How do you take a photograph when there isn't enough ambient light? Sometimes you can use a tripod and take a long exposure. At other times, where you have moving subjects that you don't want blurred, you have to generate the required light.
Most cameras these days come with a built-in flash(usually a pop-up flash on DSLRs). While this is sufficient for using as a fill light to brighten shadows during daytime (FEC* at -2 to -1 EV), if used as a primary light source, you are likely to get a harshly lit photograph(hard light from the same direction as the camera) lacking in texture, probably with some red-eye problems(due to the close proximity of the flash to the axis of the lens).
DIRECT LIGHTING BY FLASH IN THIS MANNER SHOULD ONLY BE USED WHEN YOU HAVE NO OTHER CHOICE.
At all other times, you will want to modify the light; either soften it by increasing the effective area(by bouncing off a wall/ceiling or using a light modifier like a softbox/umbrella) or by taking the flash off the camera(using a TTL cord or as a slave) or both.
To do the above, you need an external flash unit. Flashes made by Canon and Nikon are quite pricey, especially for non-professionals, such as students (like myself). Since I use a Canon system, I will stop mentioning Nikon from now, except if absolutely necessary.
There are many 3rd party manufacturers(Metz, Sunpak, Sigma, Nissin come to mind) that make flashes with equal(or almost equal) features as a Canon unit for a fraction of the price. They may not have Canon's built quality or HSS(High Speed Sync), but they serve the purpose, in most cases.
I bought the Nissin Di466 from smartshoppers.in after doing some research. Reasons for doing so were primarily the price(INR 5000≅ $100) , ETTL II metering capability, good reviews on amazon & apparent ease of use.
When I opened the package, I was surprised at how well-built the flash was. I was half expecting a fragile chinese product, with a flimsy battery compartment(something many 3rd party flashes are notoriously famous for). Instead, it was a well-built product I soon fell in love with!
I ordered Sanyo Eneloop rechargeable batteries from flipkart (after reading very favorable reviews online). While waiting for the delivery, I(like a complete idiot- penny wise pound foolish) bought a Zn-C battery pack. The flash seemed to malfunction and the batteries died in about 3 flashes(and the batteries became extremely hot). I should have known better. I then bought Duracell Alkaline batteries. They worked fine.
The first thing I noticed was that the stepper motor of the flash, which controls the zooming(24mm-105mm [35mm equivalent]), works with almost no lag. Also, the AF assist LED worked well with the central focus point (and is much more pleasant than the flickering of the pop-up flash or the Canon 270 EX).
The flash can be tilted(but not swiveled) from 0°-90°. It locks with nice clicks at 45°, 60°, 75° and 90°. It has a built in reflector(for adding fill light when pointed upwards & adding catchlights to eyes) and a wide angle diffuser panel which can light up a scene for a lens as wide as 14mm[35mm eq].
The flash is quite powerful for it size. The popup flash has guide number 13m @ISO 100. The guide number of this flash varies(according to zoom). Here are the guide numbers of the Di466 for people who care:
2) Manual Mode: The flash power can be adjusted from 1/1 (full power) till 1/32. Useful if you are going to take exposures at constant settings and fixed distance. It will eliminate shot to shot variations that ETTL produces(due to slightly different framing for example).
3)S1(digital slave): Works wirelessly as a slave when a digital camera flash is used as master(digital flash= flash+preflash). The flash has an optical sensor which detects light from the master flash and syncs accordingly. It worked very well in my tests. Useful to provide directional light to your subject. Power has to be set as in manual mode.
4) S2(film slave): Same as S1 but for use in systems without the preflash. I never needed to use it.
A unique feature of Nissin flashes is what they call 'My-TTL'. Usually in TTL mode, you can set a bias to the default value(FEC*), like +0.5EV (Can be set between -1.5 to +1.5 on the flash in steps of 0.5EV). Using My-TTL, you can change the default flash exposure bias to a value between -0.75 to 0.75 in steps of 0.25 EV, in case you are not happy with the factory set default value. I found the factory value exposes correctly, so I didn't have to use this feature. Some people feel the factory value underexposes slightly and add a My-TTL bias of +0.5EV.
After a couple of months of use, my power button has become a little hard... though annoying, its not a deal breaker!
All in all, I can recommend the flash to someone who wants more than what the popup flash offers, but doesn't want to spend a lot of money.
Update: 22DECEMBER 2014:
Two years later, the flash still works very well. That proves that this Nissin flash is not some cheap Chinese stuff with low reliability! The flash still gives consistent color and e-TTL works very well. The only problem is the power button- it has become very difficult to turn on(I have to use both thumbs, with nails trimmed, and push it in a particular way). Turning off via the power button has become impossible(you have to hold the button in that position for 5 secs!), so I just slide the battery slot out an in :-)
I really hope Nissin takes care of this in their future flashes.
*FEC= Flash Exposure Compensation. The normal Exposure Compensation is for Ambient Light(on Canon) or Total Light(flash+ambient on Nikon: meaning -1EV will underexpose ambient light as well as flash by 1 stop).
Most cameras these days come with a built-in flash(usually a pop-up flash on DSLRs). While this is sufficient for using as a fill light to brighten shadows during daytime (FEC* at -2 to -1 EV), if used as a primary light source, you are likely to get a harshly lit photograph(hard light from the same direction as the camera) lacking in texture, probably with some red-eye problems(due to the close proximity of the flash to the axis of the lens).
