Forsythia Stem Gall

Growing in the corner of next doors front garden is an old forsythia bush. It had got to the stage where some of it was almost blocking the grass verge which is the nearest we have to a public footpath so I asked permission to chop it back somewhat.

While I was disposing of the branches I noticed many of the smaller twigs were covered with nodules. A search found that these are Forsythia Stem Galls, probably caused by the bacterium Pseudomonas savastanoi.






It seems a long while since I tried a serious macro using stacked photos so I got out the Heath Robinson effort I built a few years ago. This consists of a stripped down PC DVD player and an Arduino Nano. The Arduino drives the small stepper motor in the DVD player which moves the item being photographed a tiny distance further away from the camera at each pulse. At the same time it tells the camera to take a photo once any vibration has settled down.

 

The Canon 350D was fitted with a 70-200mm zoom lens with a Raynox DCR-250 macro lens added. As well as natural light an LED ring flash was used on continuous light. Each photo has a very small depth of field:



72 photos were taken, each with the gall a tiny fraction further away from the lens so each had a different part in focus. Finally I used CombineZP which stacks together the in focus bits from each photo. The idea is to end up with one photo with all the subject in focus:

 

This is the best result I have ever had using CombineZP so am well chuffed, worth waiting over 20 minutes of processing time to get the finished photo.

A Closer Look

Quite some time ago I bought one of the plastic USB microscopes hoping to get some reasonable micro photos. Unfortunately the results were disappointing not least being the annoying way the program provided with it changed to a low resolution monitor screen and moved all my desktop icons about. Also the plastic would stick and jump when focussing, very frustrating. Oh well, you get what you pay for!

Later I bought a used optical microscope hoping to use the same technique as  Phil for some of his excellent shots on his blog Beyond the Human Eye. That is to use a digital camera in place of the eyepiece of the microscope. No joy here. I just could not get the idea to work.

Finally I bought a USB microscope camera which fits in the top of the microscope in place of the eyepiece. Once again I was disappointed with the results. The 5 megapixel camera worked just fine but the depth of field was extremely limited so I packed everything away.

Can you see where this is leading? Enter the program CombineZP. I decided to try again. Not brilliant photos but a vast improvement on past experience. All I could find on scouring the garden yesterday was a discarded feather so I had a go to see what I could see.

First the setup - microscope with USB camera sticking out of the top.


I used my bright LED lamp as light source. I think the camera works about the same as a 10x optical eyepiece so this first photo is at 40x magnification.


Now at 100x magnification


Finally at what is probably 400x magnification.


Each of the above was made with a pile of nine individual photos each focussed slightly differently and processed using the program CombineZP. To give an idea this is one of the nine taken for the 100x magnification showing how quickly parts of the view go out of focus. No further processing of the photos except cropping to remove a small extra reflected area the program adds to the edge of each.


Now I have to experiment more with the lighting as this is quite critical in obtaining clear photos but at last it is worth persevering with my investment.

CombineZP - Updated

Another test of CombineZP

Set up the 350D with bellows to get a close look at a strawberry flower.
Lighting from a bright LED lamp.



Took 12 photos varying the focus a little between each.
One of the shots showing how shallow the depth of field was.



Let CombineZP align and then  Stack the photos



A better lens, better lighting and operating the camera with a cable release would make for a crisper result but this certainly shows the possibilities of the program.

Later.
It was later that I noticed some aberration at the bottom of the stacked photo and the next try I carried out with a different lens taking 16 shots had distortions on all edges. Possibly a result of the shots differing in subject size as the focus is altered. The centre part of the picture is fine and it is possibly better to make sure the subject doesn't fill the frame.



This is a crop of the main part of my final session for now.
The lens used was an old Super Takumar 55mm f1.2 manually set to f4 as wider apertures gave poor results. The 350D was set to ISO 400 and 1/200sec

For Adrian - CombineZP

Yesterday Adrian was experimenting with a commercial program which combines a set of photos of the same subject but with different focus points. The idea being to make a resultant photo where everything is in focus. Very useful for macro shots where the depth of field is very shallow. See his post HERE. Without Adrian's blog I would never have know that such programs existed.

That caught my imagination so I decided to see what could be done for free! After a hour searching and looking at various options I eventually found a great free (released under the GNU Public License) program - CombineZP - and tried it out. My simple test involved placing five batteries at different distances from the camera and taking five shots each with one of the cells in sharp focus. Point CombineZP at a folder on the PC which contains the five shots, tell it to Align and Balance them and then tell the program to 'Do Stack' - result, all in focus on one photo.



From top to bottom, the first and last of the five individual photos and finally the result of stacking / piling them with CombineZP.  Looks a handy utility to have for still subjects where it is hard or impossible to get everything in focus with one shot.  CombineZP site is HERE.