-Flash which offers the same flash output control system but without distance information and operation superior to single-sensor systems-is performed. Multi-Sensor Balanced Fill-Flash, minus Monitor Preflash, is also performed with newer Nion flash models as well as older series such as SB-24, SB-23,, SB-22, SB-20 and the MF Nikon Speedlight SB-15/16B.
Centre-Weighted and Spot Fill-Flash For Ai-type Nikkor lenses that have no computers, there's Centre-Weighted or Spot Fill-Flash. The many Nikon AF SLRs that offer such possibility in TTL Multi Sensor's elements, functioning as one, control flash output for a natural fill-flash effect.
Standard TTL Flash Using standard TTL flash control, the flash operates independently from the camera's computer, providing a traditional flash exposure. Even for this basic operation, most Nikon AF SLRs offers advanced performance. The manual flash compensation control provided is a small detail that can make a big difference.
Unique TTL Multi Sensor The first of its type for flash photography. this sensor provides multifunction performance. With the Monitor Pre flash of the SB-25 AF Speedlight, it provides flash exposure analysis before the picture is taken, it then controls the flash during the actual exposure. Virtually. Monitor Pre-flash operation is so fast that you cannot even see it. and camera operation remains the same.

Specifications for Nikon SB-25 TTL AF Speedlight
Electronic construction:
Automatic silicon-controlled rectifier and series circuitry
Flash modes: f
F our settings (TTL, A, M and Repeating/Strobe Flash)
Guide Number:
GN 36 (meters and ASA 100); GN 20 with flash diffuser.
Angle of coverage:
Coverage as wide as 20mm with built-in wide flash adapter, auto power zoom 24mm-85mm with the Nikon F5, F100, F90x/N90s, F90 Series/N90, F4 Series, F801/N8008 and F801s/N8008s and and other capable/newer Nikon SLR bodies; manually set with other cameras.
Bounce flash:
Flash head tilts from -7° to +90° with click stops; flash head rotates through an arc of 270°, 90° clockwise and 180° counterclockwise with click stops.
Flash exposure control:
Nikon F5, F100, F90x/N90s, F90/N90, F4, F801/N8008, F801s/N8008s, F601/N6006, F601M/N6000, F50/N50, F401x/N5005, F501x/N2020, F301/N2000, F401/N4004, F401s/N4004s and other capable AF Nikon models in conjunction with any AF-Nikkor CPU** lense; MF Nikon SLRs such as FA, FE2, FG, Nikonos-V. Usable aperture f/1.4 - f/22 at ISO 100. Shooting distance .6-20 meters (2-66 ft.). Distance scale can be changed from meters to feet with lever inside battery compartment. Nikon F3 series only operates in Auto mode but TTL flash is possible via AS-7 and/or AS-17 flash coupler.
Multi-Sensor Balanced Fill-Flash with the later Nikon AF cameras such as Nikon F5, F100, F90x, F85, PRONEA 600i or F70 etc. with any AF-Nikkor CPU lense * Matrix balanced fill-flash: with F4-series, F801/N8008, F801s/N8008s, F601/N6006, F50/N50 or N5005 and other capable/newer Nikon SLR bodies with AF and Ai-P Nikkor lenses.
Auto flash Mode:
Non-TTL, light measured via sensor on front. Usable apertures : f/2, f/2.8, f/4, f/5.6, f/8 and f/11 (at ISO 100). Shooting distance .6-20 meters (2-66 ft.) Manual control: full output light output set in 18 steps from Full to 1/64 power in 1/3 steps.
* "CPU" lenses refer to those AF Nikkor, AF-I Nikkor, IX-Nikkor or Ai-P Nikkor lenses which feature a built-in microcomputer and CPU contacts. ** With F4-series, Manual Focus Ai-S or Ai Nikkor lenses are also usable.
# Coverage as wide as 20mm with built-in wide flash adapter, auto power zoom 24mm-85mm with the Nikon F90x/N90s, F90 Series/N90, F4 Series, F801/N8008 and F801s/N8008s; manually set with other cameras.
