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Guide to Nikon TTL Flashes

by Shun Cheung, December 2008 (updated February 2011)

Photography is about creating images with light. For indoor, night, fill light, or certain special effects, using electronic flashes to generate light becomes an important component in modern photography. Nikon’s current flash technology is called i-TTL, and they offer five different external flash options. So far all of those i-TTL flashes have three-digit model numbers in the form of SB-n00 (e.g. SB-600, SB-900 and there is also an SB-R200) while the older, non-i-TTL flashes have two-digit model numbers (e.g. SB-28 and SB-80 DX). Therefore, it is very easy to determine which ones are i-TTL compatible. This article provides a brief history of the evolution of Nikon TTL flash technology and a guide to those five i-TTL flashes.

The intro image demonstrates the size differences amongst the SB-900, SB-800 and SB-600.

The Introduction of Digital and D-TTL

Nikon introduced the TTL (through-the-lens) flash technology to its film SLRs (Single-Lens Reflex Cameras) in the mid 1980’s. The major advantage of TTL flash is that flash exposure is measured during the actual exposure, as the amount of light reflected off the film is detected by sensors placed inside the mirror box. When a sufficient amount of light is detected, the flash is electronically shut off instantaneously.

In 1999, Nikon released its first digital SLR, the D1. The new problem then was that the digital sensor and the anti-aliasing filter in front of it did not reflect light the same way traditional film does. As a result, Nikon had to modify its TTL flash technology as it was no longer possible to measure the amount of reflected light during the actual exposure. Instead, Nikon used pre-flashes and measured their strength to determine how much flash power was needed.

The initial technology was called D-TTL. It is merely a slight modification from film TTL. Instead of measuring the light reflected off the film during actual exposure, D-TTL carries out a quick series of pre-flashes after the mirror has flipped up but before the shutter opens. On D-TTL DSLR bodies, the outward-facing side of the shutter blades is painted light gray to reflect more light so that it would be easier to measure the pre-flash. Flash metering is still carried out by sensors placed inside the mirror box as before.

Correspondingly, Nikon also made a slight modification to its last film flash, the SB-28, into the SB-28 DX. All three D-TTL flashes Nikon would eventually introduce all have the “DX” suffix. (Subsequently, there were also the SB-50 DX and SB-80 DX.)

The D-TTL era lasted four years and Nikon only introduced four DSLRs that use D-TTL exclusively: the D1 family: the D1, D1H and D1X and the subsequent D100 in 2002. However, the entire D2 family is also backwards compatible with D-TTL; in fact, they are the only cameras that are both D-TTL and i-TTL compatible.

i-TTL and the Creative Lighting System (CLS)

In July 2003, Nikon announced the D2H, the first of what would be four cameras from the D2 family, along with a new SB-800 flash. They were the first installment to Nikon’s iTTL and Creative Lighting System (CLS). The new triple-digit model number without the DX suffix indicated the new flash technology. The pre-flash is still required for digital, but it takes place slightly earlier in the exposure cycle, before the mirror flips up. Therefore, pre-flash exposure is measured inside the viewfinder instead of inside the mirror box.

In addition to TTL flash, CLS is a complex system of master and remote wireless flashes. There can be up to a total of three groups (A, B and C) of wireless remote flashes that can be controlled independently with different exposure compensations. There are also four separate channels (1 to 4) so that multiple photographers will not interfere with one another in the same room.

Nikon Flash Terminologies

  • TTL: Through-the-Lens flash metering
  • TTL-BL: Balanced fill flash between flash and ambient light
  • TTL-FP: Focal Plane flash: permits flash photography with a shutter speed faster than the camera sync speed, which is typically 1/250 sec or 1/200 sec on Nikon DSLRs. In the * TTL-FP mode: the flash uses a sequence of pulse flashes to get round the sync speed limitation so that it can sync with as fast as 1/8000 sec but at reduced flash power. The higher the shutter speed, the greater the flash power reduction.
  • A: Auto, instead of using TTL flash with a flash meter inside the camera to measure the amount of flash, use a flash metering sensor built inside the flash to control the flash level. Among iTTL flashes, this feature is only available on the SB-800 and SB-900
  • M: manual, control the flash level manually at full, 1/2, 1/4, 1/8…typically at 1/3-stop increments.


The SB-800 is essentially the same flash as the SB-80 DX, which was the last D-TTL flash, with a different pre-flash and exposure measurement technology. In fact, the two look very similar. From the back side, other than the model number, they look identical.

As the very first in the i-TTL/CLS series, the SB-800 can either be a stand-alone flash, a CLS master that is mounted onto the camera and controls other remote flashes, or a CLS wireless remote slave. As either a CLS master or slave, the SB-800 can use all three groups and all four channels.

