Depth of field question?

[paule]

How do i get the flower in the background sharp without under exposing picture?
Attached picture was shot @ f22 , 1/60 exposure , iso1600 @ 135mm with my 75-300mm lens and processed with photoshop...:confused:
I thought f22 would be adaquat enough..

[CyberDyneSystems]

The longer the focal length,. the narower the depth of feild,.

At the same time,. the closer you are to the subject,. the narrower the depth of feild,..

So you could try to gain a larger depth of feild in two ways,. use a wider lens... or move further away..
Also, on your 10D you have a "depth of feild preview" button,. that will show you in the viewfinder the "stopped down" version...

[Dchemist]

I would suggest using manual focus so that you can choose to focus on the flower (if you have one, a tripod might be useful). The foreground and background will be somehwat out of focus depending on distance from the flower and the other lens settings but this might be pleasing in any case.

[RTMiller]

Its kinda hard to tell from your picture but the flower in the background looks to be about 4-5 feet behind the hanging half-coconut-like-thing. Just a quick check of my Depth of Field chart shows that at 135mm and f22, you would need to be 15ft away to get a DOF of 4.74 feet. Try backing up and re-shooting then crop the picture as you desire.

Here's a link link to a nice DOF chart you can customize... http://www.johnhendry.com/gadget/dof.php

[RJSorensen]

It will make a great composition when you achieve your desired results . . . nothing like having the desire to work for your art, until you achieve your goal. It will be very nice when complete.

[DaveG]

How do i get the flower in the background sharp without under exposing picture?
Attached picture was shot @ f22 , 1/60 exposure , iso1600 @ 135mm with my 75-300mm lens and processed with photoshop...:confused:
I thought f22 would be adaquat enough..

I'd set up my view camera so that I was focused on the foreground subject. Then I would swing (pivot) the front lens standard forward on the right. I'd watch the ground glass until both foreground and background subject were in focus. I'd close the lens, select an aperture and put a sheet film loader in the back of the camera, take out the dark slide and I'd take a shot.

That's what I would do. You can't. At least you can't with a conventional lens and camera. As you've discovered the depth of field won't cover - even at f22. You can try to focus one third to midway between the foreground subject and the background subject and see what you get. You could take two pictures one focused on the near and then on the far. Later you could blend them in Photoshop, and for the shot that you sent this might actually be a solution.

The other technique is to use a tilt/shift lens. In the camera you have right now the depth of field is always parallel with the back of the camera. Now that is caused by the lens not the camera. If you can tilt the lens down the depth of field plane tilts down too. In this shot tilting the lens may not work but swinging the lens (sideways tilt?) probably would.

Canon makes three tilt/shift lenses. They are completely manual by the way, with no AF at all. The Nikkor 35mm shift lens that I used to own didn't even have diaphragm control with the camera. You had to pre-set the aperture before you took a picture, and while I suspect that these lenses are the same, I'm not sure.

Before anyone runs out and buys a bellows so they can adapt their current lenses to some kind of ad hoc tilt/shift version there's a couple of things to consider.

A 35mm lens makes an image circle that will be just barely large enough to cover the 35mm format it's designed for. When you tilt/shift you are moving a rectangle around inside of that circle and if it's too small, you can easily run out and see vignetteing - really fall off. Large format photographers use movements (tilt, shift, swing and others) all the time, and in that niche of photography lenses are more valuable if they have larger image circles. Now with the 1.6 conversion factor with Canon's EF lenses we do have a larger than needed image circle. Unfortunately we have no way to control and actuate the diaphragm.

[Jim_T]

To increase DOF, you need a small aperture.

Using Av mode and choosing f/16 to f/32 might help. But not always.. You'd have to know the distances involved and consult a DOF chart to know for sure. Sometimes it's physically impossible :)

[paule]

Thanks guys for all your suggestions really greatfull.. I think i will try and do what daveg suggested and use photoshop to combine two images together, i will let you all know IF i can pull it of... Thanks again...

[milou]

Useful stuff on DoF: http://www.shortcourses.com/using/sharphess/chapter2.htm

[Jon]

Have you considered trying A-DEP mode (page 88 in your manual)?

[ed2day]

I second the A-DEP mode--this is one circumstance where it may be useful. It gets a bad rap, but I find it useful as a quick check to see if it's at least possible to get all the elements in focus from where you're standing. What's your focus point? That's critical. You need to be fousing somewhere between the near and far objects ( ideally at the "hyperfocal" distance).

edit: Hyperfocal is probably the wrong term since you are not focusing to infinity, but similar concept. There's an optimum focal distance for the range you are trying to capture.

[robertwgross]

A-DEP sounds like a good suggestion. If it forces your aperture very small, then that might force your shutter slow. So, use a tripod.

---Bob Gross---