DOF + more on crop ?

[r.morales]

In macro , the DOF almost doesn't exist .
If I shoot with a 100 mm [ not in macro mode ] and crop I get a better DOF . But I don't know if a shot on a canon 85 1.8 cropped would be better than a 100 macro .
I don't own either - but want a better DOF . Since I seldom go below F 8 the 1.8 and 2.8 would not normally be used .
I have the Quantaray 70 - 300 macro lens which according to a chart I downloaded isn't a true macro . It is only in macro mode at 300 .
I am using an XTI , From what has been posted I need a 100 canon macro and or a 5D . Which brings up another question - would a 5D be better than a 50 D ? The 5D is 12.8 megs and the 50 D 15.1 megs . I should be able to back up with the 50 D and then crop [ ? ] for a better DOF .
I hope this makes sense

[JeffreyG]

You've got a lot going on there. I'll break it down a bit.

To start, in the realm of macro (1:2 magnification and greater) the magnification itself is what determines the DOF. Focal length is not a factor. So a 180mm macro and a 50mm macro will have equal DOF if both are being used at f/8 and 1:1 magnification.

The reason you got more DOF when you shot further back and cropped the shot is because you were shooting at significantly less than 1:1 magnification and then enlarging the image more. Using a smaller sensor (like the 50D) over a 5D does this to some extent as well and so the 50D will yield greater macro DOF given equal subject framing in the final image.

The number one thing you need to do to get more DOF is stop down more. I rarely shoot even 1:2 at less than f/11 on a 5D. You should be shooting in the range of f/11 to f/22 for the most part. If that isn't enough still, try focus stacking in Photoshop.

[gasrocks]

It doesn't really depends on how you got to 1:1, you'll have the same DOF with any set-up. Be very cautious about going over f/13 or so because most lenses have a severe drop in IQ over that. Big trick is to learn the correct way to use the DOF that you do have.

[Glenn NK]

Consider focus stacking.

http://en.wikipedia.org/wiki/Focus_stacking

http://www.flickr.com/groups/macroviewers/discuss/163367/

http://www.digitalgrin.com/showthread.php?t=61316

Hopefully you have a tripod somewhere in that gear list - it quite useful for closeup and macro work.;)

The software won't cost a penny:

http://www.hadleyweb.pwp.blueyonder.co.uk/CZ5/combinez5.htm

[r.morales]

Thanks , Yes I have a few tripods. I'll read up on the stacking later .
The software won't cost a penny:

http://www.hadleyweb.pwp.blueyonder..../combinez5.htm
This is for a PC . I am on a Mac .
I do have CS 3 extended - still trying to figure it out tho . I jumped from PS7 to CS3 when I went to OS 10.5