Win a Pentax Limited Lens: Raffle Now Live!

Edvinas · 02-22-2008, 02:12 PM

Yes, AF-540FGZ underexpose. Fortunately it gives quite constant overexposure and +1EV fixes the situation

I just wonder if it is just some underexposing batch of AF-540FGZ or this is a problem which Pentax simply don't bother to address?

Sample shots are below:

Peter Zack · 02-22-2008, 02:26 PM

I'm seeing something slightly different than you here. Agreed on the first 2.

On the second set, I much prefer the 540/0Ev shot. The other 2 look overexposed and on the verge of blown highlights. The best flash shots are those that don't look like a flash was used and the 540/0Ev shot comes closest to that.

The third set well, no doubt, the 1st and 3rd closely match and have the most even light. So in you little test, +1Ev doesn't always solve the problem IMO.

I guess +1Ev for indirect flash shooting and 0Ev for direct.

**Ash** · 02-22-2008, 02:40 PM

Would others agree this is the case all the time?
With those who just have the 540, are they happy with the results at 0Ev, or does Ev/FEC need to be bumped up to improve it?
How do the results look on the histogram?

From the results above, it does seem bounce flash is inadequate at 0EV, esp the first set, and wonder why - P-TTL should meter both direct and indirect flash equally. Or are there other variables (given that the bounce surface is relatively close by and is white) that affect the metering?

Would be interesting to know...

deejjjaaaa · 02-22-2008, 03:34 PM

just wait for RiceHigh

Confused · 02-22-2008, 04:06 PM

Hi Edvinas

Well to my untrained eye, the first two bounced sample shots (AF-360FGZ & AF-540FGZ respectively) perfectly illustrate the oft-quoted tendency of the AF-540FGZ to underexpose when used in this mode. All I can say is that if I'd just laid out the kind of money demanded for the 540FGZ flashgun in typical Rip-Off UK-Land, I'd be distinctly underwhelmed (and believe me, that's a polite way of putting it !). I'm currently in the market for a separate flashgun to suit my K10D, but as far as I'm aware, there is not ONE single product available which addresses the shortcomings of all the other models from competing manufacturers.........hence a great deal of thoughtful head-scratching ?

Best regards
Richard

stewart_photo · 02-22-2008, 05:02 PM

Originally posted by Edvinas

Thread Title: Quick unscientific AF-360FGZ and AF-540FGZ comparison shots

Yes, AF-540FGZ underexpose. Fortunately it gives quite constant overexposure and +1EV fixes the situation

I just wonder if it is just some underexposing batch of AF-540FGZ or this is a problem which Pentax simply don't bother to address?

Sample shots are below: (snip)

Well, you're starting off with a wrong assumption. The camera, not the flash unit, controls exposure, so there's something more than just the AF-360FGZ versus AF-540FGZ going on here.

Remembering the AF-360 has a minimum flash range of .7m (2.3-ft) and AF-540 a minimum flash range of .8m (2.6-ft), what is the actual distance to each of the subjects in the unbounced shots? If they're at the edge of that minimum flash range, the exposure results could indeed be unpredictable.

The exposure results might also vary depending on where and how your camera's 16-segment metering system actually measures. Without some control on your part (spot metering, etc), the metering algorithms within the K10D may not always emphasize the exact same areas in the exact same way with each exposure even though the subject remains the same. This could perhaps account for at least some of the differences in the images using bounced lighting.

stewart

**Lowell Goudge** · 02-22-2008, 05:12 PM

I would have to agree with stewart here.t is the camera not the flash that controls exposure, unless you are using the 540 in "auto" mode

the other question is, what camera are you using?

Is it an *istD or DS and your running in TTL mode?

In my opinion, I have used the 540 a lot in bounce mode with the K10D and been very pleased with exposure, however I am generally 5-7 feet away from subjects at a minimum, otherwise, the flash is bright enough to give them sunburn.

I also think the test title says it all, unscientific. Where is RH when you need him

02-22-2008, 02:12 PM	#1
Edvinas Veteran Member Join Date: Sep 2006 Location: Kaunas Posts: 1,458	Quick unscientific AF-360FGZ and AF-540FGZ comparison shots Yes, AF-540FGZ underexpose. Fortunately it gives quite constant overexposure and +1EV fixes the situation I just wonder if it is just some underexposing batch of AF-540FGZ or this is a problem which Pentax simply don't bother to address? Sample shots are below:

