Sunday, July 31, 2016

The Getty Center

Wiki tells us that Getty Center, in Los Angeles, California, is a campus of the Getty Museum and other programs of the Getty Trust. The $1.3 billion Center opened to the public on December 16, 1997 and is well known for its architecture, gardens, and views overlooking Los Angeles. The Center sits atop a hill connected to a visitors' parking garage at the bottom of the hill by a three-car, cable-pulled hover train funicular

This post is an opportunity to publish a few images taken with my new best (travel) friend: my Magic Lantern enhanced EOSM, with my 10-20mm Sigma lens.

Friday, July 29, 2016

Couldn't get it out of my mind

In the last post I hinted at not being content with the blown out highlights in the All Saints church images: after all Magic Lantern Auto Bracketing should have taken care of things.

So, within an hour of getting home, I popped up to our local church, Christ Church in Ramsdel, to do a quick experiment, ie in a relatively high dynamic range environment: although the weather was a little flat, so the Church windows were not really ultra-bright. Nevertheless, a reasonable test scene.

Still using my EOSM with the 10mm end of the 10-20mm Sigma, I decided to expose for the highlights and let the Auto Bracketing in ML handle the rest. Here are the two test images - one with the chandelier lights on and one with them off:

In both images, the windows are fully captured, with no 'highlight end damage'.

Bottom line: I think I'll switch my ML bracketing strategy, at least in churches. Rather than expose for the shadows and let ML handle the highlights, I think I'll set the exposure for the highlights myself, eg a stop down from the highlights being clipped, and let ML handle things from there.

Sometimes it's best not to plan

Although today, as a non-working Friday, I was hoping to get out and do some photography: when I looked at the flat-white sky I knew the day would have to unfold in its own way. So the first decision was where to have breakfast?

So it was off to the Saddleback Farm Shop at Brightwalton

Once we were suitability refreshed with Eggs Benedict and a Cappuccino, and we had purchased some bespoke Gin, we were ready to return home: but then we saw this church in the distance, which we found out was All Saints in Farnborough, ie Farnborough in Berkshire not Hampshire. 

Farnborough was apparently held by Abingdon Abbey before and after the Conquest, and up to the Dissolution. The manor was assessed at 10 hides before the Conquest but only 4½ in 1086.  The church is in the centre of the village, and has a Perpendicular West tower of ashlar, squared blocks of masonry cut to an even face, and single nave and square chancel of flint rubble. The church has opposed North and South doorways, with a South porch.

It has a ring of 5 and the largest and oldest bell, the 8 cwt tenor, was cast at the Wokingham foundry sometime around 1400.

We found out that stained glass of the west window of the nave was designed by John Piper as a memorial to his friend John Betjeman, who lived at the Old Rectory at one time. They collaborated on architecture books; such as “The Berkshire Architectural Guide ” 1949.

The inscription in Delabole slate beneath the window was cut by Simon Verity and placed there in 1986. It reads: In memory of

1906 - 1984 Poet Laureate
sometime resident at the Old Rectory Farnborough
This window, designed by his friend John Piper
and executed by Joseph Nuttgens, was placed here
by the Friends of Friendless Churches.

I am the Resurrection and the Life
As far as the photography side, I used my EOSM and my 10-20mm EX DC HSM Sigma, via a EOSM-2-EOS adapter. In all the images I first ETTRed via Magic Lantern and then used the ML Auto Bracketing. Focusing was a non issue at 10mm, F/8, ie I focused at about a meter to ensure acceptable (hyperfocal-like) sharpness from about 0.5m to infinity.

Post processing followed my normal workflow: I first ingested the images into Lightroom; I then use the native HDR feature in LR to create 32-bit DNGs; I then made basic adjustments in LR and did a round trip to Photoshop, to undertake some luminosity masking and local tonal tweaks.

The one thing I was not happy with is that Auto bracketing didn't give me enough 'protection' at the highlight end, hence the window above, for example, is a little blown out for my liking. This is something I intend to explore further, ie how to guarantee full highlight capture in high dynamic range scenes such as one finds in churches.

