FMF - Friends of Minerals Forum, discussion and message board

[Matt_Zukowski]

I have always been disappointed with my mineral photography. All my pictures looked somehow "fuzzy," even though I have what should be a good camera (Canon xsi), a good macro lense (Tamron SP AF90mm F/2.8), and good lighting (color matched compact fluorescents). To get an adequate depth of field (DOF), I always used a high f stop (like f/32). But that, I think, was the problem. I have since learned that lenses loose sharpness at high f stops. This means that there is a tradeoff between DOF (requiring high f stops) and sharpness (requiring relatively lower f stops). Since mineral photography seems to require both a large DOF and sharpness, I thought perhaps my problem was that I had a defective or inadequate camera or both, and I pondered spending the big bucks without any guarantee that this hypothesis was correct.

Recently I discovered a procedure in photoshop that helps mitigate the tradeoff between DOF and sharpness. The way it works is you take a number of photos at low f stop (I am now using f/7.1) at different focuses. I plug the camera into my USB port, and using the live view function on the computer, focus in and take a separate picture of all parts of the specimen I want to be in focus in the final picture. Then I load all the pictures into photoshop as separate layers, and then align, merge, and flatten the layers into one image. Photoshop seems to know how to take the in-focus pieces from each picture and stitch them together. In more detail, the procedure is:

1) Open Bridge
2) Pull in photos as layers by:
. opening folder with images in bridge
. selecting all photos
. ToolsPhotoshopLoad Files Into Photoshop Layers
3) Select all layers in layers panel.
4) Align layers by going to EditAuto Align Layers (use auto)
5) Merge layers by going to EditAuto Blend Layers (choose stack)
6) Flatten result into one layer by going to LayersFlatten Image
7) Make any other edits you want
7) Save as a jpeg

I found a demonstration of this at
https://www.cameratown.com/guides/index.cfm?id=173#axzz0omfGxCPV
(link normalized by FMF)

I am attaching two examples. Pict "0094 Heulandite Savada, Jalgaon Dist 1" was the best I could do with a single high f stop picture. Compare this to Try3. "0081 Fluorite Shangbao Mine, Hunan 1" is my old picture, Untitled2 is the new picture (the colors on the old Shangbao fluorite were also incorrect for some reason.

Some might say that this photoshoping is cheating or is adding "fakeness" to my pictures. I disagree. The human eye is an amazing creation and it seems to do much better than any camera in providing a wide DOF with good sharpness. The photoshop procedure produces pictures that look much more like, and indeed almost just like, what my eye sees when I hold the specimen up to my computer and compare the picture to the real thing.

It is possible that I may have still have an inadequate or defective lense of camera. If this is the case then this photoshop procedure may not be useful to people who do have good or properly functioning equipment. But for me, with my equipment, this has rekindled a desire to photograph my specimens, without so much disappointment.

[Vinoterapia]

Hello Matt.

The procedure that you described is called focus stacking and is widely used in macro photography. There are several dedicated programs that you can test besides photoshop, ie. Zerene Stacker, Helicon Focus and CombineZ. People using some of these programs are able to shoot stacks of over 100 pictures in order to obtain the desired DOF, and in my opinion that is not cheating.
Depending on the Canon camera that you are using you may try a freeware program named Magic Lantern. This program adds features not included under the standard canon menus, and focus stacking is one of them.
In both parts of the forum ( Spanish and English) there are several persons using this technique, if you are interested I can look up their names to direct you to their posts.

Best regards.

José Luis.