02-22-2008, 05:02 PM	#6
stewart_photo Veteran Member Join Date: Apr 2007 Location: Heidelberg, Germany Posts: 1,864	Wrong Assumption. Originally posted by Edvinas Thread Title: Quick unscientific AF-360FGZ and AF-540FGZ comparison shots Yes, AF-540FGZ underexpose. Fortunately it gives quite constant overexposure and +1EV fixes the situation I just wonder if it is just some underexposing batch of AF-540FGZ or this is a problem which Pentax simply don't bother to address? Sample shots are below: (snip) Well, you're starting off with a wrong assumption. The camera, not the flash unit, controls exposure, so there's something more than just the AF-360FGZ versus AF-540FGZ going on here. Remembering the AF-360 has a minimum flash range of .7m (2.3-ft) and AF-540 a minimum flash range of .8m (2.6-ft), what is the actual distance to each of the subjects in the unbounced shots? If they're at the edge of that minimum flash range, the exposure results could indeed be unpredictable. The exposure results might also vary depending on where and how your camera's 16-segment metering system actually measures. Without some control on your part (spot metering, etc), the metering algorithms within the K10D may not always emphasize the exact same areas in the exact same way with each exposure even though the subject remains the same. This could perhaps account for at least some of the differences in the images using bounced lighting. stewart Last edited by stewart_photo; 02-22-2008 at 05:08 PM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Wanted - Acquired: AF-360fgz or AF-540FGZ	Duch	Sold Items	1	02-12-2010 05:40 PM
Trigger voltages of AF 540FGZ, AF 360FGZ and AF 200FG ???	GerryL	Pentax Camera and Field Accessories	26	07-12-2009 05:58 AM
Unscientific (but representative!) comparison of 50-200 & 70-300	Marc Sabatella	Pentax SLR Lens Discussion	14	04-23-2009 12:49 PM
360FGZ or 540FGZ for a K10D	calicojack	Pentax Camera and Field Accessories	8	09-02-2007 11:22 PM
The big unscientific RAW Converter Comparison	HogRider	Photographic Technique	0	02-21-2007 11:27 AM

02-22-2008, 02:26 PM	#2
Peter Zack Pentaxian Moderator Emeritus Join Date: May 2007 Location: Edmonton Alberta, Canada Photos: Gallery \| Albums Posts: 10,643	I'm seeing something slightly different than you here. Agreed on the first 2. On the second set, I much prefer the 540/0Ev shot. The other 2 look overexposed and on the verge of blown highlights. The best flash shots are those that don't look like a flash was used and the 540/0Ev shot comes closest to that. The third set well, no doubt, the 1st and 3rd closely match and have the most even light. So in you little test, +1Ev doesn't always solve the problem IMO. I guess +1Ev for indirect flash shooting and 0Ev for direct.

02-22-2008, 02:40 PM	#3
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Would others agree this is the case all the time? With those who just have the 540, are they happy with the results at 0Ev, or does Ev/FEC need to be bumped up to improve it? How do the results look on the histogram? From the results above, it does seem bounce flash is inadequate at 0EV, esp the first set, and wonder why - P-TTL should meter both direct and indirect flash equally. Or are there other variables (given that the bounce surface is relatively close by and is white) that affect the metering? Would be interesting to know...

02-22-2008, 03:34 PM	#4
deejjjaaaa Veteran Member Join Date: May 2007 Location: steel city / rust belt Posts: 2,043	just wait for RiceHigh

02-22-2008, 04:06 PM	#5
Confused Inactive Account Join Date: Jul 2007 Location: London Posts: 1,067	Hi Edvinas Well to my untrained eye, the first two bounced sample shots (AF-360FGZ & AF-540FGZ respectively) perfectly illustrate the oft-quoted tendency of the AF-540FGZ to underexpose when used in this mode. All I can say is that if I'd just laid out the kind of money demanded for the 540FGZ flashgun in typical Rip-Off UK-Land, I'd be distinctly underwhelmed (and believe me, that's a polite way of putting it !). I'm currently in the market for a separate flashgun to suit my K10D, but as far as I'm aware, there is not ONE single product available which addresses the shortcomings of all the other models from competing manufacturers.........hence a great deal of thoughtful head-scratching ? Best regards Richard

02-22-2008, 05:12 PM	#7
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,892	I would have to agree with stewart here.t is the camera not the flash that controls exposure, unless you are using the 540 in "auto" mode the other question is, what camera are you using? Is it an *istD or DS and your running in TTL mode? In my opinion, I have used the 540 a lot in bounce mode with the K10D and been very pleased with exposure, however I am generally 5-7 feet away from subjects at a minimum, otherwise, the flash is bright enough to give them sunburn. I also think the test title says it all, unscientific. Where is RH when you need him