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08-25-2008, 01:10 PM   #1
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K20D + Metz 58; what'm I doin' wrong?

First, let me flash back 20 years to my SuperProgram and AF200SA (with Pentax 50mm kit lens, CPC 28-85 and 80-200 zooms--they have Ricoh mounts which nearly gave me heart failure when I first attached one to the K20D). It didn't matter which lens I used or at what zoom or which speed film I used (64-1600). With the camera set on auto (I don't remember how well it worked with shutter priority and aperture priority), I always got near perfect exposure with that flash and camera, even at ranges close to or somewhat exceeding the flash's 20' max range. I even got a fairly decent picture inside a Carlsbad Caverns big room, bracing the camera, setting it for an 8 sec. exposure, blocking the flash's sensor and manually firing the flash several times to light up the room.

Six years ago I bought a Sony F707. It's an adequate snapshot camera, but after 6000 pictures, I've outgrown its uneven colors, ultra-slow autofocus and extremely limited capacity (128MB memory stick). So it was time to buy a real camera again.

So I bought a K20D (w/18-55 kit zoom) and a Metz 58 ("pay once, cry once" was recently advised in this forum). I played with setting the 58 as a wireless slave in the middle of a large-ish room with vertical bounce. (The 58 doesn't seem to want to fire as a slave unless it gets a strong flash from the K20's built-in flash; hence putting the 58 on its stand in the middle of the room.) But by golly the entire room was well lit; I was amazed.

However, with the 58 attached to the camera, I'm finding it nigh-on impossible to get a properly-exposed picture. I got slightly better exposure but still inconsistent results setting exposure compensation to +.5-1.5. SO far I haven't found any combination or camera and flash settings that even approaches consistency.

Whilst I'm certainly not new to photography and am quite familiar with depth of field, aperture, shutter and other effects of SLR cameras, I'm at a loss here. What'm I doing wrong? Or what am I not doing that I should be doing? Do y'all have any concrete ideas on where I can start to get consistent flash pictures and to get consistent fill-flash pictures? (I expect they would be two very different settings.) Even enigmas and conundrums might be helpful.

Much of my picture-taking is of people in dynamic situations, so there is typically little time available to compose the picture and really not enough time to manually set the camera and flash for each and every picture. Someone in a thread here called it 'press photography', which is a rather apt description.

I generally try to record 'memories' for people, so snapshot mode generally works well. But to avoid the 'I wish I'd had/used a better camera for that shot" times, I take all pics in high resolution. If I end up with 1-3% gems out of 500 snapshots, it's worth it.

Thanks!
Neal

08-25-2008, 01:30 PM   #2
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Fest3r

I have no experience with the Metz... just a question though seeing your using a zoom.

Is there a setting on the flash unit for the different focal lengths or does the Metz auto detect.

Neil
08-25-2008, 02:21 PM   #3
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The Metz 58 autozooms with the DA lens at least when it is connected via the hot shoe. The flash's zoom can also be set manually.
08-25-2008, 03:55 PM   #4
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It sounds like you Metz is on manual zoom or has the exposure compensation cranked up.

08-29-2008, 09:28 AM   #5
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First, disable auto ISO on your body, because that causes all kinds of trouble.

Second, to rule out P-TTL errors, try using the automatic mode on the flash first.

Select an aperture, eg F5.6 and eg 1/125s and ISO-200 in manual mode on the K20 and show some results.

Last edited by tomtor; 08-29-2008 at 10:01 AM.
08-29-2008, 08:59 PM   #6
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QuoteOriginally posted by tomtor Quote
First, disable auto ISO on your body, because that causes all kinds of trouble.

Second, to rule out P-TTL errors, try using the automatic mode on the flash first.

Select an aperture, eg F5.6 and eg 1/125s and ISO-200 in manual mode on the K20 and show some results.
Thanks! You inspired me to set up the tripod!

I started at flash (auto, vertical bounce), 1/60 sec, f5.6, ISO 100 and cycled to 1/180 sec. The result was the generally dark picture (#430; 1/60, f5.6, 18mm, ISO 100). I worked my way up to ISO 400, which resulted in a not-as-dim picture (#462; 1/160, f5.6, ISO 400, 18mm). There were taken whilst there was still good light coming in the skylights.

Next I took a bunch at ISO 400 with the flash set in front and set as wireless slave. Pictures were better, but perhaps having the flash in the frame didn't help much (#481; 1/160, f5.6, ISO 200, 18mm).

