focusing issues

[nursemandalyn]

I'm just learning what I'm doing, pretty much just trying to shoot in different lighting situations, so I can work on my exposure, etc. Trying to practice on my 18 month old daughter is a bit of a challenge though, lol.

Anyways, I realized I'm having some trouble with getting a sharp focus. Obviously with an active toddler, I can't manual focus. But even on auto I'm having an issue at times. I realize the exposure is off in these. It was middle of the day, and I forgot to lower my ISO down from 800 I'm wondering if the focus issue can at all contributed to the lens I'm using, and focal length, or is it all me? I was shooting with a 70-300. I don't have the steadiest hands, which I'm trying to work on. Any suggestions, critique, anything appreciated. I'm here to learn.


This one wasn't so bad, but still not great


f4.5, 1/1600, ISO 800, focal length 176


This one to compare, I thought I was focusing on her face, but it didn't come out very sharp.



f4.5, 1/1250, ISO 800, focal length 70

[inkista]

Originally Posted by nursemandalyn

...I'm wondering if the focus issue can at all contributed to the lens I'm using, and focal length, or is it all me? I was shooting with a 70-300. I don't have the steadiest hands, which I'm trying to work on.

Ok, first issue about the steady hands. Are you holding your camera like this?



Or is your left hand on the top/side of the lens, and making it really really hard to hold everything steady? The main weight of your lens/camera combination should be resting on the palm of your left hand. With a telephoto lens like a 70-300, you can have your left hand under the lens barrel, vs. the base of the camera, but you really don't want to be relying on just your right hand on the side supporting all the weight.

Second issue: focal length.

Consumer 70-300 lenses (i.e., $300 or less) tend not to be at their sharpest at the ends of the focal length range, or aperture range. Stopping down from wide open can help make the lens perform a little better, as well as giving you more DoF so focus won't be so critical.

Third issue: shutter speed

The rule of thumb, assuming you are holding your camera correctly, and not using some form of stabilization, is that your shutter speed needs to be 1/focal_length or faster to eliminate camera shake blur from handholding. Some folks throw in the crop factor. This is probably not your problem, given how fast your shutter speeds were, but is something to keep an eye on, as it's related to

Fourth issue: iso
The higher your iso, the more noise you have, and the less sharp stuff looks. This may be playing a small role in the fuzziness of your photos.

Five issue: controlling your AF system.

Computers are dumb. They don't actually think; they just follow preset orders. When it comes to autofocusing, some systems are set up to simply focus on whatever's the closest. In your first image, your daughter's shoulder looks like it's in focus. I think the camera front-focused on her left shoulder in both shots.

Portraits tend to look sharpest when the subjects eyes are in focus. The technique you may want to learn here is to use the center autofocus point (if you have an entry level camera body, it's typically the most sensitive one) and place it on your subject's eye, half-press to set the focus, hold the press (to lock the focus), reframe, and then take the shot.

[nursemandalyn]

Originally Posted by inkista

Ok, first issue about the steady hands. Are you holding your camera like this?



Or is your left hand on the top/side of the lens, and making it really really hard to hold everything steady? The main weight of your lens/camera combination should be resting on the palm of your left hand. With a telephoto lens like a 70-300, you can have your left hand under the lens barrel, vs. the base of the camera, but you really don't want to be relying on just your right hand on the side supporting all the weight.

Second issue: focal length.

Consumer 70-300 lenses (i.e., $300 or less) tend not to be at their sharpest at the ends of the focal length range, or aperture range. Stopping down from wide open can help make the lens perform a little better, as well as giving you more DoF so focus won't be so critical.

Third issue: shutter speed

The rule of thumb, assuming you are holding your camera correctly, and not using some form of stabilization, is that your shutter speed needs to be 1/focal_length or faster to eliminate camera shake blur from handholding. Some folks throw in the crop factor. This is probably not your problem, given how fast your shutter speeds were, but is something to keep an eye on, as it's related to

Fourth issue: iso
The higher your iso, the more noise you have, and the less sharp stuff looks. This may be playing a small role in the fuzziness of your photos.

Five issue: controlling your AF system.

