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08-22-2010, 01:47 PM   #1
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Sigma 10-20mm and on-camera flash shadows

I recently used my still somewhat new sigma 10-20mm lens indoors, and due to limited lighting, at times used the on-camera flash, and found out later that I get a (not so nice) shadow on all the pictures. I presume the lens is causing it. An external flash would take take care of this, but I would have thought this issue would have been considered as part of the lens design.

I presume this is a well-known issue (to everyone but me)?

08-22-2010, 01:54 PM   #2
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Many wide angle lenses will not work with on board flash because of the wide field of view. They're not going to cut the lens in half just to accommodate an on-board flash.

You need to bounce the flash off a wall or ceiling instead.
08-22-2010, 03:08 PM   #3
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QuoteOriginally posted by krs Quote
I recently used my still somewhat new sigma 10-20mm lens indoors, and due to limited lighting, at times used the on-camera flash, and found out later that I get a (not so nice) shadow on all the pictures. I presume the lens is causing it. An external flash would take take care of this, but I would have thought this issue would have been considered as part of the lens design.

I presume this is a well-known issue (to everyone but me)?
any long and wide lens is susceptible to blocking the flash's light path. the DA15 pancake would avoid such thing from happening. as far as on-camera use is concerned, just get a light scoop to bounce off the light and should illuminate the whole area. aside from that, you'll get the benefit of avoiding nasty flash exposure.
08-22-2010, 03:54 PM   #4
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Check your owner's manual, there's even
issues using genuine Pentax lenses.

On page 161 of my K-x manual there's a list of Pentax
lenses/limitations if using the on-camera flash.
A similar lens to your 10-20mm, the DA 12-24mm mentions:
'limited/unavailable because of vigneting'.*

Also in the flash's specs on page 301 it also mentions;
'angle of coverage 28mm lens angle of view (35mm equivalent)'*
so I'm guessing from 10mm all the way 18mm or so
you're very likely to see darker borders on your pics
when using your Sigma 10-20mm or any wide angle
lens with the on-camera flash.

*note these are the specs for a K-x flash , a K-7 may be similar?


Last edited by mlatour; 08-22-2010 at 04:39 PM.
08-22-2010, 07:08 PM   #5
krs
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Thanks all for the insights - one of those cases that it did not even occur to me that I might have an issue until I tripped over it!
08-22-2010, 09:42 PM   #6
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I keep goofing and trying to use the on board flash with the DA* 16-50. I never, ever, remember to take the lens hood off, and to shoot within the permissable range of focal lengths. I'll learn to use my 540 FGZ one of these years.
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