Focus Frustration! - DPChallenge Forums

Canon EF-S 18-135mm f/3.5-5.6 IS

10/31/2004 09:29:07 AM · #1

It seems like I can never get crisp focus, what is the best action settings? i seen on another thread where someone said that the best aperature is 2.8, mine goes to 2.5 is that better. and my shutter speed goes to 2000, is this where it should be? i am getting so frustrated, i get really good pics outside and with natural light, but with this new camera 2/10 of them are in focus. any hints or tips....please!

SteveJ

Canon EOS-7D

10/31/2004 09:32:00 AM · #2

Originally posted by riotspyne:

Are you giving it time to focus properly. Centre weighted focussing will often focus behind subject if subject is offset.

Nikon AF Nikkor 50mm f/1.8

10/31/2004 09:39:02 AM · #3

well i usually use auto focus and it beeps when it is in focus, but then if the subject moves even slightly ...then forget it. that is why i was wondering about like sports shots, moving subjects in focus

Message edited by author 2004-10-31 14:39:20.

pcody

Canon PowerShot G6

10/31/2004 09:45:51 AM · #4

A lot of cameras have focus lock, just keep the shutter release button depressed 1/2 down after you focus on your subject. You should be able to move the camera around to compose the shot with the same focus point as long as the release was kept depressed. I know you knew this, just a reminder to mself really.

Canon EF-S 17-85mm f/4-5.6 IS USM

10/31/2004 09:46:28 AM · #5

For sports there's a technique called pre-focus. You focus on the spot where you think you're subject will be. Keeping the shutter button half pressed wait for your subject to show on that spot then press the button completely.

Another technique is panning. With prosumer cameras this can be a bit tricky especially if focusing is slow. However, once you have focus follow your subject with the camera while pressing the shutter button.

kadac00

Canon EOS-20D

10/31/2004 10:00:49 AM · #6

Two things to consider with regards to f/2.8 - on some lens the lowest number is not the sharpest. You might want to try some test shots on a static subject at f/2.8 and f/5.6 to see if you notice a difference in sharpness.

Second, I don't know how far away from the subject you are, but f/2.8 gives you a fairly shallow depth-of-field relative to other settings where the f# is larger. This effect will be more noticable if you are closer to the subject. If you have enough light to keep your shutter speed up, you might set your f# higher. That way if the subject move a little from the focus point it will be a little more forgiving.

10/31/2004 10:07:08 AM · #7

thanks guys i took some advice here and my pictures are comeing out better, at least outside. i was taking pics of the kids in the yard playing

Message edited by author 2004-10-31 15:07:29.

10/31/2004 10:25:03 AM · #8

Examine the EXIF data of your shots. Look at aperture and shutter speed.

For action shots and photographing moving subjects, Shutter Speed Priority (or Manual) would be a good mode. If you want sharp focus (as opposed to a blur), the shutter speed should be appropiately high. A heron, for instance, flies sharp at a minimum of about 1/640 sec. If you were to shoot him at, say, at 1/100 sec, you'd likely get a strong blur of the wings and a lousy focus on the head and eye, if you were panning.

To get some reliably sharp shots out of your camera, I suggest you choose S and, on a bright day, shoot a whole role on 1/1000 sec. Then, adjust your speed for slower action as you go along. Once you have a good feel of what this does, start experimenting with A, so you may see what it's like to have shallow or deep focus. Keep checking your EXIF against your shots.

Sooner or later you'll be shooting on M altogether, coz not only will shutter speed and aperture make better sense to you, but also their relationship.

Nikon AF Nikkor 50mm f/1.8D

10/31/2004 05:10:39 PM · #9

my boy was out playing in the water today, yes on halloween, i hate it that it is not cold here..i tried the things suggested and this is what i came out with. can it be even better? this is about as good as i got

deapee

Kodak V803

10/31/2004 05:17:35 PM · #10

Looks like you tied him up by his right arm and blasted him with a fire hose just for the sake of photography! I'm very proud...lol j/k

That's a nice shot. Freezes the image fairly well and the brightness and sharpness look just great. The shutter speed could stand to be a higher still to fully stop the water and his left hand a bit.

