focus help - DPChallenge Forums

Tamron AF 28-300mm f/3.5-6.3 XR Di LD Aspherical IF for Canon

12/04/2004 09:03:49 AM · #1

I have been trying to get this entire piece in focus, but it is just not happening. any suggestions??

right now i am on macro, but i know that is whats making the front right look out of focus. any early am DPC'rs want to help out?

SDW

Canon EOS-60D

12/04/2004 09:23:41 AM · #2

What are your settings? A/S and Lens

Message edited by author 2004-12-04 09:24:01.

Canon EF 17-40mm f/4.0L USM

12/04/2004 09:39:58 AM · #3

actually am using my canon g2. that pics is a 1/5 @ 2.2. i tried closing the fstop to 5.6 and 8 though but it didnt help

soup

Canon EOS-30D

12/04/2004 09:57:23 AM · #4

you could try moving farther away from it with the camera - this will give wider depth even at the same settings.

then crop what you want out of the file. not sure it would work, but worth a try.

also you could try shooting at more like f:16 or f:22 if you can get enough light.

also the wider angle settings on the lens will give you wider depth than when the lens is zoomed in. again - even at the same settings.

Canon EF 28-135mm f/3.5-5.6 IS USM

12/04/2004 10:02:46 AM · #5

excellent, thanks for the help

dr rick

Canon EOS-300D Rebel

12/04/2004 10:04:43 AM · #6

I don't know what point you are focusing on, but try a point closer to the front. Not the front corner; that will probably push the back corner out of focus. But maybe 1/3 of the way back from the front corner. You may need to focus manually. And I would suggest using at least f/8; f/16 if you can.

scottwilson

Canon EOS-350D Rebel XT

Canon EF 28mm f/2.8

12/04/2004 10:08:35 AM · #7

Originally posted by jjbates4:

actually am using my canon g2. that pics is a 1/5 @ 2.2. i tried closing the fstop to 5.6 and 8 though but it didnt help

You should have seen a large differance between shooting with an fstop of 2.2 and 8, if shooting at 8 did not greatly improve the depth of field something is wrong.

How large is the part we are looking at? small objects are harder to get all in focus then larger ones.

Tamron AF 28-300mm f/3.5-6.3 XR Di LD Aspherical IF for Canon

12/04/2004 10:41:34 AM · #8

yeah thats part of the problem, its about the size of a postcard

scottwilson

Canon EOS-350D Rebel XT

Canon EF 28mm f/2.8

12/04/2004 11:37:37 AM · #9

Originally posted by jjbates4:

yeah thats part of the problem, its about the size of a postcard

There are some hard limits to what you can do with DOF for small objects. This is due to the diffraction of light. Simply put to get the DOF you would really like the fstop has to be so small that there is blurring from the light diffracting. In a case like this I have has some success taking two or more photos, adjusting the focus point between shots. Clearly you need a tripod to make this work. The two shots can then be blended in PhotoShop taking the infocus part from each. This is a bit tricky since a change in focus will make a small change in the magnification.

The other thing you can do is shoot looking more straight down, this will limit the DOF you need..

SDW

Canon EOS-60D

12/04/2004 11:56:26 AM · #10

One thing that seems to be wrong is within the cameras limits. It looks like your camera [g2] has a lens range of 34mm to 105mm but the aperture is 2.0-25 / 8.0. I donâ��t know for sure but it looks like everything taken below the maximum zoom range will be set at an aperture of 2.0-2.5 giving you a very small DOF. But if you use the Zoom you can get an aperture of 8.0. If this is the case then you may want to step further away and zoom giving you the 8.0 aperture you need.
Hope this helps.
Info from DPReview

Message edited by author 2004-12-04 11:58:57.