CF or FF for Macro

Hi,
I've posted this in the Macro forum without reply and I'll try it here again. My questions are:
1) Does 50D has better live view functions compare to 40D?
2) For Macro, which body will be better, CF or FF?
I'm doing research for an upgrade from XTi.
Thanks.

I can't answer about Live View, as I don't use it. For your question 2): do you mean would a 1.6 crop body, like the XTi/40D/50D or a full-frame body like the 1D or 5D be better for Macro work?
I would think a crop body like the XTi/40D/50D would be fine for macro. With a full-frame body, you would have to get closer to your subject to get the same view.

Like with the 100mm f/2.8 Macro lens. At 10" from your subject, the subject will be larger in the viewfinder (and in the resulting image) with the Xti/xxD bodoies than it would be with the 1D or 5D full-frame body.
I have an XTi and it does a very nice job with Macro shots. I would suggest getting a good Macro lens like the Canon 60mm or 100mm, TAmron 90mm or Sigma 105mm if you don't already have one.

Not sure this helps, but it looks like you've been waiting for someone to chime in.

thanks so much for the reply.
I currently have XTi and Sigma 105mm Macro and am checking out a FF body, 5D II. It appears that's not necessary and the cropped body might be better for macro anyway.
In that case, I'd really like to know if there are differences for the live view function between 50D and 40D. Anyone?

live view on 50D is same as 450D which have contract detect (not available on 40D), other than that everything else same. Contrast detect sounds good on paper but when i tried it, it takes around 5 secs to focus (which is impracticable for me even for general shooting), you'll better using 5/10x zoom and manual focus for macro

as for macro, with FF and same lens let say 100 macro, you would have to get closer to the subject to fill the same image, which result smaller DOF (need to stop down alot to get same DOF as 1.6x crop camera), whereas with Crop factor some said it easier to produce diffraction on smaller aperture (which i never experience it myself)

I see it a little differently. Macro work is all about magnification, and usually as much as you can get. That means that you are operating most often at the minimum focusing distance. That will give you 1:1 whether you use the 60/2.8 on a cropper, or the 100/2.8 on FF. The size of the image of the subject falling on the sensor will be the same. The cropper will of course crop it.

There are therefore 3 advantages at least for using the FF/100 combination over the APS-C/60, even though the image size on the sensor is the same at minimum distance and 1:1 magnification:
1) The FF sensor will capture more of the subject
2) The working distance is greater, so
2a) greater DoF
2b) less chance of spooking timid subjects
3) The larger sensor also allows a smaller aperture before diffraction softening sets in (helping DoF even more)

P.S.
Note on 2a. Although the greater distance means greater DoF, the longer focal length means shallower DoF. If that was all there was to it, the 60 would have the greater DoF, but once you take the circle of confusion into account, it is the 100/FF that is favoured. Or so my calculations lead me to believe - I'm very receptive to correction by better informed POTNers.

P.P.S.
OK - on doing a little more reading, it turns out that at macro distances DOF is proportional to the CoC (and dependent on other things, like magnification and aperture), but independent of distance. The FF body, with the larger circle of confusion will have the deeper depth of field. The factor? You guessed it: 1.6 x.

xarqi wrote in post #6755156
Macro work is all about magnification, and usually as much as you can get.

True, and the op gets more magnification with same working distance with his 105mm Sigma on a crop camera than FF
But very good points on the crop vs. FF comparison while having equivalent fov.

vincent_su,
First... the reason why you might not of gotten a response in the macro section is: your question is in the macro photo sharing section, not the macro talk section

Second... I haven't used the 50D, but I don't believe you would get a major difference. However the LCD on the 50D is known to be better quality.

vincent_su wrote in post #6753604
2) For Macro, which body will be better, CF or FF?

I have both a FF 5D and a APS-C 40D and the live view really helps with larger then life size (greater then 1:1) macro non moving subjects. However unless using a tripod, using live view doesn't make macro photography any easier (for me). The APS-C sensors also make the subject seem like 1.6 times more magnification vs. a FF.

Both types of cameras (5D and 40D) can produce excellent macro photos, I personally would rather have my 40D

Mazu wrote in post #6755268
True, and the op gets more magnification and greater working distance with his 105mm Sigma on a crop camera than FF
But very good points on the crop vs. FF comparison while having equivalent fov.

I don't know much about the Sigma 105 in particular, but it will have the same maximum magnification and minimum focusing distance no matter what body you mount it on, surely; the sensor doesn't change the optics. He'll still get a 1.6x DoF advantage on the FF due to the larger CoC though.

Thanks Everyone.
The info is very much appreciated. I do have focusing rail for the macro shots. That's why I want the best live view fuction to aid the process. Sounds like 40D or 50D will be better in macro.
Meanwhile, I'll go look for the Macro Talk section.
Thanks again.

For true macro, the sensor is irrelevant. For closeups, crop sensors will give you a much tighter shot and more usable resolution.