Recommendations please

[sandra_henderson]

I've been reading some reports written by Bob Atkins on focusing and

sharpness of photographs. Well, I've had some issues with "my

camera" but am starting to think that maybe it's me and my choice of

distance vs. subject vs. aperture and was wondering if you guys

could recommend a good book that explains what my distance should be

from the subject when I want to use such and such aperture or is

this something I just have to learn on my own?

[beauh44]

Hi Sandra, Ansel Adams - "The Camera" is very good. They have it at Amazon for $14.28 new. Good luck!

[rob_murray]

What camera? Film or digital? what issues?

These sound like photography 101 questions.

Go to your local bookstore for a basic book.

Apertures like F1.8 throw the background out of focus (portraits)

Apertures like F11 makes things sharp thru most of the pic (landscapes).In between them F5.6/F8 is where most lenses are the

sharpest. If you have not gotten aperture figured out, you might

have questions about shutter speeds too.

[ian riches]

There are no hard and fast rules as to what to use and when. It is often either forced on you by circumstances (e.g. light levels), or a subjective artistic judgement.<p>

For the basics, read:<p>

 

<a href="http://www.photo.net/learn/making-photographs/exposure">http://www.photo.net/learn/making-photographs/exposure</a>

 

In short, the characteristics of various apertures are as follows:<p>

<b>Large</b> (e.g. f/1.4 - 4ish)<p>

<ul>

<li> Allow faster shutter speeds

<li> Have shallow depth of field (typically a small range of distances from the camera will be in sharp focus)

<li> Typically non-optimal lens performance. This is especially the case for lower-cost lenses, which typically get notably softer at their maximum apertures

</ul>

<b>Medium</b> (e.g. f/4 - 11 ish)<p>

<ul>

<li> Force slower shutter speeds than the larger apertures (all other things being equal)

<li> Have more depth of field

<li> Typically optimal lens performance. This is especially the case for lower-cost lenses, which often get noticably sharper in the f/8 to f/11 range.

</ul>

<b>Small</b> (e.g. f/11 and smaller)<p>

<ul>

<li> Force even slower shutter speeds (again, all other things being equal)

<li> Have even more depth of field (typically a wide range of distances from the camera will be in sharp focus)

<li> Typically sub-optimal lens performance. Diffraction effects (a law of physics, and thus unavoidable) mean that lens sharpness begins tailing off as the aperture gets smaller.

</ul>

<p>

You can see that there is no one answer. Shooting a soccer match with a handheld telephoto lens on an overcast day? You will need your lens pretty much wide open (a large aperture, small numeric value, e.g. f/2.8) to get a fast enough shutter speed to get a good shot. Shooting a landscape with a tripod-mounted wide anfle lens? You may well decide on a small aperture (say f/16) to get good depth of field, ensuring that the strategically-placed foreground bush is in focus as well as the trees on the horizon. Yes, f/8 may have given you slightly better sharpness, but then you couldn't have both the bush and horizon in focus.

[digitmstr]

The first recs. I would make:

 

1) set the AF on a button OTHER than the shutter. This will make focus much more precise and indipendent of metering. Once you try it, you'll never go back. I forget the CF number to change the AF button...maybe 14(?) but, if you look in the manual you'll find it quickly.

 

2) even at f/2.8 a subject should be in focus. I take portraits at anywhere between f/1.4 and f/2.8 all the time.

 

3) If you are shooting a couple you'll have to make sure that you cover enough DOF to have at least both their faces in equal focus. That is accomplished both in posing the people correctly and setting an appropriate f stop.

 

4) proper ligthing also make the image look sharper by increasing the contrast. That doesn't mean there should be harsh light & shadows. It means a good *quality* and quantity of light is paramount to the look of the image. Even if such light is more dramatic (i.e. a spotlight, one side only, window, etc...).

 

5) isolate the subject from the background either by way of lighting or DOF (or both). Distracting backgrounds make the image look soft even if it's in perfect focus.

[digitmstr]

forgot post-processing:

 

for *best* results shoot RAW and use a program like C1 PRO or similar to "sharpen" the image as it is developed

 

Use USM judiciously after loading the imaged in Photoshop for final editing. Only sharpen at the END of the editing process as the USM should be relative ONLY to the desired output (i.e. print size, web, etc...). Save one edite image WITHOUT any USM applied as well.

[picturesque]

Since you have a 20D, do the tests yourself. Use two targets, place them in various positions/distances from each other, select different focal lengths and shoot with different apertures. You will soon see for yourself what apertures for what subject matter will work for you at specific focal lengths. Doing the research on theory is good, but the book you read may not, for instance take into account the smaller sensor in your camera and it's effect on DOF. And there are no magic formulas or charts that will tell you what aperture to use for the subject matter--only general guidelines.

[yakim_peled1]

Experiment in a variety of apertures, distances and focal lengths and see what you like.

 

Happy shooting,

Yakim.

[michael_ziegler2]

Check out this web site. Very instructive for auto focus

 

 

 

http://www.cps.canon-europe.com/kb/overview.jsp?categoryId=1000