Sunday, January 26, 2014

Macro or Micro?

As I look deeper into my ‘macro’ experimentation, it is clear that I need to learn a new way of looking at my equipment; for instance ‘normal’ depth of field and apertures cannot be estimated by using the standard equations or Apps. When you are within a few centimeters of your subject, you need to account for things that can be ignored if your subject is meters away.
It is also clear that my current experiments are ‘beyond macro’, as macro is usually defined as 1:1 magnifications, ie 1mm on the image plane (the sensor) is actually 1mm. What I am experimenting with are magnifications greater than unity, ie in the micro-photography zone.

Most lens manufacturers tell you what your base lens is capable of, for instance my 50mm F/1.8 only gives a native magnification of a x0.15, and adding extension tubes would ‘only’ take this maximum magnification to .39x and .68x for 12mm and 25mm tubes respectively. Which is why, of course, I need to use bellows and/or to use a reversed 50mm lens, say, to get above a magnification of unity.

Before I spend more time in the micro world, ie magnifications of greater than unity, I thought I would remind myself what a 1:1 magnification lens could do for me, ie what could I get out of my 100mm F/2.8L?

The set up was simple, my 5DMkIII, my 100mm F/2.8L set at F/16, an off camera flash and my Promote Remote. Why my Promote Remote, because I could set the 100mm F/2.8L to auto focus mode and use the Promote to automatically carry out linear focus steps. In the image below, ‘Dying Days’, I simply focused on the front of the tulip and, using Promote Remote, moved the focused to the back of the tulip, and told Promote how many slices I wanted (20 in this case); and pushed the start button. Promote then did the rest, ie drove the lens to the start and took 20 images from the front to the back of the tulip, with no intervention from me.

Once ingested into Lightroom, I exported the bracket set to Helicon Focus for focus stacking, and reimported it back into LR to 'finish off'. Although the composition is not brilliant, and the flash settings could have been tweaked a bit, the focus stacking worked really well. Thus, if I can stay in the macro world, ie 1:1 magnifications, I have a very easy process to capture as many focus slices as I need, ie using my Promote Remote (or my Cam Ranger).

The challenge is going to be when I move into the micro world, where the depth of fields are going to be smaller than with my 100mm macro lens and my current equipment is all manual, eg the camera-bellows-lens system has to be handraulically driven to change focus, and the (flash) lighting, because my lens will be closer, is going to need some thinking.

Bottom line: if your subject is of a similar size, or larger than your camera sensor, then normal or macro techniques will get you what your want. However, if the subject is, say, just a few plus millimeters, ie, say, a tenth of your DSLR sensor, then you will need to consider other techniques to nudge you into the micro capture world of magnifications of x2-x4 plus, say. Which is where I will be going next.

Friday, January 24, 2014

First ‘hardcore’ Macro Experiment

I’m just coming to the end of post-operative recovery, following eye surgery, thus, over the past week of so, I have had a chance to ‘play around’ inside the house with some photography; and, in particular, macro photography.

Although I have a 100mm F/2.8L macro lens and a set of extension tubes, both of which I have used many times, I wanted to experiment with a few other macro technics, namely, reversing my 50mm prime and bellows.

I already had a set of 2-axis focusing rails and therefore all Amazon had to provide was a reversing ring adapter for my 5DIII body and a set of bellows, all of course care of China Inc.

The reversing ring macro was OK, but I need to carry our more experiments to convince myself that this is a useful approach. On this occasion my main focus (sorry) was to get to know the bellows. 

The setup was pretty simple (see image below). I first put my 50mm prime on the 5DIII and set the aperture I wanted to shoot at, ie F/16; I then carried out the ‘lens twist trick’ to lock the F/16 setting into the lens. Of course the effective aperture, because of magnification, would push the set up into ‘diffraction problem territory’, but on this occasion I ignored that. In future I will likely lock the lens at about F/8.

I then mounted the camera and lens to the bellows and the camera-lens-bellows to the cross rail and a tripod. I set the bellows at just over the 2x magnification point for the 50mm focal length of the lens, where the depth of field was sub-millimeter (see one of the images from the stack below).

Because I was using the bellows I could not use any auto focus stacking tools, ie my Promote Remote, Cam Ranger or my Tethered EOS-Utility. It was going to be handraulic test.

The third image shows the result from my first stack of 40 images, processed in Zerene Stacker. My subject was a small, dying (dead!) paperwhite narcissus, with a piece of debris (just under 3mm long), which I had not spotted with my recovering eye sight!

