thereisnobeginning
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I had heard that every lens has a sweet spot in its aperture range which results in sharp pictures. I was curious about how this range is determined.
A search revealed a number of sites which described the procedure,. Essentially, one took multiple pictures, at different apertures, of the same object from the minimum distance at which the lens focuses.
Having some time to spend, I decided to see if I could find this range in the lenses that I have.
A picture of the setup that I used is appended. The camera is the Nikon D5600, with the AF-P 18-55 G VR kit lens that it came with. It is tethered to a laptop running Darktable under Linux. All operations are done from the laptop. The lens is placed at the minimum focus distance (in this case about 28cm) from the object, which is a large book supported in an open position. I took pictures at all the apertures at both 18mm and 55mm. All pictures are in RAW format. The procedure was repeated for the AF-P 70-300G ED VR lens, whose minimum focus distance is 110cm.
I found that, from the subjective viewpoint of my jaundiced eye, the sweet ranges are as follows:
For the 18-55: At 18mm : f6.3 to f11. At 55mm : f8 to f16
Can I conclude that f8 to f11 will give me the sharpest images at all focal lengths for this lens?
For the 70-300: At 70mm: f7 to f14. At 300mm: f10 to f20.
Similarly, can I conclude that f10 to f14 will give me the sharpest images at all focal lengths for this lens?
Is it necessary to repeat this at different object distances as well?
Is this in line with what is typical of these lenses? I would be grateful for comments from those with more experience in this, as well as suggestions which can improve the observations.
I realize that this setup is just too crude to give reliable results. However, it did give me some results, reliable or no.
Many thanks in advance.
The D5600 is tethered to the laptop via the USB cable, and pictures are taken remotely using Darktable.
A search revealed a number of sites which described the procedure,. Essentially, one took multiple pictures, at different apertures, of the same object from the minimum distance at which the lens focuses.
Having some time to spend, I decided to see if I could find this range in the lenses that I have.
A picture of the setup that I used is appended. The camera is the Nikon D5600, with the AF-P 18-55 G VR kit lens that it came with. It is tethered to a laptop running Darktable under Linux. All operations are done from the laptop. The lens is placed at the minimum focus distance (in this case about 28cm) from the object, which is a large book supported in an open position. I took pictures at all the apertures at both 18mm and 55mm. All pictures are in RAW format. The procedure was repeated for the AF-P 70-300G ED VR lens, whose minimum focus distance is 110cm.
I found that, from the subjective viewpoint of my jaundiced eye, the sweet ranges are as follows:
For the 18-55: At 18mm : f6.3 to f11. At 55mm : f8 to f16
Can I conclude that f8 to f11 will give me the sharpest images at all focal lengths for this lens?
For the 70-300: At 70mm: f7 to f14. At 300mm: f10 to f20.
Similarly, can I conclude that f10 to f14 will give me the sharpest images at all focal lengths for this lens?
Is it necessary to repeat this at different object distances as well?
Is this in line with what is typical of these lenses? I would be grateful for comments from those with more experience in this, as well as suggestions which can improve the observations.
I realize that this setup is just too crude to give reliable results. However, it did give me some results, reliable or no.
Many thanks in advance.
The D5600 is tethered to the laptop via the USB cable, and pictures are taken remotely using Darktable.
