Thursday, July 8, 2010

Search for a second flash (Intermediate)

To give myself more creative lighting possibilities, I've been thinking about getting a second flash.  I'd like to use the second flash for "special effects" like lighting the background, adding rim light, etc.

There's a philosophy that artificial light (generally flash) should simulate natural light, and there's only one natural light source - the sun - therefore we should need only one flash.  Indeed, in some of Dean Collins' portraits ( http://www.software-cinema.com/training/photography/dean-collins/4/the-best-of-dean-collins-on-lighting ), he uses only one flash, although he masterfully uses several diffusion panels and reflectors to allow one flash to accomplish multiple functions simultaneously.

However, I think the foregoing philosophy about needing only one flash is an oversimplification.  First, the philosophy neglects the fact that the flash is far weaker than the sun.  It's not like you can put just one flash outside your house to send light in through all windows.  Secondly, it's not true that there's only one "natural" light source.  Outdoors, besides the sun, we have the light from the sky itself. Open light is a beautiful light source when properly used. Indoors, there are many situations where there are multiple light sources, as when there are multiple windows.  Third, I think using multiple flashes is not so different from using panels and reflectors, except that it's more portable and you can have more control. Fourth, most photographers don't have to limit ourselves to a natural appearance (photojournalists and documentary photographers excluded)  - we are free to create an unrealstic image to match our artistic vision.

Going back to the second flash, my requirements are:
1. The second flash doesn't need TTL, and in fact manual mode would arguably be more useful than TTL because when it comes to special effects, there is far more latitude and room for interpretation.  I like this quote by strobist.com's David Hobby:
"I think of [rim lights] as being a little like pizza: When they are good, they're good. But when they are bad -- well, they're still pretty good." http://strobist.blogspot.com/2010/06/upgrade-your-rims.html
2. My plan is to use the pop-up flash to command my SB-800 as a CLS AWL slave, and trigger the second flash either with an ebay radio trigger (if it doesn't interfere with CLS) or optically in sync with the SB-800 which I will control.  In the latter case, it would be great if the flash could ignore the TTL and CLS pre-flashes.

I'm really annoyed that Nikon discontinued the SB-800 and priced the SB-900 way too high (I think they were copying Canon's pricing model). I thought about getting an SB-600 and researched third-party flashes. 

The chart below shows some of the alternatives for Nikon cameras, and what you are getting for your money.  The chart is organized into two broad categories based on power: "entry level" and "high power". I don't want to mislead though -- there's only slightly less than 1 stop difference between the entry level models and the high power models.  Explanation of the terms:
  • GN: guide number, a measure of power. Because manufacturers inflate their GN, I only included tested guide numbers at 100 ISO.
  • Zoom: whether the flash can be zoomed. This is useful not only for efficiently filling the frame with flash, but also important for creative purposes.
  • CLS AWL: Nikon Creative Lighting System  - Advanced Wireless Lighting. Allows remote adjustment of slave flashes in TTL or manual mode or auto mode through preflashes from a commander flash.
  • Digital optical slave: an optical slave that can ignore preflashes.  Normal optical slaves can often be triggered even by the TTL preflashes, dumping their light before the shutter actually opens.  Digital optical slaves ignore preflashes or use a delay mechanism to release their light when the shutter has opened.  For my purpose, I need the digital optical slave to be able to ignore not just the TTL preflashes but also the CLS AWL preflash commands to the SB-800.
  • HSS: high speed sync.  Allows the flash to be used in shutter speeds faster than the camera's sync speed.  This is useful for allowing wider apertures in bright conditions.  A substitute for this is an ND filter (which is in fact more efficient - see here).
  • HSS slave: high speed sync slave.  Nikon's AWL allows slave flashes to function in HSS mode (a feature not available with Canon).

ENTRY LEVEL (competes with SB-600)

a. Manual + optical slave:
YN-460 II ($46)
Real GN: 22m See http://www.flickr.com/groups/strobist/discuss/72157624180121385/ (tested at 1m) or 23m - http://www.flickr.com/groups/yongnuo/discuss/72157620880376984/72157620930372772/
Zoom: No. --> possible deal breaker
TTL: No.
Manual: Yes
CLS AWL: No
Digital optical slave: Yes. Usually compatible with CLS.  See http://www.flickr.com/groups/strobist/discuss/72157623646899772/72157623536303845/
caution: slave sensor is in the flash head, has issues triggering in sunlight.

b. Same as YN-460II but loses optical slave, and adds TTL:
YN-465 ($90)
Real GN: same as YN-460, i.e. 22m
Zoom: No.  --> possible deal breaker
TTL: Yes.
Manual: Yes.
CLS AWL: No
Digital optical slave: No.  --> deal breaker

c. Same as YN-460II + TTL + zoom:
Nissin Di622 ($169)
Real GN: ?? Less than SB-600. http://forum.lowyat.net/topic/1140175
Zoom: Yes.
TTL: Yes.
Manual: Yes
CLS AWL: No
Digital optical slave: Yes.  Advertised as compatible with CLS but cannot be adjusted remotely by the commander flash.

d. Similar to Di622 without optical slave, adds CLS AWL + HSS + HSS slave:
Nikon SB-600 ($220 new, $180 refurb through jr.com)
Real GN: 1/3 stop more than YN-460, i.e. ~25m @ 35mm.  See http://speedlights.net/2010/05/21/yongnuo-flash-guide-numbers/
Zoom: Yes (to 85mm).
TTL: Yes.
Manual: Yes
CLS AWL: Yes.
Digital optical slave: No.
HSS on remote: Yes.


