 - Mary Beth Aiello  Contact Mary Beth Aiello Mary Beth Aiello's Gallery |
Depth of Field - Where to Focus?
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- Mary Beth Aiello Contact Mary Beth Aiello Mary Beth Aiello's Gallery |
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- Mary Beth Aiello Contact Mary Beth Aiello Mary Beth Aiello's Gallery |
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- Mary Beth Aiello Contact Mary Beth Aiello Mary Beth Aiello's Gallery |
I'm having trouble rotating the photo. Sorry.
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Pete H |
Mary Beth, This is a great example of finding and using hyperfocal distance. Unless you have Depth of Field markings on your lens, you will have to do this by trial and error. There are tables you can find on the net that will also help you find the hyperfocal distance. It is dependent on (focal length) of your lens AND the (f/stop) chosen. The first thing I notice is your focus point is probably too close or near if you prefer. Try focusing about 1/3rd into the frame. Next, you shot this at 55mm. As focal length increases, getting a deep depth of field becomes increasingly difficult. If you shoot this again at 18mm, you will see a deep DOF is far easier to accomplish. All the best, Pete
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- Mary Beth Aiello Contact Mary Beth Aiello Mary Beth Aiello's Gallery |
Here's the rotated shot. MB
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- Carlton Ward Contact Carlton Ward Carlton Ward's Gallery |
Hi Mary Beth, What Pete said. With my 17-40mm lens shooting at f/22 (its max DOF), I sometimes find it focuses a little softer than at f/18. I have a couple of longer lenses that go to f/36 & f/40 when I am positioned back enough to use them.
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Alan N. Marcus |
Hi Mary Beth, Your problem relates to a misunderstanding regarding the width and origin of the zone we call depth-of-field. Many falsely believe depth-of-field mainly impacts the background. Others falsely believe the span of depth of field is split down the middle equally. However, the span or zone that will be acceptably sharp, extends 1/3 back toward the camera, and 2/3 away from the camera as measured from the point focused upon. We can put this knowledge to good use. In the case of a field of flowers we view the vista and guess-ti-mate. the center point, then we choose a point inward (back towards the camera) to focus upon. Likely the depth-of-field zone is 5 feet - 20 feet. The center of this span is about 12 feet. Knowing the 1/3 - 2/3 rule of thumb as described above, we focus upon a flower at about the 8 foot mark. This plan maximizes depth-of-field. Hope this helps, Alan Marcus (marginal technical gobbledygook)
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Raymond H. Kemp |
A point of clarification on Pete’s post. A 55mm lens on a crop factor camera will always produce a focal length of 55mm. A crop factor camera does not increase the focal length of a lens. It produces a comparative focal length, which is usually compared to 35mm. So if a 55mm lens on a crop factor camera of 1.5 will produce an image equivalent to an 82mm lens on a 35mm camera but with an actual focal length of a 55mm lens. The focal length of a lens is controlled by the optical design of the lens and not the format size of the sensor. Ray
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Pete H |
Thanks Ray, Very true indeed. I should have ammended it to read "your (actual) focal length was about 82mm (in comparison to a 35mm full frame).
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R K Stephenson |
Hmmmm....or perhaps, "while your focal length is 55mm, your field of view is equivalent to 82mm on a full-frame camera". Cheers, RK
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- Mary Beth Aiello Contact Mary Beth Aiello Mary Beth Aiello's Gallery |
Thanks, all.
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Bob Cammarata |
So when do we get to see Mary Beth's photo rotated? (...my neck's getting sore.:) Hyperfocal distance will vary with a given aperture setting and lens focal length and even how far away from your subject you are shooting. Apparent focus from foreground to background requires a small aperture setting and focusing approx. 1/3 into the frame. (...as others have suggested.) Since focus points are easy to select manually in a controlled setting, it's often wise to bracket critical focus.
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- Mary Beth Aiello Contact Mary Beth Aiello Mary Beth Aiello's Gallery |
I can't GET this rotated. Any suggestions are welcome. Thanks for straining your necks to help me out.
