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Focus Issue


marypar4

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I have been trying without much success to get a sharp picture from my D80. I have tried just about

everything..changing various settings..my latest attempt at roses is clearly NOT sharp. ANy advice would be

welcome. The Picture is located in my portfolio "Roses" I took this picture on a tripod..VR off..<div>00PvEX-51287584.thumb.jpg.46f0bf88f617a0865d8a2e93857018b2.jpg</div>

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At 200mm or so, you have pretty shallow depth of field. Unless your subject is literally blowing in the wind, you might want to take advantage of the fact that you're using a tripod, and go with a slower shutter speed so that you can stop the lens down to more like f/11.

 

Speaking of tripods... is it a nice solid one? You may also be introducing some camera movement just by touching it on the tripod as you take the shot. Do you have a remote release? If not, try the self timer on the camera, once you have things composed.

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According to its EXIF data, your photograph was exposed with the foll0wing settings:

 

# Exposure Time (1 / Shutter Speed) = 10/1250 second = 1/125 second = 0.008 second

 

# Lens F-Number/F-Stop = 53/10 = F5.3

 

# Exposure Program = aperture priority (3)

 

# ISO Speed Ratings = 100

 

# Focal Length = 2100/10 mm = 210 mm

 

Longer focal lengths decrease depth of field, which is the z-axis of the photograph that is in focus.

 

You can increase the depth of field using aperture priority, where you set a higher aperture and let the camera

determine the correct shutter speed for that aperture setting. Try taking a series of shots at f/6.3, f/8, f/11,

f/16, and so on, and compare the depth of field in each.

 

Another way to help insure maximum focus, and focus at the desired location in the photograph, is to use manual

focus point selection, and to use the C (continuous) focus mode. Even though the photograph is a still life, a

small breeze can move the object ever so slightly, and de-focus an object focus with S (single shot) focusing mode.

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I will try suggestions..and hope to get something acceptable. I looked at Matt's portfolio..and now I am really depressed..LOL. Sharp pictures are my goal. This appears to be almost as illusive for me as breaking 80. Thanks to both of you for advice.
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No Michael..it was a 70-300Vr which I have had some good success with..probably some dumb luck involved..but obviously this depth of field thing is more complex then I had realized..I just simply thought if you want to blur the background ..you open up the aperture..and you have a nice sharp picture with a blurred background just like Bryan Peterson explains in his book "Understanding exposure" Obviously there is more to this aperture thing! As you said..the depth of field in not sufficient to spread the narrow focus..across the distance of the picture.
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Take a 12" ruler and focus on the 6" mark. Take a picture. Is the 6" mark in focus? If not, where does the focus fall? Try all your lenses. Is the focus off on all of them? If so, contact Nikon for adjustment.

 

In a complex subject such as a rose blossom your camera may be focusing in an unexpected place. Try a simple subject to see if there's truly a problem.

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The problem with depth of field is that it's not a situation with absolute boundaries that expand with smaller stops, within which everything is sharp. There's really only one critically-focused spot, and everything in front and in back becomes progressively unsharp. The smaller the stop, the broader the range over which this happens. So in order to make a thicker subject appear in focus, it's inevitable that things in the background that you don't want in focus will become gradually sharper.
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Well, to make matters even more complicated, it's also a function of the focal length of the lens, the distance between the camera and the subject, and the distance between the subject and the background. All of these interact for an apparent depth of sharpness around the subject, and the apparent isolation from the background.

 

Mary: in your second attachment, you'll notice that it's not a matter of sharpness (since there ARE areas that are sharp). DoF, in this case. Try moving closer, and using the lens at a shorter focal length. The laws of physics dictate a deeper DoF when you do that.

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Another couple notes:

 

1) Be certain to turn VR OFF if you are using your VR lens on a tripod.

 

The motor in a VR or IS lens goes berzerk when placed on a tripod, its gyroscopes look for non-existent camera

shake and create blur because the camera isn't moving.