Although I give myself zero points for composition, I think the overall experiment was a great success. 

Bottom line: using a cheap (made in China) set of bellows, a 50mm prime and a little patience, I believe high magnification, focus-stacked macros are going to allow me to explore the small world that exists around us!

Saturday, January 18, 2014

Insight into things to come?

Many who, like me, took the plunge and decided to jump on the Photoshop-CC subscription bandwagon hoped it was the right choice. Well this week, I’m pleased to say, I began to see the benefits of being with Photoshop-CC, when they pushed out some new features.
The one that got my attention was the perspective warp. Rather than explain how it works, the attached illustrates what can be achieved with this new feature, namely correcting poorly aligned compositions. In addition, those that do a lot of compositing will love the ability to ‘perfectly’, match one layer with another:

BTW the attached image of Winchester Cathedral was taken with my Canon 50D some time ago. The new perspective warp allowed me to bring the image into better symmetrical alignment.

Bottom line: a good start for those of us that have shown a commitment to the Photoshop-CC vision. I’m looking forward to more feature releases in 2014!

Friday, January 10, 2014

Multishot Imaging: Another step forward

Those of you that read my ramblings will have spotted a theme: that is I like exploring multishot techniques to overcome the limitations of the current generation of camera systems. For example, even with a Canon 5DMkIII, I sometimes hit scenes where the sensor, or the lens I have with me, can't cope.

For example, if a scene has more dynamic range, ie photon contrast, than my sensor can capture without saturating, I will consider exposure bracketing and using either tone-mapping or fusion (HDR) software to create an exposure merge image.

If I need to extend the focus limitation imposed by the lens and aperture settings that I need for a (non-macro) scene, I will consider focus bracketing and using Photoshop, Helicon or Zerene to focus stack the scene.

If I wish to capture a larger scene than my lens is able to do, I will consider spatial bracketing. That is taking overlapping images and merging/stitching them together in, say, Photoshop or some other stitching software. A panoramic capture is one example of spatial bracketing.

Finally, if the scene requires it, and I have the time, I may even consider using two or more of the above bracketing strategies at the same time. For example, an HDR timelpase, or an HDR and focused merged image.

Finally, if I wish to convey a more temporally dynamic sense of a place, rather than ‘just’ using video, I might consider doing a (RAW) timelapse, where I can undertake temporal compression, ie take hours down to minutes – great for sunsets or sunrises. In this case I would use LRTimelapse, which is fully integrated into my Lightroom workflow.

Now we have another bracketing tool: and it’s fun!

Microsoft introduced its Photosynth technology some time ago. This allowed the photographer, using anything from a iPhone to a DSLR, to spatial bracket a scene, upload the brackets to the Photosynth website, where the propriety Microsoft software would do its magic. The resultant image, if accessed through the Photosynth site, allowed the viewer to ‘interact’ with the image, eg by moving the PC mouse, one could move around in the scene and look into ‘every corner’ of the image.

Recently Microsoft have extended the Photosynth technology into ‘4D space’, that is movement and spatial appreciation of a scene. The process is simple and great fun:
  • Decide on the capture format. There currently are four capture strategies – walk, spin around an object looking in, create a pano or  capture a wall by walking parallel to it;
  • Capture your images, typically no more than 20-30 as a max. Note this is a factor of 10-100 less than timelapse so don’t worry about shutter burn out
  • Carry out any initial corrections in, say, LR, for example white balance and exposure etc;
  • Upload to the Photosynth site and wait about 5 mins for an email to be sent to you;
  • View your Photosynth using Photosynth technology and share with friends.

As a (poor) example I attach an HDR Photosynth I took in our home (note this should work fine on a PC, but I have not tested it on a Mac). I simply walked around a room and took three exposure brackets every step. The total number of images captured was 69, ie 3 x 23. I batched processed the exposure brackets, using interior fusion setting, in Photomatix, did a few corrections in LR and exported 23 JPEGs to Photosynth. I didn’t take any special time with the capture. It was handheld HDR bracketing.

You will see that Photosynths have a ‘look about them’, ie they are not videos. You get a sense of 3D but, in places, the result looks like a David Hockney inspired collage. When you see ‘artifacts’ this is where there wasn’t enough overlap to create a ‘smooth’ transition between scenes. I personally think these artifacts add to the unique feel of a Photosynth.

Bottom line: I believe the new Microsoft Photosynth technology provides another option for the multishot enthusiast. For those that wish to provide a greater sense of presence, you can let friends actually interact with the scene you saw. We now have a more dynamic way to present our photography: and it’s fun and free!