Question on Macro lenses

[j-digg]

I was just wondering whether the DoF gets more shallow with a longer macro lens. I.e. would a 180mm generally have less in focus at the same f-stop as say an 85 or 100mm? Just wondering because a decent macro lens is more than likely next up on my list. Thx in advance for any helpful advice.

[daft_biker]

Yes.

But the closer you go the less difference it makes. At 1:1 it doesn't really make any practical difference that I can see...maybe a few hundredths of a mm if you're well stopped down.

If working at lower magnifications you might be able to use the extra DoF from a 50mm over a 180mm but the difference between 100mm and 180mm isn't as much.

I find the nicer bokeh from the 180mm lenses far outweighs any slight DoF loss. However, if working handheld the extra shutter speed needed for the longer lens could mean you won't be able to stop down as much...that'll probably make more difference.

[j-digg]

ahh.. great answer, tyvm!

[lowbone]

If you take a 180mm macro lens and a 100mm macro lens and you take the camera with the 180mm lens and back up until the image in the viewfinder is the exact same size as the camera using the 100mm lens and both cameras are using the same f stop the depth of field will be identical on both lenses.