First Macro shot (new lens)

[barabe]

Hello,

I just bought a new sigma 70-300 DG macro a couple of days ago. I decided to try the macro function on it today. I was looking trough the threds here and i see 1:1 ratio mentioned and this lens is a 1:2 so i do not think it is a real macro but i think it will do the job for now because i bought it mainly for sports shot. I am used to working with DOF but this is new to me, I think that in macro DOF is no longer measured in meters but milimeters, am I right? I took this picture a few hours ago and found that auto focus is almost impossible with Macro so i had to focus manually, am i doing something wrong?

[PhotoNewt]

Originally Posted by barabe

...am i doing something wrong?

No, on the contrary you are learning and that is always good.

You are correct, the DoF on Macro photography (and close up shots in general) is very small indeed, usually about the same in front and behind your focus point. Manual focus on Macro is absolutely necessary to get maximum control. Smaller apertures are always needed to maximize the DoF and get sharper images.

When I use my macro, most times I shoot at f/16 or higher to maximize the DoF, manual focus and exposure control, almost always on a tripod and with an external diffused flash on 2nd curtain to help "freeze" my subject.

[barabe]

Thank you Photonewt for clarification, It was my first attempt at Macro and when i saw the results i got, I realized a few things and wanted to confirm what i was thinking.

What about the 1:2 ratio on my lens, anyone can tell me what this will do?

[Stryker]

Originally Posted by barabe

What about the 1:2 ratio on my lens, anyone can tell me what this will do?

A 1:2 ratio means that the subject size will be rendered at half size on your camera sensor. In that sense, the lens is not a true macro which would be at least 1:1 meaning the subject is rendered at the same size on the sensor. For example, if the sensor size is 22.7 mm x 15.1 mm (for APS-C), then a 1 mm subject size would be shown as 1 mm on the sensor. This has got nothing to do with the megapixel size of the sensor, just the physical dimensions.

For more information, see this Wikipedia page.