When focus stacking fails

In camera focus stacking on Olympus/OM systems bodies is wonderful.  Providing that:

• the subject remains still
• the camera remains still
• the initial focus point is correctly chosen

Get any of these slightly wrong and at worst the stack completely fails in camera, at best the result is some ghosting that can be edited in Lightroom using the Generative AI remove tool after stacking in Photoshop.

But occasionally the OM stacking algorithm throws a wobbly and actually manages to complete a stack.in camera when it shouldn't.  Is it trying to create it's own art?  Take this example:

Painted lady butterfly on Eryngium

Five handheld stacked images of the butterfly at 1/1250sec all overlaid on a still image of the Eryngium it's feeding on. The subject moved but the stack was still generated.  Motion blur without the motion blur.

A little while later I was shooting a pair of  Azure damselflies.  They tend to stay fairly motionless during the egg laying process and I used focus stacking to increase the apparent depth of field and get both male and female reasonably sharp.  Then they took off...

...and what I actually got was this:

Focus stacking failure I'm very familiar with.  I stack, see the orange failure message and try again.  But this is not just failure, it's spectacular failure.  One to play with perhaps.

 

 400mm portraiture

I take a lot of images of my own and my daughter's dogs.  Sighthounds are very photogenic when they're running or playing.  But rarely would I take a portrait shot at the full 400mm reach of my OM systems 100-400mm Mk II.  Particularly wide open at the f6.3 and ISO 1600 settings that I use on my OM-1 for the action shots.  Why bother when you can easily get closer, shoot at lower ISO to cut noise and close down the lens for greater depth of field.

But sometimes you work with what you've got.  And that shows you how good or bad your lens is pushed to it's limits.  So, how good is the 100-400mm handheld with the above parameters?

This is Sam, my daughter's greyhound x deerhound longdog.  He specialises in exhausting high speed runs followed by prolonged resting far in the distance.

Here's a 100% crop of his face.

Just to repeat the exercise here's another full scale shot,,,

...and the crop.

Three things come out of this.

1. Animal eye detection works on the OM-1
2. 400mm wide open on the 100-400mm MkII is sharp
3. The isolation and out of focus blur (bokeh) at 400mm produces excellent portraits

No wonder this relatively inexpensive (compared to lenses with similar reach in both m43m, APS-C and full frame formats) is proving popular among we budget limited photographers.  Though I wouldn't recommend it is a daily portrait lens for ordinary portraiture.

An encounter with Hummingbird hawk-moths

Years ago - September 2013 to be precise - I took one, very lucky, shot of a Hummingbird hawk-moth, Macroglossum stellatarum,  Here's the shot:

Lucky in the sense that I was photographing this Ceratostigma willmottianum in my garden and the moth appeared, paused briefly to drink nectar, and then flew off, giving me time for only the one shot.  Lucky in that I had the Sigma 105mm macro on my, at the time, Canon 60D.  Lucky in that I was working at ISO 400, f6.3, and 1/200 sec and I somehow managed to get the eye, flower and proboscis reasonably sharp.  

Unfortunately everything else was blurred.  No wonder it's never sold.

I've seen these occasional UK summer migrant moths a few times since but never again managed to successfully photograph them.  Until last Monday.

I was working at The Garden House, collecting my usual social media shots.  I'd temporarily fitted the 100-400mm to the OM-1 to capture some nesting Jackdaws in the roof space of the old bothy behind the Walled Garden. I had bird detect on, continuous autofocus and sequential shooting set, ISO 1600 selected and the lens wide open at f6.3, giving a shutter speed between 1/000 and 2/1000 sec.  I happened to be near a patch of Nepeta (catmint) when a Hummingbird hawk-moth came to feed.

And then the fun began.  

Like hummingbirds these little moths flit about in unpredictable direction, wings blurred with the speed of their motion, briefly hovering in front of a flower to insert their long proboscis and drink the nectar.  Above all, they never settle while feeding.  Blink and they're gone.  Surely the harshest test of an autofocus system possible.  I had a lot of failures.  As evidenced by these three shots:

At first sight they look quite reasonable (I've cropped the images to square format only to cut out some extraneous content at the sides)  Now look at a 100% crop of the last image.

Not quite the success it appeared to be on first examination.  The swift, unpredictable, darting flight was producing real problems in attaining and keeping focus on the moth.  The others are slightly better but they've still missed focus.

But gradually, and aided by the arrival of a second moth*, I started getting a few better shots.

Sharper, more detailed and, most importantly, with better focus accuracy.  There's still the problem of wing blur but I didn't have enough light to raise the shutter speed to further freeze motion.  

In the end I finished with 3 shots I was reasonably happy with, and another shot (#1 in the final sequence) that was passable out of 46 in total.  The 100-400mm autofocus is just fast enough for the job though I suspect the PRO series lenses such as my 40-150mm might have been a bit faster and more capable of holding focus.  But you work with what you've got and an unpredictable small insect in flight would test any camera and lens combination.

An enjoyable experience.  I'd have continued but the moths took off for pastures anew and I didn't see them again.

* How do I know there were two moths?  Look at the backs.  One is fully covered, one distinctly worn where the scales have been rubbed away.