So I aimed the flash away a little. Better, but still not as good as I would like (#487; 1/100, f5.6, ISO 400, 18mm), and now there's visible shadow. And zooming in was still dimmer. So I moved the flash out of the frame and installed the hoodie. Better, but still not great.

This batch was about 120 pictures. Time for a smoke, a glass of wine and make supper. And I'll try more later.

N
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08-29-2008, 10:23 PM   #7
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Thanks for the examples.

The last two look correctly exposed. if it is too dark to your liking, that's caused by the large white background wall.

About the first, you are perhaps using the second reflector? That will result at distances over 6 feet with 100 iso in those dark images. The reason is the fixed power ratio, eg 1/4 between main and secondary flash.
08-30-2008, 12:43 AM   #8
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I did some homework and looked up the guide number of the Metz with the reflector in the 28mm (35mm film equivalent of 18mm APS-C) position: 31 at 100 iso!

This means flash range: 31 / 5.6 = 5.5 meters WITHOUT bounce.

That is the simple explanation for the first two darker images. You used bounce against the ceiling and at 100 iso the Metz-58 has simply insufficient power for the range.

400 iso helped somewhat for the second image.

#4 with 400iso without bounce is fine. #3 at 200 iso should also be fine, it is slightly darker probably because the flash is visible in the frame.

Your equipment looks ok. You should be careful when using bounce, use iso 400 and when the subjects are over approx 4 meters away you'll need higher iso, open the aperture (use eg F4 instead of F5.6) or stop using the bounce technique. The Pentax flashes will have exactly the same limitation.

Note that in the first two images the Metz will not have generated the OK sound and the red flash OK lamp (button 3) will not light up. Just set the flash to A, detached from the camera and hit the flash test button to test the range with varying F, ISO and with and without bounce. You'll see that the flash will not give the flash range ok signal beep and lamp in the first two situations...


Last edited by tomtor; 08-30-2008 at 02:04 AM. Reason: edit control sound
08-30-2008, 09:00 PM   #9
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QuoteOriginally posted by fest3er Quote
... And I'll try more later.

N
It's later. I'm still working on the first set of test pics. They were all taken without using the secondary reflector. These test pics are taken at max resolution JPEG and scaled using Imagemagick's 'convert -sample 500x500' command. Any rotation is done using 'jpegtran -rotate 90'. And they're all from before tomtor's 'homework' reply.

Here're three more shots. I'm getting a little better; or at least I'm achieving some consistency. These were taken using my ancient CPC 80-200 zoom with A-ring on auto. (I'm using a 1.5 multiplier to convert the 35mm focal length to digital equivalent; so it's about a 120-300 zoom in digital.) Distance to subject was about 3m. The pics are still a little dark (the walls are actually pretty close to white, and his hair *is* white) but at least they're getting brighter. From the settings below, you can see I'm still experimenting.

Some relevant info from the JPEG info:

Pic 1:
Horizontal flash
Exposure Time: 1/180
F Number: 40/10
Exposure Program: 3
ISO Speed Ratings: 400
Exposure Bias Value: 10/10
Metering Mode: 5
Flash: 9
Focal Length: 30000/100

Pic 2:
Flash 45 degrees up
Exposure Time: 1/180
F Number: 40/10
Exposure Program: 3
ISO Speed Ratings: 100
Exposure Bias Value: 20/10
Metering Mode: 5
Flash: 9
Focal Length: 30000/100

Pic 3:
Vertical flash
Exposure Time: 1/180
F Number: 40/10
Exposure Program: 2
ISO Speed Ratings: 100
Exposure Bias Value: 20/10
Metering Mode: 5
Flash: 9
Focal Length: 30000/100

I was having doubts about using those old lenses, but it looks this one still takes a nice picture.

The Metz 58 can put out a nearly blinding flash. It has the power. As a slave, it *can* light up the whole living room in a picture.

As a preview to another goup of pics I'll prepare, I switched to ISO 400-1200 and turned on the secondary reflector. The results are much more satisfactory.

N
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08-30-2008, 09:27 PM   #10
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QuoteOriginally posted by fest3er Quote
... And I'll try more later.
Another group from the same batch. I'm achieving more consistency across different settings and program modes. The first four should be vertical bounce. The last was angled down some, to 60 or 45 degrees.

