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Old Jun 3, 2009, 11:04 AM   #1
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Default Lens hood half moon shadow?

Hi everyone. I'm new to the forums and have had my digital slr for about 6 months now.

I have a Sony A200 with Sal-1800 lens and sh0006 lens hood (both came with the lens kit).

I am having a problem when I take a photo zoomed out all the way with the lens hood on and the flash, there is a half moon effect on the bottom center of the photos. I do not know why this is. When the flash is off it is fine, and when I zoom in a little bit it is fine, and when I take off the lens hood all is fine.

Is this a problem with the flash (not going up as high as other cameras)? a problem with the lens hood (get a flower lens hood)?

Any advice on how to deal with this. I mean, I could just zoom in a little bit and be OK, but I want to know if this is a problem everywhere.
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Old Jun 3, 2009, 12:03 PM   #2
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That's a problem with many DSLRs and built in flashes. The other alternative is to use an external flash whose light will not be blocked by the lens/hood.
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Old Jun 3, 2009, 12:07 PM   #3
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That's a problem with many DSLRs and built in flashes. The other alternative is to use an external flash whose light will not be blocked by the lens/hood.
oh ok, so a different kind of lens hood, like a petal/flower lens hood wouldn't help? They look different so I'm not sure. Is it because the A200 built-in flash doesn't go up as high as some other flashes?
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Old Jun 3, 2009, 12:38 PM   #4
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it's a combination of the hood and the flash. The core problem is the height of the built in flash. Tough to say if a different hood would solve the problem - although it's unlikely to (unless the hood being used wasn't really designed for the lens and is bigger/longer than needed in which case using the proper size hood MIGHT solve the problem).

But as mentioned, this problem will occur in any system. I can't say wheater sony's camera flash design makes it occur more often than other systems.

The reality is though that built in flashes in any system are pretty bad - if you find yourself doing a lot of flash work then an external flash will greatly improve the shots you're taking with flash.
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Old Jun 3, 2009, 1:11 PM   #5
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Simple think about problem is to imagine a straight line from the top edge of the flash to the top tip of the lens hood (and continuing past the end of the hood to the subject) anything below that line will be in the shadow of the lens/hood/etc. (as you zoom in, the lens gets longer, and that line gets closer horizontal, creating a bigger shadow at the bottom of the frame)

I have exactly the same problem with my longer lenses on my D50 which is one of the many reason I invested in an external flash.
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Old Jun 3, 2009, 2:05 PM   #6
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Welcome to the real world. Lens hood designers don't take the built in flash of any specific camera into account when designing the lens hoods. They are designed to minimize flare from external light sources near the field of view. Generall the shadow you're seeing occurrs only on very close subjects especially when using macro mode. The shadow is the result of both the length/diameter of the lens/hood combination at the focal length you're using and the height of the flash over lens axis. A petal hood won't help if it is the same length and diameter (equal effectiveness).

Two solutions:

1) Expensive - buy a hot shoe mounted external flash as it will place the flash higher than the built in flas.
2) Cheap - remove the lens hood when taking flash photos. Generally (there are exceptions) it won't improve flash photos anyway.

A. C.
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Old Jun 3, 2009, 3:44 PM   #7
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A.C. is right except that a shoe mounted flash doesn't have to be very expensive if you are willing to figure out how to use an old fashioned thyresistor unit with an adapter. If you get one that can be bounced you will be much happier with your flash pictures even neglecting the lens hood issue.

If you get the Sony flash unit that does everything but cook breakfast, it will be expensive.
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Old Jun 3, 2009, 3:48 PM   #8
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do any of you think that if the a200 flash popped up higher (like the a700, t1i) then it wouldn't have this problem?
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Old Jun 3, 2009, 5:40 PM   #9
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I agree you should get another flash for better quality work.

Until then you can solve your problem by simply removing the lens hood. The lens hood is there to keep light from striking the lens from the side and causing glare. That is not likely to happen with you pop up flash unless you have a strong light source elsewhere.
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Old Jun 3, 2009, 5:56 PM   #10
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Quote:
Originally Posted by BillDrew View Post
If you get the Sony flash unit that does everything but cook breakfast, it will be expensive.
Sony recently announced a less expensive dedicated flash. Of course, it's not as powerful as their more expensive models. It's available for pre-order now at sonystyle.com, and it looks like they'll probably start shipping within the next week from what their site indicates (estimate of June 8), so vendors should start getting them in soon, too.

HVL-F20AM Compact Flash for $129.99 at sonystyle.com

Here's what it looks like on a Sony A330 when raised. I don't know how much higher it would be compared to the built in flash. But, the light bounced back from a ceiling should help some with shadows.



It can be folded down when not in use, as shown on this photo of a Sony A230 with the new flash attached.

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