increasing depth of field : macro

Hi everyone, i was hoping someone might be able to help me out here. I use a canon rebel T1i, and a f 2.8 100 mm macro, and i have a

set of three extension tubes. I find it difficult to increase my depth of field, how can i get the maximum depth of field ?

There is a tutorial on the photo.net home page about focus stacking. Otherwise your choices to increase depth of field

would be to use a smaller apeture, shorter focal length, or greater lens to subject distance. (the last two choices are not

that helpful for macro)

<p>When I am doing macro since I tend to photograph insects outside and they don't hold still long enough for focus stacking I have started either stopping down (to a certain point to avoid diffraction) or I move a little bit further back from my subject and then crop the photo in post. These techniques are all from suggestions provided to me by the photo.net community and have worked quite well for me so far. A combination of both can work as well.</p>

<p>Your ability to move back and crop down might be limited though by the resolution of your camera and how large you intend on printing your photos once you are done.</p>

<p>You can try and rework your composition to get the important plane you want to align with your sensor/lens plane. Unfortunately this usually ruins the composition you will want. But sometimes only a small shift in perspective is needed.<br>

You could find a lens that offers tilt. This lets you move the plane of focus onto the plane of your subject. The Nikon 85mm PC-E Micro is a good example of this type of of lens. I'm not sure if Canon makes an equivalent, but you can use Nikon lenses on your camera with an inexpensive adapter.<br>

Moving to a smaller sensor camera can also work. For example you could pick up a micro 4/3 camera with an adapter for macro work. You can find adapters that work well for most lenses on these cameras. Another advantage is you can sometimes find a tilt adapter, but these are usually on adapters for medium format lenses.<br>

What type of subjects are you shooting? Fiddling with tilt and focus stacking really only works well for static subjects.</p>

<p>Depth of field is very limited when you use a macro lens even when it is stopped down--the f stop is set to a large number like f 16 or f 22. To increase DOF you need to increase your distance from the subject, other things being the same. This link provides good info on various macro subjects and gives you calculators for key things like depth of field and diffraction once you enter your variables for focal length, etc. <br>

<a href="http://www.cambridgeincolour.com/tutorials/macro-lenses.htm">http://www.cambridgeincolour.com/tutorials/macro-lenses.htm</a><br>

With digital sensors, diffraction seems to be more of an issue than it was with film. I try and limit my smallest aperture settings to around f11.</p>

<p>Joe Smith</p>

<p>1) stop down - decide for yourself whether the increased DOF gained from f16 or f22 is preferable to any diffraction issues<br>

2) for stacking insects out of doors, take bursts of photos - if handheld your own movement may lead to several differently-focused frames that you can stack<br>

3) or consider a camera with a smaller sensor </p>

<p>Thank you everyone for the feedback this is very helpfull.<br>

one last question, i think i know intuitivley what it is, but can someone explain or at least point me in the direction of an explanation of "focus stacking"</p>

<p>thanks again everyone!</p>

<p>Here's a tutorial on focus stacking:<br>

<a href="../learn/macro/focus/stacking/harold-davis/">http://www.photo.net/learn/macro/focus/stacking/harold-davis/</a></p>

<p>The addition of extension tube(s) would shorten depth of field. Depth of field can be improved if you hold the camera parallel to the subject. For example, holding the camera parallel to the butterfly wings (<strong>not</strong> at an angle) would capture the textured detail of the wings.</p>

<p>I have to dispel the myth that a wider angle gives a greater DOF. For a given magnification of the subject it makes no difference.</p>