Sharp Photos - Where am I going wrong?

Help! Where am I going wrong when it comes to getting sharp photos?

I saw the fox below in the field at the back of my place today and took a few shots. However, every single one came out similar to the one below - lacking in sharpness with the subject out of focus!

I had the camera set up on a sturdy tripod with a cable release attached to avoid camera shake. I chose an apeture of f5.6 and ensured that the seleceted focus point was over the fox's face in an attempt to make sure that the eyes were sharp. Despite this, I ended up with the usual disappointing results??

I was using a Canon 20D with a Sigma 100-300mm f4 lens and a Sigma 1.4 converter attached.

Any help would be much appreciated!

Thanks,

Were you at the extreme end of your telephoto? For instance, when I have my 80-320mm lens on, I find that anything above, say, 270mm tends to be very soft. A 300mm with converter at the long end could cause the same problem. Another thing is that lenses tend to be sharpest in the f8-f11 range.

Mike

Quote:

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Originally Posted by Didache

Were you at the extreme end of your telephoto? For instance, when I have my 80-320mm lens on, I find that anything above, say, 270mm tends to be very soft. A 300mm with converter at the long end could cause the same problem. Another thing is that lenses tend to be sharpest in the f8-f11 range.

Mike

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I have had success in the past with this same set up http://forums.photographyreview.com/...863#post137863 and this was again at the extreme end of the telephoto with the converter attached. These shots were also taken using f5.6 in aperture priority and turned out so much better!

Seems to be hit and miss but I can't quite work out where I went wrong with the fox shots??

Mark,

This seems an overcast day and I was wondering if you were using AF or manual. It could be that if its AF the system was having problems.

I noticed that the other shots were in bright sunlight can make a big difference to AF.

Roger

Can you confirm that you can get a sharp photo at all in a controlled environment?

Grab that rig and take a pictue right now. Use auto and manul focus and make sure you can even get a sharp photo.

The reason I say this is becuase I have an old Canon EF 100-300 lens that is broken. The results looks like the photo you posted. Nothing comes out sharp, always fuzzy.

the DOF looks on, it SHOULD be sharp. If you notice the grass in front and behind the fox is even more out of focus, so the depth of field is right and it should be sharp there. I would get the lens checked out. Even at the end of the zoom range, it shouldn't be that bad, that's a decent lens. the 1.4x decreases sharpness, but not this much. definitely...have it checked out.

I think three words sum up the problem. Selected focus point. Try manually focussing at the end of the lenses range in similar light (same f-stop) and see if the results are similiar.

What was the shutter speed. Could be too slow of a shutter speed, ie camera movement? You need about 1/200 of a second or faster to get sharp photos with telephotos.

no its not motion blur. motion blur and OOF blur look much different. general rule of thumb is the inverse of your focal length. I'm telling you, its the lens. the DOF makes sense. it SHOULD be in focus but its not/

That doesn't look right at all...

I am leaning towards agreeing with Brent, but I think we'd need to see a larger version to be sure. Either that or a crop of the area around the fox maybe?

To me, I think the focus is off. If you look at the blades just to the left of where the fox is sitting, it looks softer there than the blades about a foot or two behind that. Keep in mind that the fox's face is about a foot in front of his butt, and it compounds the problem.

The other important point is your aperture. If you're shooting at f/5.6 with an f/4 + 1.4xTC combo, then you're shooting WIDE OPEN. Definitely not the way to shoot with a TC. With primes, I always stop down at least one full stop. With zooms even more. So with your rig, I would recommend shooting at no faster than f/9.5 or f/11. Experiment with your particular lens to find where the sweet spot is.

Thanks for the replies guys. I think you're right, I need to take a few controlled shots to confirm that it's human error on my part, as opposed to the lens being the problem!