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Focus, Depth of Field and Sharpness, 3 different things
#1

I've read post here where the photographer is asking about how to improve their photography by improving their focus. I think that in some of the post I've read focus is the issue but in many, sharpness is the issue. When you look at an image and your subject isn't crisp, the first thing that comes to mind is focus but that may not be the problem.

SHARPNESS
Lack of sharpness is usually attributed to camera or subject movement during the exposure. Many of my students (most new photographers actually) go through a learning curve where they learn what can be hand held and what can't. Long lenses and low light are the enemies, shutter speed and ASA settings are your friend when you have to hand hold, tripod or a monopod is your best bet when you can use them. For moving subjects, learn and practice the techniques of panning with your subject or prefocusing at a spot on the ground that You know your subject will pass over.

Modern DSLR cameras have awesome light sensitivity and allow you to shoot in low light levels (at a high ASA) without picking up a lot of noise in the image. Try bumping up your ASA and shooting at a higher shutter speed to counteract camera shake. See if that helps if you're having an issue.

The other factor affecting image sharpness is equipment (lens and sensor) quality. There's a reason pros use expensive glass, the image quality is much better. (among other things) I recommend to my students that are on budgets, that they purchase a cheaper camera body and spend most of their money on lenses. As far as the sensor, the general rule of thumb is bigger is better. a small sensor can be bumped up mathematically to give an impressive MP size but the image quality just isn't there.

FOCUS
Two parts to the focus discussion, Focus and Depth of Field. Focus is a mandatory part of the image and DOF is a design element (with an exception for moving objects). Your subject or the part of your subject you want to emphasize must be tack sharp. In a portrait it's the eyes, in a head a shoulders shot you might want all the subject in focus. In these same examples DOF is used in conjunction with focus to control how your final shot will look. A shallow depth of field will enhance your subject by making it pop. A deep depth of field will keep everything in focus which may or may not be a good thing.

Focus is critical and the ability to do it well is somewhat controlled by the equipment you use. A nice bright viewfinder on your camera is necessary to help you see what's going on and in the case of an auto focus, what your camera is actually focusing on. A dark viewfinder or trying to use an lcd viewfinder on the back of a camera to determine sharp focus is a recipe for disaster.

DEPTH OF FIELD
The 3 main variables in depth of field:
Focal length of the lens (The longer the FL the shallower the DOF)
Distance to the subject (The closer you are the shallower the DOF)
Aperture (The smaller the aperture, the shallower the DOF)

A 4th variable is sensor size. Smaller sensor cameras tend to have a greater DOF (but less sharpness).

As I mentioned earlier, DOF should generally be used as a design element and not as a focus tool. What I'm trying to say is that you shouldn't be trying to shoot using setting that provide a large DOF with the hope that your subject will be in focus. Focus first and then control the DOF to give yourself the shot you want. Use the concept of pre-visualization. [undefined=undefined]See the shot in your head and use the camera as the tool to make it happen.[/undefined]

There's a lot more that goes on in the discussion of the subjects that's beyond the scope of of a simple forum post but these are the basics... I hope this helps!

Kevin Whitcomb
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#2

Kevin,

Thank you so much for posting this valuable information! It is greatly appreciated!

Barbara - Life is what you make of it!
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#3

(Dec 7, 2012, 10:53)photokev Wrote:  DEPTH OF FIELD

Aperture (The smaller the aperture, the shallower the DOF)


Kevin Whitcomb


Sorry kev but - The larger the aperture the smaller the DOF

Lumix LX5.
Canon 350 D.+ 18-55 Kit lens + Tamron 70-300 macro. + Canon 50mm f1.8 + Manfrotto tripod, in bag.
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#4

Good catch! Thanks!
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#5

It shows I'm reading the posts. Big Grin

Lumix LX5.
Canon 350 D.+ 18-55 Kit lens + Tamron 70-300 macro. + Canon 50mm f1.8 + Manfrotto tripod, in bag.
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#6

Yup, I definitely should have worded it differently!
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#7

I always wondered about something, and I hope I'm not too off-topic, but how can I get more intense colors? I see pictures from higher-end cameras whose colors look a lot more intense than my D3100 produces. I fiddled around with the settings the best I could, but without some post-processing my photos never look as intense. Any advice?
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#8

You could try filters, (i.e. polarising or coloured) but I believe most (not all) highly saturated photo's are produced with post processing. I have a friend who uses 'lightroom' and the difference between his and mine are quite considerable. I use as little pp as possible.

