Why the poor image quality? Or is it me?

Recently, I've been noticing that my pictures are very clear, or crisp at a larger size. I know this is normal, as the larger a picture becomes, the more pixelated it appears to be, unless you take a couple steps back

Below, I have attached a picture I took the other day, at medium size:

That picture is huge.

My guess is diffraction. You shot at f22. Try at at least f16.

It's a 5 sec. exposure. How solid is your tripod, and how solid was the surface the tripod was resting on?

just sharpen the image in PS...

The first thing I would suspect is the tiny aperture. Once you get below between f/11 and f/16 on most lenses you start running into diffraction, which is likely to be what is going on with the building.

There also seems to be a fair amount of chromatic aberration (CA; the red/blue fringing visible when viewed at full resolution) around the building and rocks where they back against the sky.

CosmoKid wrote in post #9981138
That picture is huge.

My guess is diffraction. You shot at f22. Try at at least f16.

Thanks -I'll have to read up on diffraction! It didn't cross my mind!

Jon wrote in post #9981143
It's a 5 sec. exposure. How solid is your tripod, and how solid was the surface the tripod was resting on?

My tripod is decently solid -a Manfrotto 190XDB, and a Manfrotto ball head. I don't recall the models off the top of my head, sorry.
Everything was set on a cement rising, so I suspect that isn't going to move anywhere

i would say almost definitely diffraction. an UWA lens on a crop body causes diffraction over f16.

if you are trying to get everything in focus, f9 would probably do it. if your looking to slow the shutter to get that dreamy water effect, get some filters.

Snydremark wrote in post #9981368
The first thing I would suspect is the tiny aperture. Once you get below between f/11 and f/16 on most lenses you start running into diffraction, which is likely to be what is going on with the building.

There also seems to be a fair amount of chromatic aberration (CA; the red/blue fringing visible when viewed at full resolution) around the building and rocks where they back against the sky.

That's two people for diffraction

I'll look into for sure, when I get home!

Does a dirty sensor have anything to do with this?
I know I am overdue for a sensor cleaning

Add me to the "f/22 diffraction" list. I usually don't go beyond f/16 for these type of shots.

Thanks everyone; this is why I love this forum.
Always learning something new!

A_lee wrote in post #9981726
Thanks everyone; this is why I love this forum.
Always learning something new!

There are two other things to learn with diffraction: first is how to really avoid it; using that lens at 10mm gives you a WHOLE lot of Depth of Field. In fact, your Hyperfocal distance (the distance at which, if you focused, would give you from slightly in front of that point all the way to infinity in focus) is only 0.8 feet. At f/11 - a nice sweet spot for most lenses - the hyperfocal distance only doubles to 1.56 feet (according to this website). So you can see that gaining 2 stops of aperture really only narrows your DOF slightly; so slightly in fact that I doubt it would affect this picture.

Second is that, if you were using f/22 to get a very slow shutter speed, you should look into neutral density (ND) filters. These are optically clear, but cut the light that comes into the camera so you can get those nice, slow shutter speeds at apertures that don't force you to deal with things like diffraction.

Third (although I know I only said there'd be two - this one's important, though!), [B]don't let worries of diffraction keep you from getting the shot!! There is nothing more important than the shot itself, so get it. I took a shot at f/29 that is now hanging in the store at 20x30" size, and I've sold more than a few of them. Standing at a normal distance away, you don't notice. Viewed at 100% on a monitor, maybe not so much, but the print is what counts!

CosmoKid wrote in post #9981589
i would say almost definitely diffraction. an UWA lens on a crop body causes diffraction over f16.

if you are trying to get everything in focus, f9 would probably do it. if your looking to slow the shutter to get that dreamy water effect, get some filters.

I say there's more than just diffraction going on. There has to have been camera shake. Did you use mirror lock up? Timer? Remote cable release?

Canon 40D, 5sec., f/22, ISO100, +1EV; I used the Sigma 10-20 @ 10.
A used a tripod, a cable release, and [Under custom functions] used mirror lock up, and turned on long exposure noise reduction.