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jpeldrid · 12-04-2011, 04:22 AM

Hi all.

Thinking of buying the Pentax AF 360 GZ flash for my K-5 camera.I have been taking indoor shots of the kids with my 16-50 pentax lens and I kept getting very soft and blurred images. After reading other threads on the forum I figured it was because my shutter speed was way too slow. The shots varied between 1/15sec to 1/6sec and the apertures were very wide. I had my ISO set at 400 but I now think I could have safely boosted that to 1600 without a huge impact on noise. Obviously I dont like the effect of the in camera flash.

My question is how does my camera know how to expose for the attached flash? If I use the flash to bounce of a ceiling how does the camera know it is not pointing at the subject. If I put a diffuser on the flash how does the camera know I have done this? Do I need to tell the camera somehow? Do I need to manually set it and how do I know what to set it to? I guess I need to know how to use an external flash. I'm sort of hoping I just need to take it out of the box, attach it and start taking photos.

Dark_Mist · 12-04-2011, 04:39 AM

When using P-TTL flash the flash unit fires off a low power pre-flash and the camera meter measures the amount of light reflected back from the subject. The camera then calculates the amount of light required for a correct exposure and then fires the flash. It all happens in milliseconds and most people don't notice the two flashes, though it can cause sensitive people to blink.

You can adjust the exposure for ambient light using manual camera settings of exposure compensation and adjust the flash exposure using flash exposure compensation.

BTW for taking pics of kids I'd use a shutter speed of at 1/100, more if they are moving about quickly.

Cheers
Col

jpeldrid · 12-04-2011, 05:53 AM

Thanks Dark Mist.

I have much more confidence in buying the flash now. I think it is just what I need. Still think my camera did a wonderful job taking the photos given the shutter speed was way too slow.

Should I use a diffuser or should I bounce the flash of a white ceiling for indoor shoots at day/night time? Everything I know is from reading and I have zilch practical experience.

sterretje · 12-04-2011, 07:30 AM

Bouncing is the better option; even with a diffuser you you can get unnatural shades.

Also consider that the AF360 only has tilt, no swivel; so with camera in portrait position you can only bounce of walls and not of the ceiling.

mtansley · 12-04-2011, 07:45 AM

As well as the Pentax flash, you might consider looking at the Metz 58 line.

I don't know how prices stack up where you are but about 3 years ago the Pentax flash was cheaper in Canada than the Metz, however, the reverse is now true with the Metz 58 AF-2 being several hundred dollars cheaper.

I have used both, I had a Pentax AF540 and liked it, however, it had an accident involving gravity and a lightstand and the flash not being attached firmly enough, (Newton was right about gravity and apples, it applies to flash units as well!). It smashed it's flash tube. At the point I replaced it with the Metz.

Both flashes do work very much the same, the Metz does offer a couple of additional options like stroboscopic mode and the addition of a small 2 power catch-light flash on the front. It will also remember it's settings when you turn it back on again, the Pentax tends to forget things. That's no problem if you just use the P-TTL mode, otherwise it can be a hassle resetting the flash to 'auto' or 'manual' every time.

DogLover · 12-04-2011, 08:12 AM

I would also urge you to consider a Metz, though if you are looking at a AF360, the Metz equivalent would be the 50, formerly known as the 48. The higher-end models will mainly give you more power. Even this cheaper model still swivels like the big boys, unlike the 360. Bouncing flash should pretty much always be your first choice, using a diffuser when bouncing isn't an option.

sterretje · 12-04-2011, 08:14 AM

OP is talking AF360, not AF540

But I agree that Metz models equivalent to the 360 or in a similar price range are worth a look.

mtansley · 12-04-2011, 09:27 AM

Originally posted by sterretje

OP is talking AF360, not AF540

But I agree that Metz models equivalent to the 360 or in a similar price range are worth a look.

Ooops, somedays I do act like a Metz marketing agent. Sorry.