Lumix LX5.
Canon 350 D.+ 18-55 Kit lens + Tamron 70-300 macro. + Canon 50mm f1.8 + Manfrotto tripod, in bag.
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#9

So mine is not broken after all! I have a friend that shoots with a D90 and his photos are always so impressive compared to mine!
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#10

kNox, try this.... Go into your camera settings and just bump the saturation. Your N90 will give you more saturated colors right from the camera:

Menu-> Shooting Menu-> Set Picture Control-> Standard (or any other)-> Saturation



Kevin
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#11

Thanks Kevin, that's great!

My D90-owning friend did tell me to go to that menu and I had selected "Vivid", but I didn't know you could edit saturation as well. This is *exactly* what I was going for, thanks!

But I'm starting to have some second thoughts - is this standard or would you rather have it on default and bump the saturation in post-processing?
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#12

"is this standard or would you rather have it on default and bump the saturation in post-processing?"

I'm not a good person to ask about that, I shoot everything RAW... With that said, I'd shoot everything standard and edit whatever needs it in PP.
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#13

Can you show us some of your shots? Love seeing peoples work!
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#14

Well, I have some of my favorite photos up on http://500px.com/andreim Smile
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#15

Great information thanks. Can you explain how DOF works between you and the subject. I have tried to take shots of, lets say a house fifty feet away in a wheat field, I would like the wheat between myself and the house in focus and sharp. I don't really care about whats behind the house, its usually just sky. How do I get the house in focus and everything in front of it in focus too? I tried this many times and have had mixed success. What happens is, the house and most of the foreground is in focus but the area closest to the camera is not as sharp as I would like. Any help would be much appreciated.
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#16

(Dec 7, 2012, 10:53)photokev Wrote:  I've read post here where the photographer is asking about how to improve their photography by improving their focus. I think that in some of the post I've read focus is the issue but in many, sharpness is the issue. When you look at an image and your subject isn't crisp, the first thing that comes to mind is focus but that may not be the problem.

Modern DSLR cameras have awesome light sensitivity and allow you to shoot in low light levels (at a high ASA) without picking up a lot of noise in the image. Try bumping up your ASA and shooting at a higher shutter speed to counteract camera shake. See if that helps if you're having an issue.

FOCUS
Two parts to the focus discussion, Focus and Depth of Field. Focus is a mandatory part of the image and DOF is a design element (with an exception for moving objects). Your subject or the part of your subject you want to emphasize must be tack sharp. In a portrait it's the eyes, in a head a shoulders shot you might want all the subject in focus. In these same examples DOF is used in conjunction with focus to control how your final shot will look. A shallow depth of field will enhance your subject by making it pop. A deep depth of field will keep everything in focus which may or may not be a good thing.

Focus is critical and the ability to do it well is somewhat controlled by the equipment you use. A nice bright viewfinder on your camera is necessary to help you see what's going on and in the case of an auto focus, what your camera is actually focusing on. A dark viewfinder or trying to use an lcd viewfinder on the back of a camera to determine sharp focus is a recipe for disaster.

DEPTH OF FIELD
The 3 main variables in depth of field:
Focal length of the lens (The longer the FL the shallower the DOF)
Distance to the subject (The closer you are the shallower the DOF)
Aperture (The smaller the aperture, the shallower the DOF)

A 4th variable is sensor size. Smaller sensor cameras tend to have a greater DOF (but less sharpness).

As I mentioned earlier, DOF should generally be used as a design element and not as a focus tool. What I'm trying to say is that you shouldn't be trying to shoot using setting that provide a large DOF with the hope that your subject will be in focus. Focus first and then control the DOF to give yourself the shot you want. Use the concept of pre-visualization. [undefined=undefined]See the shot in your head and use the camera as the tool to make it happen.[/undefined]

There's a lot more that goes on in the discussion of the subjects that's beyond the scope of of a simple forum post but these are the basics... I hope this helps!

Kevin Whitcomb
Hi Kevin
I noticed the initials ASA in this article. That has been completely replaced by ISO.
Here is a link to the history:
http://www.ehow.com/about_6736352_differ...-iso_.html
... On aperture. "Aperture (The smaller the aperture, the shallower the DOF)"
You mean the smaller NUMBER of the aperture (f2 instead of f16). The f16 is a tiny opening with great depth of field.

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#17

Hi, I'm new to the forum so please forgive me if this doesn't post correctly. When you speak of the sensor size can you explain what you are referring to? I am confused as to how that pays into DOF? Thank You!!!!
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#18

(Mar 6, 2014, 19:12)dianebaughn Wrote:  Hi, I'm new to the forum so please forgive me if this doesn't post correctly. When you speak of the sensor size can you explain what you are referring to? I am confused as to how that pays into DOF? Thank You!!!!

One of the differences between full-frame and cropped sensors is that full-frame gives a shallower depth of field. The full-frame sensor is bigger than a cropped sensor.
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