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12-09-2010, 12:47 PM   #16
Ira
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Bear is helping me and others out a lot as we get into the realm of older flashes in M.

Many more illums for the dollar, but longer learning curve.

12-09-2010, 02:54 PM   #17
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If you are bouncing the flash or shooting through a gel or diffuser, how does the flash know this and compensate for the lost effectiveness?
12-09-2010, 03:30 PM   #18
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A "bounce" icon appears on the LCD of the 540 and 360 when you turn the flash head upward.
12-09-2010, 03:31 PM   #19
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Same way you know when to stop pouring coffee in a cup. A sensor on the camera or on the flash monitors light reflected from the subject and turns off the output of light when appropriate.

12-09-2010, 03:40 PM   #20
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I'd start with either the 540 or an old $20 flash, not something in the middle of the road. The cheap old flash will provide a nice learning experience for you and you're not out much money. The 540 is the top-of-the-line from Pentax, so you won't be wishing you bought the next model up from it.

Years ago I used the Vivitar 283 on a K1000. I measured the output voltage at its highest just above 600 volts, enough to fry the circuitry on any digital camera out there. I bought a $50 Wein Safe Sync that attaches to the shoe and makes it safe for my K10D. Shortly after that I bought a 540 for wireless triggering through the camera, a feature I've always loved from Pentax. A year ago I had two 540s, a 360, a 160 and the Vivitar 283. Once I bought remote triggers (see this thread: https://www.pentaxforums.com/forums/pentax-camera-field-accessories/31950-tho...lashwaves.html) I got rid of one 540 and the 160. I can light just about anything I need to with the flashes I have.
12-09-2010, 04:01 PM   #21
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QuoteOriginally posted by mikemike Quote
If you are bouncing the flash or shooting through a gel or diffuser, how does the flash know this and compensate for the lost effectiveness?
Through the magic of pTTL Just before the start of the exposure the camera sends a pulse of light at a known power level and then measures how much light reflects back. From that it calculates how much power it needs to arrive at a correct exposure.

If you are bouncing, have a diffuser on it or whatever, that will all impact how much light is reflected back through the lens and it will therefore factor into how much power the camera calculates it needs for it's real pulse of power for correct exposure.

As The shutter opens it then delivers that amount of power. All this happens in a fraction of a second, so fast you can't even distinguish between the 2 separate pulses.

Last edited by twitch; 12-09-2010 at 04:06 PM.
12-09-2010, 04:49 PM   #22
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My last word on this for flash newbies who may be afraid to go the old manual route with flashes that fire at full power. No P-TTL, no TTL, and no sensor in the flash that adjusts for anything. (Aside from the fact that you may be able to choose full power, 1/2 power, 1/4 power, etc.)

When you're shooting indoors, ambient light conditions don't change at all. So, it will take you about 4 minutes to figure out the optimum F stop to use for subjects within 8 feet. And 15 feet. And the entire room, if possible with the power of your flash and as said here elsewhere.
12-09-2010, 05:01 PM   #23
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QuoteOriginally posted by mikemike Quote
If you are bouncing the flash or shooting through a gel or diffuser, how does the flash know this and compensate for the lost effectiveness?
Others have told you about the magic of TTL or p-TTL. I'm telling you about the lowly light sensor on the flash used in flash "auto" mode. It's not as high tech, but is just as effective. In the case of K10D and K20D, it's even more accurate than p-TTL.

Many flash units, the ones with "auto" mode setting, have a light sensor to tell the flash's electronics when there has been enough light and turn off the light output.