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Ken Henry |
The following is my opinion. It dosen't matter what focal length your lens is, don't get confused about weather it's APS size or full frame 35mm. That 1/3 & 2/3's rule doesn't rule me. I go for 1/2 & 1/2 and up. The foreground is not that important. Who looks at the foreground anyway? Subconsciously we are looking at the background and it's sharp detail. It's an automatic reaction. It's what sells. If I want those mountain peaks in the background dead sharp then I focus on them. From f16 to f32 will still give me very decent fore and middle ground sharp focus. This is why you should experiment, to learn how your lenses perform at various focal points and and f-stops. So my first test will be to start at f8 and focus 1/3 out, next focus 1/2 distance out, then 2/3 out, final focus, where? then repeat at f11, f16, f22, f32, etc.
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- Mary Beth Aiello Contact Mary Beth Aiello Mary Beth Aiello's Gallery |
Thanks Ken. For some reason, getting sharp focus is really a challenge for me. Thanks all for your help.
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Alan N. Marcus |
Depth-of-field is that span of distance between the nearest and the farthest objects in the vista that appear acceptably sharp. Focal length does matter! The span of depth-of-field increases greatly if a short focal length lens is used. Conversely, the span of depth-of-field compresses when a long focal length lens is mounted. In other words lens focal length strongly affects depth-of-field. Subject distance has a powerful influence! The span of depth-of-field is greatly increased if the near and far positions are more distant. If the subject is close, the span of depth-of-filed is greatly diminished. The span of depth-of-field is not split 50 – 50, it extends further to the rear 1/3 – 2/3. Check depth-of-field tables and see for yourself. As to sensor size: The same lens mounted on a full frame and a compact will perform the same as to depth-of-field. However, this is true only if the conditions of use are equal. Consider that sensor size is likely to have a profound effect. We naturally compose via the view as seen on the LCD screen or in the viewfinder. The compact digital with its smaller sensor presents a cropped view (crop factor). The typical compact has a crop factor of about 1.5 or stated another way the viewfinder shows a cropped image that is 66% reduced (as compared to a full frame camera). Thus when composing we have a natural tendency to step back to nicely compose the space around our principle subject. This act increases subject to camera distance causing the depth-of-field span to widen due to the increased subject to camera distance. Now Mr. Ken Henry is right on target in some respects. Likely most pictures are taken without the photographer giving much consideration to depth-of-field. This is as it should be. Photography is mostly art and science must take a back seat. Our prize winners are often due to luck and not design. He is right, one should experiment and learn. My though; why plow a field that has already been plowed, why not learn a thing or two from an older plow boy. Best regards, Alan Marcus
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- Mary Beth Aiello Contact Mary Beth Aiello Mary Beth Aiello's Gallery |
Thank, Alan.
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Ken Henry |
Thank you Alan for your kind words. True as Alan says, every focal length lens has it's own depth of field vision. Now that I have seen your photo Mary Beth It looks like you have focused directly on those front flowers. Which explains why the far flowers are out of focus. Alan, wouldn't you say her photo is more of a close-up shot and therefore it becomes more difficult to obtain greater depth of field? I've done very little close-ups and the depth of field tends to be much shallower versus landscapes shots. I like Bob C.'s answer about bracketing your shots at various focus points in the scene. Also try this Mary Beth. Besides going after one photo with the most depth of field, focus only on one or group of selective flowers and open your lens up to f2.8 which will cause all other flowers to be out of focus. This will add more interesting photos to your stock. Mary Beth, You might want to try this. Our instructor told us to take 36 different photos of an egg. We thought he was nuts. We could only use one 50mm lens and no flash. Well, I didn't win, but I did get the best "recognition" for using moon light and yes the moon was in one of the shots right behind the egg. Also this was done on film so we had no clue how these egg shots were going to turn out. So we really had to to read light. So I think maybe you should have taken 36 photos of your flowers without moving your tripod fron sunsrise to sunset. And I'll allow you to use lens filters, reflectors, diffusers and flash. Yeah, a hundred photos may be enough. Remember, you're taking the picture, we can only give the clues. Regards Ken
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- Mary Beth Aiello Contact Mary Beth Aiello Mary Beth Aiello's Gallery |
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