Wednesday, June 12, 2013

Photographing Micro Precision Product Shots using Focus Stacking

I have many great clients, including Gene Kozak. Gene’s company is Kozak Micro Adjusters He sells high quality micro adjusting screws, bushings & gauges for a variety of industries. Gene is a brilliant guy and designs all his products himself. He came to me at the end of last year to shoot some of his products. The catch is most of them are quite small - less than one (1) inch long and very thin. The threads on the screws are also very fine - some of the finest in the industry.

A. Depth of Field

Photographing tiny objects presents some unique challenges. The biggest challenge is getting the entire object in sharp focus. This is because the combination of close shooting distances and high magnification results in very shallow “depth of field.” Depth of field is a fancy way of saying how much of an image is in focus.


Sometimes we want shallow depth of field. We’ve all seen (and I have done) photos where the main part of the image is sharp and the rest of the image falls into soft focus. Using shallow depth of field is a way to increase drama, and if you’ve read some of my prior blog posts, you know increased drama = increased interest = increase sales. But just as often, especially for technically precise products like Gene’s, you want deep depth of field so the entire image is in clear focus. This allows potential customers to see the quality and detail of what you’re photographing.
There are three common ways to increase the depth of field in a photo:  

1) Close down the aperture (F-stop) of the camera. The smaller the aperture (higher F-stop) the greater the area in focus.

2) Manipulate the focus plane to increase the apparent depth of field of the image. This can be done either with a “tilt-shift” lens or a “view” camera. Both tilt-shift lenses and view cameras allow you to tilt the focus plane parallel to the subject matter allowing it to appear that more of the image is in focus.

3) Use focus stacking. Focus stacking uses several photos of the same object taken at different focus points. Those multiple photos are then combined in Photoshop to create one image where everything is in sharp focus.

B. Focus Stacking

With regard to very small objects, the first two methods of increasing depth of field - shooting at small apertures, or using a tilt-shift lens or view camera - usually come up short. Thus, focus stacking is the only way to get everything in sharp focus.

Below is an example of a group of Gene’s products. The first shot is the final image after focus stacking is applied. The individual shots I used to create the final image are below it.


There is no set formula for number of photos you’ll need to do focus stacking. The general rule is the smaller the object and/or higher the magnification, the more photos will be required. There is specialty software that automates the focus stacking process but I prefer to use Photoshop. Photoshop can automatically stack and align the individual images. Then I mask off the unsharp portions of each image by hand. This tends to be more time consuming, but I feel it yields better results.
A final side note: the higher the magnification the easier it is to see dirt, dust, dings and other imperfections in the product itself. This is true whether it’s an expensive piece of jewelry or a precision adjusting screw. So the better the condition of the samples when they arrive at my studio, the easier it is to get great product shots. That said, even the best samples usually require a fair amount of retouching when shooting at high magnifications.
So there it is: focus stacking to create deep depth of field in your micro precision product photos.
As always please contact me with questions or leave comments in the space below.