I posted about half a dozen images giving a somewhat broad range of lighting and settings. Hopefully they will give somewhat of a baseline to help visualize possible outcomes.

Obviously you're milage will vary. Also these were back in my istD days. By the time I got the K10D I was roped into to judging if I was not competing and it never got much use.

I wouldn't say they were pro-quality, I was probably using a Tamron 28-300 or Sigma 18-200 lens at the time. Oh how I would like a re-do with the K10 and DA*16-50!! Also with the heads in the shots, I didn't have the best seat in the house.

Anyway, hopefully they help.

http://www.flickr.com/photos/91954128@N00/sets/72157606894014400

BTW: I'll probably take these down in a few days.

If you want to stop the action, you're going to need a high shutter speed. If the f1.4 can give you 1/250s shutter speed, then no "need" for flash.

Technically, the shutter speed doesn't have to be very fast since the flash is so much faster than your shutter could ever possibly go. The flash will/should out-blast the ambient light and the ambient light will not expose to make much difference.
The K10D will sync at /180s which is not very fast, but will help cut down motion blur if the ambient light is moderately high. You're still likely to get slight blur on fast action like the snap of a front kick unless the ambient light is quite low in relation to the flash output.

At f4.5 I was getting 1/60s in a gymnasium under fluorescent tubes about 15 feet overhead. With a f1.4 lens, you could get away with 1/250s or even 1/500s, which I would personally find quite acceptable for most shots without a flash.

Sadly, not many lenses come down to f1.4.
Probably a good thing... I'd be living on the street corner with a bag of f1.4 long range lenses.

Well, technically you can.
In theory, the lower power you set the flash, the less reserve power it uses. Thus if you set the flash to one half power, you should be able to get two flashes in a row before a recycle is necessary. If you set the flash to 1/16 power, you should be able to fire almost until you blow up the bulb due to overheating.

I have been able to keep the flash down to 1/2 power and shoot maybe two frames in a row, but I have not had consistent luck in practice. It seems PTTL will attempt to override the visible settings and try to push more power from the flash than you'd expect.
I haven't done measurements but it seems to work that way in real life, unless I'm failing to understand another factor that might be changing (and causing power to drain faster than expected).
Sometimes I'll use the trick to set the flash in manual mode at 1/4 power, and the camera in manual mode. This seems to work better.
(turn off the camera, turn on the flash and put in manual mode, then turn on the camera. If the camera times out or you turn the camera on first, the flash will go back to PTTL mode. Sorry, more info than you really want right now, but note it down for later. You'll find it handy if not necessary. )

If you're within a few (ten?) feet or so, you might find 1/4 power good enough. I've been able to shoot four to ten shots in a row before it started to slow down and need a recycle -- same camera settings, manual mode, yet number of flashes is not always consistent. Odd! ( I wouldn't shot for too long without a good cool down anyway!)

I'll try to dig up some old shots.
Looking forward to seeing what you get.
Again, practice a bit up front and see what will work for the environment you'll be in.

I'd say for the money, go with the 360 or two. The numbers for the 540 sound good on paper but I really don't see that much difference in the amount of light that the 540 has to offer in real world shooting.
(The 540 should be, what, one half a stop brighter than the 360? Not a whole lot on paper either. Is my math correct?)

I've got some pretty good lighting from the 360, bare flash, twenty to thirty feet away, blazing shadows onto the back wall behind the subject.
One of the earlier competition photos I posted here had a good example... I'll have to dig that up again, as I think my server stopped hosting those for some reason.


One additional thing to be aware of, is that the 360 and 540 recycle at about 5-7 seconds. From what I hear the external power supply available for the 540 does not help the recycle times by much. So when you want to take a shot, make it count! Not like the competitor's flash that can recycle full power in about 1-2 seconds!!

Someone might have some better options for brand of flash if you feel you might want faster recycle times (I know I did). Although they will likely have to be set in manual mode and you loose the automated PTTL functionality. Probably not a big loss but it takes some practice or at least some up front time to see what will work in the current location. (or good knowledge of the math involved... I'm still a bit of a hunt and peck kind of shooter, myself -- but getting better )

For whatever lighting is in your environment, you'll probably want your shutter speed to be about 1/250 or faster. For long zoom lenses, you will want even faster shutter speeds since the subject will move through the field of view so much quicker.

That is assuming you want to freeze the action of course.
Blurred action is often acceptable and even important in order to show the speed of the movements, but you usually need/want to obtain some portion of the image to be as sharp as possible.

That is likely going to be out of range for most zoom lenses in a room with standard florescent tubes for lighting if your f/stop of 6.3 or greater.
I would suggest going to the arena or similarly lighted location and see what your current lenses can do. Shut them down to f6.3 or f8 and see what sort of shutter speed you'll need.

