Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Reply
 
Thread Tools Search this Thread
Old Jul 29, 2008, 9:59 PM   #1
Senior Member
 
nhmom's Avatar
 
Join Date: Jun 2006
Location: Southern New Hampshire
Posts: 5,202
Default

I didn't get a chance to thoroughly digest all of your post, Scott. But, here is one of the photos I took on Saturday that is what I was talking about.

I only resized in Windows, so hopefully the EXIF data is still there. This was using the 360 flash, not the onboard flash. It was taken in a shady area, the reason for my using the flash. I did eventually get a shot by turning off the flash and adjusting the shutter speed and fstop.

I will have some more time tomorrow night to go through the posts today in more detail. But, figured in the meantime, you could see an example of my problem.

I'm still having problems with my new glasses, so hopefully I'm picking ones that are clear. I'm posting a second one that was taken at different settings, but again with the flash. It was only about 10 feet away from the other one, still in the shade.

Patty


Attached Images
 
nhmom is offline   Reply With Quote
Sponsored Links
Old Jul 29, 2008, 10:00 PM   #2
Senior Member
 
nhmom's Avatar
 
Join Date: Jun 2006
Location: Southern New Hampshire
Posts: 5,202
Default

Here's the second one.
Attached Images
 
nhmom is offline   Reply With Quote
Old Jul 30, 2008, 12:56 AM   #3
Senior Member
 
snostorm's Avatar
 
Join Date: Jan 2004
Location: Chicago Suburb, IL, USA
Posts: 2,770
Default

Hi Patty,

These weren't caused by the dreaded reflections, so after looking at the exif, I'll make some suggestions.

1. These were shot at f11 and f19. I'd use a more moderate aperture like f5.6 to f8 for most flash shots, with the possible exception of when working at very close macro distances. My Pentax flashes tend to overexpose when my lenses are set at the wider aperture extremes and underexpose at the smaller aperture extremes.

Also, as a practical matter, the flash doesn't have to work as hard with a wider aperture (or at higher ISO, for that matter), so it'll recharge faster between shots. Which brings in another possible factor -- did you wait for the "flash charged" indicator (bottom left in your viewfinder) to stop flashing before you took the shot? I believe you can set the camera up so it won't let you take an exposure when the flash is still charging, but I think this only works with the pop up flash, so when you're using an external, you have to stay aware of this. My flashes will sometimes fail to fire, even when everything seems to be alright, but this only happens maybe 1 out of a hundred shots, and because I can see it happen in the viewfinder, I know when I have to retake a shot.

2. You were using spot metering -- I'd try center-weighted. With spot metering, there's a chance that the area metered will be at a highlight in the shot, and that would cause underexposure. With center-weighted, small highlights wouldn't effect the P-TTL metering as drastically as with spot.

and two other things -- make sure your 360 is fully seated and locked down in the hot shoe, and wipe the bottom contacts every once in a while to make sure they're clean.

Keep experimenting with it -- if you continue to get a lot of these kind of images, I'd contact Pentax service to see if they have any suggestions or if they'd recommend sending it in for warrantee repair.

Scott
snostorm is offline   Reply With Quote
Old Jul 30, 2008, 5:44 AM   #4
Senior Member
 
a200user's Avatar
 
Join Date: Aug 2005
Location: Western New York
Posts: 942
Default

Based on Scott's reply I assume you are using the AF360 flash?

If you are, and if you haven/t already tried this, go to your Custom Setting Menu on your camera, set the Link AF Point and AE to option 2 - On.

This made a huge difference for me, as I was getting dark results similar to yours.

Also on either the AF360 and/or your camera, boost up the flash exposure compensation. I find if I set the AF360 flash comp. up to about +.5 or +1 I get better results. The problem with doing this on the flash is that it doesn't remember your setting when you turn it off, so you have to reset it with each use.

Another, more tedious fix is to set the AF360 into Auto mode rather than P-TTL mode.

In Auto mode however you have to manually set the AF360 flash to match the ISO, Aperature, and Focal length that your camera is set for. The instruction manual for the AF360 is poorly done, but it will tell you how to change these settings in Auto mode. Wonder why they call it Auto mode? What I understand of Auto mode is that it does not use pre-flash, it uses a senosr on the AF360 flash unit to determine the intensity of the flash output. Having said all that I find that I get better, more consistentresults in Auto mode than I do in P-TTL.

Good luck.

Jim
a200user is offline   Reply With Quote
Old Jul 30, 2008, 5:26 PM   #5
Senior Member
 
Join Date: Aug 2006
Location: Essex, UK
Posts: 1,868
Default

One other thing to check is the ISO.

The dark shot was using ISO200. You may want to try ISO400 for that type of shot, with the lens stopped down.