Over all: an enjoyable Friday :-)


Monday, July 25, 2016

Getting Ready for a Trip

I'm off to the US next week for a business trip and want to travel light: so I've decided to make use of my EOSM, which, of course, comes with Magic Lantern :-)

The current weakness of the EOSM is that the lens focus features in Lua don't work. So my landscape focus bracketing script is a no go. But, I have other options for achieving great depths of field: namely my Rokinon 12mm Full Frame Fisheye, which fits the EOSM via the Canon Adapter.

The great thing about the 12mm, on the EOSM cropped sensor, is the huge depth of field. For instance at the hyperfocal distance of about 5ft at F/8, everything from about 2.5 ft to infinity is at acceptable sharpness. 

But is the HFD the right approach? Are there other focusing strategies? There is one that all photographers should try and remember and it follows from the work of Harold M. Merklinger of Halifax, Nova Scotia, Canada. Merklinger stated that by focusing your lens at infinity, the smallest object resolved in your image will effectively have the same width as the focal length divided by the aperture of your lens.

So for my 12mm lens at f/8, this size is 12mm divided by 8, or 1.5mm.

Yes, I can carry on using the HFD, but this will mean the distant details will not be optimally sharp, just acceptably sharp according to the Circle of Confusion criterion I have selected.

Using the Merklinger strategy, I simply focus for the farthest object, ie towards/at 'infinity' and that's it. Details greater than 1.5mm are resolved from near to far.

To test things out, and show the power of the defishing software, here is one bracket from a six bracket Auto Exposure Bracketing capture, taken with Magic Lantern.

You can clearly see the fisheye distortion.

Post processing followed these lines:
  • Ingest all six images into Lightroom;
  • Use LR's Merge to HDR to create a 32bit DNG;
  • Correct the basic exposure for this 32bit DNG, before exporting a 16bit TIFF to Photoshop;
  • Once in PS-CC, use the Fisheye-Hemi Plug-in to correct the fisheye distortion;
  • Return to LR and finish off, finally arriving at this test image, with no fisheye distortion and everything looking 'crisp' from near to far.
I've got the rest of the week to 'muck about' with the EOSM, deciding what other gear to take with me. But one thing is clear: the Rokinon 12mm Fisheye is the one thing I will not be leaving at home!

Monday, July 18, 2016

Story of an Image

Yesterday a few of us from our Camera club (Boundary Camera Club) decided to use our club night for a field trip to Pangbourne. 

Wiki tells us that Pangbourne's name is recorded from 844 as Old English Pegingaburnan, which means "the stream of the people of [a man called] Pǣga". This name was shortened to make the name of the Pang.

In Norman times, the manor was given to Reading Abbey and the manor house – also called Bere Court – became the Abbot's summer residence. The last abbot, Hugh Cook Faringdon, was arrested there in 1539 and subsequently executed in Reading. The manor was later purchased by Sir John Davis, the Elizabethan mathematician and the Earl of Essex's fellow-conspirator. His monument is in the Church of England parish church of Saint James the Less. 

Other monuments and hatchments in the church are mostly to the Breedon family, John Breedon senior bought the manor in 1671. He was High Sheriff of Berkshire and brother of the Governor of Arcadia and Nova Scotia, whose son later succeeded him. The family produced a number of sheriffs and MPs for Berkshire, as well as doctors and rectors of the parish.

Kenneth Grahame, author of The Wind in the Willows, retired to Church Cottage in Pangbourne. He died there in 1932. E. H. Shepherd's famous illustrations of his book are said to have been inspired by the Thameside landscape there.

For the technically minded, the attached was shot using my 5D3 with a 24-105 F4/L at the 24mm end. I used ISO100 and an aperture of F/14. I focus and exposure bracketed at 3 focus points (to get the foreground and background in focus) and at 2 exposures: giving 6 images in the set.

I processed initially in Lightroom for the exposures, then did a round trip to Zerene Stacker, finally doing a round trip to Photoshop CC.

Saturday, July 16, 2016

Goring-on-Thames Field Trip

In order to break the relentless posts on scripts, I thought I would post a few images from our short trip to Goring today. 

Wiki and other sources tell us that Goring-on-Thames and its neighbour Streatley are both very old villages indeed. Due to their unique location at the intersection of three of the most ancient routes in Britain, they have been inhabited continuously for at least 5,000 years.

There is evidence that Old Stone Age man travelled from Europe through Goring and Streatley along the Ridgeway before Britain was separated from mainland Europe and became an island after the last Ice Age.