If the zoom you're interested will function in that range of lighting, go for it.

How far away from the subjects do you plan on being?
Personally, I think 55mm might limit your use unless you have two cameras or have the freedom to change lenses. But that does depend on your position from the subject.
Out of the two suggested I'd go with the 18-250 for ease of use.
Of course, if you're going to do this professionally I'd suggest two cameras, each with a shorter and longer range lens, so you don't have to sacrifice quality for ease of use.

I used to take my 18-200 to matches but eventually settled on my 16-50 just for quality and constant f2.8. When it went from rignside seats (2 feet from the matt edge) to further back in the crowd or when the subjects went on stage and seats were further from ringside I'd switch over to the longer range lens like the 50-135. A longer lens would have been nice but I got away with that for most shots.
And for the twist...
If your'e looking mainly for closeups rather than full body shots, then the 50-300, definitely, regardless!

Good point. Most competitions I've been in or photographed allowed flash, but there are cases like sparring or some of the acrobatics where I just wont use flash out of concern for the participant's safety. (or at least I'll try to be in a position where the flash won't momentarily blind someone.)

Being in the ring, I've never noticed cameras or flash, but I'm still hesitant to subject others to flash and potentially cause a problem.

I think these are amazing. Did you have the camera on a bracket?
Honestly, without seeing the full sized images, it would be difficult to tell if you might get better results with another lens. The images look quite acceptably sharp (other than the hand scribbling at the top of the first one). Either way, with long exposure in the dark, noise is going to kick in. If you an shorten your exposure with a faster lens, then less noise. If you're intent is to make long streaks of light, then you need the same number of seconds anyway and the lower f/stop of a faster lens will not likely come into play.
A higher quality lens would probably have limited effect on resolving past the noise.

I have used the 18-55 for a while before getting the DA* 16-50. Honestly, the only time I see that the DA* is better is when I take two identical images and put them side by side. (may just be my lack of ability to see the difference... I used to like the quality of my tamron 28-300... now it is clear that it is quite a crappy lens :blush
Anyway, I got the 18-55 for $10 more when I bought my K10D body. For the $989 difference against the DA* 16-50, I would have stayed with the 18-55 or perhaps upgraded to the 16-45.
But -- I REALLY REALLY REALLY appreciate the water seals and slightly lower light capability that the DA* gives me.

For long exposures, the extra f/stop may or may not be desired. You may be shifting down the aperture anyway to get better DOF so why pay for f2.8 when you'll probably use f/11 or higher.

Dunno if that helps or not, but gives one more opinion to wade through.

I think I'd have to agree with the 360 flash over the 540 if mere power is concerned. But if you're doing indoor portraits, the swivel head on the 540 is quite useful. Worth the extra couple hundred bucks?? Maybe not. Another one that really depends on what you feel is important or required for the result you want to achieve.

Pretty open ended question that could fill several books, and probably has.
Deciding on which The lens you want to use really requires you know what you want to achieve.
Obviously for portrait work, if your going to be very close, a 16 mm lens is right out due to distortion. But if you're doing full length in limited space, the lens may be perfectly acceptable.
The same lens may give you a lot of background, or if not desired, use a longer focal length, and back off away from the subject. You get a similar image of the subject but a lot less clutter in the background.

Generally 50mm is thought of as a "normal" lens giving you a similar view as what the human eye creates. On a DSLR the angle of view is that of 75mm but DOF and distortion is still pretty much that of a 50mm lens.
Some prefer 100mm if they can get far enough away from the subject because of the effect it has on the subject.

I have used my 16-50mm most for martial arts competition photos since I am within 6-15 feet of the subject at most times. I've switched to the longer lenses, obviously, when on a stage that is further away.

I have been quite happy with the 16-50 for static portraits where I can get in close or back off for full length. You may want to go as far as 70-100 if you have the space.


For indoor shots, you may want something ultra wide like a 10mmm if you don't mind the fish eye look. otherwise plan on stitching photos to get more than a small corner of the room. I find 16mm good, but still limits me to a small area of a room.

edit: he, he, took to long to type. Looks like Malo1961 beat me to it...

he, he, tried the 2x on my 28-300 lens (not a great hunk of glass to begin with by any means). No luck auto focusing with that lens. The mechanics function but there is no way for it to lock on at f5.6 plus the two extra stops added by the converter.
The focus ring has such a short range to begin with, even manual focus is nearly impossible.

Guess that means I *need* to buy a better lens.
"Oh, honey... we need to mortgage the kids, er, no kids? OK, we need to mortgage one of your kidneys..."

Now why would that be? Is there more to the tele-converter than simple pass-through of the contacts? I'd think it would just be a simple wire straight through. But apparently not.