Hand held focus stacking

One of the reasons I first tried and then fully switched to Olympus / OM Systems cameras and lenses was the built in focus stacking and bracketing computational facility.  For a lot of my plant portrait, and macro work I need a combination of good depth of field with clean(ish) backgrounds to give both subject separation and sharp focus across as much of the subject as possible.  This image of the spring flowering shrub, Stachyurus praecox 'Rubriflora' is a good example:

Although both stacking and bracketing modes work by taking a sequence of images with a progressive adjustment of the focal plane they work slightly differently.  Bracketing allows up to 999 images, moving the focal plane through the image from the frontmost point chosen.  The images can then be combined into a single image using stacking software (I use Photoshop but others are available). Stacking takes up to 15 images both before and behind the initial focal point and then combines them in camera into a single JPG. When RAW shooting is used the original RAW files are saved with either option but stacking also generates JPGs with the RAW files.  Either method works well to generate images with the necessary characteristics of depth of field across the subject and separation from the background but for best results both require a stable tripod to keep the stack of images aligned.

But using a tripod is not always possible. Which brings me to hand-held focus stacking.  At 75 my hands and posture are not as steady as once they were.  OK, I shake a little. It was only with the more recent purchase of the OM-1 body and it's insanely effective 7 stop IBIS that I've been able to explore hand held focus stacking.

So what works for me?  After experimenting I've set up and assigned to a Custom Function the following:  

• Focus bracketing - set from Camera settings menu 2 and Computational modes menu - ON
• Number of shots = 5
• Differential = 3
• ISO 250mm - to keep noise low
• Aperture f3.2 - to provide the subject to background separation.

I find this works well to give me both a better depth of field across the subject and, when feasible, subject separation.  As with this image of Erythronium tuolumnense, one of the North American trout lilies, taken in a fairly crowded planting.

Or this shot of Snake's Head Fritillaries in a wildflower meadow.

All the images so far were taken were taken with my 40-150 f2.8 PRO lens.  This combines superb image quality, extremely fast transitions between the stacked shots, and close focusing, ideal for plant portraits...

...lichens...

... or larger insect shots, albeit with the 1.4x teleconverter attached:

Also working well is my 60mm macro.  I don't expect to get the depth of field attainable with tripod mounted shots but anything that produces better results than a single shot with a wide aperture is worth while.  Such as this little Heliophilus pendulus hoverfly, photographed in natural light by the side of my little pond. It's not all in focus (abdomen and top wing) but it's given me better depth of field across the eyes and thorax.

What hasn't worked that well is my newly acquired 100-400mm MK II.  Yes, the sync IS is great for single hand held shots but the transition speed between stack shots and the weight of the lens conspire to produce too much movement and blur in the final images.

The only niggle I do have is with the Automatic JPG production.  This is both a boon and a curse.  The boon is that I can immediately see an the in camera stacked shot to see if it has worked and not produced blur or ghosting as images haven't aligned.  The curse is that I also generate 6 JPGs per stack, 5 of which are useless for my immediate workflow and a stacked JPG that I also have to delete if I've done a RAW stack.  

Of course, hand held focus stacking is subject to the same limitations of any bracketing / stacking operation.  Subjects must be still and / or the wind almost zero.  But even so it's a valuable technique to provide a good depth of field on the subject with background separation where appropriate.

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Photo stacking and spring bulbs

Much as I enjoy photgraphing early spring bulbs, getting down to ground level can be a strain on my old bones. Thank goodness for flip out screens on my Olympus cameras which means I only have to bend. Thanks also for built in focus stacking which allows me to generate more detailed images with nicely blurred backgrounds.  It did require a nice still day and, fortunately, last Monday provided.  Here's some recent results, all taken at The Garden House.

Chionodoxa forbesii

Narcissus 'Rip van Winkle'

Scilla bifolia

Trillium chloropetalum 'Rubrum'

All taken with either the 40-150mm f2.8 or the 60mm macro, my lenses of choice for plant portraiture.

Lichens

Curious things lichens, composite organisms where green algae or cyanobacteria live among fungal threads in a mutualistic relationship.  Neither plant nor fungus, they're a complex symbiosis that can cover large areas of suitable substrate when conditions permit.  And the wet South West of England certainly does permit.  So I get plenty of opportunities to photograph them.  Though, I have to admit, I can't identify most of them.

Take these two images of an assortment of fruticose (bushy) and foliose (leaf like) lichens growing on the trunk of Styrax hemsleyana in the cool, damp environment of the edge of Dartmoor air at The Garden House:

They're almost a mini jungle in their own right, using the fissured bark of the tree for support but not sustenance, and supporting smaller organisms such as nematodes, mites and springtails which feed on the lichen growth.