Guide Number

For four years since its 2004 introduction, the SB-800 was Nikon’s best flash that has a lot of advanced features:

  • A 270-degree rotating flash head
  • TTL, TTL-BL, A, GN, M and RPT options
  • Manual mode from full power down to 1/128 power, in 1/3 stop increments
  • AF assist LED
  • Modeling light
  • Built-in bounce card and flip-out diffuser, supplied removable diffuser dome
  • LCD brightness control
  • Illuminated LCD

The SB-800 has a unique 5th battery option. It comes with an add-on compartment that can hold one AA battery. You can replace the regular battery chamber door with that compartment so that the SB-800 can use 5 AA batteries simultaneously, thus getting a slightly faster recycle time. Additionally, the SB-800 has an external high-voltage power input to use an external power supply for even faster recycle time.

The FP (focal plane) sync feature allows flash photography at any shutter speed, including faster than the typical maximum sync speed at 1/250 second. Under the FP Sync mode, the SB-800 will fire a number of flashes to cover the entire frame as the focal plane shutter moves across the frame. However, flash power is greatly reduced.

The SB-800 also has the best compatibility going forward and backward. It can work with film TTL and D-TTL bodies.

A minor downside for the SB-800 is that it has a somewhat cryptic menu system. The key to remember is that you need to hold down the center multi-selection pad for two seconds and the menu on the back LCD will switch to a different mode for master/remote selection as well as several optional settings. One example of the somewhat problematic menu system is the lock feature: on the SB-800, if you hold down both the Select (SEL) button and the on/off button for two seconds, the flash will enter the lock mode with a lock icon appearing on the LCD. All of a sudden, the controls on the SB-800 “will not work” any more. You need to hold down those two same buttons for two seconds to unlock the flash. I have seen people entering the lock mode accidentally and got stuck.

While the SB-800 is still widely available at various camera stores at the present time (December, 2008), it is quite clear that the new SB-900 is its replacement so that the SB-800 will unlikely to stay in the market for too much longer.


The SB-900 was introduced in July 2008 along with the D700 DSLR. It has a similar amount of flash power and the same CLS master/slave capabilities as the SB-800, but the SB-900 has a much improved menu system as well as a lot of new options. In particular, the SB-900 has a huge zoom head that can focus its flash beam to the 200mm angle of view, thus making it an excellent choice for long telephoto work. As a result, the SB-900 is much bigger in size than its predecessor and can be a little unstable when it is mounted on top of a small DSLR.

Concerning features, the SB-900 retains essentially all capabilities the SB-800 has and then some:

  • The flash head can now rotate a full 360 degrees
  • The 5th battery option is gone, but with 4 AA batteries, the SB-900 still has improved recycle time and the option to use an external high-voltage battery pack remains.
  • FX/DX coverage with auto detection: Given the popularity of DX DSLRs, this is an obvious improvement that was clearly missing in the last several years. In previous Nikon flashes, the angle of coverage only corresponds to the angle of view for FX for each focal length. The SB-900 can cover either the FX or DX angle of view, thus conserving some flash power on DX DSLRs.
  • Built-in thermostat with auto shut off for overheat prevention. While this is a good feature to have, I have read a number of complaints that the flash shuts off after only a dozen or so full-power flashes, thus causing problems to some wedding photographers as their SB-900 shuts off at critical moments. However, keep in mind that this feature can be switched off.
  • Center Weighted, Standard and Even flash coverage selection
  • Gel filters with auto white balance control

However, Nikon has removed backward compatibilities with D-TTL and film TTL from the SB-900 as those old cameras are no longer popular any more.

The SB-900 also has the lock feature, but they have apparently learned from the SB-800 experience so that the SB-900 has clear markings on the back of the flash about which two buttons to press simultaneously to engage and disengage the lock. There are many of these little improvements that make the SB-900 much easier to use than its predecessor.

Text ©2008 Shun Cheung. Supplemental images ©2008 Shun Cheung and courtesy of Nikon, Inc.

Article revised February 2011.

Readers' Comments

Add a comment

Michael Ellis , December 22, 2008; 04:22 A.M.

Hi Shun,

Thanks for the article which I have found very helpful. I basically 'did a mad one' and plunged into DSLR with my purchase of a D700 and a SB-800 flash. Of all the mysteries I have encountered the 'cryptic' flash menu system is the greatest one and their manual is almost as 'cryptic'. Your clarification will go some way in my journey of knowledge.

Thank you.


bill parney , February 23, 2009; 06:16 A.M.

I just want to add that there is a great article about how to set up the diffirent Nikon flashes and cameras at http://www.momentcorp.com/review/wirelessflash.html I found this article really helpfull:)

Bill Nelson , May 07, 2009; 01:06 P.M.

Excellent article. Just purchased the sb-900 as the sb-800 is out of production. Works great except for the overheating. Was shooting a wedding and it locked up on me even though I thought I had turned off the temp sensor. Other than that this is a great flash. The menu is very easy to access and read. Can't say the same for the sb-600. Is there some other way to turn it off?

James Naka , May 15, 2009; 04:30 A.M.

Kudos and Bravo to you. Such a detail and comprehensive guide to Nikon DSLR Camera TTL Flashes. I really need some time to digest and understanding it :) .

Roger Smith , June 18, 2009; 02:17 P.M.

