Wide Angle Landscape Advice Needed

[mjindustries]

Hey Everyone,

Im new to this forum and relatively new to photography! I have a Canon 550D (Rebel t2i) and have just brought a Sigma 12-24 mm F4.5-5.6 EX DG HSM lens.

I have previously taken some great in-focus with the standard kit lenses (18-50mm canon and 50-250mm canon) but got sick of photo stitching and wanted a better lens hence buying the sigma.

Now my problem is I seem to be getting everything in the foreground in great focus but nothing in the back ground seems to be.. It just appears blurry and not sharp. I have trialled so many different f-stops and focus distances and researched into hyperfocal distance (have a broad understanding of the technique just cant put it into practice) I am aware that the wide angle lens probably needs some different techniques applied to get a sharper background.

Any help or tips would be greatly appreciated!

[Nicole]

What kind of settings are you using (could you provide a specific example maybe with the image and EXIF)? I find that my Sigma 10-20mm gets everything in the shot sharp once I hit about f/8.

[mjindustries]

Hey, maybe Im expecting a bit to much out of it! Below is a photo I just went out and took with it.. F11, 1/100seconds, ISO 100, shot with a tripod and remote to eliminate shake... Is the background (ie the hut on the side of the pond) in focus/sharp? is this acceptable? I took photos at every f-stop and every focus distance (from the lens focus window) so I have over 100 photos of exactly the same scene and the f-11 looks fairly similar to the f-22 I can post this if anyone needs to look closer.

[Tzetsin]

I'm looking at it as closely as I can, but when i zoom in on the browser the hut looks as sharp as the forground is. Now thats not to say that the forground looks all that sharp. It doesnt. Its just "bigger" so its harder to notice until your looking at a similar sized area in the forground as the hut is in the background.

This could be because its on a web page, but its something to look at on the original. Perhaps your copy of lens isnt very sharp.

[mjindustries]

Is there any way to test if my lens isnt that sharp?

[Tzetsin]

well... hehe, I sat a cheerio box up 10 feet from my camera and shot it with off camera flash at every f-stop (on a tripod with remote) and then looked at them in lightroom at 100% and looked at how sharp the nutrition information lettering was.

I dont recomend cheerio boxes though because the writing on cardboard isnt very sharp... but you get the idea.

I'm sure there are much more technical ways of doing it, but that cost me nothing and gave me a pretty good idea of how sharp my lenses were at each f-stop.

[Doug Sundseth]

The classic way to check focus and sharpness is to stick a newspaper* to the wall and shoot it, then pixel peep. This lets you check both central and corner sharpness pretty effectively.

Note that anything you post here is unlikely to be even close to full resolution, and peeping low-res jpg images is unlikely to tell you much about actual lens sharpness. Also, things that take up only a few pixels in the original file are limited by physics in the amount of detail you can hold.

* An obsolete method of information delivery widely used last century. It was printed on the corpses of murdered trees. (Really! You can look it up!)

[doubleconvex]

Your lens appears to be fine (the Sigma 12-24 is a very decent lens).
A couple of things to note
a. try to go with the highest f-number possible. I shoot my landscapes at f22;
b. assuming that you are on auto-focus, ensure that you are not using a centre-weighted focussing method. I recommend going with an evaluative focussing method.

Hope this helps.

[AdrenoJunkie]

Center weighted and evaluative have nothing to do with focusing, those are for metering your exposure. If you're shooting on a tripod (and you should be) go into live view, zoom in on a spot about a third of the way into the shot and manually focus. Your aperture should be at least f16. But I think, not positive, that the more extreme your f stop is the less sharp it will be. Lenses have a sweet spot for sharpness, about two stops down from wide open, the further you get from this the less sharp it will be. May not be alot but it will be something. Which is why f16 is a good aperture too hang around. There is also a depth of field calculator you can look up to help figure out what aperture and where to focus. Are you doing any sharpening in post?

[Islandcrow]

Originally Posted by AdrenoJunkie

Center weighted and evaluative have nothing to do with focusing, those are for metering your exposure. If you're shooting on a tripod (and you should be) go into live view, zoom in on a spot about a third of the way into the shot and manually focus. Your aperture should be at least f16. But I think, not positive, that the more extreme your f stop is the less sharp it will be. Lenses have a sweet spot for sharpness, about two stops down from wide open, the further you get from this the less sharp it will be. May not be alot but it will be something. Which is why f16 is a good aperture too hang around. There is also a depth of field calculator you can look up to help figure out what aperture and where to focus. Are you doing any sharpening in post?

Good points. Getting to understand hyperfocal distance can be useful. I made up a quick little card that I laminate and keep in my camera bag. Usually, I have a pretty good idea of what f-stop I need and only calculate hyperfocal distance when I purposely want a particular part of the photo to be out of focus or I need to shoot at the widest possible aperture to get a faster SS (e.g. windy day). Your focus point is very important, though. 1/3 of the way into the scene is a pretty common rule of thumb, but that certainly isn't always the case. Of course, with an f-stop of 16 on a wide-angle lens, you can probably focus anywhere from 1/3 to 1/2 of the way into the scene and be just fine. Using live view and zooming in is an excellent practice. That way, even if your autofocus is a little bit off it won't matter (because you're not using it).

Lastly, if you're shooting in RAW, your image is naturally going to be a little bit soft. Post-process sharpening is going to be essential.