The Church of England parish church of Saint Thomas of Canterbury is Norman, built early in the 12th century. The bell-stage of St. Thomas's bell tower was added in the 15th century and has a ring of eight bells, one of which dates from 1290. The rood screen is carved from wood taken from HMS Thunderer (1783), one of Nelson's fleet at Trafalgar.

All the shots where taken with my 5D3 and my 24-105mm F/4L lens: and all of them, other than the two internal images, where taken with Magic Lantern Dual-ISO switched on, for a 3Ev boost to the dynamic range coverage. Exposure was set using ML ETTR.

The indoor shots were taken using my auto focus and exposure bracketing script. The images were composed of four focus sets and four exposure sets, giving a total of 16 images for each shot.

Auto Bracketing: Rev 4

This is a short post to say I'm releasing the 'final' beta of version 4 of my auto bracketing script.

In previous versions, you had the option of focus stacking from the focus point (FP) to either the HFD, the macro end of the lens, or the infinity end of the lens. 

In version 4 I've added the option to focus stack between two focus points (A/B).

To use the new functionality all you need to do is open the script's menu and in the focus bracketing sub-menu select SET-AB. Having selected this run the script, ie don't just leave the script.

In LV you then focus at the first point you wish to stack between (you can set A and B focus points in any order). When focused press the RATE button (this is the button I use on my 5D3, on other cameras you will need to change RATE to another button that is available on your camera), this will set the first focus point. Focus on the other focus extreme and press RATE again. Repeat this A/B process if you wish to, ie to change the focus extremes.

Return to the script's menu and in the focus bracketing sub-menu select the FP2FP option. Select other options as you wish, ie exposure bracketing options and bookend (a dark frame at the beginning and end of the focus/exposure stack).

The A/B points remain as long as the camera is not switched off, or the points are explicitly changed by running SET-AB again. This allows you to rerun the script in FP2FP mode and change the exposure without impacting the focus points you have set.

You can find version 4 on the right.

The usual caveats apply: the script works for me and my workflow, and on my 5D3: and, of course, I welcome feedback of any kind.

Sunday, July 10, 2016

Bringing it all together

It’s Wimbledon week and Men’s Final day, so it’s raining! Of course. But that gives me an opportunity to write a few things that I hope will bring into focus (sorry!), what I’ve been trying to do over the last few months: at least until the final starts, albeit undercover.

I started with the idea of using the power of Magic Lantern Lua scripting to create an in-camera tool to carry out auto bracketing sequences for exposure and focus.

The script is now close to what I envisioned: it works and, on my 5D3, it’s stable and fast.

The script allows me to capture exposure stacks using two basic workflows. The first is to set the base, shadow end exposure and the script will set the highlight end exposure and grab the required brackets (with 1Ev or 2Ev separation). The second workflow is fully auto, with the script setting both shadow and highlight and grabbing the required number of brackets (once again with a user selected 1Ev or 2Ev separation).

For focus stacking the script assumes the user has set a base/starting focus point. The user then has three focus stacking workflow options: to focus stack to infinity stop (FP2INF); to focus stack to the macro stop (FP2MAC); to focus stack to the hyperfocal distance (FP2HFD), as long as the FP is less than the HFD.

In addition, if in FP2HFD mode, the script provides realtime feedback to the user on the estimated number of focus brackets that will be taken. This feature is important if you are using ‘long’ lenses; as the number of focus brackets to cover the full depth of field will potentially be large. The script also allows the user to change aperture to see the impact of the number of focus brackets. For optimum results, ML depth of field feedback should be set to diffraction aware.

The final bracketing options in the script cover long exposure use cases. The first allows the user to simulate a long exposure by taking many shorter exposures, and joining these up in post. The second case is related to the first LE one, but rather than setting the number of exposures based on time, this option lets you specify the number of images to capture. This mode is useful for super resolution photography or eliminating people from a scene, for example.

The latest version of the script may be found on the right.

However, getting the ‘data’ is only part of the story. Until you bring it all together in post, all you have is a ‘load of images’.