Nikon AF Nikkor 50mm f/1.8

10/31/2004 05:36:44 PM · #11

trust me i didnt have to hold him, he loved it!

pcody

Canon PowerShot G6

10/31/2004 06:03:58 PM · #12

I like the movement in the picture. It captures the rush and joy of the activity!

11/02/2004 01:25:24 PM · #13

once again had the opportunity for a good shot and failed

new question...does the ISO play a part in the speed of the shutter
should my ISO be set higher, i have it on its lowest setting

NO FOCUS!

Message edited by author 2004-11-02 18:25:42.

11/02/2004 01:30:06 PM · #14

> riotspyne

Can you post the EXIF for this shot?

11/02/2004 01:39:38 PM · #15

File Name
quack.jpg
Camera Model Name
DSC-F828
Shooting Date/Time
11/2/2004 3:44:31 PM
Tv( Shutter Speed )
1/100
Av( Aperture Value )
4.0
Exposure Compensation
0
ISO Speed
64
Image Size
440x392
Flash
Off
Color Space
sRGB
File Size
32KB
Owner's Name

now my stupidity is on display but whatever it takes

11/02/2004 01:44:48 PM · #16

It looks like focus locked on the tail rather than the head. A shutter speed of 1/100 should have been ok. How close were you? You might have been too close for focus to lock on the head. Your manual should tell you what the minimum focusing distance is at both the wide and tele ends of the zoom. I may be way off base on this.

There are three components that are used by the camera meter to determine proper exposure, ISO, shutter speed and aperature. ISO is the setting for how sensitive to light the sensor will be, the higher the ISO the more sensitive therefore the other components need to be adjusted to compensate. By increasing the ISO you can increase the shutter speed. Just remember that the higher the ISO the more likely there will be noise in the image.

Message edited by author 2004-11-02 18:48:55.

11/02/2004 01:53:48 PM · #17

i think my distance was okay, i thought the reason the bill was out of focus was because it was moving.

11/02/2004 01:56:10 PM · #18

Originally posted by riotspyne:

i think my distance was okay, i thought the reason the bill was out of focus was because it was moving.

You're probably right so a faster shutter speed is required to stop the action. Probably one full stop. This means you need to open up the aperture by one full stop or increase the ISO by one full stop to keep the exposure correct.

11/02/2004 02:02:23 PM · #19

It's strange, the focal length isn't listed.

I've pulled your image off the page and sharpened it in Photoshop via USM. It is, in fact, sharp along the left side of the goose and, a lil harder to see coz of all the white, in the ruffles just below the beak.

The beak itself shows motion blur, which is understandable given a shutter speed of 1/100 sec. If your intent was to freeze motion, your shutter speed should be higher, 1/640 - 1/1000 of a sec.

To see all this, clearly, in the image in front of you, you need to sharpen it, at least a little.
You also seem to be very close to the subject. Not knowing what your actual focal length was (whether or not you zoomed in or just approached closely), I can't say if you exceeded your minimum focal distance.

Message edited by author 2004-11-02 19:16:21.

11/02/2004 02:19:20 PM · #20

Originally posted by cpanaioti:

Originally posted by riotspyne:
i think my distance was okay, i thought the reason the bill was out of focus was because it was moving.

You're probably right so a faster shutter speed is required to stop the action. Probably one full stop. This means you need to open up the aperture by one full stop or increase the ISO by one full stop to keep the exposure correct.

To keep things very, very simple and to isolate the symptom, I'd suggest instead that he shoot at Shutter Speed priority (let the cam pick the aperture value) for the length of this exercise.

11/02/2004 02:24:56 PM · #21

Originally posted by zeuszen:

The beak itself shows motion blur, which is understandable given a shutter speed of 1/100 sec. If your intent was to freeze motion, your shutter speed should be higher, 1/640 - 1/1000 of a sec.

i seen the 1/100 and i thought that seemed funny so i checked my camera and i had it on 2000, am i missing something?

11/02/2004 02:27:30 PM · #22

In shutter priority mode the camera will try to accomodate but will adjust if a proper exposure cannot be obtained with the selection.

Experimentation will give you insight into what the camera is acutally doing. As zeus said keep it simple until you understand what the camera is doing.

Message edited by author 2004-11-02 19:54:29.