[mikknu]

I recently bought the AF540fgz because I plan to do wireless highspeed at some point, when I can afford another AF540, which I was told this flash can do... and it also being the only flash for Pentax that can do that apparently. I wonder if it is even worth it/doable when shooting mountain bike races?

Anway, it seemed to work as expected, but the flash does at times make a loud mechanical stuttering sound, as if it was rapidly adjusting focus, is this normal?
Furthermore, when using the trailing curtain setting, the flash did not seem to fire at all, only after setting the camera itself to trailing curtain in the K-5's flash option menu, did it seem to work correctly, can that really be right? My Metz 48AF does not need for the camera to be set to trailing curtain, so that was a bit odd to me.
The AF540 seems like a decent flash, but it sure does take some getting used to, when it constantly forgets the power compensation. Kept burning out colour every now and then because it...

The rest of the time the pictures did seem to turn out well (K-5 + DA* 16-50 + AF540fgz, on trailing curtain)

[jase036]

In my experience you don't need HSS for photographing mountain bike races for 2 reasons: if there is little ambient light such as in woods, you probably won't be using high shutter speeds or you would end up with a nicely light rider in a sea of black. If you are in a lot of light, I just stop down and use the flash as fill. I think one of the main reasons I don't use HSS is simply because I prefer to pan the camera with the rider, this way you get a very nice dynamic shot. Here an example, bright day, one Metz 48 with radio trigger mounted off camera right (in front and to the left from rider's point of view)



However, having said that, I believe the only way to achieve wireless HSS is using a commander such as the 540 or the 360 (the Sigma 610 Super is also supposed to have it as well as the Metz 58, although I've read the Metz has a bug that doesn't allow it to function properly as a commander).
You won't be able to do it with the built-in flash.
I don't know about the stuttering sound, I've never heard it, but then again I don't own a 540, and have only used it briefly.
I use Metz and will most likely never go back to Pentax brand flashes.

[mikknu]

Thanks for the reply! Indeed, HSS does leave me with a sea of black deep in the forrest at times, but so does rear sync every now and then, probably due to the dark weather in general. I did have the Metz 58AF briefly before I got the 540fgz, it did seem quite nice. I was sad to find out that it has the mentioned commander bug and aparently Metz have no intention of fixing it, from what I have heard, it may not be true though.

Nice picture, I was not aware you could use rear curtain sync with radio triggers, I have JJC JF-T2 triggers myself, I will need to test that! Also I bet that requires some good timing
Beginning to wonder if I should have gone with the Metz 58AF afterall.

[jase036]

I don't use rear curtain with radio triggers, not possible with Pentax unless you rig up some homemade DIY remote trigger that piggybacks off the rear sync of the on board flash.
Then again that's not much of an issue as long as shutter speeds are not too slow and you practice your panning.
For short exposure times, second curtain makes little difference, I shot this image somewhere around 1/60 or so and since the rider was shooting downhill it was "slow" relative to his speed and I was able to pan fast and get some movement in there. I hardy ever expose for more than 1/30 s, it is too difficult to follow the movement enough to not blurr everything, flash of course helps, but since it's first curtain you don't freeze at the end but rather let ambient bleed over the sharp flash capture.

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Last edited by jase036; 07-21-2012 at 03:53 PM.

[mikknu]

I had a feeling it wasn't possible to use rear curtain with triggers. I remember reading in my Metz manual that first curtain sync is just like rear curtain, except the "speed lines" will go in front of the rider, rather than after. "let ambient bleed over the sharp flash capture" is a very good explanation, thank you for that.

Next time I'm bringing the triggers for experimenting.

[jase036]

Well not the speed lines per se, that will depend on what you are capturing, if you shoot a car at night with first curtain sync you will get an image of the car first, then the headlights (or taillights) will create light streaks in front of the car, however when you pan, the car is supposed to remain static while the world around it is moving, so you wouldn't get speed lines from the car but from the static elements in the scene and those are not in front or behind, they are both. Of course this is all with longer exposure times, in practice, short shutter times do not allow the ambient to bleed much over the flashed image, and when panning only the things that are not aligned with the pan seem blurred (like the hand and part of the arms which vibrate due to the bike shaking, or the feet when pedaling, the tire spokes, etc), the rest of the static elements in the scene also get blurred and that conveys a sense of motion, how much blur will depend on your shutter speed and how fast your camera is moving (which of course depends on subject speed and the distance the subject is from camera - you have to pan faster for subjects that are closer to the camera).
Go out, have fun, experiment with flash on camera (I use it when I'm in tight tracks where I can really place a tripod or light stand with a flash) or off camera with triggers or with the Pentax wireless system, get a feel for what works and what doesn't. I don't use the same recipe for all shots, it just depends on what I want to convey or capture.
I sometimes talk to a friendly rider and schedule a shoot with him/her so I can practice panning or different lighting setups, they walk away happy with great action shots they can brag about and I have great images for my portfolio and knowledge for the next competition or private shoot. Also when their friends see the images, they want some too and I begin to make money from shoots. Big win for all concerned if you ask me!

