Hello, using an Xsi and 17-40 L @ 17mm I attempted a hyperfocal distance using an aperture of F8 and focusing around 6.3 feet away

here is my resulting image can you please provide any C&C regarding it ? Please ignore the "bridge" at the bottom right of the image, I'm aware its there and would like that to not be apart of any additional C&C.

I'm interested in hearing about thoughts on the focus and sharpness of the image

Thank you

There's no problem with the focus and sharpness. However, the high noise takes away from the sharpness; you might want to use a longer exposure at lower ISO for a cleaner image.
There is also a slight greenish color cast (common for night cityscapes due to the lighting); you might want to tweak the color balance a bit away from green.

I agree there's no problem with the focus and second mpmendenhall's comments on sharpness and color cast. I'm guessing you steadied the camera on the bridge or used a tripod. Did you use a cable release or the self timer to minimize vibration further?

Compositionally, I think the picture could be improved somewhat by cropping up from the bottom (to lessen the amount of the dark, empty space above the bridge and if you go high enough, to get rid of the unfortunate rectangular sign at left). Maybe shooting from another position on the bridge would make for a more pleasing composition altogether.

http://www.dofmaster.com/dofjs.html says 17 at f8 at 6.3 ft would be focussed from 3.2' to infinity. Focussed on infinity it shows 6' to infinity. But it is more complicated than that.

My understanding of hperfocal distance is an subjective measure area that would reasonalbe sharp when printed at a specfied size with average eyes. It is not a really sharp standard since larger printing or more pixel peeping will notice less sharpness.

17-40L is a good lens that should be sharp.

f8 is the right choice for most lens because they are generally sharper 2 stops from wide open.

It looks sharper on the buildings in the middle than the back. I suspect it would be sharper looking if you focussed at near infinity because closer objects would not be as noticable lacking sharpness.

Sharpness would likely improve if you focussed further back from 6'1 to almost infinity.

Try it and see. Scott

Further to the above:

see http://www.cambridgeincolour.com/tutorials/hyperfocal-distance.htm

"The problem with the hyperfocal distance is that objects in the far background (treated as ~infinity) are on the extreme outer edge of acceptable depth of field [ soft] . These objects therefore barely meet what is defined to be "acceptably sharp." This seriously compromises detail, considering that most people can see features 1/3 the size of those used by most lens manufacturers for their circle of confusion (see "Understanding Depth of Field"). Sharpness at infinity is particularly important for those landscape images that are very background-heavy.

Sharpness can be a useful tool for adding emphasis, but blind use of the hyperfocal distance can neglect regions of a photo which may require more sharpness than others. A finely detailed foreground may demand more sharpness than a hazy background . Alternatively, a naturally soft foreground can often afford to sacrifice some softness for the background.

One often has to choose where to allocate the most sharpness (due to aperture and shutter speed limitations). "

All of which means - hyperfocal distance is a optimistic low bar standard if you want a very sharp picture. So move fstop up from hyperfocal distance and plan where you want the picture sharpest when choosing where to focus, and trying for maximium sharpness.

Scott is, as I recall, correct about hyperfocal distance. Why try for near camera sharpness unless the bridge railing is vital to the image? Do you believe it adds to it and would detract if it was less sharp? You sacrifice too much long distance sharpness. Despite the small screen size of the image, it doesn't look sharp. A dose of sharpening would improve it significantly. Cropping out the railing, the sign on the left and cloning out the power cable I suggest may also improve it.

mpmendenhall wrote:
There's no problem with the focus and sharpness. However, the high noise takes away from the sharpness; you might want to use a longer exposure at lower ISO for a cleaner image.
There is also a slight greenish color cast (common for night cityscapes due to the lighting); you might want to tweak the color balance a bit away from green.


20 second exposure at ISO 100..