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

Well if I can get anywhere near the fly in the Helicon Focus page then I will be dead chuffed.

Interesting show of how a stack is focussed. Maybe I needed more than 15 images for my sample.

Harry, do you have any other samples you could post here.

Don

Hi Don.

Sorry, no I do not have any samples apart from the one embedded.
Only this series of photos taken just a few moments ago as an example.

I have just fired of 6 shots all hand held using flash, so excuse the quality.

You mentioned the spurious effect that you experience using ZM. I guess this is the rotational affect on the extreme edges of the image, hence the need to crop. This does not happen when using Helicon. So the attached images are uncropped and apart from levels and USM no post processing.

As this has been a rush job please excuse the quality.

Harry

Thanks for that Wolfie - looks good but I definitely DON'T like the idea of a time limited Licence. I notice you are feeding our little green friends again:)

Andy, you could always pay the £126.80, then there's no time limit :)
As an alternative you cold also dump the Mac :) :) and use Combine ZM

Harry

Nice ones Harry. Stevie cringed at the wildlife. :eek:

For Lello and others I have had another go. Pushing the boundarys a bit but then I want to do this for free so I'll stick with CZM.

I had a bit of a problem trying to do the lathe. I needed a 28mm lens to get it in, and due to the inherently wide dof manually focussing accurately along various points that I could later identify for this post was a nightmare. So an alternative subject had to be found where I could mentally note the focus points between frames, hence this choice of currently completed workshop projects. Repaired ballhead, rotating base and stub centre column on Manfrotto 055 tripod.

Manual refocussing of the lens between frames was chosen as opposed to my Micro plate. This was to confirm that it could be done for the benefit of those without such a plate. Aperture was kept to a shallow f8, again to check the effect over a subject with a depth of 130mm. 9 focus points over 130mm of depth is probably the fewest I would currently recommend. Camera was set to jpeg medium fine again to replicate a fairly worse case scenario for those that do not use RAW. ( I can sense Foxy's thoughts from here. :D :D )

Attatched images :
1) Image with explanitory notes
2) The first frame at focus point 1 to show dof at f8
3) The final stacked image

Don

This image looks a bit up Andy's street :) and is image 9 from the stack overlayed on to image 1 to give an idea of how magnification changes as focus alters.

It also shows how nifty this program is when arriving at the final result and the benefit of providing sufficient frames to help it do that.

Don

Don, Again an excellent example of focus stacking, but just one point, especially when using a focus rail (screw/worm drive) you only need to establish your first point of focus, then depending on the thread size just give it 1-2 revolutions to obtain the varying focus points.

not quite so simple when you're out in the field hand holding the camera.

Harry

:eek: :eek: :eek:

Can it handle those frames then ?

Don

Don I agree - those separate frames need some of my playthings on them - how about a bright orange "Rudra Glass" base plus a little solarization?? Definite possibilities ;) - Still think its a bit pricey Harry - cannot deplete the D3 fund as I have a bad attack of NAS (Nikon Acquisition Syndrome) at the moment!! :o

The short answer is yes, but out in the field I would use a small aperture such as f/16 - f/22 so as to obtain maximum DOF and only take approx 5-6 images. Occasionally discarding one image.
Obviously these 5 images will not be perfectly aligned, I think this is why we need to allow for cropping so as to crop out the rotational effect on the extreme edges. (Rotational being my description for what I assume you mean by spurious information)

Harry

Harry,

That was the reasoning behind the micro adjuster I made. If I use a reversed 28mm then I loose auto diaphragm so multiple focussing ops would just be a pain. Todays effort was really for Lello's benefit so focussing was by lens only.

Don

:eek: Looking at your signature " Equipment: Nikon - D2x; D300; D2h; D200 - More than enough !!! "

Perhaps a revision required - Not quite enough !!! :D :D

Don

PS : When you have spent that bankroll you can save up for whatever the replacement for the D2X is called.

Hi Don
sorry I have Been busy, Well the experiment seems to have worked well using the focus only technique, I will try the same sort of thing over the weekend and let you know how I get on.
Lello

Hi Don - am holding fire as there are rumors of a D3x in August - FX format and 24mp plus the soup-up like the D2x to D2xs. Also there is the new D3p series with the extra picture control button on the body rather than in the menu.

CZM Update
 

No bugs yet but experimentation continues.

I have tried a stack as large as 32frames now, but unlike Astro stacking where more is best, I have found this does NOT apply with CZM. 32 frames was a bit of a disaster when compared to a 9 frame stack from a selection taken from the same set of images.

As posted previously as focus changes so does magnification.
I have compared the difference between moving the sliding rail and refocussing the lens between shots. Refocussing the lens reduces the magnification difference between first and last frames significantly when compared to the sliding rail focussing method.
Two images attatched to show the difference.
Image 1 is an overlay from the sliding rail focussing method, of Frame 32 on Frame 1 from an earlier experiment. Zone of focus - bias weight to back edge of the head is 70mm.
Image 2 is an overlay from refocussing the lens method, of Fame 6 on Frame 1 of the attatched main image from the experiment.

Image 3 is the result of a stack of 6 frames with refocussing by way of the lens between shots. Zone of focus 80mm taken at f8.
Image 4 is a 100% crop from image 3 as an example of the accuracy of registration from the stacking program.

Hey ho, back to the drawing board to come up with a means of micro adjusting focus on the lens without having to peer through the viewfinder to determine the points. :rolleyes:

Don

Sounds like thats worth a thread on its own ..... Nikon rumours. :D
I know I've been out of circulation for a few days, so where did this come from ??

Don

Been meaning to have a play with this program since this thread went up & a wet Sunday afternoon seemed the right time.

Used my 70-300 IS lens with a Canon 500D close up filter. To judge my focus points I just stuck a sliver of post it note on the lens focus grip and another on the lens barrel marked out with the furthest & nearest points of focus and 5 intermediate positions, aperture set at f8

Neat trick with the post-it note Clive, and the resulting image ........................ SUPERB. :cool:

Don