Image Sharpness Problems
Dear all,
i have a small problem and maybe someone can help me with it.
Have you ever taken a picture of a subject which looks quiet sharp. You have a very good dof and your exposure is great but once you open it in your editor and you put your image in 100% it is not as sharp as you like? I don't know if it is me or if the image should be like that but it seems that all my pics are not sharp. Even those that i put on my tripod. Can anyone please help me with this?? I don't know what i do wrong. Maybe its the camera??
Thanks.
Brian Tyler Administratively edited on 24.04.15, 17:19.
i have a small problem and maybe someone can help me with it.
Have you ever taken a picture of a subject which looks quiet sharp. You have a very good dof and your exposure is great but once you open it in your editor and you put your image in 100% it is not as sharp as you like? I don't know if it is me or if the image should be like that but it seems that all my pics are not sharp. Even those that i put on my tripod. Can anyone please help me with this?? I don't know what i do wrong. Maybe its the camera??
Thanks.
Brian Tyler Administratively edited on 24.04.15, 17:19.
Try is might be due to the resolution of the screen you use while working in the editor program. I for instance find pictures looking much sharper and more vibrant when viewing them on my IPad in comparison to viewing them on my (okay I'll admit) old laptop.
So try loading the same images onto an iPad if you have acces to one and see what the images look like then.
So try loading the same images onto an iPad if you have acces to one and see what the images look like then.
25.04.15, 11:59
Post 3 of 5
Hi Brian, could be a matter of front- or back-focusing. Don't know what camera you use but a check-up due the service department or calibrating it for your selves depending on your camera
gr.Rob
gr.Rob
Looking at a picture on 100% enlargement with no matter what screen will allways look unsharp. That has nothing to do with any front or back focus.
Checking sharpness by opening to 100% is definitely not the right way.
Look at the picture on normal scale then you can see easy enough whether it is sharp or not. Last edited by Ruud van der Lubben on 06.05.15, 20:33, edited 1 time in total.
Checking sharpness by opening to 100% is definitely not the right way.
Look at the picture on normal scale then you can see easy enough whether it is sharp or not. Last edited by Ruud van der Lubben on 06.05.15, 20:33, edited 1 time in total.
You can easily test your camera and lens for sharpness using a white piece of paper (use a good quality printer paper)
Draw a skinny line with a pencil on the paper.
Photograph it using normal day light, no flash.
Camera on a tripod, vibration reduction set to off.
Open the image using Imager.
I created Imager for my students and it can be downloaded from my web site for free.
http://www.MyCIGroup.com then navigate to Imager.
It is not great looking software but serves the purpose for research!
Open the image and save it to text file.
Open the text file using EXCEL.
Scroll down until you find the Grayscale section. For each pixel there is one number listed.
Find the transition from white to black. It should look something like 175 175 175 70 60 55 55 55 55
This may vary in numbers, which is not important. It all depends on how white the paper is and how dark the line is.
Again, this is not important.
Count the number of pixels it took to transition from white to black. In my example above it took 3 pixels.
This transition is what humans interpret as sharpness or in focus. If it takes 5, 6, 7 pixels to transition, then the image is less sharp. Measure it.
Repeat the test by taking the camera out of autofocus, change aperture, etc. You will soon understand your camera.
A standard 35 mm camera will not transition in 1 pixel, it should be 2 to 3 pixels.
A couple of things to consider, keep the distance just far enough to allow the camera to focus properly. I would say 6 feet. Experiment with zoom settings but don't try to macro the object. That defeats the purpose of the test.
Draw a skinny line with a pencil on the paper.
Photograph it using normal day light, no flash.
Camera on a tripod, vibration reduction set to off.
Open the image using Imager.
I created Imager for my students and it can be downloaded from my web site for free.
http://www.MyCIGroup.com then navigate to Imager.
It is not great looking software but serves the purpose for research!
Open the image and save it to text file.
Open the text file using EXCEL.
Scroll down until you find the Grayscale section. For each pixel there is one number listed.
Find the transition from white to black. It should look something like 175 175 175 70 60 55 55 55 55
This may vary in numbers, which is not important. It all depends on how white the paper is and how dark the line is.
Again, this is not important.
Count the number of pixels it took to transition from white to black. In my example above it took 3 pixels.
This transition is what humans interpret as sharpness or in focus. If it takes 5, 6, 7 pixels to transition, then the image is less sharp. Measure it.
Repeat the test by taking the camera out of autofocus, change aperture, etc. You will soon understand your camera.
A standard 35 mm camera will not transition in 1 pixel, it should be 2 to 3 pixels.
A couple of things to consider, keep the distance just far enough to allow the camera to focus properly. I would say 6 feet. Experiment with zoom settings but don't try to macro the object. That defeats the purpose of the test.