Stacking It In the Studio - And not at the Motorcycle Races

I mentioned earlier in the week the unending quest for depth of field with studio tabletop illustration. In most cases of products or packs, we can shoot from such a distance that we avoid running out of depth of field. We select medium focal length lenses and stop down enough to get the thing sharp from the front of the product to the back.

 I do not know if anyone uses the facilities of the older monorail large format cameras to gain this sharpness - perhaps they would if there were an affordable digital sensor that you could slot into the back of the camera. But there isn't - no great new discovery of a 4 x 5 digital back has appeared.
The pack shots take care of themselves - people also have the option for tilting and shifting if they use the larger full-frame cameras. For an amazing amount of money they can get tilt and shift lenses for their DSLR. Few give way to the need for amazement and many save their money...

Well today I tried the Olympus solution to this problem - the focus stacking program inside the new OM-D E-M1 mk II camera. Thanks to YouTube I found out the difference between focus bracketing and focus stacking and watched the camera do both things.

 Focus bracketing is the automatic process of shooting slices of an image with different focus points and then having them ready to present to a suitable external processor - Zerene or Helicon or Photoshop - for combination. You get to specify how many slices and how deep they are, and once you press the go button the thing is automatic. You can apparently use it to fire flashes as it works, though I did not achieve this. In any case you can watch the back LCD screen as it shoots and see the focus travel back from the start point.

Focus stacking is similar, but you don't get to choose how many slices - just the depth.  Compensation is provided by the fact that this Olympus program does the processing in-camera after the final shot and presents you with a final result.

Here's an illustration of the basic problems - this Soviet motor bus is 1:43 scale, and ends up being about the length of your hand. A conventional shot with a macro lens leaves soft edges at the front and back bumper.

You don't have this sort of problem with a shorter model such as this taxi.

I was unable to get the 25mm f:1.2 lens to work with the focus stacking, but the 300mm f:4 lens did go very well. It meant retreating to the back of the studio to get the thing in frame...not a practical way to shoot... but look how well it stacked in front and back.

Perspective is different as it is a tele lens. But the fact that it has a much shallower intrinsic depth of field due to the focal length - but still renders the thing sharp - means that with one of the smaller Pro zoom lenses you could get even better backdrop. The smaller sensor size, allowing a shorter focal length for the same angle of view, scores here. The Focus stacking is the sweet icing on the cake.

Can it pass the Pontiac Test? The 60's Pontiacs were some of the longest American cars available to the general public and the 1:18th scale models of them are nearly impossible to adequately illustrate with a standard lens - they run out of focus front and back. But look what happens with the 300mm Zuiko and the focus stacking....

I see a few shiny blob artifacts where the lights bounce off the chrome but the overall rendition is sharp. You see the same compression of perspective in the heading image round the studio Muzz Buzz bar.

The process of the stack is very fast, but you need to have the camera on a tripod, as well as constant lighting. I selected Incandescent WB for the strobe modelling lights and it all worked well.

  

Burke Flynn Stacks It Here At Camera Electronic

Relax - the car's all right.

Yesterday, Burke gave a great 3-hour display of the new Olympus OM-D E-M10 MkII camera to an appreciative audience. As with many new cameras, the Olympus has a number of features that involve bracketing. One of them is apparently focus bracketing. I was puzzled and asked Burke what it was.

Burke was puzzled.

After the demo we did some experiments here on the editorial desk and found out the answer - and it is a ripper.

Do you do focus stacking with your camera? You know - where you shoot a number of images of a fixed object with a slight change of focus between each shot. Then you put the images into a computer program like Photoshop and it blends them into a single presentation with greatly increased depth of field. It's a sophisticated technique that lets the macro worker overcome some of the optical limitations of shallow depth of field when you are in close.

Well - that what it does...but it does it in-camera and automatically. Wow. You can specify number of shots in the stack...think of it as the number of slices of an apple...and the sort of distance you want between each slice. Then press go and it goes. We tested it on a plastic ruler and found that we could ask for slices 1mm to 10mm wide - and we can ask for 999 of them if needed.

That's a lot more than most programs would handle, or most people would need, but the possibilities it sets up for tabletop or close-up workers is mind boggling.

You still need to use it for completely still objects so exercise your ingenuity ( and Cullmann clamps ) to do this.

Stack It! And in A Good Way! Olympus!

News just to hand. ( I love that phrase. If we had presses I would hold them. Hold them and squeeze them and love them and call them George...but I digress.) News just to hand.

Part of the v4.0 firmware update for the Olympus E-M1 camera that will be coming in November has to to with close focusing - with the macro capability, if you will.

Macro is mightily popular with enthusiasts - every camera club has regular competitions for images shot in the macro range. It is essential for scientific work and for a number of commercial applications. People need to get close and sharp.The problem with getting close is the optical fact of life: the depth of field gets perilously shallow as you get closer. Many subjects are very difficult to portray as there is never enough DOF to render them in their entirety - something is always fuzzy.

The solution up until now has been to employ a stack of separate images that can be blended in a computer program to feature the sharp plane fore and aft -it gives what is false but what seems real. In any case the sharpness is the reality we wish for so that is what the program makes.

Only works with static subjects and the static really does have to be just that - the object and the camera cannot move about. The focus can be adjusted with the lens in some case and in others complex computer-driven racks have been employed to track the camera and lens in and out on the subject. However it is done, the idea is to present the computer with a variety of images to combine.

Well, it looks like Olympus is going to make it easier. The press release states:

" Two powerful focus stacking and focus bracketing modes assist to improve depth of field for close-up imaging."

That's pretty slim, but encouraging nevertheless. If Olympus have arranged for the camera to do the stack shooting automatically in conjunction with their AF macro lens the way is clear to a lot more better macro shots.

Note the heading mage is also a stack, but a simple three-level one to make the model cars and the background blend together. Not macro but operating on the same principle.