I have played around with several post processing workflows and the following works for me. As an example, let’s assume we took a focus and exposure stack (which I just did sitting in our front room, to illustrate things in this post):

  • Ingest all images into Lightroom. 
  • Decide on your exposure blending strategy: fusing or tone mapping. 
  • Process your exposure stacks. I tend to use either the inbuilt ‘HDR’ tool in LR (select images in a given exposure set and press Ctrl+Shift+H and repeat for the other exposure sets) or LR/Enfuse (put each exposure set into a LR stack, select all the stacks and do a round trip to LR/Enfuse in Enfuse batch mode). 
  • Once I have the exposures back into LR I will correct one for Lens Correction and tonal balance. 
  • I then do a round trip to Helicon Focus and, according to the scene, select an appropriate focus stacking method: 
    • Method A computes the weight for each pixel based on its contrast and then forms the weighted average of all pixels from all source images. This method works better for short stacks and preserves contrast and color. 
    • Method B selects the source image containing the sharpest pixel and uses this information to form the "depth map". This method imposes strict requirements on the order of images - it should always be consecutive. Perfectly renders textures on smooth surfaces. 
    • Method C uses pyramid approach to image processing dividing image signals into high and low frequencies. Gives good results in complex cases (intersecting objects, deep stacks), though increases contrast and glare.
  • Once I have the exposures back into LR I will correct one for Lens Correction and tonal balance. 
  • I then finish off in Lightroom and/or Photoshop as required.

Here are a few screen shoots and the ‘final’ image showing things at various states in the above workflow. The use case was with a 5D3, a 24-105 F4/L at 24mm, F/7.1 and ISO-100, with a macro to HFD focus request and a 2Ev full auto exposure request. The scene, as calculated in-camera by the script, required 4 focus stacks of 4 exposures, ie 16 images in total.

Bottom line: At first, many may be put off by the amount of work required to undertaken bracketing. However, until we have a light-field camera that is able to take a full depth of field in one shot, and cover a 20Ev, say, dynamic range; photographers need to learn how to bracket. I hope, at least for the Canon Magic Lantern shooters, my script and my workflow allows you to achieve your vision.

Tuesday, July 5, 2016

Rev 3

Just a quick post today to say that version 3 of my auto bracketing script (Canon Magic Lantern based) can be downloaded from the link on the right.

In addition to tiding some things up in the code, this version has the handy facility of reporting the number of focus brackets required to cover from the current focus point, which must be less than the hyperfocal distance (HFD), to the HFD.

This is a useful, realtime feedback when you are about to run the script, as the number of brackets gets very large with long focal lengths. For example, the number of focus brackets to cover the full range of a 24-105mm lens, at 105mm and F/14, from the macro end to the HFD is some 63 and at F/4 some 110!

IMHO you really don't want to landscape focus stack beyond, say, 10 brackets. Thus, the guidance: is restrict landscape focus stacking to focal lengths, say, less than 24mm, ie wide not long lenses.

Friday, July 1, 2016

Dual-ISO continues to deliver!

As readers of my posts know, I am a single-minded Magic Lantern user. As the UK summer has decided to not show its face yet, or at least until Wimbledon is over :-), I found myself 'playing around' in Lightroom this afternoon, and decided to see what ML Dual-ISO can really do.

For those that don't know what Dual-ISO is, the simplest way of understanding Dual is to think of it as ISO bracketing but all within one image capture. Thus, rather than take one image at ISO100 and one at ISO800, say; in a Dual-ISO capture alternate Bayer line pairs are switched between ISO100 and ISO800.

As an example, let's look at this Dual-ISO capture from last weekend's National Garden Scheme trip. The RAW Dual-ISO, unrocessed, image looks like this:

That is, not very impressive. If we zoom in to an area of the image we can clearly see the Dual-ISO 'bracketing':

BTW the image was captured handheld on my 5D3 at 24mm, F/13 and with an ETTRed shutter of 1/160 sec. Using ETTR I was guaranteeing that the sky would not be blown out, and by using Dual-ISO I was giving the shadows a 3Ev boost at a Dual-ISO setting of 100/800.

After processing the Dual-ISO to a 16bit TIFF file, I played around a little with LR's sliders, eg bringing down the highlights and boosting the shadows. I then did a round trip to Photoshop and applied some local contrast adjustment, to bring a little pop to the image; ending up with this:

Bottom line: IMHO the Magic Lantern ETTR and Dual-ISO combination remains THE killer feature for still photographers.