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Old Jan 2, 2013, 9:06 AM   #1
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Default Flash with Pentax 10-17 Fisheye?

Anyone got any tips on using flash with a Pentax 10-17mm fisheye? [Indoors at night . . .]

I've gotten into using my fisheye to shoot our New Year's Eve parties. Started a few years back just trying to capture everyone (in a small room) at the moment that all the streamers got tossed in the air. I'll stand beside the TV and with the FE I can get the TV in the pict, everyone, and all the streamers frozen in the air.

But . . .

Its dark, so I use flash.

But using flash with a FE @ 10mm seems problematic.

If I bounce the flash, I can notice that half the pict is darker than the other half. If I flash direct, even with the built-in diffuser on, there doesn't seem to be enough spread.

I thought about an omni-bounce, or maybe a ring flash adapter. Even thought about rigging up two flash units. One on each side of the camera.

Anyone got an idea what to try?

Any help greatly appreciated! Thanx!
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Old Jan 2, 2013, 10:47 AM   #2
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I think your best bet are two off camera flashes one on your left and one on right in room corners. But that's just educated guess. I have sigma 10-20 and my metz 48 will not cover that wide angle.

Greg
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Old Jan 2, 2013, 4:23 PM   #3
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I would trythe slow sync falsh modes where the shutter will stay open to expose the backgeound while the flash could illuminate the subject or foreground. In any other scenario, you'd be hard pressed to find a flash that gives you up to 180 degree coverage.

Jehan
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Old Jan 2, 2013, 9:36 PM   #4
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I'm fairly hopeless when it comes to flash(just started reading Bryan Peterson's book on flash), but my guess is that a ring flash would still limit you. The omni bounce might work better than one flash, but since I don't have one, I don't really know (don't have a ring flash either). Two flashes seem like the best idea to me.
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Old Jan 3, 2013, 8:49 AM   #5
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I've got a couple of flash units to try that, but I'd lose TTL. And I'd probably still want to diffuse them, probably with omni-bounces. I was thinking that, but the flash units I got are really big.

I was kinda thinking maybe a step up from my K100D to something like the K-30 (for the cleaner higher ISO) might be part of a solution?

If I have higher ISO, I could "almost" shoot without a flash. (except for losing detail or losing faces in shadow.) The higher iso might help reduce motion blur? and take in the ambient lighting better? which might reduce the use of flash to just fill-flash? (as opposed to being the main light.)

So in that case, the omni-bounce (which might just extend far enough to get past the lens) or ring-flash adapter would be that kiss of flash to get people's faces out of the shadows?

Stepping up to something like the K-30 would also get me the dedicated autofocus assist light which I like and faster autofocus than my K100D, which both would help in this situation IMHO.

Last edited by tacticdesigns; Jan 3, 2013 at 8:54 AM.
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Old Jan 3, 2013, 3:28 PM   #6
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Depending what flashes you got it may be possible to use them off camera with pTTL. Not sure if k100 supports it though. I got k7 and metz 48 and I set up camera flash as master/controller and flash as slave and it works in pTTL.

Greg
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Old Jan 3, 2013, 5:51 PM   #7
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The K100D doesn't support wireless flash. But I could get a pTTL cable to get the flash off camera.

I've got a Pentax AF540FGZ that can do off camera flash, but no camera to trigger it.

For my off camera flash experiments I've been using three Vivitar 285HVs that I picked up for cheap. But I have to set everything manually when playing around. Those were the flash units I was thinking of setting up as a spare to experiment with the fisheye.
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Old Jan 4, 2013, 10:33 AM   #8
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If the vivitar flashen can be used as dumb slave that fire when they see main flash fire you don't have any problems:

Put two of those in room corners, set your iso rating and aperture you want to use on them. Now when you change flash power it should give you distance at which you'll get correct exposure.

Example: you set ISO 100 on flash and F5.6
Set your camer to same settings.
If your room is 4x4m adjust flash power until it shos correct exposure at 2m
fire your camera with pentax flash set at minimum power
if both vivitars fire off check your LCD screen to see how the photo came out. Adjust power as necessary.

With this you shoud get perfect exposure in few tries. You could also try bouncig both flashes from walls or celing to diffuse light but that requires increasing flash power.

You really don't need pTTL in controlled environment like this

Post some photos of your efforts as well, that could help.

Greg
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Old Jan 4, 2013, 10:58 AM   #9
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I don't think a ring flash would help you, I know when I have used mine with the kit lens, you get some vignetting at 18mm, so 10mm would probably give it tunnel vision. The ring flash (mine at least) just sticks out too far forward for wide angle lenses.

I would try Jehan's suggestion of using trailing curtain or whatever it's called in the flash menu.
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Old Jan 4, 2013, 2:06 PM   #10
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Quote:
Originally Posted by gfurm View Post
If the vivitar flashen can be used as dumb slave that fire when they see main flash fire you don't have any problems:

Put two of those in room corners, set your iso rating and aperture you want to use on them. Now when you change flash power it should give you distance at which you'll get correct exposure.

Example: you set ISO 100 on flash and F5.6
Set your camer to same settings.
If your room is 4x4m adjust flash power until it shos correct exposure at 2m
fire your camera with pentax flash set at minimum power
if both vivitars fire off check your LCD screen to see how the photo came out. Adjust power as necessary.

With this you shoud get perfect exposure in few tries. You could also try bouncig both flashes from walls or celing to diffuse light but that requires increasing flash power.

You really don't need pTTL in controlled environment like this

Post some photos of your efforts as well, that could help.

Greg
Just couple things to add - this scenario will light properly subject standing in the middle of that room, walls will be little underexposed.

Use your master flash in manual mode as pTTL preflash will set off your slaves too early (unless they have preflash ignore function).

Since you using 10mm lens DOF is not an issue (at f5.6 everything is sharp from 3ft to infinity) so if you don't get enough light you can just open up a little instead of adjusting flash power.

Why I don't think slow sync or rear curtain won't help:

The issue is not lack of light but flash coverage. If you slow your shutter to get correct background exposure you only use flash to freeze movement, since it doesn't cover the whole scene it won't work properly anyway.
Rear curtain sync is for long exposures with moving subjects that have lights to get the correct movement in the light trails (that's my take on this anyway).

If your flashes don't work as slaves you need cheap radio triggers to set them off.


I'm not a flash expert, all this is just from experience and basic flash photography rules.
Hope it helps.

Greg
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