Pentax AF540 FGZ flash user guide?

[jasonlow]

Hi all... 

I had just recently bought my very first flash unit! The 540, and had been enjoying it during this festive season of Chinese/Lunar New Year!

Well, to be honest, I sometimes couldn't get consistent results too. But that doesn't bother me much since i would shoot a couple of photos before being satisfied with the results i wanted.

Most of the time i was shooting group photos of my friends using the 18-55 kit lens with the flash mounted together on the tri pod. I know slow shutter speed and higher ISO settings can let more ambient light into the photo. But with my shaky hands and the performance of the K10 in high iso (800 is the max for my auto settings), and also not liking heavy shadow casting in my photos, i tend to bounce the flash a lot. Most of my direct flash pictures came out having darker backgrounds since i would limit the iso to 400 n using 1/40 shutter speed. Anything i can improve on this?

But there are some problem that i always encounter. First of all, i don't really know the "correct" metering technique while i'm using the flash. Most of the time, i would just set multi-segment metering on the camera, and just set the flash in pttl mode. Is there something wrong with that? I do compensate in the positive ev in my camera, and sometimes in my flash too quite often, since most of the time the photos came out quite dark. I move the focus point a lot while shooting portraits of ppl around me, so i guess the multi-segment metering will do well in this kind of situation? Any advise here? Maybe i should just use fully manual while shooting with the flash unit?

Well, there's one more problem that i can't find the answer while looking tru this forum. While shooting a person who wears glasses, light reflecting off their glasses gave a nasty flare effect, especially direct flash, even when i use the flash for fill flash purposes. How can i avoid this kind of problem? 

Hope you guys can kindly give me some advice on these problems that i face. Thank you in advance. 

[Prieni]

Jason,

there is no easy solution for the problem with the glasses, I think. But for a general flash guide I have put a link to MattMatic's Pentax flash guide in this thread: http://pentaxworld.com/fo...um/index.php?topic=3968.0
Meanwhile I did buy the guide myself and find it quite useful, some things in there I hadn't thought of before. You could also send a private message to LaRee, as I know she did buy the guide (and you would have two opinions that way).

If you are shooting your friends, do you have "slow speed sync" or "trailing sync" set on the camera? That way the camera meters as if the flash is not present and the flash fills the ambient light.
You also could try the flash in A mode.

Prieni

[spyglass]

Hi Jason,

You know the old saying "you get what you ask for"? I believe the same is true with camera metering. Try and find a neutral value to meter in your shot. Determine whether the light making its way back to the camera is ambient light, reflected light, or direct light.
Backgrounds or even subjects when photographing a large group, can be affected by the properties of light. Light intensity decreases with distance. "The intensity of light from a point source is inversely proportional to the square of the distance from the source" Basically if you double the distance to your subject you get a 1/4 of the intensity.
One of the biggest problems I see when people use a flash is that they get too close to their subjects. Try stepping back several paces, zoom in to frame the shot, and allow the light to spread and fill - reducing flash burn. The 540 can generator a fair bit if light intensity and can be overpowering at very close range.

For glasses, the easiest solution is to get the subject to remove their glasses..... but unfortunately glasses often make the subject recognizable as everyone is used to seeing them wearing glasses. Direct flash can seem to produce glare or flare off off glasses. Pay attention to your angles. You can try getting the subject to turn slightly to try and minimize the effect. Use the 540's wide angle lens diffuser. If you have the ability (set up type shots, not needing to be highly mobile), shooting your flash through a translucent diffuser or umbrella can be a huge improvement.

I would also suggest that you try and keeping the shutter speed within the range that the flash typically favours (1/125th - 1/180th). Remember that the burst of light from your flash is intense and short lived, long shutter speeds when used with a flash tend to produce ghost like qualities. (plus 1/40 of a sec is getting slow for people shots unless the people are controlled or frozen.
Unless you are shooting under night or difficult conditions I would be surprised if you need an ISO setting as high as 800.
While you are getting the hang and feel of your flash, perhaps leave the EV compensation at 0 and set your camera to bracket the shots (3 shots arrangement 1/3 ev increments).

Slow fill can be a wonderful option as it allows the camera to meter for the general lighting conditions (allowing background scenes to receive the correct exposure) while provide the crucial fill light for your subject.

If you look at this first example, you can see that I metered for the rock work, locked the exposure, turned to frame my shot, and got what I asked for a reasonable rock wall - but the sky is blown right out, ruining the shot.



In the next example, you can see the effects of Slow Flash fill. The sky is visible while the rock work is filled in. Without the use of a flash I would have only gotten one or the other (sky or rock) not both.


