macro work

[pinakibaidya]

Recently i bought Tamron 90mm macro lens.I took thi pic at iso 400,aperturef/18, and shutterspeed of 1/50.I am not satisfied with sharpness.Depth of field is very shallow.I cannot decrease aperture further as it will decrease shutterspeed further.What should i do?

[Bobobird]

Bit soft but not too bad either. Perhaps going to f18 is causing this. Try moving back a bit and cropping instead of trying to get all elements sharp from this short distance.

[DanK]

Yup, you are confronting one of the toughest problems in macro: shallow DOF. It's particularly hard to deal with deep flowers like this one. Bobo is of course correct that f/18 is well into the range that causes softness from diffraction, but frankly, I don't think that is your main problem. There are some edges that seem sharp to me, which would not be the case if diffraction were the main problem. Also, in my experience, you can do fine with flowers at that aperture.

One option for dealing with this problem is to keep your subject close to parallel to the sensor, to minimize the DOF you need. That does not work, however, with deep flowers. If you want crisp detail through the entire range, the best bet is to focus-stack, which also allows you to open up the aperture to lessen diffraction.

I'll give you a few examples. This one I took a long time ago with an XTi and an EF-S 60mm. It is one image (no stacking) at f/20. You can see that even at f/20, it is still fairly sharp.



Here is one I did a few days ago. This one, like yours, is deep, so there is no way I could capture all the detail with a single image. I shot at f/8 and stacked 10 images, each with a slightly different focal point.



Even with flatter flowers, stacking often helps, although with fewer images. This one, if I recall, was three images.

[WJT]

I'm guessing your hand holding? By using a tripod your options will be less limited. The other thing to sharpen the image is to try using a flash.