# Three power switch settings; OFF, STBY and ON; at STBY position with Nikon F90x/N90s, F90/N90, F4, F801/N8008, F801s/N8008s, F601/N6006, F50/N50, F401x/N5005, F501x/N2020, F301/N2000, F401/N4004, F401s/N4004s, FA, FE2, FG, Nikonos-V, FM2 or FG-20 the SB-25 turns off automatically after unit is not used for approx. 80 seconds and turns on when the camera is turned on.
# TTL Mode : Used with Nikon F90x/N90s, F90/N90, F4, F801/N8008, F801s/N8008s, F601/N6006, F601M/N6000, F50/N50, F401x/N5005, F501x/N2020, F301/N2000, F401/N4004, F401s/N4004s, FA, FE2, FG, Nikonos-V. Useable aperture f/1.4 - f/22 at ISO 100. Shooting distance .6-20 meters (2-66 ft.). Distance scale can be changed from meters to feet with lever inside battery compartment.
# AF Assist Light : LED beam automatically fired using AF in insufficient light with Nikon F90x/N90s, F90/N90, F4, F801/N8008, F801s/N8008s, F50/N50, F401x/N5005, F501x/N2020, F401/N4004 and F401s/N4004s
# Red eye reduction lamp fires before main flash with Nikon F90x/N90s, F90/N90.
# Rear curtain sync for Nikon F90x/N90s, F90/N90, F4, F601/N6006, F601m/N6000, F801/N8008, F801s/N8008s.
# FP High Speed sync flash - available with Nikon F90x/N90s, F90/N90 enables high speed shutter (1/250 or faster) for flash sync.
# Monitor pre-flash - available with when used with Nikon F90x/N90s, F90/N90 and AF Nikkor lens.
Flash working range:
0.6 to 18m (2.0 ft ~ 65 ft.) with indicative increments in 0.6, 0.8, 1, 1.5, 2, 3, 4, 6, 9, 13 and 18m
Film speed range in TTL auto flash mode:
ISO 25 to 1000 with Nikon F4-series, F90x, F-801s, F70, F-601s, F50 or F-401x; with F-401s and older: ISO 25 to 400.
Recycling time:
Approx. 7 seconds minimum (full discharge)
Red-Eye Reduction:
Lamp fires before main flash with Nikon F5, F100, F90x/N90s, F90/N90 and other capable/newer Nikon SLR bodies
AF-Assist Illuminator:
Automatically fires LED beam toward subject when performing autofocus with all Nikon AF SLRs such as Nikon F5, F100, F90x/N90s, F90/N90, F4, F801/N8008, F801s/N8008s, F50/N50, F401x/N5005, F501x/N2020, F401/N4004 and F401s/N4004s and other capable Nikon AF SLRs
Rear Curtain Sync:
Nikon F5, F100, F90x/N90s, F90/N90, F4 Series, F601/N6006, F601m/N6000, F801/N8008, F801s/N8008s and other newer/capable Nikon SLR bodies introduced at later stages
FP High Speed sync flash: a
A vailable with Nikon F5, F100, F90x/N90s, F90/N90 and other capable Nikon SLR bodies enables high speed shutter (1/250 or faster) for flash sync.
Monitor Pre-flash: a
A vailable with when used with Nikon F5, F100, F90x/N90s, F90/N90 and other newer Nikon SLR bodies with D-type AF Nikkor lenses.
Power source:
Four 1.5V AA-type alkaline-manganese or NiCd AA batteries; Accepts optional battery packs SD-7 and high performance power pack SD-8
Dimensions (without mounting foot):
Approx. 79mm x 135mm x 101mm
Weight (without batteries): Approx. 380g (13 oz)
Other features:
Three power switch settings; OFF, STBY and ON; at STBY position with Nikon F5, F100, F90x/N90s, F90/N90, F4, F801/N8008, F801s/N8008s, F601/N6006, F50/N50, F401x/N5005, F501x/N2020, F301/N2000, F401/N4004, F401s/N4004s, FA, FE2, FG, Nikonos-V, FM2 or FG-20 the SB-25 turns off automatically after unit is not used for approx. 80 seconds and turns on when the camera is turned on.
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