Dal
Dal1970 is offline   Reply With Quote
Old Jul 30, 2008, 7:12 PM   #6
Senior Member
 
danielchtong's Avatar
 
Join Date: Dec 2005
Posts: 2,888
Default

snostorm wrote:
Quote:
Hi Patty,

1. These were shot at f11 and f19. I'd use a more moderate aperture like f5.6 to f8 for most flash shots, with the possible exception of when working at very close macro distances.

Scott
Patty,

No way that AF360 is powerful enough for a 10 ft shots of F11 & F19 in normal lighting condition. Scott is definitely right.
Macro at 1 ft distance is of course different story.
Use F4 or F5.6 will be ok.
Also AF360 is very weak in terms of fire power. But even that should be ok if you are using wider aperture.
Dal's input about using iso400 is also valid.

Daniel
danielchtong is offline   Reply With Quote
Old Jul 30, 2008, 8:02 PM   #7
Senior Member
 
nhmom's Avatar
 
Join Date: Jun 2006
Location: Southern New Hampshire
Posts: 5,202
Default

Thanks, Scott and all. Well, I don't have as much time as I'd hoped tonight. But, I'll respond to what was written here.

Oh, okay, I didn't realize you should use a larger aperture when using the flash unit. Like someone said in one of these posts, the manual for the flash unit has a lot to be desired. I have no idea what I'm doing, except getting more light than theonboard flash. I'll have to remember the larger aperture.

As for the recharging of the flash, I honestly can't say. I didn't realize I needed to do that. Sometimes when I can finally get set to see through the viewfinder, I hate to move my glasses on the viewfinder so I can see the entire bottom because it will take me a while to get it back lined up again. I have progressive bifocals and these new ones are really bothering me. Going in tomorrow to ask for a different lens. I have thought of getting a pair of single vision ones just for photographing, but......

As for the spot vs. center metering, I used to use center, but was more successful using spot when I can predetermine what I want to meter off of and reposition the camera to frame. I can try center again, though.

I'm pretty sure I seated it on tightly. But, I will try cleaning the contacts. Didn't think of that. And, as for sending in for warranty. It will be two years old in about a week. So, that's not possible.:shock:

Jim - I will try changing the settings you suggested. I don't think I've ever changed anything on the flash, so it's probably still set to the defaults. I didn't know what all the settings were and keep forgetting to figure them out.

Dal - I had changed some I'd taken that day to as high as ISO800, but not sure if it was when I was using the flash. It was very hot and humid out and we had mosquitoes everywhere. So, I wasn't paying as much attention to what I was doing as I should have. As a matter of fact, after a while I set it to auto and just took in auto. Went back yesterday later in the day and retook some of them and I think was more successful. Haven't had a chance to check them out yet.

Daniel - thanks for the input on the distance. I forget that it doesn't go very far.

I'll play around with the flash some more and maybe next time I want to use it will understand better what to do. :-)

Patty
nhmom is offline   Reply With Quote
Old Jul 31, 2008, 12:03 AM   #8
Senior Member
 
DMJJR's Avatar
 
Join Date: Oct 2005
Posts: 926
Default

Back in the old days of 35mm we had to set the F stop manually-using the guide # of the flash and the distanceto the subject. My first "auto" flash was the Vivitar 283. Try this:

You figure out what f stop to use by dividing the guide number by the distance from the flash to the subject.

If a flashgun has a guide number of 80,
  • at 10 feet use f8 (80 divided by 10 = 8) [/*]
  • at 5 feet use f16 (80 divided by 5=16) [/*]
  • at 20 feet use f4 (80 divided by 20=4)
[/*]
When the film speed is increased by a factor of 4, the guide number is doubled. If the guide number for ISO 100 was 80, the GN for ISO 400 is 160.

How film speed changes Guide Number





Film speed:
Guide Number

25
40

50
56

100
80

200
110

400
160

These are all just suggestions-we had to experiment to get the correct exposure. Try using the manual mode with a shutter speed of 1/125 and adjust your aperture until you get your desired results. The AF 360 has a guide # of 119 @ISO 100. I don't have this flash so that's all I can suggest.

Good Luck
DMJJR is offline   Reply With Quote
Old Jul 31, 2008, 11:08 PM   #9
Senior Member
 
nhmom's Avatar
 
Join Date: Jun 2006
Location: Southern New Hampshire
Posts: 5,202
Default

Thanks. I will try to decipher this this weekend. It's way above my head. Especially right now when I'm up too late yet again.

Patty
nhmom is offline   Reply With Quote
Old Aug 1, 2008, 3:08 PM   #10
Senior Member
 
Goldwinger's Avatar
 
Join Date: May 2008
Location: Winter Haven, Florida
Posts: 6,515
Default

nhmom wrote:
Quote:
Thanks. I will try to decipher this this weekend. It's way above my head. Especially right now when I'm up too late yet again.

Patty
Patty, if you'd go to bed instead of staying up till all hours, you wouldn't have that problem!

Goldwinger is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 11:49 AM.