Focusing difficulties with Sigma 100-300mm f4 EX

I got this lens last week and today was the first time I was able to use it.
Went to the local park and took lots of photos. Only 1-2 shots came out good, the rest seems to be out of focus.

Manual AF point selected in the middle.

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Sounds like your first long lens. Pratice and you will get better. Did you observe the handhold rule for min. shutter speed?

In the goose pictures it looks like the focus point is on the feathers at the rear of the goose as they are sharp, the head and neck look to be outside of the DOF as it will be very small/narrow at I assume 300mm @ f4. Check the following link for DOF information for almost any focal length/aperture combo. Oh, the dog picture looks like camera shake to me, take it for what it's worth.

www.dofmaster.com/dofj​s.html

Yes, this is my first telephoto zoom lens.
So it's all about playing with the aperture to get the right DOF.

What about the dog? It's totally wack!

I took some motorsport photos with the kit lens and produced far better shots than this.

might help if you put down some exif info

right click, properties, summary

They both look like results from slow shutter speeds

The dog problem seems to be shake, the shutter speed was a bit too slow @ 1/100th, try it again at ~1/320th, faster if possible, if it means upping your ISO a few stops because your aperture is wide open then so be it, a slightly noisy image is recoverable a blurry one is a little more tricky to salvage

With practice you should be able to refine your technique to shoot at 1/100th, keep at it

Shutter Speed is you problem.

With the geese,the problem is that the shutter speed was not suffieceint to freeze motion. It is not due to shake in these pictures, else the grass would have been blurred.

In the last two images, camera shake would have been the main issue and explain why the whole picture suffered from blur. Again shutter speed is likely the issue.

When hand holding, you shoud shoot at the reciprical of the lens. So for 300mm, shoot minimium at 1/300th. If using a tripod then this can be relaxed but you still need to consider subject movement.

As Col said, up the ISO if needed. 400 ISO should not introduce too much noise.

hope this helps

Ian

I went out today and tried again
Still not getting the shots I want.

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This may be depth of field on the last one, how far away are the geese? At 20 feet the total depth of field on the last goose shot is 0.88 feet at 180mm F 6.4 (per http://www.dofmaster.c​om/dofjs.html)

It may help to do some testing with a more controlled subject/conditions and lens on a tripod, with high ISO and high shutter speeds just to eliminate variables. Using DPP (or is it Zoom Browser) - one of them will let you see the focus points on the shot which can also be helpful.

I'm not sure practice will allow consistent good results at 1/100 with a heavy 300mm lens on a crop camera - effectively 480mm on 35mm/full frame.

In the last picture posted as you quite rightly point out, the stump is sharp.
the reason the rest of the picture is not so sharp is due to "depth of field" (DOF) issues.
DOf is affected by a number of facts
1. a smaller aperture reduces the depth of field (i bet you were shooting at F4), increasing the aperture will increase depth of field
2. Increasing the focal length of a lens reduces DOF ( lower DOF at 300mm than at 100mm)
3. Distance from the subject, being closer to the subject will reduce DOF.

Try experimenting with the lens, if you can then get a tripod or at least a monopod as sturdy as you can afford. Then set up on a static subject and vary the parameters noted above and learn what affects the image you produce.

a couple of more points;
When taking pictures of live subjects, focus on the eyes. This will give the perception that the picture is sharper because we look to the eye first in an image. This means that if part of the subject is out of focus then this will be less noticed.
A shallow depth of field can be used to good affect to distance the subject from distracting fore ground or background elements (ie wire on an animal enclosure at the zoo or distracting subject matter in the background).
the Autofocus sytem will focus on a point that has most contrast, this may not be the point that you want to be in-focus. Change camera parameters to use centre focus point then use focus lock to allow you to recompose the image.
I suggest that you read further on depth of field, or look at other peoples wildlife picture to note how they have used DOF.

hope this helps

Ian

As has already been said, watch your shutter speed.

In the 1st two shots, they are in focus, have a look at their legs.
In the last two shots, they're just blurred from having too slow of a shutter speed.

"a smaller aperture reduces the depth of field (i bet you were shooting at F4), increasing the aperture will increase depth of field"

exact opposite is true, unless you're talking about f-stop values.

xft.y is right.

This is what I meant to say, obviously it was too early in the morning for normal brain operation Thank you for the correction.

I felt that an understanding of telephoto principle was more helpful than an off the cuff answer such as "its a duff lens - send it back"