Relevant info from JPEGs (I need to put names to the numeric exposure program and metering modes and the flash value; info's from a linux-based tool I'm hacking together):

Pic 1:
Exposure Time: 1/30
F Number: 35/10
Exposure Program: 2
ISO Speed Ratings: 100
Exposure Bias Value: 0/10
Metering Mode: 5
Flash: 9
Focal Length: 1800/100

Pic 2:
Exposure Time: 1/30
F Number: 35/10
Exposure Program: 0
ISO Speed Ratings: 100
Exposure Bias Value: 0/10
Metering Mode: 5
Flash: 9
Focal Length: 1800/100

Pic 3:
Exposure Time: 4/10
F Number: 35/10
Exposure Program: 4
ISO Speed Ratings: 100
Exposure Bias Value: 0/10
Metering Mode: 5
Flash: 9
Focal Length: 1800/100

Pic 4:
Exposure Time: 1/180
F Number: 35/10
Exposure Program: 4
ISO Speed Ratings: 100
Exposure Bias Value: 0/10
Metering Mode: 5
Flash: 9
Focal Length: 1800/100

Pic 5:
Exposure Time: 1/180
F Number: 35/10
Exposure Program: 4
ISO Speed Ratings: 100
Exposure Bias Value: 0/10
Metering Mode: 5
Flash: 9
Focal Length: 1800/100
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08-30-2008, 09:56 PM   #11
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I have a whole bunch more test pictures, but I think I'll put them all on my web site. What I've found so far (and these have probably been stated in this forum before):
  • The exposure meter is sensitive to light entering from the viewfinder. Use the cover when your eye isn't there.
  • The best flash results results from using ISO400 to ISO1200.
  • Using vertical bounce (on a white ceiling) and the secondary reflector results in better longer distance flash pictures.
  • In the ISO range where the camera works well, there isn't much difference between P-TTL and Auto modes on the Metz 58.

Now that I have a better idea of what works where, I'll do up a few sets of test pics that illustrate the usable ranges of the K20D and Metz 58. Hopefully I'll remember to log the flash settings; the camera seems to records all of its settings in the JPEG.

I still think the camera isn't working quite right. In green mode, I should be able to point, zoom, focus and click and get a respectable flash picture. After all, that's the purpose of Green mode, right? And in the semi-auto modes, the camera should compensate as much as is possible for the setting(s) the operator has selected and still produce a respectable picture. They did it with the Superprogram and film....

N
08-30-2008, 11:37 PM   #12
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QuoteOriginally posted by fest3er Quote
I have a whole bunch more test pictures, but I think I'll put them all on my web site. What I've found so far (and these have probably been stated in this forum before):
  • The exposure meter is sensitive to light entering from the viewfinder. Use the cover when your eye isn't there.
  • The best flash results results from using ISO400 to ISO1200.
  • Using vertical bounce (on a white ceiling) and the secondary reflector results in better longer distance flash pictures.
  • In the ISO range where the camera works well, there isn't much difference between P-TTL and Auto modes on the Metz 58.

Now that I have a better idea of what works where, I'll do up a few sets of test pics that illustrate the usable ranges of the K20D and Metz 58. Hopefully I'll remember to log the flash settings; the camera seems to records all of its settings in the JPEG.

I still think the camera isn't working quite right. In green mode, I should be able to point, zoom, focus and click and get a respectable flash picture. After all, that's the purpose of Green mode, right? And in the semi-auto modes, the camera should compensate as much as is possible for the setting(s) the operator has selected and still produce a respectable picture. They did it with the Superprogram and film....

N
You mention the ISO range in which the CAMERA works well. It is all a matter of the power of the flash and at lower ISO settings you just don't have sufficient power to lit up the subject when using bounce flash at the apertures and ranges you test. That's why you find that higher ISO works better.

Distance is GuideNumber divided by F-setting. You can look up the guide numbers in the Metz manual. When using bounce the distance halves because a lot of the light is lost.

You also don't mention monitoring or logging the flash under exposure warning of the Metz. You MUST hear the short beep (or see the red indicator light) when taking a flash image, otherwise the image is under exposed.

The second reflector only helps in those situations where you exceed the bounce range by a large margin and the main object is relatively near. Using the second reflector when the scene would be just within the bounce range (the flash is almost at full power), will result in under exposure because the second reflector lowers the power of the main flash. The second reflector can be set to 1/4, 1/2, 1/1 ratio. At 1/4 the main flash is 4 times stronger than the secondary flash, but still a lot less strong than normal, because the guide number of the secondary flash is quite small.

Finally, unless you made film slides, the exposure is corrected when printing images in the lab, so underexposed images were often not noticed.

Happy flashing!
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