Macro Frustrations

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GaryK26

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Gary
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I've had a Sigma 50mm Macro lens for about a year now and have had limited sucess with it - certainly nothing near the standard of macros that frequent this board.

The shallow DOF is a given with macro, but I'm wondering whether a 50mm would suffer more from this than a longer macro lens (Tamron 90, Canon 100, etc).

Being only 50mm means that I need to get real close to the subject - certainly not good for live bugs. Would I be better off using my 24-105 or 70-200 with extension tubes and/or TC 1.4?

In summary, I dont want to have to get so close and would like a little more DOF to play with. Any suggestions? (I'm not that seriously into macro to upgrade to a longer macro lens or the Canon MP-E)

Cheers
Gary
 
The longer the lens the less DOF you get, that's hy with a wide angle everything from 10f t to infinity is in focus. There is no escape from shallow DOF in Macro the only solution is several images focused at different points that are then focus stacked. Check out the Macro forum.
 
artyman said:
The longer the lens the less DOF you get, that's hy with a wide angle everything from 10f t to infinity is in focus. There is no escape from shallow DOF in Macro the only solution is several images focused at different points that are then focus stacked. Check out the Macro forum.
Click to expand...

It is not true that you get less depth of field with a longer lens. If the image size remains the same, depth of field remains the same regardless of focal length. So if you're at 1:1 magnification, depth of field is the same no matter what lens you use. Sure, if you don't change the camera position and just fit a longer lens, then the image will be bigger and DoF reduced, but if you then move back to regain the same framing, you end up where you started in terms of DoF.

If you desperately want more depth of field, pulling back a bit and enlarging the image from a smaller section of the frame will give you more depth of field. Eg, if you enlarge one half of the of the total frame area to get the final image you want, you will have gained extra depth of field worth one stop - with the corresponding impact on image quality, but I did say if you were desperate. If you enlarge one quarter of the frame, you gain two stops (if you are very desperate).

Effectively what you are doing here is reducing the magnification and making the image on the sensor smaller. This increases DoF.

The usual way of increasing macro DoF is to raise the f/number by using ring-flash. If that's not enough, focus stacking as artyman said works very well. The advantage of shooting macro with a longer lens is to gain working distance, and it also cuts out some of the background as field of view is reduced.
 
photo stacking definitely the way to go not as easy as it sounds cos if your subject moves a mm your stuffed hth mike
 
As Hoppy mentioned in his post the way I get a better depth of field in my macro photography is by using f/16 or higher. At the height of summer in bright sunlight occasionally I can do without the flash but most of the time I use my sigma ring flash. Focus stacking isn't an option that I really want to use as i want to be out taking the pictures not sat at the computer processing them.

There's several DIY solutions to using the onboard flash or a standard flash with a macro lens.
 
The only way your going to get 1:1 and not be as close to the subject is to get a longer lens.

The Sigma 50mm has a working distance (from the end of the lens to subject) of 40mm

The Tamron 90mm has a working distance (from the end of the lens to subject) of 99mm

The Sigma 105mm has a working distance (from the end of the lens to subject) of 122mm

The Canon 100mm has a working distance (from the end of the lens to subject) of 150mm
 
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