In March 2009 I posted a blog article comparing the Canon and Nikon flash systems. I was a Canon user back then, and after many years of hearing that Nikon had the edge on flash technology I was curious to get a better understanding of the concrete differences between them.
Then in September last year I switched to Nikon. The reasons for this had nothing to do with flash, however as a result of the switch I’ve spent a lot of time familiarising myself with the Nikon system. I thought it might interest some of you to understand how the systems vary from the point of view of someone who has (now) used both extensively.
First off let me state that I personally find that both systems give me good results in terms of TTL flash exposure – neither are perfect, and with both systems the use of flash exposure compensation under various lighting conditions will be a necessity, but I don’t find one system better than the other in this regard. Rather, it’s the differences in usage that are actually fairly significant, and this is what I’ll be discussing.
Ambiant vs. Flash control
One of the biggest differences concerns how the two systems give you control over the ambient vs. the flash exposure.
The Canon system completely separates the two exposures, such that any changes made using the exposure compensation dial will only alter the shutter speed/aperture combination – the flash exposure is not altered. To change the flash exposure the user must use the Flash Exposure Compensation (FEC) setting.
Nikon have taken another approach. The camera’s exposure compensation dial affects the whole image, so any changes made will affect both the “background” ambient and the flash exposure simultaneously. The FEC setting, on the other hand, will only affect the flash.
Bumping up or down the background exposure relative to the flash exposure is something that I do all the time. With Canon, the separation of these controls makes this very easy. With the Nikon system such a manipulation would possibly require a change to the global exposure (ambient light and flash) followed by a further change to the flash exposure to put it back where it was before.
I say “possibly” because personally I work with the camera in manual mode 95% of the time. In this case one can therefore continue to control the ambient exposure by adjusting the shutter speed and aperture, and then use either the FEC or standard exposure compensation to adjust the flash.
My opinion is that Canon’s approach is to be preferred, it’s simpler and less fiddly.
Both Canon and Nikon systems provide the ability to control groups of remote off-camera flashes, both using TTL for the flash exposure or by offering the ability to adjust the manual power of the flashes from the camera position. There are however major differences in how this is handled by each system.
The Canon system provides for 3 groups of flashes. In TTL mode Groups A and B are intended to light the main subject, and group C is independent. The flash exposure of the A/B groups is calculated such that together they correctly expose for the subject, however the A:B ratio can be easily changed by the user, and the FEC can be used to affect the exposure of the combined A/B group. In manual mode each group must be controlled independently. It’s not possible to combine TTL and manual modes.
Nikon have taken a more flexible approach to remote flash control. There are 3 remote groups + the master flash, and each can be placed into either TTL or manual. The FEC (for TTL mode) or the power level (for manual mode) can be adjusted separately for each group (or the master flash).
In my opinion the Nikon SB900 master is considerably easier to use than the Canon 580EX – the rear control screen has been very well designed in this regard. I also love the flexibility of the Nikon approach, and the independent control over each group.
Although Nikon’s flexible system would allow me to light independent subjects using different TTL groups, this would be an incredibly rare thing for me to do. Rather, the different TTL groups will typically be pointing at the same subject from different directions, and in this far more common scenario I like the ability to quickly change the ratio of the lights. Canon’s system makes this trivially simple, where’s Nikon’s makes this a little harder than necessary since each group will have to be changed individually.
Clearly Nikon themselves have realised this too since the A:B ratio mode is now available on the new mid-range SB700. Unfortunately the SB700 doesn’t allow for a combination of manual and TTL groups, so where it gains is flexibility in one area it loses in the other.
Assuming that the replacement for the SB900 keeps its existing flexibility whilst also providing the new ratio mode of the SB700, Nikon will win the remote TTL game hands down.
The two systems handle flash exposure compensation very differently, and for Nikon’s pro-body users it’s a bit of a kick in the teeth.
Canon offers a FEC control on both the camera body and their external on-camera flash units. Any changes that you make using the external flash unit will override the camera’s own setting. When using multiple off camera flashes separated into difference groups, the FEC will affect the A and B groups simultaneously.
Nikon’s approach is to offer an independent FEC control for each remote group (and another for the master flash) that can be controlled via the master flash unit. The on-body FEC has a cumulative effect with the FEC values that have been set on the master flash. This allows you to control the FEC of all the groups simultaneously via the camera body, and to adjust individual groups using the master flash unit. Note that it’s not possible to change the FEC globally for all groups using the master flash unit itself.
As a side effect of this approach, the Nikon system also benefits from a greater range of FEC. The flash offers ±3ev of compensation and the camera body offers -3ev to +1ev – since they are added together this in gives a theoretical range of -6ev to +4ev. With the camera in manual mode the global exposure compensation is also added to the mix, giving a total range of -11ev to +9ev. Obviously this can’t be achieved in practice.
If this were the situation for all Nikon bodies then Nikon’s approach would be the better one to my mind, however they’ve thrown a huge spanner into the works for pro-body users. Specifically, since there’s no on-camera flash on D3-series bodies, Nikon didn’t see fit to provide users with any on-camera flash exposure compensation. As a result of this decision, when working with the camera in a semi-automatic mode remote flash work becomes rather more complicated:
- It is not possible to adjust the flash compensation for ALL the remote flash groups simultaneously – each group has to be adjusted one at a time.
- Accessing the flash compensation on the flash is slower and more awkward than access via the camera body.
- D3-series users don’t benefit from the extended FEC range.
Note that there is a partial workaround for these issues, and that’s to place the camera into manual mode. In this situation the standard exposure compensation will continue to affect the flash exposure as explained above.
That said, the primary situation in which one uses TTL flash rather than manual flash is one in which the lighting conditions are changing – and in many of these situations the semi-automatic modes may also be useful for handling changes to the ambient exposure.
Rear curtain sync
There is one final detail that’s worthy of note: Nikon support rear curtain sync with their off camera flashes, whereas Canon don’t.
It’s hard to really say if one system is better than the other, but here are my personal conclusions after using both systems:
- The Nikon system is considerably more flexible in terms of remote flash control, and that’s a very good thing.
- The Nikon system is also far more user friendly.
- Canon’s ratio control of remote flashes provides for quicker control over the common case scenario. I hope that Nikon add this to their top-of-the range flash quickly.
- In semi-automatic camera modes, Canon’s separation of ambient and flash exposure is preferable. In manual mode there’s no difference, but I still find it clunky to adjust the flash exposure using the global exposure compensation.
- The lack of FEC on Nikon’s D3-series bodies is a significant oversight. Canon’s pro-bodies have on-body FEC.
- Nikon’s rear-curtain sync for remote flashes is a nice advantage.