What lens would I use for this?

AdamIsMyName · Sep 8, 2011

I want to take photos of objects such as flowers and shells indoors, against black backgrounds that I could print out at high resolution for prints. I dont want their to be loss of DOF in the object though, I just want it crisp clean.

I have my canon 100mm 2.8 macro lens, but it has small DOF (say just the tip of the flower, or the petals, or the center will be in focus and the rest not) so I'd have to photostack them and that can be troublesome with ghosting and whatnot.

I was looking at the 28mm 2.8 wide angle lens, and 50mm 1.8 / 1.4 lens for other applications

Then I have the 18-55mm 3.5-5.6 kit lens. and a 75-300 zoom lens

I dont want to have to significantly crop anything because that affects resolution. I want these to be close ups.

Any recommendations of what lens I should use / look at getting for this, or do I just have to stack them

analog.universe · Sep 8, 2011

Someone correct me if I'm wrong, but if you shoot an object at 28mm so it fills the frame, and then shoot it at 100mm so it fills the frame, you'll have the same DOF at the same aperture. Isn't that right? If you want to cheat dof you need a smaller sensor?

I could be wrong, but I thought that was how I remembered it. If that's the case, the 100mm would be easiest because you'll need the least amount of black background, and you'll have a comfortable working distance. The 100 is certainly the sharpest and most well corrected of all the lenses you've mentioned.

bazooka · Sep 8, 2011

It gets complicated but for the most part, the dof is the same regardless of focal length assuming you frame the subject the same way. What changes is how that dof is distributed in front of and behind the focal plane. Check out this article.... Depth of field

analog.universe · Sep 8, 2011

That is exactly what we're talking about. Read bazooka's article, it's quite a comprehensive explanation.

AdamIsMyName · Sep 8, 2011

I shouldnt have said loss of DOF, I should have said low? small? DOF Such as just one area of the subject being in focus, vs. a shot taken where the entire subject is in focus.

I guess just photostack is best

Overread · Sep 8, 2011

Just to confuse things a little

The depth of field itself will remain the same, but the rendering of the background areas will be very different; the 28mm will show far more areas in the background of the photo with reduced blurring as compared to the 100mm, which renders with a much more blurred background. So you won't gain in depth of field, but you might well gain if you want more throw of the shot outside of the key parts.
Edit - or yah read the link Bazooka gave - about 1/3 of the way down is an ideal example comparing a 100mm to a 28mm showing clearly the difference in background rendering.

Out of interest what settings and kinds of shots are you currently taking? Flowers shouldn't need too many shots to get in focus and your mention of only getting a tiny bit of a whole flower in focus with the macro lens has me wondering about your choice of setting (esp aperture).

jaomul · Sep 8, 2011

Are you trying to almost fill the frame with your shells and flowers and have a dark background, or is it necessarily a macro shot?Very small aperture and a tripod should go a long way, or use your telephoto from a distance and crop a little.