Computers are dumb. They don't actually think; they just follow preset orders. When it comes to autofocusing, some systems are set up to simply focus on whatever's the closest. In your first image, your daughter's shoulder looks like it's in focus. I think the camera front-focused on her left shoulder in both shots.

Portraits tend to look sharpest when the subjects eyes are in focus. The technique you may want to learn here is to use the center autofocus point (if you have an entry level camera body, it's typically the most sensitive one) and place it on your subject's eye, half-press to set the focus, hold the press (to lock the focus), reframe, and then take the shot.

Thanks for your help. Normally I hold the camera the way that picture is. Right now, I have a broken wrist with my left arm in a cast, so I am sure that is affecting things. It's a bit harder to hold the camera steady .Although I was having this same problem before the cast. I took a picture with someone else's lens on my camera tonight, then took the same picture with my lens on the same settings. Hers is a Cannon lens, mine is a Quantaray on my cannon camera. I noticed a difference in sharpness, hers was definetely better than mine. I also realized my lens does not have image stabilization built in. So I'm sure all that is affecting it as well.

I will work on the tips you gave me, especially focusing on the eyes the way you suggested. I have noticed my lens does tend to focus on whatever is in front. I've been working on focusing on different areas to see how it works. Thank you so much for your detailed answer. It gives me a place to start and work from!

[kencaleno]

1.Set your Focus icons - detach lens, (so you are adjusting focus on focus point, not image) - adjust dioptre (next to viewfinder) so focus points are sharply in focus. (easier against a white, or light background) Re-attach lens

2. All modern cameras have Auto-focusing, which works very well, but there are times when you need to focus manually. For auto-focus to work properly it requires a certain amount of contrast, if the contrast isn’t adequate you will need to focus manually.[ NOTE: In your camera’s viewfinder, depending on camera-flagship models generally have many focusing spots, and lesser, entry-level dslr’s will have around 5 focusing spots. With lens wide open, any of these spots can be used for selecting where to auto focus-But, depending on maximum aperture of lens in use, the ones you are able to use get fewer. Top-of-the-line cameras will only have the centre spot usable at F8,and entry level cameras at F5.6, and less than that, even these single spots aren’t reliable.]
Actually it is more beneficial to set auto focus by the centre spot, then re-compose, rather than use the peripheral spots-The reason being that only the centre spot has vertical and horizontal pixel rows. This means that if you use the peripheral spots (top and bottom spots have horizontal pixels only and right and left spots have vertical pixels only) To focus, you must have a part of the scene crossing a line of pixels at 90 degrees, and the centre spot gives you a more accurate reading ,having both vertical and horizontal pixels) It will pay you to manually focus most of the time, for full control of the situation. For instance, if an unnoticed reed encroaches into your image, when your are shooting a swan at the lake, for instance, your lens may auto-focus on that reed, rendering your actual subject out of focus.



There are times, you will find when auto focus will fail to respond favourably-although auto focus is able to lock on to any subject, there are certain conditions where it may not be possible ,even when the indicator lights are on, and the shutter releases/