At their most spectacular, some Usnea species even produce long, dangling strands hanging from tree branches in a similar way to Spanish moss in the Southern states of the USA.  

This growth habit requires constantly damp air and lack of pollution and the western edge of Dartmoor offers the ideal conditions.  Hardly surprising, the area was once covered in temperate rain forest, although only remnants still persist but still offer suitable conditions for this type of epiphytic growth.

The growth of all of these is definitely three dimensional and, because of their size, requires focus bracketing and stacking to really capture the full beauty of these lichens or lichen groups.  This image, of one of the lichens I can identify - it's Ramalina farinacea - shows the complexity of the fruticose branching form, set alongside the early spring flowers of the cherry Prunus campanulata 'Felix Jury'.

They do make lovely subjects - and are often at their best at a time when there's not much else to photograph in the winter landscape.  I've shown this one previously - but it's worth showing again just to illustrate the complexity of a shrubby form - even if I'm not sure which lichen it is.

Time to get the identification keys out yet again, methinks.

Al fresco focus stacking using flash

Macro and close focusing work is often limited by available light. The closer the camera gets to the subject the shallower the depth of field for any given aperture, Stopping down helps - with my 60mm macro I can use f9 or f10 without running into more than minor diffraction problems - but that does require adequate light. And in many cases that means the use of flash.  The alternative is to use more open apertures and focus stack multiple images.  But even then flash is often needed.

My Olympus Em1 mkii supports in camera focus stacking using flash - but only under certain parameters.  They are that'the shot limit in the in camera stack is 8 and manual mode (M on the top dial) must be used to set a speed of 1/50 sec to enable the camera to sync with the flash.  Additionally the charge time in the bracketing menu must be set to zero if you want to trigger a rapid sequence of shots.  Olympus flashes do this automatically but I use Godox so I have to set this up.

I would like to use my Olympus STF-8 twin flash for in camera focus stacking but it's not powerful enough to generate the rapid series of flash pulses needed to light eight images in quick succession, essential for handheld or non tripod supported shooting.  I use a Godox TT685o with an 11in softbox angled down to illuminate the subject from above. The flash is set to manual mode rather than TTL to ensure consistency between each flash. A preliminary shot or two allows me to set the flash intensity correctly and I can then switch the bracketing / stacking on.

I'm old, I shake a little, and I'm not as steady as I used to be so handholding can be a little hit and miss.  But the results, when they work, can be superb.

Fruticose lichen, possibly Usnea sp.

Chaenomeles x superba 'Crimson and Gold'

Crumpled leaves of curly kale

Lesser celadine flower

How well it will all work in the brighter light of spring and summer I don't yet know.  But I will find out.  And if it doesn't work - there's always the STF-8

 Focus stacking and bracketing

One reason I chose an Olympus EM1 MkI for my first foray into the M43 world was it's ability to do both focus bracketing and stacking in camera.  I was familiar with bracketing from my Canon days, using either a focusing rail or manual selection of different focusing points to generate a series of images where the plane of sharp focus was progressively moved forward within the same framing.  Those images could then be stacked using external software - I currently use photoshop - to generate a composite image with far greater depth of field than any single image in the stack.

It worked, but it was clumsy.  It took too long to set up and generate the necessary images and, because the camera and lens had to be handled during the exposure, risked introducing movement between the frames and consequent misalignment during the stacking process.

The EM-1 Mk I was a revelation.  For the first time I had a camera that would handle the bracketing automatically and, as an added bonus, perform the necessary stacking in camera.  Stick the camera on a stable tripod, frame the shot selecting a focus point for the beginning of the bracket, switch focus bracketing on in the menu and fire the shutter.  The camera then uses the autofocus motor of the lens to move the focal plane progressively forward to generate a set of bracketed images that could either be stacked on the computer or, if set up for stacking, in camera.  I was getting some excellent results.

With the EM5 MkII and now the EM1 MkII this capability has been enhanced and I find I use focus stacking more and more. Take this shot of Salvia 'Amethyst Lips':

Taken in my garden, it's a composite of 8 shots, using the 60mm macro lens at f3.5, stacked in camera to generate a final JPG, with good front to back sharpness of the subject.  It's not perfect - I have better shots available for licensing on Alamy - but it illustrates the ability of bracketing / stacking to vastly improve the depth of field within the subject while also retaining the diffuse background generated by the wide f3.5 aperture of the lens.

Or consider this shot of a forest of meadow cranesbill, Geranium pratense.  Another 8 shot in camera stack with the 12-40mm Pro at f3.5, 35mm focal length.

The image is sharp, front to back, through the whole frame.  As with the top shot, which did make a magazine front cover, it's suitable for print uses which need that level of detail across the whole image.

