In Anticipation of Bugs to Come
 

While the weather has been a bit grim I have been playing with my ' toys ' - lathe and mill to repair some of my aging kit.

Some members ( Harry - Wolfie uses it ) may be familiar with Combined ZM. Its a freebee program that can be used to stack a series of images taken at different points of focus to increase depth of field.
Link to CZM here http://www.hadleyweb.pwp.blueyonder....inezm_help.htm

Thinking about this I have a Manfrotto adjustable Micro plate, ( Dave posted some pics of it in post 95 here
http://www.worldphotographyforum.com...ead.php?t=1618
So I decided to do a little mod. and make a micro adjuster to replace the standard screw. This has engravings to allow precise movement of the camera platform in increments of 0.1mm. A bit fine you may think but then I am targeting this at Bugs possibly using a reversed 28mm lens. The idea being to focus on the subject leading edge and then drive the platform forward by an increment suitable for the subject to change the in focus point. This can of course also be done by refocussing the lens after each exposure but that is not as precise as I was looking for.

Test day today and I gave it a workout, and CombinedZM a bit of a hard task. I took a series of 15 images moving the plate forward in 5mm increments. Aperture was f8 throughout ( exif is in image 1 of the stack ) chosen to give a shallow depth of field. The stack was made from a series of jpegs as 15 x 70mb tiffs would probably have made my pc fall over. CombineZM did its work in about 10 minutes but I did have to crop a bit of spurious stuff it generated from the left and top sides. Motto seems to be do not quite fill the frame, but allow for a bit of edge cropping. Well pleased with the result, as magnification does alter as the image focus point changes. No doubt it is that that created the spurious information at the left and top side of the image. As an aside Combine ZM does not retain exif information.

Don

PS : As Foxy has reminded me Combine ZM is NOT available for Macs.

Well it worked very well.
Don I would like to try some stacking, Will it work if I don't move camera but change the focus (say focus on a pencil or whatever and focus on the front edge then change focus along the length until till I get to the end to take 6 or so shots?)
What effect will that have with CZM?

No probs at all with manual focussing through the subject. My plot is to get max magnification on small bugs and manually focussing through say subjects of between 1-3mm is a bit tricky with a reversed 28mm lens. Wolfie has used this in flowers which are big enough to allow for easy seeing of each of the manual focus stages.

Probably a bit of experimentation needed to decide how many focus stages are required for a given subject.

You need a still subject and camera on a tripod for this though as CZM takes all your images and stacks the parts that are in focus. If the subject has moved between frames then the program will get a bit lost when trying to do the combine.

Unless Harry jumps on this thread with some examples I will have a rummage tomorrow to see if I can link to some of his pics.

Don

Thanks for that Don, It's just that I tried to do some stacking today, I had three Tulips in row at an angle going away from me, I took three shots (from a tripod) and focused on each one in turn when I put then through CZM
it looked horrible (halo's all over the place) But then again it was hardly Macro work! would that have been the problem?
PS
Noticed I am now a proud owner of a D300?

Lello,

How could I not have noticed your D300. :p

Your problem was probably due to not enough focus stages.

As the workshop doubles as a photostudio but is in a bit of a mess at the moment I will try a series tomorrow of my lathe. That is 44 inches long, so a series shot on the diagonal should be an interesting challenge for a non macro stack. A bit like your pencil suggestion but on a larger scale. :D :D

Don

Look foward to the results,
Catch you later
Lello

I knew I would find Harrys post if I looked hard enough ;)
http://www.worldphotographyforum.com...read.php?t=741

Don

Hi Don an excellent thread - thanks for the info - my job now will be to find a "Toy" that will do the same on a Mac. Thanks again - that last thumbnail is superb.

Andy,

You have beaten me to it, there must be a good stacking program for a mac. Could you please check-out and report back.

Excellent example of focus stacking Don.

For Mac users have a look here http://www.heliconsoft.com/heliconfocus_downloads.html This is better than ZM, but you do have to pay for it