Understanding my Focusing problems: Single focus point (Page 4): Quite a usable way to have put it. Up-leveled, actionable; detailed but concise; illustrates how to analyze and reason;...

forjava Loc: Half Moon Bay, CA

Quite a usable way to have put it.
Up-leveled, actionable; detailed but concise; illustrates how to analyze and reason; quantitative.
Thanks, as I am reading these posts to learn.

jackpi wrote:

You problem has nothing to do with depth of field. Your problem is shutter speed. Your depth of field is 1.9m; from .9m in front of your focus point to 1.0m behind it. Since your sister is in sharp focus and you obviously didn't focus behind her (because nothing the background was in focus) the problem was shutter speed. Bump your shutter speed up two stops faster and your ISO two stops higher.

jimmya Loc: Phoenix

catalint wrote:

Hi fellow hogs,

For a while I have had this challenge regarding focusing correctly. This is not a matter of "how-to", but rather "What Am I doing wrong?". Yes I've been googling, and watched this and that, but I can't get answers from that. So I hope a good eye here can see what's wrong.

Case is like this. Dont remember exactly when I did, but like 2 years ago, I started using single focus point. Also my camera is mostly on M-mode. Camera is on AF-S most of the time. Sometimes I switch to AF-C when lot's of motion. Ofte I need to move the focus point a little to the left , right, up or down, depending. Having one single object as subject, I have no problems, but I am not happy with pictures where I have like two three persons in the picture. One persons will be focused, the other one is slightly out of focus. For me it looks like single point focusing has a very small radius. Let say you have 3 persons in the frame, you point in the middle, focus and shoot. While the middle will be in focus and sharp, it gets less sharp further from the center. I know AF-S should be used with dead stationary objects, I read it somewhere. Does this mean one should switch to AF-C as soon as you have a little movement ? Like my little niece in the picture below. She is actually in movement since my sister is swinging her. but it wasn't fast.

So how do you focus, correctly for the whole frame with single AF point?

Below is a picture to show you what I mean. My sister and one of my nieces, taken yesterday. I was like 10m away from them, and took this picture at full zoom from my 24-120mm Nikon F4.5. My sister is looking good and sharp (could have been better also in my opinion), while my niece is a little blurred. From the exif data I see I should have probably raised up the shutter speed a little more, and maybe I would have had both as sharp? Or is it cause my camera was back focusing on my sister? I can't determine if this it's clearly from low shutter speed or wrong focusing system.

What settings would you fellow hogs have used in this kind of situation ? I know lot's of you also swear to single focusing point, so I hope to hear if you encountered this problem. I do not think there is something wrong with the equipment, it has to be ME. I need to improve.

Hi fellow hogs, br br For a while I have had thi... (show quote)

It takes plenty of light, as in your example shot, to get the entire frame in focus. I only use single point because I've found that in a group of people say, the camera will choose where to focus and it may not be the point I want. Single point allows me to force the camera to focus where I want it. In low light you're going to find a short DOF... bright a longer DOF but that's not always true either. Best of luck.

catalint Loc: oslo

forjava wrote:

Quite a usable way to have put it.
Up-leveled, actionable; detailed but concise; illustrates how to analyze and reason; quantitative.
Thanks, as I am reading these posts to learn.

That's cool Forjava :) . I too often read threads where I can learn from. I find it a very good resource. Your opinion is as mine also. I am sure that more shutter speed would have worked here. But also it gave me a clue about what I need to look more into. Must admit , I skipped many pages and section about DOF before. Now I think I'll go back to them.

charlespkeith

Single point or multi-point, whether in single or continuous mode is not your issue. I have seen from a number of posts, technical responses and recommendations for apps to determine depth of field. These are useful, but mostly in a studio setting. I shoot birds in the air in single and multi-point, continuous focus mode. Your issue is predominately a depth of field issue. At 10 m, f4.5 provides a nice depth of field for one person. But the child is some distance in front of the woman and is actually moving out of the forward edge of the depth of field. Remember that a depth of field is split: 1/3 is in front of and 2/3 is in back of the target. You targeted the woman as the focus point and even her shoe, about 2 ft. behind her face, is sharp. If you had targeted the child, then the woman's face would most likely have been in focus. I would recommend my starting set-up: Aperture mode (allows you to rapidly control depth of field), f-11, ISO 400 (as a starting point), and speed will automatically be fairly high, at least 200+. Try doing some testing with f-11 vs. f-5 at 10 m on an object on a fence (shoot at about a 45 degree angle to the fence line) and you will be able to see the shift in DOF in the fence (near vs. far). Depth of field is your paint brush for great photos, allowing you to acquire that soft bokeh effect while having your main subject sharp as a tack. If you choose to use the above settings, in the following order (1) set your aperture (change it from f11 or to what you want to create the image you need), (2) set ISO to 400, (3) determine if resulting film speed is adequate for your needs (in your test photo, 160 should be about the minimum - especially if you are handholding the shot.). If film speed is not high enough, change ISO first. Remember, your aperture is controlling your depth of field and is the primary contributor to the photo you envision so change it only if you really want to change the DOF of your photo. Hope this helps

catalint Loc: oslo

charlespkeith wrote:

As I progress , I do see the flaws in pictures :) . definitely lot's of good information I received and grateful for all suggestions, which I will try.