[mikknu]

Sorry, I forgot that it is only moving "light sources" that go forward or trail if you don't pan but I know what you mean. I certainly wouldn't mind earning a few bucks at some point, course lts face it, the equipment isn't cheap.
I will most definitely give the radio triggers a spin on the track, only drawback I predict, from the top of my head, is that they are entirely manual set up, so you have to go to the flash if you want to make any changes to them, if I don't want to change the aperture or ISO. I have a 12 hour race coming up in august, so plenty of time to experiment there over and over.

I know panning works, but the easiest are not always the best. Took this at a straight road, but I couldn't stop because it was just so easy at that spot. Used the catch in focus option aswell.


I do however want pictures with more action in it, than above one, but again, it was just so easy to pan there.

[jase036]

I will most definitely give the radio triggers a spin on the track, only drawback I predict, from the top of my head, is that they are entirely manual set up, so you have to go to the flash if you want to make any changes to them, if I don't want to change the aperture or ISO.

You can always use VALs (Voice Activated Light Stands - The strobist term for an asistant or friend who helps out with the light) XD

[steve1307]

You can always use VALs (Voice Activated Light Stands - The strobist term for an asistant or friend who helps out with the light) XD

They work well,
...but they're expensive and heavy and protest loudly when you try to stuff them into a flight case.

[mikknu]

You can always use VALs (Voice Activated Light Stands - The strobist term for an asistant or friend who helps out with the light) XD

Hahaha, that's a good one, got to get me one of those

[mikknu]

In my experience you don't need HSS for photographing mountain bike races for 2 reasons: if there is little ambient light such as in woods, you probably won't be using high shutter speeds or you would end up with a nicely light rider in a sea of black. If you are in a lot of light, I just stop down and use the flash as fill. I think one of the main reasons I don't use HSS is simply because I prefer to pan the camera with the rider, this way you get a very nice dynamic shot.

Had a splendid day out last Saturday (before mentioned 12 hour race), carried with me two flashes and stands to put them on. I want to thank you for opening my eyes to the wonders of radio triggered flashes, it simply just gives better results when photographing mountain bikers.

And this is the result:


So thank you Jase036!

Another question, If you own a K-5, does it give you trouble when trying to focus in low light? I can't figure out what I might be doing wrong, sometimes it gets it right shot after shot but then at other times it gets it wrong shot after shot, especially below f/4 it seems. Or it's just less apparent because of the higher aperture number.

[jase036]

DOF will certainly have a large impact on what you "see" as being focused, I try to give myself some room for error by using higher f numbers as long as exposure allows. The k-5 focus system is pretty decent but is in no way a speed demon, a lot of the times I just use manual focus, set to the spot where I want to capture the rider, easier and more reliable if I'm going for a particular shot.
Nice image BTW. Very nicely captured, only thing I would change is to have the light come from above rather than from below, your images will look more natural.

[mikknu]

Indeed, that is good advice. I have noticed with the DA* 16-50 I don't really want to go below f/4 for several reasons, like DOF because I am usually up close and sharpness isn't that great below f/4. But I do wonder how high a number I can go in aperture, will have to test that. For me the focus speed is not as much of an issue as the K-5's tendency to focus on stuff in the background at times. The larger, than some other brands, focus spots are the only thing I really hold against Pentax. That being said, autofocus seem to work a lot better up close than when I zoom in. In those cases I also tend to prefocus manually.

Noted, I kinda forgot to vary the flash position in the vertical position for the most part. I do like to use the flash to make pictures look a bit unnatural, from what the riders are used to see, for variation. It's still new to me, so I will have to practice some more, but I did do some shots with the flash mounted on a tree.

Again, your feedback is much appreciated!