I bought the SB 80 DX and was frustrated with how it wouldn't securely mount onto an umbrella stand adapter. Recently I heard on Strobist about a new adapter offered by flashzebra.com. I bought two and they work quite well to connect my flash to a tripod and lightstand. http://flashzebra.com/products/0137/index.shtml

Theodore R. Swantek , October 15, 2009; 10:36 P.M.

I am still confused, the SU-800 is approx. $80 or so cheaper than the SB-800. I do not intend to use either as a commander. Would the SU-800 perform as well as the SB unit? Camera is the Nikon D300

Sevad Strapotua , November 04, 2009; 04:59 A.M.

You dismissed the SB-400 rather too easily. In fact,it will do most of the things the more expensive flashes will do but in a smaller package - and that means you're far more likely to have it in your camera bag. It's great for fill-in flash for outdoor portraits when you hardly even notice it on the camera unlike some of the bigger flashes which make a DSLR feel top heavy. With its bounce capability it's also perfect for many indoor shots in the landscape orientation.

It's true that it can't be bounced off the ceiling in portrait orientation but it can be bounced off a wall and that often creates more interesting lighting anyway. You can also slot a filing card into the gap between the body and the flash tube to direct a little flash at the subject to help fill in any shadows caused by the main bounce flash. Overall, it's a lightweight, portable, versatile and effective flash that will handle most jobs most of the time. Only if you have a need to bounce off the ceiling in portrait orientation, require more power (i.e. if you're shooting in a room with a very high ceiling) or need to set up more than one flash should you consider one of the more expensive and bigger flashguns. For a multiple flash set up, it's also possible just to use some sort of slave trigger on a non-Nikon flash - you don't need the most expensive just because it's available.

Lonnie Howard , February 25, 2010; 12:27 P.M.

Thank you for the excellent and helpful article. Minor typo: 'flash “extension cord” such as the SB-28 and SB-29' should be SC-28 and SC-29. 8^)

Shun Cheung , October 31, 2010; 04:57 A.M.

There are very good reasons that serious photographers dismiss the SB-400. See this discussion on the Nikon Forum: http://photo.net/nikon-camera-forum/00WRQr


And yes, the flash "extension cords" are SC-28 and SC-29. There is also an SC-17 that is now discontinued.


Moreover, in the fall of 2010, Nikon has added a new SB-700 flash that is a mini SB-900 with some of the same new features such as color gel filters and an improved user interface menu.

Steven Seelig , January 16, 2011; 10:28 P.M.


For the Nikon TTL of today, do the monitor the whole field of view for light returned or if you are on spot exposure metering does it only measure the light at the spot where you are measuring from? 


Shun Cheung , January 19, 2013; 10:28 A.M.

With the introduction of the SB-700 and SB-910, replacing the SB-600 and SB-900, respectively, the updated "family portrait" of the flashes looks like this:

The SB-910 is very similar to the SB-900 but handles the overheat issue better. The SB-700 is actually a little larger than the SB-800, and unlike the SB-600, the SB-700 can be a CLS master. The SB-700 also has SB-900-style controls so that it is much easier to use, but the cost goes up.


On the Nikon Forum, we have a new thread on the Nikon flash battery packs: Nikon SD-8A and SD-9 Compatibility with SB-800, 900, and 910

Patrick S , February 11, 2013; 11:19 A.M.

I don't know that something being "no longer popular" is a basis for a marketing decision. Most cameras sold now are indeed digital, but I'm betting Nikon didn't drop flash support for film cameras because they felt people weren't using them. They WANT people to stop using film cameras and this pushes them that way, whether they want to or not.

Gerry Schnaible , February 13, 2013; 01:59 P.M.


"They WANT people to stop using film cameras and this pushes them that way, whether they want to or not."

Spot on. The impulse marketing is perhaps most prevalent in electronics but if you look at the release of cameras it is the perfect example of what you say.

People are constantly pushed to the "bigger", "better", "more advanced" model all the time. There is something that feels comfortable about equipment that is around long enough to be an extension of yourself. Truth be known  there is a very, very small number of people that use even 10% of the capabilities whether it is a blu-ray player or the DXXX fill in the name.

I became really aware of this while in a discussion about a photograph and the other party said well send the EXIF data so we can see whether it was you or the product. The photo was shot about 20 years prior to the EXIF age. Totally blew me away as I had never even considered EXIF as any thing other than a "nifty" gadget. LOL

Sem Svizec , August 12, 2014; 09:04 A.M.

All these speedlights are powered by AA cells, preferably the NiMH type, either the high-capacity self-draining ones or the longer-holding Eneloop or similar. There is the question why flashes haven't moved to Li-ion like cameras.

The running assertion was that Li-ions in the same volume were not good at pulling out juice fast enough for quick recycling; while folks have already been using larger external 3rd-party or DIY Li-ion-based battery packs successfully for fast recycling. 

Now it appears the assertion is false, as Godox made Li-ion powered flashes (V850c, V860c, recently V860n), where a Li-ion cell looking smaller than 4xAA manages to pull out twice as many full-power pops, with faster max recycling time (1.5s), and with the battery not running as hot as standard cells. It will be interesting to see how long it takes canikon speedlights to follow suit. 



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