DIRECT LIGHTING BY FLASH IN THIS MANNER SHOULD ONLY BE USED WHEN YOU HAVE NO OTHER CHOICE.
At all other times, you will want to modify the light; either soften it by increasing the effective area(by bouncing off a wall/ceiling or using a light modifier like a softbox/umbrella) or by taking the flash off the camera(using a TTL cord or as a slave) or both.
To do the above, you need an external flash unit. Flashes made by Canon and Nikon are quite pricey, especially for non-professionals, such as students (like myself). Since I use a Canon system, I will stop mentioning Nikon from now, except if absolutely necessary.
There are many 3rd party manufacturers(Metz, Sunpak, Sigma, Nissin come to mind) that make flashes with equal(or almost equal) features as a Canon unit for a fraction of the price. They may not have Canon's built quality or HSS(High Speed Sync), but they serve the purpose, in most cases.
I bought the Nissin Di466 from smartshoppers.in after doing some research. Reasons for doing so were primarily the price(INR 5000≅ $100) , ETTL II metering capability, good reviews on amazon & apparent ease of use.
When I opened the package, I was surprised at how well-built the flash was. I was half expecting a fragile chinese product, with a flimsy battery compartment(something many 3rd party flashes are notoriously famous for). Instead, it was a well-built product I soon fell in love with!
I ordered Sanyo Eneloop rechargeable batteries from flipkart (after reading very favorable reviews online). While waiting for the delivery, I(like a complete idiot- penny wise pound foolish) bought a Zn-C battery pack. The flash seemed to malfunction and the batteries died in about 3 flashes(and the batteries became extremely hot). I should have known better. I then bought Duracell Alkaline batteries. They worked fine.
The first thing I noticed was that the stepper motor of the flash, which controls the zooming(24mm-105mm [35mm equivalent]), works with almost no lag. Also, the AF assist LED worked well with the central focus point (and is much more pleasant than the flickering of the pop-up flash or the Canon 270 EX).
The flash can be tilted(but not swiveled) from 0°-90°. It locks with nice clicks at 45°, 60°, 75° and 90°. It has a built in reflector(for adding fill light when pointed upwards & adding catchlights to eyes) and a wide angle diffuser panel which can light up a scene for a lens as wide as 14mm[35mm eq].
The maximum guide number is 33m as you can see(at 105mm). The canon 430ex is 43m, but costs thrice as much! the canon 270 EX is 27m and costs twice as much here in India(and doesn't have a dedicated AF assist light or any controls on it).
The Di466 has 4 modes:
1) TTL(technically ETTL 2): Evaluative Through The Lens metering works only when connected to the hotshoe of the camera(or extended with a TTL hotshoe cord). It fires a 'pre-flash' just before the shutter opens and evaluates the effect of it on the exposure. Based on certain algorithms, it determines how much flash power should be used to correctly expose the photograph. While this is great technology, it has two disadvantages:
i) It can cause sync problems with old slave flashes(designed for film cameras which didn't have the pre-flash.
ii) It can cause some people to blink just after the preflash(by reflex) and their eyes will be closed when the actual flash fires.
2) Manual Mode: The flash power can be adjusted from 1/1 (full power) till 1/32. Useful if you are going to take exposures at constant settings and fixed distance. It will eliminate shot to shot variations that ETTL produces(due to slightly different framing for example).
3)S1(digital slave): Works wirelessly as a slave when a digital camera flash is used as master(digital flash= flash+preflash). The flash has an optical sensor which detects light from the master flash and syncs accordingly. It worked very well in my tests. Useful to provide directional light to your subject. Power has to be set as in manual mode.
4) S2(film slave): Same as S1 but for use in systems without the preflash. I never needed to use it.
A unique feature of Nissin flashes is what they call 'My-TTL'. Usually in TTL mode, you can set a bias to the default value(FEC*), like +0.5EV (Can be set between -1.5 to +1.5 on the flash in steps of 0.5EV). Using My-TTL, you can change the default flash exposure bias to a value between -0.75 to 0.75 in steps of 0.25 EV, in case you are not happy with the factory set default value. I found the factory value exposes correctly, so I didn't have to use this feature. Some people feel the factory value underexposes slightly and add a My-TTL bias of +0.5EV.
After a couple of months of use, my power button has become a little hard... though annoying, its not a deal breaker!
All in all, I can recommend the flash to someone who wants more than what the popup flash offers, but doesn't want to spend a lot of money.
Update: 22DECEMBER 2014:
Two years later, the flash still works very well. That proves that this Nissin flash is not some cheap Chinese stuff with low reliability! The flash still gives consistent color and e-TTL works very well. The only problem is the power button- it has become very difficult to turn on(I have to use both thumbs, with nails trimmed, and push it in a particular way). Turning off via the power button has become impossible(you have to hold the button in that position for 5 secs!), so I just slide the battery slot out an in :-)
I really hope Nissin takes care of this in their future flashes.
*FEC= Flash Exposure Compensation. The normal Exposure Compensation is for Ambient Light(on Canon) or Total Light(flash+ambient on Nikon: meaning -1EV will underexpose ambient light as well as flash by 1 stop).