There are some drawbacks:

1. You have to make sure the light sensor is facing the scene being photograph. If the flash unit has head that can bounce and swivel, this is pretty simple to do (you as the operator still have to pay attention though). If the flash can't bounce or can't swivel (e.g. Vivitar 285, 283, or Pentax 360), this may be difficult or impossible. Some flashes have "remote sensor" to handle this situation. Here's one with such remote sensor:




2. The light sensor has a fixed field of view, which may not match the field of view of the lens. In most cases in which the scene is "average," this is not a problem. Some remove sensors have two settings, one "normal" (e.g. 35mm FL in 35mm format) and a "tele" (70mm FL). It's not obvious in the photo below, but with the Metz remote sensor Mecamat, I call pull the lens of the sensor out for the "tele" setting:




3. The light sensor on the flash doesn't know if there is any filter attached to the lens to compensate for the filter. But with DSLR, how often do you use lens filter for flash photo?


"Auto" mode does have some advantages over p-TTL:

1. No preflash: some people and animals react to the preflash strobe. For this reason, I don't use p-TTL when taking photo of a group of people - someone may blink at the preflash and appears to close his/her eyes when the photo is actually taken.

2. Works with any lens. p-TTL requires at least an A lens to work properly. This is a reason why I don't recommend Metz 48. It does not have "auto" mode so has to be in manual mode when used with a manual lens. It's not the end of the world, just not as convenient.


Last edited by SOldBear; 12-09-2010 at 05:12 PM.
12-12-2010, 06:32 PM   #24
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I have decided that the price is not the issue. What is important is I want a good quality one time purchase flash that will serve me for a long long time. I want something that can do a good job fully auto if possible and is extremely simple to use.
I am thinking the Pentax 540. Unless you feel strongly about a different unit.

Thanks for your help
12-12-2010, 09:47 PM   #25
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If you remove price from consideration then the 540 is a good choice.
12-13-2010, 12:48 AM   #26
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I have the AF540 (only because the local Metz agent as well as a dealer did not come back to me with prices) and I needed a flash.

There are NO Pentax accesories for the Pentax like diffusors and reflectors; you have to resort to 3rd party or make them yourself. Something to consider.
12-13-2010, 01:13 AM   #27
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QuoteOriginally posted by sterretje Quote
I have the AF540 (only because the local Metz agent as well as a dealer did not come back to me with prices) and I needed a flash.

There are NO Pentax accesories for the Pentax like diffusors and reflectors; you have to resort to 3rd party or make them yourself. Something to consider.
ummm...

I don't think Metz makes any either. Not for the current lineup anyway.



You can buy a Stofen to fit just about anything though. I've recently replaced the 360 with a Metz 58 AF-1. Fantastic flash and more feature packed than the 540 for less money in some cases.



4100
12-13-2010, 02:32 AM   #28
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For the Metz 48:

Mecabounce 58-90 (similar to the Stofen?)
Bounce diffuser 58-23 (also fits on the 58 )
12-13-2010, 11:51 AM - 1 Like   #29
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QuoteOriginally posted by sterretje Quote
There are NO Pentax accesories for the Pentax like diffusors and reflectors; you have to resort to 3rd party or make them yourself. Something to consider.
So all other makers of flash guns offer accessories for their flashes?

None of diffusers and reflectors I've used are from the same maker as the flash unit.

3rd party accessories, including home-built, are OK.




12-13-2010, 06:48 PM   #30
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Hi, Sitting Bull
I have a range of the basic Pentax flashes, from the AF16 that came with the ME super kit, up to the AF360.
I would suggest that a 2 axis flash bracket/grip and cable is more bang for the buck than an elaborate and costly flash mounted on camera.
Also it seems that while using classically high flash levels on-camera and stopping down the lens was the most reliable way in the film days, it was garish in the foreground and dark in the distance.
With Pentax dlsr in MANUAL mode and AWB we have the opportunity for more pleasing/natural shots using a mix of available light and fill flash. Even at a conservative iso 800 and f 2.8, try a test shot with NO flash at 1/60th or so, then progressively adjust flash as SOldbear mentions in another post. Need more DOF at the distance? Read the DOF tables for your lens. Stop down as a compromise and add a bit more flash. As I mentioned in another thread, the AF360 works OK indoors for me when turned down to around 1/32 of its maximum.
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