HOW DO I SHOOT WIDE OPEN ON 50MM 1.8 ?!

Those look completely out of focus too.

MLphoto wrote in post #10234213
here are some random photos from today to show you an example,

full resoltuon straight from the camera:
http://img203.imagesha​ck.us/gal.php?g=img406​0rc.jpg

so basically this isn't exactly the best lens for what I'm shooting mounted on a 1.6 crop body?
maybe something like a 35mm would be better.

No part of these images is remotely in focus. You weren't shooting MF were you? Can you do a test shoot on a newspaper for instance and focus on the large type so we can see if the lens focuses ok? Has it worked ok before?

Shot #1, maybe the nose of the car is in focus, but hard to tell. Shot #2 is entirely out of focus. Shot #3 shows the effects of narrow dof when shooting at f1.8. The front of the car is in focus, the rear isn't. Also, the more separation you can put between your subject and the background, the better the bokeh.

MLphoto wrote in post #10234213
here are some random photos from today to show you an example,

full resoltuon straight from the camera:
http://img203.imagesha​ck.us/gal.php?g=img406​0rc.jpg

so basically this isn't exactly the best lens for what I'm shooting mounted on a 1.6 crop body?
maybe something like a 35mm would be better.

You may or may not want a lens that is wider, but the focal length is not the issue with these shots.

The first thing I notice is that you appear to have been using all focus points and letting the camera select what it thinks is correct. This is often a cause of "focus problems."

crn3371 wrote in post #10234277
Shot #1, maybe the nose of the car is in focus, but hard to tell. Shot #2 is entirely out of focus. Shot #3 shows the effects of narrow dof when shooting at f1.8. The front of the car is in focus, the rear isn't. Also, the more separation you can put between your subject and the background, the better the bokeh.

i don't see how you see anything in focus in any of them to be honest...

i don't know...i'm blaming the use of AI Focus...that mode is useless in my opinion

And as a followup, AI Servo should only be used for moving subjects...for shots like this focus will jump to whatever is under your active focus point. My bet is that you were using AI Servo and the "focus/recompose" method of feing your shots.

This would lead to your focus shifting behind the cars, which at 1.8 would be utterly OOF.

I guess I'll shoot at a lower aperature next time, thats all I needed to know thanks

MLphoto wrote in post #10234314
I guess I'll shoot at a lower aperature next time, thats all I needed to know thanks

it's not a DOF problem...there's nothing in focus in any of your shots...

yeah it won't hurt to stop down your aperture...but you'd still have bad shots coming out with the same settings...

to the OP you have a couple things. first is none of your shots even look like they made it in focus. with that it doesn't matter what you do if the focus isn't down. this should be visable through the viewfinder that the images aren't focused before you take the picture. the 50 1.8 is kinda of hit and miss at times with focus it seems though not always

the 50 1.8 is ver hit and miss wide open for quality. some lenses seem to do ok but many others (Well most others that I have seen) are soft at 1.8 no matter how good the focus is. usually you need to stop down at 2.8 to get sharp shots and then they are usually tack sharp at that focal length.

the other thing is depth of field. at 1.8 you have very litte. if your goal is to make the eyes of a fly in focus but yet have his butt out of focus then yes 1.8 works great otherwise you usually need to close it down a smidge and when doing shots of a car even more so as there is a lot of field there that you need to be in focus.

Snydremark wrote in post #10234290
And as a followup, AI Servo should only be used for moving subjects...for shots like this focus will jump to whatever is under your active focus point. My bet is that you were using AI Servo and the "focus/recompose" method of feing your shots.

This would lead to your focus shifting behind the cars, which at 1.8 would be utterly OOF.

some of us us ai-focus all the time without problem even if we have to do the focus and recompose method. that's what the af-on button or the * button is for with disabling focus on half press of the shutter

gives you one shot and AI focus in the same mode BUT not all like it and it seems that doing that on the 7d doesn't quite work as well as it did on my xsi.

DreDaze wrote in post #10234346
it's not a DOF problem...there's nothing in focus in any of your shots...

yeah it won't hurt to stop down your aperture...but you'd still have bad shots coming out with the same settings...

If he shoots at f11 then he has a good chance of hitting focus without trying, right?

I wonder if the OP is using manual AF point selection? It would be pretty hard for the camera to guess where to focus on shots like these.

MLphoto wrote in post #10234314
I guess I'll shoot at a lower aperature next time, thats all I needed to know thanks

And One Shot AF

Good luck!

this is a very informative thread.. i've learned a lot! i have shot (still) cars before with a 50 1.8 and didn't really have that much problem.. then again.. i think it's cuz i had the shutter open for a while.

Also you used f14 for plenty of DOF - not f1.8

jimmyneyugn wrote in post #10234426
this is a very informative thread.. i've learned a lot! i have shot (still) cars before with a 50 1.8 and didn't really have that much problem.. then again.. i think it's cuz i had the shutter open for a while.

ISO: 100
Exposure: 8.0 sec
Aperture: 14.0
Focal Length: 50mm

It's always nice to see a Miata.

MLPhoto, was your lens set to manual focus? I'm just guessing that it was MF because looking at the last two pictures, and assuming you didn't touch the focus ring between the two shots, the Ferrari looks further away from the lens and less in focus than the Lotus which looks to be closer to the lens and more in focus. Do you have any images that came out in focus, taken at the same location?

EDIT: Nevermind.. the two pictures look about the same distance away.

If you still belive that your AF doesnt work correctly.... if the lens it's still under warranty send to Canon for checking.... it's free ....