Why is my lens searching?

STINKY PICTURES · Apr 13, 2008

Ok I got the great little 50mm 1.8mm Canon Lens and I love it. Some of my shots have been OUTSTANDING!!! But today it seems to be searching and searching and searching and not locking down..... (I`m shooting indoors in my sunroom, its an over cast day with no sun, but i`m 4 feet from a glass door, plenty of light) I just got it a few days ago. I`m wondering if i should send it back. its really getting to be a pain in the butt. I also can see LOTS of dust inside the lens... I`m shooting a doll (I sell on ebay for a living, work from home). I have a Canon 40d and I can select a focus point with my camera, I`m selecting hight points, dark points, flat places. I`m trying every thing. I`m moving the tripod all over the place. I keep getting the focusing searching with the lens. Then i put on my 28-135mm and its solid as a rock. But I want the sharpness of the 50mm 1.8.

should i send the little bugger back, first because of all the crap inside, and second because of the searching?

also what causes a lens to search. i`m sure its me, how can i help this little fellow. my big lens is having no problem at all. I don`t see the dust on my pics, i just wanted to add that.

I also tried changing the focus points in my camera to other focus points thinking that maybe that was the problem but it didn`t matter. sometimes it locks on and when it does WOW.. NICE SHOT. so any advice??

I got it at B & H and while there is still time if i need to send it back.... well....if i have to i will.

Battou · Apr 13, 2008

Post a pic of the back of the lens for me if you could.

Sorry I am ignorant with the EF lenses.

STINKY PICTURES · Apr 13, 2008

Is this what your talking about?

WDodd · Apr 13, 2008

I'm assuming that this isn't the problem that you are having, but a lot of times when I try to use that lens I get too close for it to focus and I have to move back from the subject.

Battou · Apr 13, 2008

Try taking a pencil eracer to your elements, Make sure you have good communucation, they look a tough hazy.

As for the dust, it does not look like you are going to be able to get in there to do anything about it at the moment.

With some of my older lenses there is some sapce I can get a jet of air into and blow some of it out but I dfon't see the room on that.

STINKY PICTURES · Apr 13, 2008

Battou,Thanks for you help i`m going to try the eraser thing.

and WDodd I may be too close, i have the subject in my entire frame.

I`ll try ANYTHING!

RyanLilly · Apr 13, 2008

Well, the 1.8 does not have ultrasonic focus, it uses a much cheaper, louder,and slower motor. So don't expect performance like your other lens. Also, like WDod, mentioned make sure you not trying to focus closer than the minimum focusing distance for that lens.

LaFoto · Apr 13, 2008

My 50mm lens has a lot more problems in autofocussing than the other lenses have. So often when it searches for too long, I just go manual. If manual doesn't give me a sharp picture, I'm sure to be too close. But particularly in dark surroundings (and dark seems to start a lot earlier for the 50mm lens than for the others!), I cannot but focus manually.

RebelTasha · Apr 13, 2008

I'll bet you are too close!!
I have to be at least 1 1/2 feet away before I can get a lock.

STINKY PICTURES · Apr 13, 2008

I`m more like 3 feet because i`m trying to get in the entire doll.

LaFoto · Apr 13, 2008

I think the minimum distance is 70cm, so if you're at 3 feet, you are not too close (which is around 90cm). I guess it is a light problem which goes with this particular lens (like I'm saying, mine's the same), and my personal solution is manual focusing. Fastest solution, too.

STINKY PICTURES · Apr 13, 2008

I`m going to clean the sensors and see if it makes a difference.

OK i just cleaned the sensor on the lens, and i took a few pics. there is no difference. i moved my set up right in front the door. its very bright. still only searching no locking on anything just that chugging and chugging and blurry pics... i was almost 3 feet away from my subject.

tomorrow i`ll try again with better light if it doesn`t work then back it goes for a new one.

PattiS · Apr 13, 2008

I find this to happen in two situations- one is if I'm too close, and the other is if there is not enough contrast in the area I'm trying to focus on. The latter is especially pronounced in hazy or backlit situations. You can always switch to manual, but something else I might try is to focus on an area with more contrast (on the same plane if you are shooting with a wide aperture) and then recompose. I recently photographed a little boy with very fair skin, eyes and hair, in full sun, and I could not get focus to lock on his face, but if I focused on his brown and white sweater there was no problem. It can be very frustrating!

abraxas · Apr 13, 2008

LaFoto said:
...focus manually.

Louder.

LaFoto said:
... manual focusing. Fastest solution, too.

Louder Corinna

Battou · Apr 13, 2008

STINKY PICTURES said:
Battou,Thanks for you help i`m going to try the eraser thing.

and WDodd I may be too close, i have the subject in my entire frame.

I`ll try ANYTHING!

I was not sure if that made it threw or not, my browser froze after hitting the submit button, I was going to add that I was not sure if it would be of much help, but worth a shot. I have heard of the searching problems with the lens but it sounded like you had gone somewhat beyond that.

Additionally, I appologize to the mods if I posted it half a dozen times.