HIGH POWER (competes with SB-900)

a. Manual + optical slave + zoom:
YN-560 ($85)
Real GN: 32m (45m @ 105mm zoom).  See http://www.flickr.com/groups/strobist/discuss/72157624180121385/  see http://www.flickr.com/groups/strobist/discuss/72157624180121385/72157624475116401/ (tested at 1m); see also http://www.lightingrumours.com/yongnuo-yn-560-first-impressions-427
Zoom: Yes.
TTL: No.
Manual: Yes
CLS AWL: No
Digital optical slave: Yes. Will ignore CLS preflashes. See http://www.flickr.com/groups/strobist/discuss/72157624180121385/72157624196263437/
HSS on remote: No.
*additional benefit: 2-second recycling time at full power.

b. same as YN560 features + miniplug sync:
Lumopro LP160 ($160)
Real GN: "similar to SB-900"
Zoom: Yes.
TTL: No.
Manual: Yes
CLS AWL: No.
Digital optical slave: Yes.
HSS on remote: No.

c. same as YN560 features + TTL + CLS AWL + HSS:
Nissin Di866 ($300)
Real GN: 34m (39m @ 105mm zoom) See http://www.dpanswers.com/content/rev_nissin_di866.php
Zoom: Yes.
TTL: Yes.
Manual: Yes
CLS AWL: Yes (commander or slave)
Digital optical slave: No.
HSS on remote: No.

d. same as Di866 + HSS slave:
Nikon SB-800 (~ $300 used)
Real GN: 36m (45m @ 105mm zoom) See dpanswers.com/content/rev_nissin_di866.php
Zoom: Yes (to 105mm).
TTL: Yes.
Manual: Yes
CLS AWL: Yes.
Digital optical slave: No.
HSS on remote: Yes.

e. same as SB-800 + 360-degree swivel, better interface:
Nikon SB-900 ($440)
Real GN: ??
Zoom: Yes (to 200mm).
TTL: Yes.
Manual: Yes
CLS AWL: Yes (commander or slave)
Digital optical slave: No.
HSS on remote: Yes.


WHAT I CHOSE
I really wanted the SB-600 because of the remote adjustment through CLS.  However, in many of the shots I've seen that I'd like to emulate, the photographers used very powerful strobes such as the White Lightning X1600. 

For some perspective, the White Lightning X1600 has a guide number of 450 ft. (ISO 100) when used with an 11-inch reflector. In other words, at a distance of 10 feet, the aperture is f/45.  Based on the Sunny 16 rule of thumb, bright sunlight is f/16 at 1/125 at ISO 100, or equivalent to f/11 at 1/250 (the D300 sync speed) at ISO 100.  f/45 is 4 full stops smaller than f/11.  In other words, even with the flash 10 feet away, you can underexpose bright sunlight by 4 stops.  In fact, even with a medium softbox, it's rated at f/22 - f/32 (with the softbox 10 feet away!), which is 2-3 stops more powerful than bright sunlight if you're at 1/250 sync speed. 

What I don't like about the X1600 and studio flashes is that they need a portable power source or a power outlet, and they're much heavier and bulkier than hotshoe flashes.  I just can't imagine bringing one around on vacations.

If I were to have any chance of achieving anywhere close to the same look as a studio flash, I thought I would need the most power I could get.  Considering the flashes in the high power category, the YN560 seems to offer the most bang for the buck.  In fact, it even offers a bit more light for your money than an Alien Bees B1600.  A B1600 has a guide number of 220 feet or 67 meters (with a 7-inch reflector).  The YN-560 has a real guide number of 32 meters (at 35mm zoom).  The difference between them is slightly more than 2 stops.  In other words, four YN-560s is equivalent to one B1600 (with a 7-inch reflector).  At a cost of about $85 apiece, four YN-560s is a bit less than one B1600, even without considering the cost of the $300 battery pack for the B1600.

What about the YN-460 II?  It costs about half as much as the YN-560 with about 1 stop less power.  Wouldn't having two YN-460 II's be more versatile than one YN-560?  Yes, however, I had read that the YN-560 had a much more reliable optical trigger, plus I wanted the zooming function.  Those benefits were enough to convince me to get the YN-560 instead of two YN-460 II's.

As for the lack of remote adjustment, I figured I would only need the YN560 for setup shots.  The incremental time needed to adjust the YN560 manually is not such a big deal for a setup shot.  I also plan to use the YN560 together with the SB-800 to act as one light source when I need power.  Again, in such a situation I wouldn't need remote adjustment -  I would simply put the YN-560 at full power.

I ordered the YN560 through ebay (the only place it's available at the time of this writing).  Hopefully it won't take too long to arrive and that it doesn't disappoint.  I'll test it (especially whether it can function with the CLS) and post some sample shots when it arrives.

Update:  first impressions here

RELATED POSTS:
Second Search for Second Flash