>I've used a SB-700 on both a D7000 and D7100. It works well >and the size is nice for travel. > >However, its power, controls and other features are somewhat >limited. You may be happier with a SB-800, 900 or 910, >depending on whether you prefer new or used.
Just to be clear: the 800 and 900 discontinued models, with only the 910 a current choice for new.
>That's a pretty significant difference in power, especially >when you consider the inverse square ratio for light falloff. > Mick, you certainly have way more experience than me with this stuff. Can this be cast in more useful terms? Does it in fact correspond to a 1-stop difference in most shooting situations? Are there any "commonsense" guidelines that would help the OP choose between the 700 and the 910 for power output?
>>I've used a SB-700 on both a D7000 and D7100. It works >well >>and the size is nice for travel. >> >>However, its power, controls and other features are >somewhat >>limited. You may be happier with a SB-800, 900 or 910, >>depending on whether you prefer new or used. > >Just to be clear: the 800 and 900 discontinued models, with >only the 910 a current choice for new. > >OP: check out >http://photographylife.com/nikon-flash-comparison for a quick >comparison. > >The 700 is a nice unit, pairs well with the 7000 IMO. > >As far as power output goes, the 700 (first) is pretty close >to the 910, as the Guide Numbers show: > >92' (28.04 m) ISO100 at 35 mm position >111.5' (33.99 m) ISO100 at 35 mm position > >I believe that this typically means about 1 stop difference in >a typical scenario. > >
If I'm calculating correctly, the difference in power amounts to *about* 1/2 stop. That 1/2 stop difference is the same at any distance; f = GN/d (the inverse square law applies to all flashes equally). So, it's a 1/2 stop difference at 3, 30, or 300 feet.
For example, using the published guide numbers, the 910 would be f/9.3 at 12 feet. The 700 would be f/7.67 at 12 feet. I did a little real-world testing with my SB700 and SB24 (old model, GN of 118). At 12 ft, 35mm coverage, my Sekonic indicated f/8 for the 700, and f/9 for the SB24 (the old gal may not be firing on all cylinders).
But, consider that the discrepancy is only apparent if the flashes are both at full power. How many flash situations call for that? There is a reason these flash units can be popped down to 1/128 power.
There may be other features and advantages of the 910 that would make it the better choice, but unless you need that extra 1/2 stop of exposure, raw power may not be one of them.
I will tell you based on using them that the 900 is noticeably more powerful at a distance than the 700. I haven't spent the time studying it in detail to give you the numbers, but that is how it works.
If you are shooting at the extreme margin of flash effectiveness, that extra power is useful and required. So, yeah, there is a need for full power. Sue, if you always shot a single, centered subject at 12 ft, you can probably use either one. (I doubt either unit is of much use at 300ft. ;-0)
There is a reason that Nikon makes more than one model flash, and has for years, and there is a reason there is a price difference.
>There is a reason that Nikon makes more than one model flash, >and has for years, and there is a reason there is a price >difference. >
Certainly, no argument.
I absolutely agree that if I'm shooting an event outdoors, I grab a 910 - I'll probably need it. If I'm shooting indoors, a 700 will probably be ok.
But I could probably come up an indoor scenario using a diffuser, in a large room, with 25' vaulted ceilings, where the 700 isn't sufficient.
I know this is starting to get into SpeedLight Forum type stuff, but: assuming that the OP has a limited budget, I'd probably suggest going with the 700, and getting a good bracket and cord to get the flash off-camera. Knowing that the OP likes his Meike(?) grip, he must shoot portrait mode; being able to use the flash in portrait mode might be good. Add in a basic snoot, etc., to give some more control.