Thursday, November 27, 2014

BIFing


Last weekend I was fortunate enough to attend a workshop on Birds in Flight (BIF) at Bosque del Apache (BDA) in New Mexico: which is less than two hours from where I live.

There were about a dozen of us in the group led by three very talented instructors. This was my first ‘photo course’ and was it was hard work! 

Each day started with the alarm going off at about 0515, so we could get to the birds before they took off from their evening roost, which at BDA means Sandhill Cranes roosting on ponds.

The mornings were cold with temperatures hovering around 20F on one morning: I soon learned the value of toe and finger warmers I had taken with me!

The day consisted of class time, daylight shooting, and preparation from the evening sunset session. Meaning we were ‘working’ 12 hour days.

In addition to what nature provided to us, we were fortunate enough to have access to a local falconer who was well tuned to the needs of a group of photographers. BTW I wonder what the collective noun for a group of photographers is? Maybe a snap of photographers ;-)

The weekend’s success was rounded off by being with a great group of photographers, all, like me, wishing to learn more about their craft and passion.

So what were some of the things I learned? 
  • Sunrise photography of moving targets is hard! In addition to coping with a 500mm lens at F/8, to get ‘most’ of a large bird in focus, you need to shoot at very high ISOs: at least until the sun comes to your rescue. I was lucky in that my 5DIII can be pushed, so I was shooting in the morning at ISOs of 1600-3200 and getting reasonable shots. Shutter speed is critical, ie at least 1/1000 and ideally higher.  
  • Before the workshop I would have been tempted to use Tv mode and auto-ISO; and this would be OK if the scene’s overall brightness remain ‘constant’. However, as the birds fly past you the background shifts from water, to mountains, to mountains & sky, and finally to sky. Using auto ISO would have shifted the exposure of the bird all over the place: resulting in black birds against a perfectly exposed sky. The ‘secret’ is to use a fixed (high) ISO and meter on the bird and set this in M mode. OK you may get some blown out backgrounds, but at least you will see feathers!
  • I was using a Wimberley Sidekick ( http://www.tripodhead.com/products/sidekick-main.cfm ) with my ballhead ( http://www.acratech.net/ballheads/gp/gps ) and I decided rather than mount the lens directly to the sidekick, I would use an L-bracket to create a quasi-full-gimbal head arrangement. I considered this set-up a great success as it allowed me to control the camera’s direction with my right hand whilst laying my left on the lens barrel for stability.
  • I did consider renting a 600mm prime, but stuck with my Sigma 150-500mm, and I’m glad I did. The Sigma is a great ‘BIF beginners’ lens, ie before you decide to shell out the big money! At F/8 I was able to make full use the 5DIII’s fantastic focus tracking system.
  • I also attached my battery grip, as I didn’t want to ‘waste time’ monitoring power. But I did need to keep an eye on my CF cards! In BIFing photography you are usually shooting in burst mode and hence, over the weekend, I shot some 4500 images! You need a lot of cards! 
  • I also decided to use this first ‘BIF training’ session to see if Magic Lantern Dual-ISO would help me. The answer is yes and no. When I was shooting with the falconer, ie in bright sunshine, I was using a base ISO of 100, bumped up by dual to 100/800. Dual worked well here, giving me a 13-14 Ev dynamic range. For the sunrise sessions, where I was shooting at ISO 1600-3200, dual was not much help here, as I found out in post. 
  • Also, for the 5DIII the 1600-3200 zone is where metering strategy changes. Below this zone and certainly at the native ISO of 100, where the camera DR is limited by its electronics, it is best to use ETTR. Above this zone, where the camera is limited by its sensor, there is no point in using ETTR. See http://www.clarkvision.com/articles/iso/index.html for some great insight.

In a future post I intend to write more about my BIF photography developments, especially after I have revisited my local BDA ‘training ground’.

So what about results? Well here are a few images, which I have taken from my first ‘quick and dirty’ post processing session: the day I returned from my wonderful weekend excursion. More can be found here: http://grayheron.smugmug.com/Birds-in-Flight/






Saturday, November 8, 2014

Wide Angle Corrections

Today was all about exploring the extreme end of my new 12-24mm lens, as I know this will be the end that will require the most corrections.

As a Photoshop-CC user I have three main tools to ‘play around’ with when correcting WA lenses. First, simply let the Adaptive Wide Angle filter do all the heavy lifting. Secondly, use the free Transform tool. Thirdly, and the one I like using with WA lenses, is to use the Perspective Warp tool.

As usual with my photography, it’s all about workflow, so here is how I currently use the perspective warp tool.

