Why does this happen

Fritzvds · 08-18-2008, 03:31 AM

Hi all,

Here is a photo taken just this weekend of a southern right whale. We get a lot of these down here and on saturday alone saw about 8 of them. Anyway its a lousy shot on my behalf but what really bugs me is that it just isnt sharp. Taken in the middle of the day at full zoom (sigma 18-125 (yes I know its not the sharpest lens in the world)) but it just doesnt seem so focus on inffinity well. Is this a problem with the camera or lens or ME

???

The second shot of a seal was taken a few hours after and that worked fine (apparently we could get so close to it because it had been attacked by a shark and was injured

)
Any advice would be appreciated

Lowell Goudge · 08-18-2008, 03:42 AM

I guess the question is, what focusing mode are you in?

Depending on the mode and location of the actual focus point used, it mght be that it has focused on the foreground.

Can you post the settings. ISO, Shutter speed, F stop, focal length etc?

garth1948 · 08-18-2008, 03:52 AM

I got some very sharp images of porpoises from a boat recently.
K100D with Tamron 18-200 zoom (not especially high-rated lens).
Important thing is to set camera to spot metering, centre spot focus and Link AF spot to metering spot and if you have shake reduction, turn it on.
The blurred whale could be the result of it's movement.
How fast was your shutter?

Fritzvds · 08-18-2008, 04:30 AM

Thanls for the quick replies,

Image detail 180@f19, ISO 200, spot metering and spot focus shot wis a istDL.

It should have just focused on infinity because the whale was a fair distance away.

Cheers!

garth1948 · 08-18-2008, 04:45 AM

f19 should make everything from about 10 metres in front to infinity in focus.
Still reckon it's movement - long telephoto shots are not kind to small movement.

cupic · 08-18-2008, 06:09 AM

I have the same problem( gotta to cut back on the caffeine)

Doesnt need much to get it off focus

cheers

silent_eyes · 08-18-2008, 12:27 PM

Originally Posted by Fritzvds

Thanls for the quick replies,

Image detail 180@f19, ISO 200, spot metering and spot focus shot wis a istDL.

It should have just focused on infinity because the whale was a fair distance away.

Cheers!

hm, maybe you should do a little aparture test for your particular lens, f/19 might be the problem, since most lenses are not so great at smaller apartures, this especially goes for cheaper lenses. I had pentax 18-200 and everything under f/11 was so soft it was practicaly useless. I'd say sharpness drop was at least 20% per every f-stop. If not lens issue, then it's movement, but 1/180s should be about right

silent_eyes · 08-18-2008, 12:31 PM

Originally Posted by cupic

I have the same problem( gotta to cut back on the caffeine)

Doesnt need much to get it off focus

cheers

this is so true... when I received my 50-135 I was so annoyed with softness in closer focusing, I almoust cryed... then I was convinced it was F/F or B/B issue... so I did some testing, and it turned out, naturally, it was me

it's only few mm of DoF at 200mm and 2,8 and leaning+shaking hands - soft shots

Alfisti · 08-18-2008, 12:41 PM

f/19? There is the problem. F/8 or f/9 would be way sharper with more than enough DOF.

cygnet · 08-18-2008, 02:40 PM

I don't see a point of focus in the shot, so I would agree that it's camera movement. When at the far end of the zoom range, it doesn't take much. I would bump up the speed and down the aperture a bit, to see if a higher shutter speed helps the movement issue.

Alfisti · 08-18-2008, 02:42 PM

Originally Posted by cygnet

I don't see a point of focus in the shot, so I would agree that it's camera movement. When at the far end of the zoom range, it doesn't take much. I would bump up the speed and down the aperture a bit, to see if a higher shutter speed helps the movement issue.

It's diffraction, f/19 on APS i slike f/32 or less on a film camera. It's stopped down WAY too much.

Lowell Goudge · 08-18-2008, 04:05 PM

Originally Posted by Fritzvds

Thanls for the quick replies,

Image detail 180@f19, ISO 200, spot metering and spot focus shot wis a istDL.

It should have just focused on infinity because the whale was a fair distance away.

Cheers!

The problem might be up and down motion of the boat/camera affecting where you are focused at the instant the shutter is pressed.

Also, I have found that sometimes when focusing at a distant object near the horizon the camera has a hard time determining correct focus. This has been especially true shooting wildlife on the ground from a long distance

Marc Sabatella · 08-18-2008, 05:19 PM

Originally Posted by Fritzvds

Image detail 180@f19, ISO 200, spot metering and spot focus shot wis a istDL.

1/180 is *very* borderline for shooting at a focal length of 125mm. It's barely good enough when you're standing on solid ground, aiming directly at the subject, taking your time, and pressing the shutter very carefully. But you were on a moving boat (!), and I *know* that whale didn't sit there and poe for you long enough to carefully frame the shutter and gently press the shutter button with your arms properly braced against your body. Between the motion of the boat and your own motion in attempting to take a picture of an object that appeared only for a moment, you really didn't stand much of a chance of getting a sharp picture. Plus, as others have mention, the lens probably isn't verygood stopped down that far.

Had you been at f/8, you would have had a *much* better chance. As it is, you cannot blame the lens or the camera.

It should have just focused on infinity because the whale was a fair distance away.

From the looks of it, though, not even close to all the way to the horizon. That's probably a little less than infinity as far as the camera is concerned.

But more to the point, there is absolutely *no way* the camera could have been relied on to actually focus on the whale and not, for instance, on the horizon line, or on some wave in the foreground. Just because you and I know the whale was the point of interest, the camera is not that smart. Again, given how hurried the shot must have been, there is no real reason to expect the camera would focus well. In situations like this, it is probably better to pre-focus manually on the spot where you expect the whale to surface (assuming you can predict that).

Arpe · 08-18-2008, 06:08 PM

And your are standing in a moving boat or on land?

Fritzvds · 08-18-2008, 06:46 PM

Thanks again for all the suggestions!

I was acctually standing on the shore not a boat (you would be suprised how close these animals come in

) but I have cropped the image slightly so its easier to see the problem.

What is diffraction????

The only thing I could think that would maybe effecting it is the blue sky and blue water making it hard for the autofocus and it was a very bright glary day. Guess I learned my lesson and will have to go back to my manual focus days!