dirty lens

poochiem

maybe I can get some advice? I just bought a 50mm 1.8 II prime for canon Dslr. Yesterday I took it out for the first time and noticed a fleck of dirt. But it seems, on inspection, to be inside the lens or somehow suspended in the back lens. looks to be about a mil in length not just a dust speck. I haven't taken any completely blank backgrounds to see but I would assume this will show up somehow on my photos? I bought it new but from Hong Kong online so not sure whats my best move now.

thanks

trishw78

have you been in touch with the seller? Have you checked the return policy of the seller?

poochiem

trishw78 wrote: »

have you been in touch with the seller? Have you checked the return policy of the seller?

Not contacted them yet. they have a policy of return 7 days after receipt, I'm just checking now. I just wonder is it covered by an international warranty which might mean I could exchange it here rather than going through hassle of post and maybe another week like I just spent trying to find the lens which was travelling around dublin between Revenue and An Post!

mrmac

I'd check your pictures first, before trying to return the lense. It's common enough to see some dust inside a lense, but very few actually effect the picture.

There are several ways to check this, but here is how I do it, remember, you may need to do this with more than one lense, just to verify it's not actually the sensor that is dirty.

Create a new, blank, image with any photo software, even ms paint will do.
Make sure to fill the image with a fairly bright colour, I use white, and have it fill most of the screen.
Set your camera to aperature priority.
Set your lense to the smallest apperature, i.e. f22
Set to manual focus, and position the camera the closest you can to the screen, while in focus.
When in focus, zoom in, if you have to, to fill the viewfinder with the screen.
Set your ISO fairly low, so to avoid any noise.
Turn off any "noise reduction" or "sharpening" features that your camera may have.
Take a picture.

You may notice that the shot may take a few seconds. This is good! Move the camera slightly sideways, back & forth. This will eliminate any dust marks that may actually be on the computer screen from appearing in your shot.

Open the pic with some photo software, and zoom in to where you think the dust is.

How bad is it?

HTH.

poochiem

mrmac wrote: »

I'd check your pictures first, before trying to return the lense. It's common enough to see some dust inside a lense, but very few actually effect the picture.

There are several ways to check this, but here is how I do it, remember, you may need to do this with more than one lense, just to verify it's not actually the sensor that is dirty.


HTH.

thanks I'll try that, I was thinking that just photos of sky or white card etc wouldn't be reliable. The piece of 'foreign substance' is definitely in the lens not the sensor. I can see it when looking through the lens unattached and it seems to be inside the back part of the lens - sorry, I should look all the technical terms up before posting.

poochiem

Well I took the lens out today to run the little test ^ mrmac posted above. Sure enough the brown fleck has disappeared. A camera buff I spoke to said this might happen, it might have simply fallen off the glass into the plastics?

I wonder does anyone else have this lens as I'm finding it a little annoying. The canon 50mm 1.8 II ef prime lens? Just the autofocus seems to be constantly 'searching'. I have a habit of leaving my finger on the shutter button once focused, I'm sure its a common style but doing so with this lens it doesn't hold the focus it keeps doing what i would describe as micro-movements and can hop on and off focus. Is there something I'm doing wrong in my setup perhaps? I have an Eos 20d body.

Any advice appreciated.

Same body and lens as yourself. Are you using AI Servo autofocus?

Mine does a bit of hunting alright, but nothing I could ever complain about. There is a learning curve with the lens, though, there's no doubt about it. A lot of my first shots with it were out of focus (and many still can be, so i tend to take a machine gun approach now... though I always kinda have taken that approach).

Steve Reddin

Deleted User wrote: »

Same body and lens as yourself. Are you using AI Servo autofocus?

I'd second this approach, you will have to go into the settings to set it up but once you are using this approach with your camera you'll wonder how you did without it. In a nutshell it splits the focus and shutter release into two separate buttons, you can hold the focus button down then to keep focused on a subject and just hit the shutter release when you want to take a photograph...very useful for wedding photography I've found.

poochiem

Steve Reddin wrote: »

I'd second this approach, you will have to go into the settings to set it up but once you are using this approach with your camera you'll wonder how you did without it. In a nutshell it splits the focus and shutter release into two separate buttons, you can hold the focus button down then to keep focused on a subject and just hit the shutter release when you want to take a photograph...very useful for wedding photography I've found.

Thanks! I'm still learning obviously. Yes changed AF to 'one shot' right there and the 'hunting' is gone. Love the lens. Watching this guy right now, pretty interesting but want to get out and take shots now youve solved my little issue.

cheers for the feedback

Steve Reddin

Steve Reddin wrote: »

I'd second this approach, you will have to go into the settings to set it up but once you are using this approach with your camera you'll wonder how you did without it. In a nutshell it splits the focus and shutter release into two separate buttons, you can hold the focus button down then to keep focused on a subject and just hit the shutter release when you want to take a photograph...very useful for wedding photography I've found.

I actually meant AI Servo as in the Focus that keeps on tracking for moving objects (helps with panning, etc.)

Possibly he could have had that selected and the lens could have kept adjusting as something in front of the camera moved or wobbled about.

poochiem

Thanks everyone, that did the trick, setting it back to one shot instead of servo. Brought it out yesterday evening loved it. Here's a dog and a hen