To give you an idea of what is possible here is the pre-processed 12mm Dual-ISO image, taken on a tripod at F/16. BTW the front of the orchid was about 16in from the sensor plane of my 5DIII.
First, in LR, I put the base corrections in place, which in this case gives me this image.


I then export to PS-CC from LR and create a Perspective Warp frame for the image: in this case it looks like this.


The positioning of the middle, where the two grids join, is dependent on your camera orientation relative to the image. Once the frame is in place I adjust the WA ‘distortion’ as I see fit. In this case I decided to ‘correct’ the lower half like this:


After playing around a little bit more I arrived at the following final boring image!


Bottom line: although one can make an image out of an uncorrected WA shot, with a little bit of LR and Photoshop magic, you can create an image with a reasonable looking feel to it: it’s your artist choice!

Friday, November 7, 2014

Another couple of mm



Given the choice between a wide angle lens and a ‘normal’ or ‘tele’, I would always go for the wide angle. OK there is the ‘downside’ of spatial distortion and you certainly don’t want to shoot people up close, unless you wish to create a caricature. But the upside is the large field of view and depth of field. Set a wide angle lens at its hyperfocal distance and you’re good to go, as they say.
 
With my 5DIII my go to lens is the 24-105 F/4 L; but, although 24mm ‘wide’ end is reasonably wide, on a full frame I really need to be shorter than this. 

I have my prime Rokinon 14mm F/2.8, which is great for (high ISO) night sky shooting, ie light capture because of the F/2.8 capability. But as a carry-around lens it is rather constraining.

So this week I decided to treat myself to a Sigma 12-24mm f/4.5-5.6 EX DG HSM II, which has a Hypersonic Motor Auto Focus system: with a minimum focus distance of about 11 inches. 


 With such an extreme lens, well at 12mm anyway, one needs to know how to use the lens, as you can quickly become disappointed, ie if you simply focus and shoot and don’t think about the optics.

At the 12mm extreme the edges and corners will be very soft shooting wide open, say at F/4.5. To get the best out of this lens you need to stop down to the F/11 to F/16 zone. As an example of what 12mms looks like on a FF Canon 5DIII, here is my first ‘yard test shot’. The yucca plant was slightly less than 2 ft from the camera. BTW this was a handheld, Magic Lantern enhanced shot: I first ETTRed to set the optimum exposure and captured the scene in Dual-ISO at 100/800.


And here is the image after being 'corrected' in Photoshop-CC Wide Angle filter.

 

As I was only going to show the image on a PC screen, ie not a print, I chose a diffraction corrected circle of confusion of 30 microns, rather than my usual 20. This gave a hyperfocal distance of about 18 inches at F/16, resulting in a near in-focus (according to my selected CoC) distance of much less than 12in. 

To illustrate the focus stability of such an extreme lens, even if I had focused at ‘infinity’, the near (CoC-based) in-focus distance would only have moved to just over 18in! The trick with any wide angle lens is to always focus beyond the hyperfocal, as doing so will guarantee you are sharp in the far field and you only sacrifice inches in the near field.

First impressions are that, at 12mm, the Sigma 12-24mm f/4.5-5.6 EX DG HSM II provides very reasonable results. I intend to provide further feedback on the lens in future posts, but suffice it to say, I’m looking forward to using this new piece of kit: but I wont, of course, be forgetting my trusty 24-105mm :-)

Monday, November 3, 2014

On the Road - Part 2

Photography these days is a very technical affair: all very digital. Of course if we go out for day long shoots we rarely worry about protecting our images, as, when we get home, we simply ingest the images into our PCs and undertake additional back-ups for added protection.

But what do we do on the road? There are of course dedicated memory drives that allow us to back-up our CF or SSD cards. But these are expensive and only useful for this one purpose. Which is why many of us these days make use of our laptops, or our tablets.

Having looked into various options I decided to adopt two approaches, rather than just relying on my laptop's internal SSD.

First, I bought a cheap 1Tb ‘mechanical’ HDD, at about $75: a WD My Passport Ultra powered over USB-3.



Secondly, I decided on a more up market approach: a robust USB-3 SSD memory stick, in particular the Ventura Ultra with a max read speed of 450 MB/s and max write speed of 445MB/s. At $135 the Ventura gives you an ultra fast 240Mb SSD: a great on the road protection for your images.

Finally I bitlocked both drives for security. BTW for those that are not aware, Bitlocker is available from Windows 8 Pro or Win 7 Ultimate.  Bitlocker uses the PC's or the laptop's Trusted Platform Module (TPM) to store cryptographic information, such as the bitlocker encryption key. Information stored on the TPM is more secure from external software attacks and physical theft.

Thus, for those multi-day/week photo trips, I now have no fear of loosing my captured images and I can safely free-up my CF cards each day: as long as I remember to back up every night that is!