sharpness problems
Discussion
Since getting my camera I'm finding that images taken of objects in the middle distance - by this I mean anything over about 20 metres away - are very often not remotely as sharp as I would hope for.
Take for instance this:
[pic]http://www.skinfull.co.uk/i/crop.jpg[/pic]
That's a 100% crop of an image taken a couple of weeks ago. It was taken at f8 1/640th and it's clearly not very sharp. It was on a tripod with a remote release, which frankly at that shutter speed shouldn't even be necessary. Focusing was AF-S and the focus point was central, which meant the cars should have been in focus.
Another example taken just now - notice the wheels rear wheel of the car - that's where I was focusing.
[pic]http://www.skinfull.co.uk/i/crop2.jpg[/pic]
Is it simply the case that I need to use a smaller aperture, or am I doing something wrong? Is it that it's hazy and I'm never going to get it as sharp as I want it to be?
My 18-70 lens has picked up a slight "wobble" in that the front part has a bit of play in it, though if this was the cause I would have thought it would effect all images - anything up close is just as sharp as I would want it to be.
Help please! This is really bothering me.
Take for instance this:
[pic]http://www.skinfull.co.uk/i/crop.jpg[/pic]
That's a 100% crop of an image taken a couple of weeks ago. It was taken at f8 1/640th and it's clearly not very sharp. It was on a tripod with a remote release, which frankly at that shutter speed shouldn't even be necessary. Focusing was AF-S and the focus point was central, which meant the cars should have been in focus.
Another example taken just now - notice the wheels rear wheel of the car - that's where I was focusing.
[pic]http://www.skinfull.co.uk/i/crop2.jpg[/pic]
Is it simply the case that I need to use a smaller aperture, or am I doing something wrong? Is it that it's hazy and I'm never going to get it as sharp as I want it to be?
My 18-70 lens has picked up a slight "wobble" in that the front part has a bit of play in it, though if this was the cause I would have thought it would effect all images - anything up close is just as sharp as I would want it to be.
Help please! This is really bothering me.
More info needed, I think 
(Which lens is this with?)
Are you shooting RAW or JPEG?
What level of sharpening in camera/post processing?
I agree that (unless you're using a 300mm lens) 1/640th should be adequate to stop wibble (or camera shake as it is known more technically). But how good a tripod? If you aren't locking the mirror up you could have an issue there?
As far as aperture is concerned, you should get focus at least somewhere in the shot.
And as for lenses wobbling, it's a Nikon "feature" I'm sure. My 20mm is pretty wobbly, the 85 less so and the 180 is built like a tank (and the 45mm hasn't got anything to wobble!) but I've heard this comment again and again about new and old Nikkors.
What lenses are you comparing?
*If you haven't done any in-camera/post processing sharpening, a little will do this.........
>> Edited by beano500 on Tuesday 7th June 12:43
(Which lens is this with?)
Are you shooting RAW or JPEG?
What level of sharpening in camera/post processing?
I agree that (unless you're using a 300mm lens) 1/640th should be adequate to stop wibble (or camera shake as it is known more technically). But how good a tripod? If you aren't locking the mirror up you could have an issue there?
As far as aperture is concerned, you should get focus at least somewhere in the shot.
And as for lenses wobbling, it's a Nikon "feature" I'm sure. My 20mm is pretty wobbly, the 85 less so and the 180 is built like a tank (and the 45mm hasn't got anything to wobble!) but I've heard this comment again and again about new and old Nikkors.
What lenses are you comparing?
*If you haven't done any in-camera/post processing sharpening, a little will do this.........
>> Edited by beano500 on Tuesday 7th June 12:43
How are you getting them off the camera? You may be suffering from the fact that digital images just aren't "sharp" straight off the camera.
The reason for this is that the Red Green and Blue sensors are separate, unlike film where they "stack" on top of each other. This means that the RGB all sample a slightly different part of the image and hence once you "zoom in close" (as you are doing by cropping the image) then it will look unsharp.
For stuff that is "closer" the effect can be less noticable as when you zoom in your brain works out that you are looking at something close and will hence "think" that it looks sharper - and indeed there is normally "more" changes that help give the impression that it's sharper.
Digital images off a camera really need to be "sharpened" if you are going to look at them close up. See www.wfu.edu/users/bennettk/sharp.html for more details.
Finally, of course atmospheric effects will have an effect on the image so an image "far away" will not be as sharp as "close up" if there is any haze or similar. Ditto the optics - remember that close up you may well have more light and so things will be "clearer" due to having more contrast in the image.
I've done an "unsharp mask" on both the images (30-40 amount, 4-7 radius, threshold around 10-30) so you can see the difference
Hope that helps!
J
The reason for this is that the Red Green and Blue sensors are separate, unlike film where they "stack" on top of each other. This means that the RGB all sample a slightly different part of the image and hence once you "zoom in close" (as you are doing by cropping the image) then it will look unsharp.
For stuff that is "closer" the effect can be less noticable as when you zoom in your brain works out that you are looking at something close and will hence "think" that it looks sharper - and indeed there is normally "more" changes that help give the impression that it's sharper.
