What causes blurrieness

[wrxflyer]

P.S. Never assume because you had a fast shutter speed and the lens was stopped down the image can't be blurry. All kinds of things can make an image blurry (or appear blurry) regardless of the shutter speed.

This is a qoute from another topic on JP, made by screener Paul (PMN), what makes me wondering.

As I had in the last few weeks quite a few blurry photos rejected, while they were taken at f/8 and shutterspeed of 1/1000 sec.
All were taken in good daylight conditions.
How is it possible with that combination to get such an extreme blurry photo.
(I am at work now, but I will post one of this pics for example if nou need one, tonight).

Is there any possible reason fot that?

regards

Freek

[PMN]

The main causes of blurry images apart from shutter speed/shallow DoF are probably poor or inaccurate focussing (things like having the wrong focus point selected so the camera focusses somewhere other than where you actually want it to) and bad processing. As explained in another thread, poor sharpening technique can make images appear blurry, not nailing the focus can make them blurry (and this can include lens faults like an element being somehow knocked out of alignment making accurate focussing impossible. In these cases the lens generally needs sending back to the manufacturer for recalibration). Heat haze can, mist/fog can (or at least they can make things appear quite soft), an overall lack of contrast can sometimes give images a slightly soft/blurry appearance because the sharpening has nothing to really work on. Overuse of noise reduction can certainly give a very soft/slightly blurry appearance.

There are probably more but they're the basic ones that immediately spring to mind. I'll add more if I think of any!

Paul

[wrxflyer]

So, I tried to find a few good examples, but that's very hard, if you search for good examples

Here are 2 blurry-looking pics, all taken at f/8 and with 1/800 shutterspeed.



This one is blurry all over. It looks like camera-shake, but it's not only this photo, but every single shot of this sequence!

And then this one:


To me, it looks like the front-site of the 737 is sharp enough, but the tailsection seems to be blurry; a situation that I have on many pictures from this very same position.

Is there a good explanation for that, or am I joking and is this a sharp and uploadable picture?

Freek

[sst001]

I don't upload photos to this site in particular (the other one normally) but I think I have a few ideas for you:

1. Was this a fairly large crop of the original image?
2. Motion blur/camera shake
3. Soft lens
4. Focus point on the wrong place

Both images are also noisy/grainy. If you want to eliminate focus problems, then focus manually and see how you go.

Looking at the 737, it seems that the focus point of the camera might have been on the nose of the plane, and not nearer the center, and depth of field blur might be responsible for the tail being soft.