Of course, there are disadvantages to the in camera stacking on the EM1 MkII.  For a start the stack depth is limited to eight shots.  That might not be enough, particularly for static macro shots. The final image is a JPG, with all the lack of post processing manipulation leeway.  Subject movement can cause the in camera stack to fail to process.  Finally, the camera is frozen while the stacking takes place.

None of these are deal breakers.  Apart from the generated stacked JPG, the individual frames are saved as both JPG and Olympus RAW formats so they can be post processed individually and then stacked on the computer.  Particularly with non macro shots even eight frames might be too many.  Easy then to discard the unwanted and then do the stacking,  Because that can take awhile - my current computer is way underpowered - I've got into the habit of using the in camera stacking and then examinng the final JPGs from a number of tries to determine which one(s) to select and post process the RAW files before putting those through the stacking procedure in Photoshop.  And, of course, if the stack fails due to movement between frames (wind is your mortal enemy) you still have the individual frames.  There might well be a good shot amongst them.

A little backlit fern photography

It's been horrible weather the last few days.  Rain, gale force winds - not the sort of environment for field photography even on the few occasions when the sun has broken through.  And, of course, I was looking for subjects to test out the cheap Opteka SB-15 flash diffuser I'd just purchased to give me softer lighting for macro and semi macro plant and insect photography.  Even in South West England there aren't too many plants in flower or insects on the wing in mid November - and especially not when the gales are blowing a hooley straight off the Atlantic.

In a few brief respites from the prevailing awfulness I wondered around the garden with my Canon 600D/Tamron 90mm/430EX/Kirk flash bracket/Opteka diffuser combination and even managed to get a few shots in before the heavens re-opened.  The lighting is definitely softer than with the Stofen Omnibounce diffuser that I've used previously, hardly surprising as the effective light source is considerably larger.  On the other hand the flash recycle time is longer, even when the light source is close to the subject on the bracket.  There is always a trade off.

One of the shots interested me and gave me an idea.  I grow a large tree fern, Dicksonia antarctica, in the rear garden.  It's currently sporing, with sporangia - the little capsules the cover the ripening spores in ferns - dotting the frond edges on the older fronds.  Here's the shot:

Dicksonia antarctica sporangia - Tamron 90mm macro, 600D, 430EX diffused flash on bracket

It's not too bad for a hand held shot but it lacks that little sparkle.  The lighting, though soft, is a little flat.  Fern fronds are thin enough to be translucent with strong backlighting but that means balancing ambient light with fill flash.  I'm never going to achieve that given the blustery conditions. 

So I gather fronds from some of the evergreen ferns I grow and move indoors.

And light breaks through yonder window.  Low angled, mid November sunlight.  Which can be used as backlight if I set up a quick studio on a suitable support.  It's very simple.  The fern frond is held vertically using an improvised clamp in a position where the sun will shine through the frond.  I angle it in such a way that I will have a dark background when I get the front of the lens parallel to the subject.  I mount my recently acquired (cheaply) Sigma 180mm HSM macro on the 600D and position the bracket mounted flash and softbox at the end of the lens.  Mirror lock up and remote release was used to produce the best sharpness on shots taken at around 0.5sec.  A couple of test shots suggests values of -1/3 exposure compensation for both metering and flash exposure using AV metering, the fill flash illuminating the front of the fronds and the sunlight providing the backlit translucency.  The difference from direct frontal flash is obvious.  Compare these two shots of the hardy maidenhair fern, Adiantum venustum:

Adiantum venustum - direct frontal flash

Adiantum venustum - backlit with fill flash

The second, with the thin halo of light around the fronds and illumination of the body of the fern and sporangias, to my eyes, far more interesting.

A few shots later and I have some backlit examples to show the different sporangia arrangements on four more of my ferns (I grow about a dozen but some have already retreated below ground and others had no suitable material for photography).

Athyrium onopordon 'Okanum'

Dryopteris erythrosora

Polystichum polyblepharum

Polypodium vulgare 'Cornubiense'

Each one is different in shape, number and arrangement of the spore cases and spores.  Indeed they are a feature used for fern identification.  And they do make good subjects for indoor shooting in wild and windy November.

There is one problem.  Fronds are not flat.  Even at f11 the depth of field is insufficient to have everything in focus.  So I tried focus stacking using Combine ZM software.  I'm still getting to grips with this and really need a focusing rail to produce the sequence of differently focused shots needed for the software to combine into a single image with far greater apparent depth of field.  I'm probably not taking enough shots for a really successful merge as I still get edge artifacts in the finished product.  Noticable at 100%, less so in a shot resized for the web.  Even so the results can be very interesting.  Adiantum venustum again, 5 shots stacked.

Adiantum venustum, 5 shots stacked using Combine ZM software

Definitely a technique to work on.  But well worth working on - the results can be spectacular.