Digital images off a camera really need to be "sharpened" if you are going to look at them close up. See www.wfu.edu/users/bennettk/sharp.html for more details.
Finally, of course atmospheric effects will have an effect on the image so an image "far away" will not be as sharp as "close up" if there is any haze or similar. Ditto the optics - remember that close up you may well have more light and so things will be "clearer" due to having more contrast in the image.
I've done an "unsharp mask" on both the images (30-40 amount, 4-7 radius, threshold around 10-30) so you can see the difference
Hope that helps!
J
Ben I've found this on my 18-70, exactly as you describe it. I haven't yet done a proper focus/sharpness test, but I think it only exhibits itself when opened up and at certain focusing distances relative to the focal length.
I get no sharpness problems with either of my two other lenses.
I don't think it's a focus problem, as there appears to be nothing in my photos that are focused! Also it's happened too often for me to consider camera shake as the cause.
Just a particular flaw in the lens under certain circumstances? In any case I find though not tack sharp, it's certainly usable.
I get no sharpness problems with either of my two other lenses.
I don't think it's a focus problem, as there appears to be nothing in my photos that are focused! Also it's happened too often for me to consider camera shake as the cause.
Just a particular flaw in the lens under certain circumstances? In any case I find though not tack sharp, it's certainly usable.
They look OK to me. As others have said, some sharpening is always necessary, either in-camera or afterwards.
I think it's a tendency to demand perfection from digital cameras - how many times have we zoomed into a photo until the pixels show, then felt disappointed when we can see the pixels? We're just suddenly much more demanding, squeezing things until the pips squeak then wondering if the camera is faulty.
Well that's my 4p anyway. And yes, the front of the 18-70 does wobble a bit! They don't make 'em like they used to. Bah, mutter...
I think it's a tendency to demand perfection from digital cameras - how many times have we zoomed into a photo until the pixels show, then felt disappointed when we can see the pixels? We're just suddenly much more demanding, squeezing things until the pips squeak then wondering if the camera is faulty.
Well that's my 4p anyway. And yes, the front of the 18-70 does wobble a bit! They don't make 'em like they used to. Bah, mutter...
Some nice info about focus and testing on the D70 here:
http://md.co.za/d70/chart.html
http://md.co.za/d70/chart.html
joust said:Fabulous link - many thanks for that, makes things much clearer.
www.wfu.edu/users/bennettk/sharp.html
LexSport said:
<a href="www.wfu.edu/users/bennettk/sharp.html">www.wfu.edu/users/bennettk/sharp.html</a>
Fabulous link - many thanks for that, makes things much clearer.
Seconded, a really good explanation and well written.
Chris
Cheers for all the comments guys. I guess it's a mixture of it all -
Deadlock - sounds like you see the same sort of results, so I don't feel too bad, and the wobbly lens seems to be a common experience as well, phew!
Simpo - I only expect results similar to that which I see in other examples from my camera, and like you say this might be unreasonable in certain cases. Someone else mentioned atmospheric effects - I guess even a slightly hazy day will do this.
I know I can sharpen the images but find that in doing so I struggle with noise, so then I chuck them through neat image but that sacrifices detail... So that leaves me selectively applying noise reduction and pasting sections of an image over another, not fun really if I could avoid all that by getting it sharp to start with...
hey ho, I guess that's life. Maybe it's time to get a prime and see if it's any better.
Deadlock - sounds like you see the same sort of results, so I don't feel too bad, and the wobbly lens seems to be a common experience as well, phew!
Simpo - I only expect results similar to that which I see in other examples from my camera, and like you say this might be unreasonable in certain cases. Someone else mentioned atmospheric effects - I guess even a slightly hazy day will do this.
I know I can sharpen the images but find that in doing so I struggle with noise, so then I chuck them through neat image but that sacrifices detail... So that leaves me selectively applying noise reduction and pasting sections of an image over another, not fun really if I could avoid all that by getting it sharp to start with...
hey ho, I guess that's life. Maybe it's time to get a prime and see if it's any better.
V6GTO said:
Don't expect too much from a kit lens. While the results will be acceptable they will never be as good as an 'L' lens costing 5-10 times the amount. HTH. Martin.
True, but don't forget that the 18-70 Nikon kit lens seems by all accounts to be much better than the Canon 18-55 kit lens.
0-15, Canon to serve
simpo two said:Twaddle.
True, but don't forget that the 18-70 Nikon kit lens seems by all accounts to be much better than the Canon 18-55 kit lens.
0-15, Canon to serve
This image was taken with the 18-55
Absolutly nothing wrong with sharpness across the whole of that image.
30-15 me thinks.
J
simpo two said:
40-15 to Nikon.... 
V6GTO said:
The white walls in Justins photo are just that...white! No problem with the WB then! Back to 30-15.
Nope, 40-30.
Plus, you can't win a point for doing what it's supposed to do anyway.
Plus, Canon are fined one point by the sport's governing body for illegal scoring, so Game Nikon
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