Subjects with low contrast

Subjects in excessively bright light

Two subjects at differing distances

Subjects with repetitive patterns

High speed subjects at close range

To ensure you are in focus, there, in the viewfinder, is the electronic rangefinder icon, that comes on when you are in focus. NOTE: Each lens has its “sweet-spot”, that is when the aperture and zoom length combine to give optimum sharpness- 18-55 mm zooms usually have this “sweet-spot” at the 35mm distance setting and 2 stops back from wide open. On a 70-300mm zoom the “sweet-spot” would be around 185-200mm aperture 2 stops back from widest.
Auto focus is good for situations where you cannot focus fast enough, manually, such as sports and wildlife photography.
Depth of field appears to be the most confusing of focus elements. Depth of field is a range of acceptable sharpness in an image, from near to far. Three factors control Depth of field: Aperture: The wider the aperture, the shallower the depth of field. Focal length of lens, The longer the focal length of the lens, the shallower the depth of field will be. and Distance from subject, Landscape images have great depth of field, whereas Macro (extreme close-up) images have very shallow depth of field. Concerning depth of field, Hyperfocal distance seems to be even more confusing -Hyperfocal distance is a point of focus where at a certain aperture, Half the distance from that point to Infinity, (which starts at 30 feet, and extends to as far as you are able to see)) will be in acceptable focus, The best lenses for hyperfocal distance are 80mm or wider ; telephoto lenses, because of their relative short depth of field, are rarely used. (Prime lenses have a scale on them for this, zooms do not) Using a 18mm setting on your zoom lens at f11, Hyperfocal distance is somewhere around 5 feet (1500mm), so depth of field at this aperture would be from 2 1/2 feet ( 750mm) to infinity, when focused at 5 feet. A good guideline for great depth of field for landscapes is to use the bottom focusing marker in your DSLR viewfinder, (either horizontal, or vertical) as this will focus 1/3 of the way into the distance, (It is on the lower third imaginary “Rule of Thirds” gridline!) ,as is usually recommended. [ NOTE: Unless your camera has depth of field preview, looking through the viewfinder all will not be in focus, because your lens, until you press the shutter button to make the shot, will be open at full aperture.]

To avoid camera-shake, always use a sturdy tripod. When using lenses equipped with VR/IS (vibration reduction-Nikon/Image stabilisation-Canon), on a tripod you will need to turn off the anti-shake, or lens will still try to counteract vibration that isn‘t there,, and cause unwanted shake. If, for some reason you cannot use a tripod, use your self as one-
Feet at “T-Stance”, left hand supporting camera, elbow against ribs
Camera pressed against nose and brow
Right hand also elbow against ribs, index finger on shutter button
Set shooting mode to continuous, and “Roll” index finger on shutter button - First couple of shots will probably be blurred, but somewhere between 3-4 and 5 you should have a shake-free shot of the scene. ( When using zoom lenses longer than 200mm-I usually set ISO to 400, when hand-holding)

“Trap” focusing: (Nikon Only)

This is a neat way to use auto focus especially for fast sports/wildlife action.

Custom (pencil) menu:
Autofocus set to AF-S
AF area mode set to single
AE-L/AF-L set to AF ON

Compose your shot and set the focus by aiming the centre focus icon at a definite target at the precise distance you want, (Say a tree branch where a bird is about to land, or on second base where the baseball player's foot will land) and pressing the "AE-L/AF-L" button near the viewfinder. This will focus the lens, let go of AE-L/AF-L button. Turn away,
press and hold the shutter button all the way down. Point camera at pre-focused point when subject approaches, and your camera will take the shot (or shots, if you are in continuous shooting mode.)

Much faster than Human reflexes.

[BigVinnie]

REALLY helps to state what camera you are using.

Here is an article from Canon on back button focusing. It is a technique I use.

[nursemandalyn]

Originally Posted by BigVinnie

REALLY helps to state what camera you are using.

Here is an article from Canon on back button focusing. It is a technique I use.

Thank you for the link. I'll be sure to include my camera from now on. It's a Cannon 300D, so it's an older model.

[BigVinnie]

I don't think that camera will do back button focusing.

BUT, doing a half press on the shutter will lock focus. My wife calls it "bobble head focusing". Essentially you set the camera to a single focus point. Set the point on the eyes, half press the shutter, recompose and push the rest of the way down.

I tend to photograph people with the aperture wide open. Focus is critical. The camera will pick a shoulder, ear, hand or whatever it gets happy about. You have to tell it who's the boss

[nursemandalyn]

Originally Posted by BigVinnie

I don't think that camera will do back button focusing.

BUT, doing a half press on the shutter will lock focus. My wife calls it "bobble head focusing". Essentially you set the camera to a single focus point. Set the point on the eyes, half press the shutter, recompose and push the rest of the way down.

I tend to photograph people with the aperture wide open. Focus is critical. The camera will pick a shoulder, ear, hand or whatever it gets happy about. You have to tell it who's the boss

Thanks! I am hoping to upgrade cameras around Christmas time, so I will hold onto the link so I can use it when I do. I think that is a major problem I'm having is focusing on the wrong part. I just need to practice on some adults so I can work on focusing on the eyes. A energetic tornado of a toddler isn't the best subject to eye focus, lol