 

You can find information about this on Nikon's web site:

 

http://support.nikontech.com/cgi-bin/nikonusa.cfg/php/enduser/std_adp.php?p_faqid=7676&p_created=1067977631&p_sid=_SDX8e5j&p_accessibility=0&p_redirect=&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9NTIsNTImcF9wcm9kcz04MSZwX2NhdHM9MCZwX3B2PTEuODEmcF9jdj0mcF9zZWFyY2hfdHlwZT1hbnN3ZXJzLnNlYXJjaF9ubCZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXZy&p_li=&p_topview=1

 

2) The additional sharpness you may see in some photographs on the web can also be the result of sharpness added

during digital post processing, using one or more of many available techniques and algorithms.

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Jerry, what lens would you recommend to crisply capture an axe being ground? :-)

 

Mary: there's no reason you can't increase the depth of field you're getting, working with the lens you have. The

comments above really do point the way. If you find yourself wanting to specialize in ultra-detailed studies of certain

sized objects (flowers, for example) that will be printed on thirty-inch pieces of paper, then a specialized lens might

be appropriate. A $110 Nikon 50/1.8 could well be all of the "sharp" you need, depending on your shooting style. But

even a very expensive macro lens won't change the problem you encountered (which is just getting DoF right for your

situation and subject).

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Mary, Please note. Your getting suggestons now of getting a new lens. At least they're not telling you spend the $500 to $1,000 for the lens they problably use. They should have done that at the start. If I didn't throw my 2 cents in they'd have you running around in circles for days.
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Your photos looks plenty sharp to me. Before buying new lenses, I suggest you to play with the light source and exposure, besides that DoF increase. Sharpness, contrast and saturation increase considerably with good illumination and proper exposure.
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Summer,

 

Thanks, for clarifying that fact. Now I can't imagine what made me think Mary was discussing a Nikon 18-200mm.

 

Jerry,

 

Thats a pretty broad assumption on your part, Jerry. Not that I would say that the images in my gallery are "cool" but

almost all of them were shot with consumer lenses; Nikon 18-70mm, Nikon 18-200mm, Nikon 12-24mm, Sigma 70-210.

The exception is a few telephoto close up shots of the Halema'uma'u steam vent on the Island of Hawaii. I understand

the shortcomings of my consumer lenses and work around them by doing such things as bumping ISO when necessary

to to us a smaller f stop for better sharpness. I don't sell my work any more, but I wouldn't have a problem selling these

images if I wanted to. Amateurs using consumer equipment can produce amazing results with a little know how.

 

Still part of what you imply is correct. If I were to return to professional photography, I would use the best equipment

available.

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Robert, Thank you for your response. Those are very good photos and done well with the consumer lens you were using. I did not intend to insult or belittle your ability. I actually never looked at your gallery until now.

 

I was actually thinking of Matt's Photo Gallery. I really doubt he use the 18-55mm on those photos.

But it general, I bet if you thought about it, most of these pro's here do use the expensive glass for their gallery photos.

 

It would be nice if the photos were notated with the lens used.

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Even with a macro lens (e.g. a Micro-Nikkor) you still have to contend with the finite depth of field, subject movement (wind), and accurate focusing. And there are so many of these available second hand that you really don't need to pay all that much for one. Look for a 105mm Ai-S Micro-Nikkor at KEH if you want one.
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Jerry,

 

I think you may be new to photo.net so you may not be aware that some while ago Elliot Bernstein put some comparison photographs up on this site. Some were taken with a D40 and the 18-55 and others with a D200 and the 17-55 f/2.8 (there was a D80 in there too). People were invited to identify which were which. I don't think anyone got it right. The photographs were considerably larger than most of those discussed above.

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00LZOI

 

When you look at the photographs Elliot references you need to click on "larger."

 

Any differences between the 18-70, 18-55 and more expensive lenses certainly won't be visible at the very modest sizes we are talking about here. In fact if you look at photozone.de you can see some objective measurements. You'll see that the differences are usually small and yes the 18-55 actually shows up pretty well, but then those of us that actually use it knew that already.

 

This is confirmed by well regraded writers such as Thom Hogan, see for example:

 

http://www.bythom.com/rationallenses.htm

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