1. Introduction, focus stacking
When taking macro photos you get a very narrow focus depth. Even with a very small aperture the focus depth is narrow. One technique to overcome this is to take a lot of photos at different focus points. Together these photos will cover the whole object in focus.
Wikipedia has more information about focus stacking:
But how to get all these separate photos to one alone photo with focus all over the object? If there are only a few photos you can do it with Photoshop or Gimp or other image editing tool. You set a layer for every photo and with mask get the areas with sharpness and then blend them together.
With focus stacking you normally have 20 photos or more and then the above method is unpractical. There are many software that can do this more or less automatic. ImageJ which I use in astrophotography is one, Hugin is another. Helicon Focus and Zerene stacker are good what I have read, they are not free but seems to have a 30 days free trail. Now in the beginning I look for a free software that I can get some experience from. ImageJ and Hugin are free but they can not handle a DSLR raw format. You have then to do it in two or more steps. After some search on internet I found a German software, Picolay. It can do everything I want to do now in the beginning.
Here is a list of the focus stacking software mention above with links:
Here is a list of free image editing tools with links:
Visit the above pages and judge yourself what's the best software for you. I have only tested the Picolay to do focus stacking with.
2. Taking focus stacking photos
I use my new macro slider to do this.
I have changed my setup since my first test of the macro slider. Now I have the camera mounted on the more stable holder and the object on the slider. Line up the camera focus-axis to be parallel with the axis of the macro slider.
The lens is a Pentacon 50 mm f/1.8 and reverse mounted. With a 28 mm extension tube I get 2:1 magnification, if I add all three extension tubes they together have a length of 49 mm and I get 2.4:1 magnification. This test is done with the 2:1 setup.
I ordered a LED light with flexible arms and synced from the camera. They can both be used as a lamp and a flash. But the flash exposure is long and you can not freeze vibration as with a normal flash.
I have the camera in manual mode, daylight white balance and raw format. I also have an intervalometer to fire the camera. Set the interval to about 2x6=12 seconds to let the camera have time to display every photo and also let me have time to change the position of the macro slider. I have the mirror lock enabled then it takes to shots to do one exposure. It was recommended to use the live view, but then the camera didn't sync the flash. Full aperture and exposure time of 1/125 sec. The LED light is set to flash mode with as bright as it can be set.
If you get photos like this with a black border at bottom you have too short exposure time, it doesn't sync correct with your flash light source.
My object is a green cough drop and it have about 35 mm depth. I try to change the position with 0.5 mm every step and then get about 70 photos in a focus sequence. I do about the same as I did here: Macro slider test
Three of 82 photos I took:
This was a bit time consuming and have to do it more then once until I get everything correct. Now I just have to set them together to a main macro photo.
3. Making a main photo from focus stack:
How to do this merge of the focus stack depends very much of which software you use. I have used the Picolay I wrote about in the beginning. Visit the Picolay homepage and read the tutorial to find the details how to use it. It's very easy to use even if the small details can be tricky to get correct. This is my first test and can for sure be much better. I need more practice and experience.
Even if it's not perfect there is a big difference compare to a single macro photo shot. What a focus depth!
I have tried many settings to get the background cleaner, but it's difficult to get it perfect. You have to do the final refinements in some other software.
4. Final refinement:
I have used the IrfanView to do some easy refinement of the image. Make more contrast and make the background more even.
Green or black back ground.
Credits to Picolay (focus stacking) and IrfanView (image processing).
With more time and maybe a more sophisticated software it can be done much more nice looking. I just wanted to get some ideas what can be done. Until now I have spent about 100 Euro at the special macro equipment, it isn't an expensive hobby.