sumo Loc: Houston suburb

On our recent trip to Costa Rica and I took over 4000 photos…. about 70% of those are slightly out of focus.
Im using a Nikon D600 with a 50-500mm Sigma lens, set on a center single focus point..

I deleted these pictures of the sand on one of the beaches there… then retrieved them for this question

If I had set a center single focus point…..shouldn't the center of this picture be in clearly in focus? to me it looks like the bottom half of the picture out of focus….
do you think this is my problem with slightly out of focus photos?

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CLP1943 Loc: Wisconsin

Most likely your aperture was quite large giving you a narrow depth of field.

oldtigger Loc: Roanoke Virginia-USA

looks as though the camera is focusing just a bit further out than desired.

Blenheim Orange Loc: Michigan

I like the images. You have a shallow depth of field, but it is a nice effect. If you want more sand in sharper focus you need to use a narrower aperture, or get the camera sensor parallel to the beach (point it straight down.)

You could spend an hour practicing on a wall, for example, using different apertures and pointing the camera at different angles to the wall and the check the results and you will get an idea of what is going on with depth of field.

Mike

Blenheim Orange Loc: Michigan

I guess autofocus could be off. I never use it and so always forget that it could possibly be the problem.

Mike

LoneRangeFinder Loc: Left field

What focal length were these taken at? Is this a new problem?

sumo Loc: Houston suburb

taken at 420mm f13 , using BB focus

not new the focus problem always seems to be an issue for me.....never quite good enough when I compare my picts with others...

oldtigger Loc: Roanoke Virginia-USA

who tuned the sigma lens to your camera for you?

Rongnongno Loc: FL

"IF"????

The center are in focus, the dof is narrow so due the distribution (more in front than in the back) the front automatically becomes blurred faster.

There is no problem with your lens, just with your* choice of aperture.

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* Or the camera's

LoneRangeFinder Loc: Left field

Agree…kinda
EXIF shows
Sigma 50-500mm F4.5-6.3 DG OS HSM
Shot at 420 mm
Exposure: Manual exposure, 1/2,000 sec, f/13, ISO 720
Flash: Off, Did not fire
Focus: AF-C, at 2.5m, with a depth of field of about 2.3cm, centered on the focus point
AF Area Mode: Single Area

It's the aperture selected but it's also how the lens/camera is set to auto focus: The focus info is the key here: You were "spot focused" with a narrow DOF; the lens focused in the "single area" of the image area. Select a different AF for number of focus points.

So, it was the combination of the focal length, the aperture AND the AF option selected.

WessoJPEG Loc: Cincinnati, Ohio

Expensive cameras don't take good pictures if you don't know how too use it.

lamiaceae Loc: San Luis Obispo County, CA

A couple issues factors:

Tripod?

Lens tangent to subject and Sensor plane?

howlynn Loc: pueblo west, co

With the focal distance being 2.5m (approx 98") this appears to be very close to the minimal focal distance of this lens. Could this cause the bottom portion of this photo to out-of-focus ?.

CO

LenTip.com does excellent lens reviews and tests lenses in twelve different categories. I downloaded the image resolution chart for the Sigma 50-500mm. You can see that the image resolution drops with longer focal lengths. Also f/8 seems to be the sharpest aperture for this lens.

I see that the camera was in AF-C mode. I would put it in AF-S mode for those shots.

Image resolution Sigma 50-500mm

johneccles Loc: Leyland UK

[quote=sumo]On our recent trip to Costa Rica and I took over 4000 photos…. about 70% of those are slightly out of focus.
Im using a Nikon D600 with a 50-500mm Sigma lens, set on a center single focus point..

I deleted these pictures of the sand on one of the beaches there… then retrieved them for this question

If I had set a center single focus point…..shouldn't the center of this picture be in clearly in focus? to me it looks like the bottom half of the picture out of focus….
do you think this is my problem with slightly out of focus photos?[/quote

Lens: Sigma 50-500mm F4.5-6.3 DG OS HSM
Shot at 420 mm
Exposure: Manual exposure, 1/2,000 sec, f/13, ISO 720
Flash: Off, Did not fire
Focus: AF-C, at 2.7m, with a depth of field of about 2.6cm, centered on the focus point
AF Area Mode: Single Area

Several setting have contributed to your focus problem:

It was shot at 420 mm so your depth of field was only 2.6mm
I would use a much smaller focal length say 50mm with an aperture of f/8 and an ISO of 100.
This would increase your depth of field so all of the frame would be in focus, and as there was no moving subjects you could shoot at a much lower shutter speed.