Looking for Sharpness

TrueIntuition · Nov 16, 2013

[FONT=Tahoma, Calibri, Verdana, Geneva, sans-serif]Hi Everyone, here is downtown Tampa.[/FONT]
This is one of about 145 shots taken the other night. Of all those shots I'm not able to get sharp focus on the buildings. This one is a 30sec exposure at F/22 ISO 200. I'm using a Nikon D5200 with the 18-55mm lens. Ive tried manually focusing, and auto focusing on the buildings, I tried shorter exposures when there was more light out, and even at 1/125 shutter speed the building are still not very sharp.
Is it a camera setting ?? Is it the Camera or lens I'm using ??
Any advice would be great !!
Thank you,
Pete

Derrel · Nov 16, 2013

Photo is too small to properly diagnose, but there are some clues. WIndows are still small, not big and ghost-edged, so I think the focus is decent. But there are two things that could be at issue: 1) diffraction from f/22. F/22 will be noticeably LESS-sharp than f/8...and 2) subtle tripod movement. I think the camera is not 100 percent ROCK-steady. Those are my feelings, but this is all being based on my own years of experience and a tiny web-reduction image.

480sparky · Nov 16, 2013

Sadly, the 18-55 kit lens isn't a stellar performer when it comes to sharpness. F/22 is going to start getting diffraction, which softens the image. Try f/8 and ISO 100 instead.

Also, is your tripod ROCK SOLID, or is it a cheapie that can still wiggle? Is there vehicular traffic nearby? Moving cars can cause vibrations in the ground.

480sparky · Nov 16, 2013

Derrel said:
Photo is too small to properly diagnose, but there are some clues. WIndows are still small, not big and ghost-edged, so I think the focus is decent. But there are two things that could be at issue: 1) diffraction from f/22. F/22 will be noticeably LESS-sharp than f/8...and 2) subtle tripod movement. I think the camera is not 100 percent ROCK-steady. Those are my feelings, but this is all being based on my own years of experience and a tiny web-reduction image.

Two great minds for but a single thought! :mrgreen:

Other things:

If the camera has it, use Mirror Up. And use a remote to trigger the shutter so you don't touch the camera at all.

Given the perspective, perhaps the tripod doesn't need to be extended all the way up. Lowering it will make it steadier.

KmH · Nov 16, 2013

Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks

With the point of focus on your main subject that far away from the camera you did not need to use f/22 to get sufficient depth of filed (DoF).

Online Depth of Field Calculator
Using 55 mm for the focal length, assuming a Canon crop sensor camera (1.6x crop factor), a 2000 foot point of focus distance, and a lens aperture of f/5.6:
the total DoF would effectively be nfinite with a near focus limit about 88 feet in front of the camera and the far limit being at infinity.

Understanding Depth of Field in Photography
Understanding Your Camera's Hyperfocal Distance

f/5.6 is 4 stops more aperture than f/22. You would have been able to use 4 stops of faster shutter speed to help control some, if not all, camera shake inherent from a not all that steady tripod.