Open

by damned truths

submit your photo


Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

Take the 2-minute tour ×
Photography Stack Exchange is a question and answer site for professional, enthusiast and amateur photographers. It's 100% free, no registration required.

I usually use F/8 and a manual zoom at 1m. What configuration should I use to assure both objects that are far away(10m) and objects that are close(1-2m) are sharp

share|improve this question
1  
I would try a depth of field calculator such as the one here: dofmaster.com/dofjs.html It should be pretty easy to get a wide depth of field if you really do have a lens at 8mm. –  dpollitt Oct 4 '11 at 16:45
    
^^^ stick this as an answer, it's a nice simple solution. Also a great lens, love mine ;) –  Dreamager Oct 4 '11 at 17:16
4  
Note that the sharpest aperture and the aperture which provides the greatest depth of field are different. –  mattdm Oct 4 '11 at 21:17
    
what is the diffrece? I am interested in a photo where everything is sharp, nothing blurred –  Ryan Oct 6 '11 at 12:36

2 Answers 2

For achieving maximum sharpness, your aperture must be

  • stopped down about a stop or two from maximum aperture for optimal optical resolution;
  • stopped down enough so that depth of field would be sufficient;
  • open enough so that shutter time would not be long enough to introduce camera shake and motion of subject would not be visible;
  • open enough so that diffraction would not cause blurriness.

According to MTF50 chart in review by Photodo, the lens has best optical resolution from about f/4.5 to about f/6.3.

Since diffraction limit for Canon 550d is about f/6.8, so the smallest selectable aperture (for largest DOF) without diffraction is also f/6.3.

If using f/6.3 results in a shutter speed too low to avoid camera or subject motion, you might get a sharper result using a larger aperture or higher ISO. Or you might have to close down further if depth of field is insufficient. At f/6.3, hyperfocal distance is half a meter, so the distances you mentioned in your question are well within focus.

share|improve this answer

This is a case where I would strongly recommend performing an experiment for yourself. With 1/3 stops, the lens only supports 17 aperture settings. Set up a tripod, manually focus the lens, put the camera in Av mode, cover the viewfinder, use a remote release cable, and take a picture at each aperture; it should only take about 5 minutes. Then you can examine the results at whatever zoom level you want on your computer monitor.

You may well find that there's a range of apertures that have indistinguishable sharpness, which would give you more freedom in the future! You'll also learn a little bit more about the characteristics of your lens+camera combination, like any exposure shifts at different apertures.

Finally, if the results aren't sharp enough for you, you may want to add light or post-process the photos to increase the sharpness of your subjects.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.