help with focus stacking, please!

[thebeing]

hey, guys!
sorry if i don't post this where i really should, but, to be honest, i can't think of a better place to start this thread in...
so, i really need help with focus stacking.
I read Brian's article on wonderful photos, but that didn't help too much (i'll explain why in a moment) and i was thinking that maybe some of you guys here use somewhat the same gear i do.

So, why wasn't Brian's article helpful? well, i use a sigma 55-200 with a 50mm 1.8 inversed in front of the sigma (hand held for the moment, waiting for the 55-52 inverse ring to arrive). Now, Brian says

Then move the camera trying to keep the FOV similar and not rotating the camera until the OOF area in the previous shot just comes into focus. Continue doing this until you have covered the required DOF. If you are using a tripod (perhaps recommended for first goes at this) then do the same thing but use the focus ring to move to the next "slice".

ok. but with that i use, i don't quite have the ability to do any of these 2 things. and here i need help, because i went up to f/32 on the sigma to get more dof, and still it's WAY too less.

Thanx in advance, guys!

[LordV]

Not sure I understand but suspect you are misunderstanding what I meant by keeping the FOV similar. When you move the camera in for the various focus points, you will lose some FOV off the edges (this does not matter) but you need to keep the central part of the image you are aiming for in the same place in the image approximately. In other words you have a specific target in the image you are moving the camera towards thus keeping it in the same approx position in the FOV. The whole reason I use focus stacking is to avoid using small apertures so for example if I'm shooting at 3:1 mag I will be shooting at F7.1
Normally when setting up for a focus stack I do a quick zoom through the image by moving the camera to check how the image framing looks before I go back to to the nearest focus point and actually take the focus slices.

Brian V.

[thebeing]

hm...but, moving toward the subject, doesn't that make the subject bigger when "reaching" for the far-end focus slice?
+ approx how many images do you take when making a stack? (and i don't mean how many images you use, but how many times you actually press the shutter)...
thanx for the answers

[thebeing]

ok, so, i gave it a try, again... (i did before, but wasn't pleased at all with the result...)

so, 3 stacked images... so, any tips, comments to what i did wrong?

thanx!

[LordV]

Yes the image does get bigger as you move in but the software re-sizes all the images during the stacking process. If I'm shooting a live bug it depends a but but I normally stack between 2 and 5 shots but may take say 2 more shots than that.

Re the stacked image not sure what aperture you were shooting at but looks fairly wide. you have at least 2 if not more slices missing. Fly's eyes are very hard and show up rather badly any missing slices. Focus stacks nearly always require some cleaning up after where you get errors- either halos around high contrast edges or loss of detail behind objects in the foreground. You can either do this using the clone or healing brushes in PS or do as I often do use the healing brush to copy detail from the original pics onto the stacked image.
Getting good looking stacks does take a lot of practice and is not a necessity for producing good macro images.

Brian v.