12-04-2011, 04:22 AM	#1
jpeldrid Inactive Account Join Date: Mar 2010 Location: melbourne Posts: 5	How does the camera meter when using an external flash? Hi all. Thinking of buying the Pentax AF 360 GZ flash for my K-5 camera.I have been taking indoor shots of the kids with my 16-50 pentax lens and I kept getting very soft and blurred images. After reading other threads on the forum I figured it was because my shutter speed was way too slow. The shots varied between 1/15sec to 1/6sec and the apertures were very wide. I had my ISO set at 400 but I now think I could have safely boosted that to 1600 without a huge impact on noise. Obviously I dont like the effect of the in camera flash. My question is how does my camera know how to expose for the attached flash? If I use the flash to bounce of a ceiling how does the camera know it is not pointing at the subject. If I put a diffuser on the flash how does the camera know I have done this? Do I need to tell the camera somehow? Do I need to manually set it and how do I know what to set it to? I guess I need to know how to use an external flash. I'm sort of hoping I just need to take it out of the box, attach it and start taking photos.

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12-04-2011, 04:39 AM	#2
Dark_Mist Senior Member Join Date: Apr 2008 Location: Adelaide Photos: Albums Posts: 102	When using P-TTL flash the flash unit fires off a low power pre-flash and the camera meter measures the amount of light reflected back from the subject. The camera then calculates the amount of light required for a correct exposure and then fires the flash. It all happens in milliseconds and most people don't notice the two flashes, though it can cause sensitive people to blink. You can adjust the exposure for ambient light using manual camera settings of exposure compensation and adjust the flash exposure using flash exposure compensation. BTW for taking pics of kids I'd use a shutter speed of at 1/100, more if they are moving about quickly. Cheers Col

12-04-2011, 05:53 AM	#3
jpeldrid Inactive Account Join Date: Mar 2010 Location: melbourne Posts: 5 Original Poster	Thanks Dark Mist. I have much more confidence in buying the flash now. I think it is just what I need. Still think my camera did a wonderful job taking the photos given the shutter speed was way too slow. Should I use a diffuser or should I bounce the flash of a white ceiling for indoor shoots at day/night time? Everything I know is from reading and I have zilch practical experience.

12-04-2011, 07:30 AM	#4
sterretje Veteran Member Join Date: Dec 2008 Location: Roodepoort, South Africa Photos: Gallery \| Albums Posts: 3,561	Bouncing is the better option; even with a diffuser you you can get unnatural shades. Also consider that the AF360 only has tilt, no swivel; so with camera in portrait position you can only bounce of walls and not of the ceiling.

12-04-2011, 07:45 AM	#5
mtansley Veteran Member Join Date: Oct 2008 Location: Ajax, Ontario, Canada Photos: Gallery Posts: 1,139	As well as the Pentax flash, you might consider looking at the Metz 58 line. I don't know how prices stack up where you are but about 3 years ago the Pentax flash was cheaper in Canada than the Metz, however, the reverse is now true with the Metz 58 AF-2 being several hundred dollars cheaper. I have used both, I had a Pentax AF540 and liked it, however, it had an accident involving gravity and a lightstand and the flash not being attached firmly enough, (Newton was right about gravity and apples, it applies to flash units as well!). It smashed it's flash tube. At the point I replaced it with the Metz. Both flashes do work very much the same, the Metz does offer a couple of additional options like stroboscopic mode and the addition of a small 2 power catch-light flash on the front. It will also remember it's settings when you turn it back on again, the Pentax tends to forget things. That's no problem if you just use the P-TTL mode, otherwise it can be a hassle resetting the flash to 'auto' or 'manual' every time.

12-04-2011, 08:12 AM	#6
DogLover Veteran Member Join Date: Apr 2010 Location: Tennessee Posts: 2,054	I would also urge you to consider a Metz, though if you are looking at a AF360, the Metz equivalent would be the 50, formerly known as the 48. The higher-end models will mainly give you more power. Even this cheaper model still swivels like the big boys, unlike the 360. Bouncing flash should pretty much always be your first choice, using a diffuser when bouncing isn't an option.

12-04-2011, 08:14 AM	#7
sterretje Veteran Member Join Date: Dec 2008 Location: Roodepoort, South Africa Photos: Gallery \| Albums Posts: 3,561	OP is talking AF360, not AF540 But I agree that Metz models equivalent to the 360 or in a similar price range are worth a look.

12-04-2011, 09:27 AM	#8
mtansley Veteran Member Join Date: Oct 2008 Location: Ajax, Ontario, Canada Photos: Gallery Posts: 1,139	Originally posted by sterretje OP is talking AF360, not AF540 But I agree that Metz models equivalent to the 360 or in a similar price range are worth a look. Ooops, somedays I do act like a Metz marketing agent. Sorry.

How does the camera meter when using an external flash?

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