450D Questions about Photo Clarity

I'm fairly new to photography and I just bought the 1.8 50mm prime that everyone raves about today. I took a couple pictures with it (a lot of them were in sunlight) and it seems like I'm not getting the detail out of my pictures (i.e. it looks like my focus point is always slightly out of focus) that other people get with the same lens + camera combo.. I also cleaned the lens pretty thoroughly, any thoughts? Thanks!

Here's an example, if you go to full screen you can see how no point in the picture is crisp. http://www.flickr.com …7604182922/in/p​hotostream

Maybe the lens is defective or try shooting the same subject (flower) using a lower aperture, maybe a f/2.8 or an f/3.5 on center metering. Bokeh will not be that smooth but most likely the subject will be on focus. Also try it on a tripod just for the sake of testing the lens. If these do not work, maybe you can exchange it with a different one. Nifty fiftys are great if you get a good copy. Hope this helps...

If you look very closely at your full size image on Flickr you may agree with me that the inner area of the top of the flower, the brown grainy area you can barely see between the extended parts the bee is sitting on, appears to be sharply in focus, as do the tips of some of the yellow/orange parts (whatever they're called) just in front of the bee. There are a couple of possibilities - the image is sharp where you focused, as it should be, and the very limited depth of field is making you think you missed focus because so little of the image is in focus, or you have a front- or back-focusing issue where you focused the camera on one area but the actual area in focus is in front of or behind the point of focus according to the viewfinder because the camera and lens are not working together perfectly during the focusing process. Even if the camera and lens are working perfectly, with the very narrow depth of field shooting this close at f/1.8, it will be very difficult to get good focus on exactly what you want unless you're very careful, preferably by using a tripod and possibly by using Live View focus, if available on your camera. For example, if not using a tripod, even if you focus perfectly if you rock your body backward or forward even a fraction of an inch before pressing the shutter you will throw off what's in perfect focus in the image because of the very narrow depth of field. You can test for front/back focus by setting up a row of AA batteries on a table top and shooting them at a 45 degree angle, with focus on the middle battery and aperture at f/1.8. If possible, use a tripod, and do the test either outside in bright light with a fast shutter speed or inside using flash. If the camera is front-focusing the middle battery, which should be sharply in focus, will be out of focus and a battery more toward the front of the row will be in focus; if the camera is back-focusing the sharper batter will be behind the middle battery.

You can get more information on depth of field here:
http://www.dofmaster.c​om/dofjs.html

Depth of field is generally defined as the area of the image in "acceptable" focus. Assuming you're shooting with a "crop sensor" camera, at 50mm focal length and f/1.8 and a shooting distance of three feet, your depth of field would be about .84 inch; shooting from two feet, it would be about .36 inch.

paddypilot wrote in post #14739914
I'm fairly new to photography and I just bought the 1.8 50mm prime that everyone raves about today. I took a couple pictures with it (a lot of them were in sunlight) and it seems like I'm not getting the detail out of my pictures (i.e. it looks like my focus point is always slightly out of focus) that other people get with the same lens + camera combo.. I also cleaned the lens pretty thoroughly, any thoughts? Thanks!

try stopping down and shooting something larger !
the depth of field at f1.8 at that distance is extremely small

XSi (450D)
Canon 50mm 1.8 mkII
f2.5
1/3200
ISO 100

In addition to those points already mentioned, be sure to use "manual focus point selection" rather than "auto focus point selection". (All focus points active)

The former alows YOU to choose what is in best focus whereas the latter allows THE CAMERA to choose what is in best focus, namely the part of the image that is the closest thing to the camera covered by a focus point(in this case the contrasty part of the top of the flower).

You can read about "manual focus point selection" in your camera manual.

Thanks for all the great tips! Yeah I think my problem is at least partially the aperture. Just took this one at f/4: http://www.flickr.com …7605299624/in/p​hotostream
the difference is night and day.

Also, watt was that picture taken at Langley?

There you go...problem solved!!! At f/4, bokeh is still great! Good start and many more to come, happy clicking!!!

paddypilot wrote in post #14740856
Also, watt was that picture taken at Langley?

yes, several years ago (when the F22's were flying!)