No, not necessary. Sunny 16 would be 1/100 sec at f/16, 1/200 at f/11,
1/400 at f/8 and 1/800 at f/5.6. Even the E-420 goes up to 1/4000 so
there's a lot of room left.
Well, unless you want to talk about that old bugaboo called fill flash.
At the 1/180 to 1/250 range available on the E-things for flash sync.
you need to shoot at from f/10 - f/12 just to contain the ambient light
at sunny 16. The 5D slips in there at f/11 at its 1/200 sync speed but
fortunately can drop down to ISO 50 to open up a bit wider.
Moral of the story... No matter what the camera, when it comes to
flash, get out of the noon-day sun.
Dr. Flash
Jez Cunningham wrote:
> So if we really should keep to f/5.6 or f/8 we should all be out buying ND
> filters for those bright days...
>
> On Fri, Nov 21, 2008 at 2:55 PM, Chuck Norcutt <
> chucknorcutt@xxxxxxxxxxxxxxxx> wrote:
>
>> In a really long and very technical article from Luminous Landscape
>> titled "Do Sensors "Outresolve" Lenses?" the cut-to-the-chase answer in
>> in many cases is... yes. The reason is the diffraction limits of lenses
>> at various apertures. You can read the entire, nerdy article here
>> <http://www.luminous-landscape.com/tutorials/resolution.shtml> or just
>> skip to the conclusions which can be found in table 3 near the end.
>>
>> The table lists different sized sensors from four thirds to medium
>> format and, under each format, three different wave lengths of light
>> ranging from red to blue with green-yellow light in the center column at
>> 0.55 microns wave length. Down the left side of the table are various
>> apertures. The larger the aperture the less the diffraction (and
>> ignoring other pesky optical problems) the greater the resolving power.
>> The data in the table are the maximum number of megapixels that can be
>> resolved with that sized sensor, wave length and aperture... and this is
>> key... using a perfect, diffraction limited lens. Since none of us own
>> any of those the implication is that our real world results will be
>> somewhat less than the theoretical maximum.
>>
>> Since green-yellow at 0.55 microns is where we see best that's a good
>> color to choose. The implications then are as follows.
>>
>> If, like me, you own a 12.7 MP Canon 5D you can scan down the table for
>> 35mm sized sensors under 0.55 microns and see that the maximum
>> theoretical resolution at f/11 is 16 MP. Since that's for a perfect
>> lens, in all probability my real world lenses won't do that well but
>> maybe I'm still OK at 12.7 MP at f/11. But going to f/16 is a no-no for
>> best resolution since the theoretical limit drops to 7 MP at f/16.
>>
>> If you own a camera with an APS-C size sensor (most of the Canon, Nikon,
>> Pentax, Minolta/Sony DSLR market) at f/11 the theoretical limit is 7 MP.
>> You have to limit the aperture to f/8 in order to reach a theoretical
>> limit of 13 MP which will maybe cover those 10-12 PM sensors with real
>> world lenses. Even a Canon 20D's 8 MP sensor isn't fully resolved at f/11.
>>
>> And finally we have the four thirds sensor where the pixels are getting
>> even smaller. The Olympus E-1 at 5 MP is OK up to f/8 but for newer
>> cameras like the 10 MP E-3 you should be limiting lens aperture to f/5.6
>> for maximum resolution... assuming your lens performs well at f/5.6.
>>
>> Remember the Olympus exec's question about using OM lenses on the newer
>> four thirds cameras: "Why you want to use old lens on new camera?" If
>> he had explained about resolution limits and that many 35mm lenses
>> perform best at f/8 or f/11 we, perhaps, might have understood better.
>>
>> Of course, resolution is hardly the only characteristic of a good lens
>> but when you've got that camera mounted on a tripod and shooting some
>> landscape or architectural subject for maximum detail remember this
>> advice on how to set (limit) the aperture.
>>
>> Chuck Norcutt
>> --
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