Fill in flash with AF-540FGZ and K5

Started Aug 17, 2012 | Discussions
jhpatmore Regular Member • Posts: 368
Fill in flash with AF-540FGZ and K5

Never used this before. I am thinking of mixing ambient light with some fill in flash. Is this set up advisable? Putting the flash into 1/16 power with say 1/60, f5.6, iso 100. Help would be appreciated.

Panasonic Lumix DMC-F5 Pentax K-5
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asp1880 Regular Member • Posts: 355
Re: Fill in flash with AF-540FGZ and K5

You have several options besides the full manual one:

1. P mode and p-ttl flash, FEC to taste, eg. -1.5. P mode will expose for the ambient and the flash will fill in. Experiment with the regular flash program or "slow sync", they act differently in slow-shutter territory. This is great for outdoors.

2. Like 1, but with negative EC and neutral FEC. That will lower the ambient exposure and give you a more flash-weighted shot.

3. M mode and p-ttl flash. This is great for indoors, where you can let the ambient exposure capture windows and lights, and light the rest with the flash, preferably bounce flash. Again, FEC to taste, eg. -1 with bounce flash works for me most of the time.

4. A mode and HSS flash. This is great for bright outdoors and fast lenses, as it permits wide open shooting for that skinny-DOF look that so many people like.

Regards,
--Anders.

Jim in Hudson Senior Member • Posts: 2,073
Re: Fill in flash with AF-540FGZ and K5

asp1880 wrote:

You have several options besides the full manual one:

1. P mode and p-ttl flash, FEC to taste, eg. -1.5. P mode will expose for the ambient and the flash will fill in. Experiment with the regular flash program or "slow sync", they act differently in slow-shutter territory. This is great for outdoors.

2. Like 1, but with negative EC and neutral FEC. That will lower the ambient exposure and give you a more flash-weighted shot.

3. M mode and p-ttl flash. This is great for indoors, where you can let the ambient exposure capture windows and lights, and light the rest with the flash, preferably bounce flash. Again, FEC to taste, eg. -1 with bounce flash works for me most of the time.

4. A mode and HSS flash. This is great for bright outdoors and fast lenses, as it permits wide open shooting for that skinny-DOF look that so many people like.

Regards,
--Anders.

Anders, for my benefit and hopefully anyone else with limited knowledge like me.... would you mind explaining the difference between "flash" and "slow-sync flash" as Pentax has implemented them? I guess what throws me off is "flash" mode doesn't default to the standard sync speed with Pentax, 1/180 second in this case. What am I missing in all of this? Thanks.

 Jim in Hudson's gear list:Jim in Hudson's gear list
Olympus E-M1 Pentax K-3 Sigma 10-20mm F4-5.6 EX DC HSM Pentax smc DA 55-300mm F4.0-5.8 ED Pentax smc DA 18-135mm F3.5-5.6ED AL [IF] DC WR +4 more
asp1880 Regular Member • Posts: 355
Re: Fill in flash with AF-540FGZ and K5

Jim in Hudson wrote:

Anders, for my benefit and hopefully anyone else with limited knowledge like me.... would you mind explaining the difference between "flash" and "slow-sync flash" as Pentax has implemented them?

The slow sync flash program allows the camera to pick shutter speeds slower than the handholdable-guideline for the focal length 1/1.5*f.

The regular flash program does not, it will bottom out at the 1/1.5*f shutter speed.

So if you shoot in dim light (slow shutter territory), the slow sync program will yield a brighter background (slower ss, higher ambient exposure) than the regular flash program. The flash exposure will be the same though.

I guess what throws me off is "flash" mode doesn't default to the standard sync speed with Pentax, 1/180 second in this case. What am I missing in all of this?

1/180 second is just the maximum possible shutter speed for flash. P and A mode will choose a slower speed if appropriate. If you really want 1/180 shutter speed, use T, M or X mode.

Regards,
--Anders.

Jim in Hudson Senior Member • Posts: 2,073
Re: Fill in flash with AF-540FGZ and K5

asp1880 wrote:

Jim in Hudson wrote:

Anders, for my benefit and hopefully anyone else with limited knowledge like me.... would you mind explaining the difference between "flash" and "slow-sync flash" as Pentax has implemented them?

The slow sync flash program allows the camera to pick shutter speeds slower than the handholdable-guideline for the focal length 1/1.5*f.

The regular flash program does not, it will bottom out at the 1/1.5*f shutter speed.

So if you shoot in dim light (slow shutter territory), the slow sync program will yield a brighter background (slower ss, higher ambient exposure) than the regular flash program. The flash exposure will be the same though.

I guess what throws me off is "flash" mode doesn't default to the standard sync speed with Pentax, 1/180 second in this case. What am I missing in all of this?

1/180 second is just the maximum possible shutter speed for flash. P and A mode will choose a slower speed if appropriate. If you really want 1/180 shutter speed, use T, M or X mode.

Regards,
--Anders.

Thank you so much. The Pentax manual (K-30 in my case) could really use a rewrite as it's nowhere as clear as your explanation.

Probably the element of user intervention needed for regular flash mode, at least in P mode, is to limit the top end ISO. Otherwise, the camera (based on your thorough explanation) will go straight to a high ISO setting to maintain fast enough shutter speed for the background -- even if you're only concerned about fully lighting the foreground subject with the flash.

 Jim in Hudson's gear list:Jim in Hudson's gear list
Olympus E-M1 Pentax K-3 Sigma 10-20mm F4-5.6 EX DC HSM Pentax smc DA 55-300mm F4.0-5.8 ED Pentax smc DA 18-135mm F3.5-5.6ED AL [IF] DC WR +4 more
asp1880 Regular Member • Posts: 355
Re: Fill in flash with AF-540FGZ and K5

Jim in Hudson wrote:

Probably the element of user intervention needed for regular flash mode, at least in P mode, is to limit the top end ISO. Otherwise, the camera (based on your thorough explanation) will go straight to a high ISO setting to maintain fast enough shutter speed for the background -- even if you're only concerned about fully lighting the foreground subject with the flash.

True, and lots of people complain about the high ISOs they get when combining P mode, flash and auto ISO.

I played a bit with the two flash programs today. P mode with flash is definitely not the same program line as P mode without flash. For one, it takes focus distance into account, opening the aperture when focusing farther away, as if it minds the flash guide number. Secondly, it chooses a smaller aperture than nonflash P mode, underexposing the ambient a couple of stops. Slow sync uses the same aperture but slows the shutter to match the nonflash P-mode exposure.

Complicated.

Regards,
--Anders.

OP jhpatmore Regular Member • Posts: 368
Re: Fill in flash with AF-540FGZ and K5

Thank you Anders for this fullsome explanation.

Rather like Photoshop, there is so much 'under the bonnet' ('under the hood', if you are state-side), that is waiting to be uncovered.

Most grateful.
James

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