While the second shot is not perfect by any means, I can improve the shadows between the rock easily in photo shop with a quick level adjustment. If you look at the intensity of the rock themselves you will see that the fill flash can create some punch, some life. If you want to reduce this effect you can step back a bit and zoom in to compose the shot.

You just have to use the flash and get a feel for it. You get better with practice, lot of practice.

Hope this helps,

Spyglass

[jasonlow]

@ Prieni
Saw the previous post about that before i made this new post too. But i wasn't thinking of purchasing that guide just yet. I had always used the normal flash mode on both the flash unit and the camera while taking shots in Av mode. I would give the slow speed sync a try next time! Thanks for the advise!

@ Spyglass
Well, i tried once shooting a portrait of my friend in a night scene with a building with lights behind him. I tried metering on the face of my friend directly, and the result wasn't great at all. But sometimes, i could get it right. That's why i'm not sure whether the way i meter is correct or not. Maybe i should manually meter the ambient light, and then recompose the shot with the subject in front?

Most of the time i would shoot indoors, which the available light isn't that much. So,  if i use a lower iso settings, the background tend to look dark while the subject being "punched" by the direct flash.

Regarding about the slow fill, did you just meter towards the sky? Most of the time while i take outdoor photos with fill flash, i would just use the multi segment metering and point the focus point at the subject directly. I get results that i am satisfied with easily that way. Maybe there's some way i could improve on that?

Well, i have to say that the 540 is a great flash, even for a newbie like me. Really enjoyed it very much and making my indoor photos look more lively compare to just using higher iso n slower shutter speeds to achieve the same lighting conditions.

Thank you for your time and you valuable advices Spyglass.

Jason

[spyglass]

I am not sure how good your memory is regarding the shot you took of your friend, but if you where taking an afternoon shot I would suggest :

(without a flash)
set the camera's metering to spot focus to ensure that the camera obtained only a reading of the face values, while ensuring that light from the back ground was not entering the camera?
Press the AEL  to lock the exposure (If you keep it depressed it will hold the AEL feature until you let it go +  roughly twice the metering time of your camera).
Release the shutter.
This approach puts all the emphasis on the subject, sets the exposure value based on the subject (and in the case of an illuminated background... tends to let the background blow out or open, effect depends on the difference between subject and background values).
 
(with a flash) -fill approach
set the camera's metering to multi segment (get the big average value from your scene), compose your shot.
with the flash set to high speed sync (P-TTL)
release the shot
(if you found that the fill was too intense you could back up and zoom in to compose)
(if you found that the fill was too low consider moving closer)
You can also adjust the flash compensate if moving and zooming are not an option, or light dispersion prevents or discourages movement.

Consider the difference between Fill & Main lighting. If the difference between the subject and the background is less than 3 stops you probably can consider yourself within the Fill approach. Past that you require a Main light approach (set the camera's flash to the correct setting (leading shutter curtain sync).

Here is a link that has all the spec nicely presents for your flash (a retail page)
http://www.digitalcameraw...house.com.au/prod5073.htm

I encourage anybody that is learning to record their settings and keep the photo so that it can be passed onto or referenced. (luckily the information should be stored automatically in the picture files (probably the one reason I have the Pentax software on my computer)

Good Luck Jason

[LaRee]

Hey Jason,

I still have a lot to learn about my 360 and 540 flashes but here are a couple links to a fellow that has helped me understand using the 540 flash much better.
http://forums.dpreview.co...1036&message=30792631
http://forums.dpreview.co...1036&message=23744061
and here is another link that proved interesting.
http://forums.dpreview.co...1036&message=23749539

[jasonlow]

Hi everyone,
Sorry for not replying for quite some time now. I had tried using slow sync while taking subjects indoors, found it working better as there is more ambient light in the shot, but hv to compensate with really slow shutter speeds, and high iso value, and that was shot with direct flash. The effect was great, but i guess i would hand held my camera most of the time, shutter speed which are too slow is really something i can't overcome... Well, at least i tried using other modes, and know how the outcome will be.

Big thanks to Spyglass who point out the very important difference of fill flash. I will keep in mind of those parameters while i shoot with my flash gun.

And to LaRee, thanks for posting those important links that really helped me while using my flash. It's really been a great help there!

I will be shooting for my brother's wedding soon enough. So i better get used to the characteristic of this wonderful flash so that I can fully utilize it!

Thank you again.

Regards.

@ Spyglass,

[LaRee]

Here is a new link to some charts that Steve Jacob put up that are very handy. I like these because I can print them out and keep them handy. I think I may even laminate a small copy and keep them in my camera backpack.
 http://www.pbase.com/steve_jacob/flashmodes

btw, like you I've been very busy lately so I understand!