Weddingguy Loc: British Columbia - Canada

catalint wrote:

Hi fellow hogs,

For a while I have had this challenge regarding focusing correctly. This is not a matter of "how-to", but rather "What Am I doing wrong?". Yes I've been googling, and watched this and that, but I can't get answers from that. So I hope a good eye here can see what's wrong.

Case is like this. Dont remember exactly when I did, but like 2 years ago, I started using single focus point. Also my camera is mostly on M-mode. Camera is on AF-S most of the time. Sometimes I switch to AF-C when lot's of motion. Ofte I need to move the focus point a little to the left , right, up or down, depending. Having one single object as subject, I have no problems, but I am not happy with pictures where I have like two three persons in the picture. One persons will be focused, the other one is slightly out of focus. For me it looks like single point focusing has a very small radius. Let say you have 3 persons in the frame, you point in the middle, focus and shoot. While the middle will be in focus and sharp, it gets less sharp further from the center. I know AF-S should be used with dead stationary objects, I read it somewhere. Does this mean one should switch to AF-C as soon as you have a little movement ? Like my little niece in the picture below. She is actually in movement since my sister is swinging her. but it wasn't fast.

So how do you focus, correctly for the whole frame with single AF point?

Below is a picture to show you what I mean. My sister and one of my nieces, taken yesterday. I was like 10m away from them, and took this picture at full zoom from my 24-120mm Nikon F4.5. My sister is looking good and sharp (could have been better also in my opinion), while my niece is a little blurred. From the exif data I see I should have probably raised up the shutter speed a little more, and maybe I would have had both as sharp? Or is it cause my camera was back focusing on my sister? I can't determine if this it's clearly from low shutter speed or wrong focusing system.

What settings would you fellow hogs have used in this kind of situation ? I know lot's of you also swear to single focusing point, so I hope to hear if you encountered this problem. I do not think there is something wrong with the equipment, it has to be ME. I need to improve.

Hi fellow hogs, br br For a while I have had thi... (show quote)

You shot your image at 1/200th sec @ F/7.1 and ISO 500.

SHARPENING

One requirement for all digital images is sharpening, usually done in-camera by point and shoot cameras. In DSLRs most often the sharpening is turned off so that sharpening is required in post processing where there is more control. If you shoot in RAW there is no in-camera sharpening.
The first image here clearly shows the need for some sharpening in post.(see Image 1)

CAMERA/SUBJECT MOVEMENT

With your lens set at 120mm, the 1/200th sec would be about right for a stationary subject, to prevent blur from camera movement . . . but as soon as you add subject movement to the mix, a faster shutter speed would be required. Image 2 here shows the subject movement on your niece, and no subject movement on your sister. If you look at the close up of the necklace (Image 3) you can clearly see the double image . . . subject movement.
MOST out of focus images taken today are in fact NOT out of focus, but suffer from camera/subject movement. This is especially true when shooting in Auto modes.

DEPTH OF FIELD (DOF)

Your problem here is definitely not one of DOF !

At F/7.1 with the focus point on your niece, your sister would also be in focus. (which in this case she is)
The apparent lack of sharpness in your sister in this image is caused by slight under exposure of the area and lack of contrast of light hitting the subject.
This is an ideal situation for fill flash set at about -1 stop compensation or a reflector.

THE ART OF FOCUSING AN AF LENS/CAMERA

Few understand how the auto focus system works and, as a result, use it incorrectly.

At 10 feet from a subject, it is impossible to focus on a subject's eye. The camera focus area is more than the size of the head at that distance so the camera will choose the brightest object with the most contrast on which to focus within that area. (See Image 4) This item could be 10 feet behind the subject.

If there are objects close to the area on which you wish to focus, that could draw the attention of the focusing pixels on the sensor, it is probably better to pick another spot on which to focus that is the same distance from the camera as the desired focal point. (see Image 5)

Every picture taken should be a three step process . . . focus by pushing the shutter release halfway and holding . . . recompose . . . fire by pushing the shutter release button the rest of the way.

Hope this helps . . .

Image 1

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Image 2
Image 2...

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Image 3
Image 3...

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Image 4
Image 4...

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Image 5
Image 5...

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catalint Loc: oslo

Weddingguy wrote:

You shot your image at 1/200th sec @ F/7.1 and ISO... (show quote)

Truly thank you very much for this awesome analysis. I really appreciate your in dept describing.

PhotoArtsLA Loc: Boynton Beach

Ah, the beauty of manual lenses and knowing how to manually focus, comes to mind. Focusing screens have suffered in the autofocus world, unfortunately. It would be nice to have the best of both worlds.

PhotoArtsLA Loc: Boynton Beach

Looking again at the photos provided, it looks a bit like motion blur, not so much bad focus. Given the lighting of the image, the camera had to add exposure to the foreground, either by lower shutter speed or wider aperture. Looks like shutter speed. In this situation you have to go for the moment the action becomes stationary. Of course, you could also light it with portable studio strobes, but this would cancel fun and spontaneity.

Meives Loc: FORT LAUDERDALE

I have your camera data. Shutter speed of 1/200 is not real fast for moving subject. ISO of 500 could be set at 1600 and given better aperture. F 7.1 could be f 11 and shutter 1/500. I am only guessing. I hope that you can see your camera settings on your computer, so you can try different ones. David