View Full Version : My lens wont focus on my grey card? Help!

18-08-2011, 2:51pm

I just purchased a 18% grey card. For some reason my 50mm 1.8 lens wont focus on it?
I have tried from various angles and distances with no luck....confused :(

Please help!!!

18-08-2011, 2:56pm
Why do you need to focus?

The card helps with metering - not focus.

JM Tran
18-08-2011, 3:05pm
Why do you need to focus?

The card helps with metering - not focus.

no the card does affect focus lock by lacking colour contrast or having shine on it if shot outdoors. AF works by focusing on contrasts so if u focus on something white, or shiny large surface it wont lock on.

OP I hope u arent using it inside the minimum focusing distance of the 50 f1.8! Have you tried opening the aperture up to say f2.8 or bigger? Also use the centre AF point as well, if you are using it outdoors or somewhere bright, go in the shade and try again.

18-08-2011, 3:08pm
Maybe you need an edge of the card in view to focus & then move to the centre of the card to snap ?

18-08-2011, 3:17pm
As colinbm said, point at the edge of the grey card, focus, recompose, take the photo.

18-08-2011, 3:22pm
Do you want to use the card to help with the camera's settings or do you actually want to take a photo of the card?

18-08-2011, 3:30pm
JM Tran, Definitly not trying to use inside the min focusing distance...
I am using it for camera settings and would also like a photo of it for reference.
If I focused on the edge of it then it wouldnt completley fill my image, so wouldnt the metering be incorrect?...Is my thinking wrong? This is all new to me, so I am getting a little confused:(

18-08-2011, 3:35pm
In order to get the settings, you don't need to have it in focus - just point the camera at it, fill the frame and that's it. Focus is irrelevant.

If you want to take a photo of the card, then the metering is not really relevant (for the purpose of getting the photo) as if, you are taking a photo of a card (and you want it to look like a card), you'll need to show the edges in order to give it some perspective. Once you do that, the metering may be affected by the light spilling over the edges.

My head hurts


18-08-2011, 3:48pm
Depending on how your camera is set up you might not be able to fire the shutter without focus lock. Just switch to manual focus for this one...


19-08-2011, 2:58pm
Just thought I'd chip in and lend support to Scotty72's posts. You do NOT need to focus on a grey card to use it. Set your lens to MF, fill the frame with the grey card, and take the shot/meter the exposure.

19-08-2011, 3:23pm
Some cameras actually are set not to take a photo if not in focus (unless in full manual) too

25-08-2011, 10:33pm
Thanks guys...being such a newbie I didnt realize that my camera didnt have to be in focus to get a metering. I also changed over to MF to get the shot of the card for reference.

05-10-2011, 10:08pm
You don't need to focus to white balance. However, if you want it for reference, get a black pen and put a few dots in the middle. It's quite acceptable and will work just as well. It doesn't need to fill the frame, it just needs to be close. However why you would want it for reference I dont know - you will never have the same light conditions again so why would you want to re use it?