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Re: [OM] (OM) OT Nature Photo Blog

Subject: Re: [OM] (OM) OT Nature Photo Blog
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Wed, 30 Jan 2013 11:27:17 -0500
You and Ken are correct.  I hadn't looked at the EXIF and didn't know it 
was a 17mm lens on full-frame with only 30 second exposure.  Looking up 
a reference on maximum exposure times to avoid star trails
<http://www.berndmargotte.com/technical/startrails_en.html>
shows a maximum exposure time of 24.3 seconds using a standard 35mm CoC 
of 0.030 mm and a rule of thumb max exposure time of 35.3 seconds.  This 
shot is right in the middle of the range.  Just wait 30 seconds and then 
fire the flash on manual before closing the shutter.  Much easier than 
PhotoShop.  :-)

Chuck Norcutt


On 1/30/2013 9:40 AM, Sawyer, Edward wrote:
>
> Um, no.  30 seconds with a 17mm lens will not blur to show star trails.
> Needs to be longer than that. Looks like a single shot to me.
>
>
>
> On 1/29/13 8:05 PM, "olympus-request@xxxxxxxxxxxxxxxxx"
> <olympus-request@xxxxxxxxxxxxxxxxx> wrote:
>
>> The rocks are
>> clearly lit by flash but I believe the sky exposure was so long as to
>> leave ghost images of the stationery rocks.  But not ghosts are seen.
>>
>> Conclusion.  Photoshop of two images.
>
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