Andrew Macpherson

Tag: Technique

Using a Tilt Shift Lens, let’s re-design for photographers not the convenience of lens makers

by on Oct.22, 2013, under Equipment, Off the wall

In the beginning cameras with lenses (vs pinholes) were built round a laboratory optical bench, where the various elements could be relatively easily adjusted. This led to the “Stand” and “Field” plate cameras where he lens and the plate (sensor) could be moved relative to each other.

This arrangement had lots of freedom, but the basic arrangements were relatively easily split into what we now call Shift or Perspective Control, and Tilt where we take control of the “plane” of focus. I put “plane” in quotation marks because in the general case, where very clever lens designers have not been at work, that plane is actually the round inside of a ball, and we rely on depth of field and the effective radius of that ball to compensate.

Perspective adjustment (shift) works by setting the back of the camera flat on to whatever we want to look straight, and then moving the lens up, down and sideways relative to the back of the camera until the image appears in then right place on the sensor. Shift lets you take photos of mirrors apparently in the centre of your frame without showing the reflection of the camera, of a tall building with its sides vertical without having to hire a helicopter to get to that position half way up and so on. The usual issue with these shots is the vignetting of the further parts of the image — in effect only half the image will suffer, and in digital post production one stage will be to add temporary blank pixels (or a layer with the 180°opposite shift for symmetry) to the “near” side of the image so that the vignetting circle is around the midpoint, allowing standard lens correction tools to be used to cancel it out in post. With a Canon TS lens on a tripod one can simply rotate the lens to get the perfect 180° reverse shift to make sure the generated composite is the correct size.

Tilt is much harder to use. What tilt lets you do is play with your plane of focus, either reducing it to a narrow line across your frame, or bringing a large receding plane into focus, from foreground right to the furthest distance. This is where the mechanical design of he lens can make all the difference to how easy the lens is to use for the photographer.

The ideal Tilt lens will have a tripod mount ring, and the tilt’s axis or point of rotation will be across the sensor of the camera. This lets the photographer compose their shot, and use the most sensitive central focal sensor on their camera to get a sharp focus, then switch to using a peripheral focal sensor and rotate the camera body (remember we’ve clamped the lens to the tripod, leaving the camera body mobile) until that point too is in focus. The central point will have remained in focus because that’s at the centre of rotation. The composition too will remain almost unaltered.

My Canon TS lenses completely fail on the usability front. They rotate about the front of the camera body rather than the sensor, with no regard to the photographer who will have to try to use it, each movement of the tilt mechanism changes the composition and the focus. This fault is also there in Lensbabys, Samyang and all sorts of other lenses with tilt capability. The “Why?” Is fairly obvious: by having a short radius the lens designer gives themselves twice the angle for a given movement, and reduces the consequential vignetting but at a massive cost in ease of use.

I’m still searching for a lens manufacturer with the guts to trade “spec” figures for usability

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What files have I worked on?

by on May.10, 2013, under Learning, Retouching, Workflow

Ever find you have to do some work in Lightroom without adding Picks, selections, stars or other obvious Metadata?

Select Develop Preset

Select Develop Preset

I recently found myself tweaking a friend’s images so she could use them immediately rather than wait to get home and work on them at her desktop…  She had literally hundreds of photos on the card, but wanted to see them full screen, then wanted a few adjusted, and the issue was, at the end of the exercise, to identify quickly which had been touched to re-export them.

All your modifications will be under "custom"

All the modifications will be under “custom”

With the folder open in the Lightroom Library Module I went to the Filter bar press ‘\‘ if it’s not showing at the top and select ‘Metadata’ then set my selection to ‘Develop Preset’ at this point you may have a few choices particularly if you have used any presets, but everything I had touched was under custom enabling me to quickly pick them out for re-export.

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Notes from the Tabernacle

by on Mar.09, 2013, under Learning

A seminar arranged through the London Photographic Meetup Group, featuring the Internationally famous photographer and trainer Frank Doorhof, who I had seen earlier this week at Focus on Imaging at the NEC

Arrived early at the Tabernacle for Frank’s show.

The Pan Man

The Pan Man

The hallway has a fascinating wireframe sculpture of “The Pan Man” a carnival Steel drum player, under a memorial to Claudia Jones the mother of the Notting Hill Carnival. As I’m sitting enjoying a mocha I get to say say good morning to Frank and Anneweik as they go past to set up.

We are asked to wait until 10:15 before going up to the theatre, a very nice space, set up with round tables, and surprisingly comfortable folding chair.

Frank Doorhof addressing the audience

Frank Doorhof addressing the audience

Frank is sitting under a spotlight, on a high chair, somewhat reminiscent of Dave Allen.

The class starts with a reprise of Frank’s theme “Why fake it when you can create it?”

Here are a few notes, points or aphorisms from the talk:

  • Emphasis on Knowing how to do it right, as second nature.
  • Great bare bulb shots to show that expensive strobes are not required
  • The seminar is “PowerPoint” but with a big emphasis on composition and audience interaction.
  • Go low for a new viewpoint.
  • “Find a stage and the players will come” – Jay Maisell
  • Interesting examples of wide angel lens fashion
  • Be careful to put in deliberate asymmetry.
  • Deliver the picture you are happy with
  • Tip try DxO Optics vs Lightroom for lens correction
  • Lose colour, and add contrast and noise for interest
  • If you have to title a photo it’s possibly not strong enough

Finished up with finally buying Frank’s “Live in Boston” instructional DVD.  Get yours here.

It was also good to meet a new people, I expect I’ll try more of these meetups.

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Rugby from the stands

by on Feb.19, 2012, under Equipment, Learning, Workflow

Penalty Kick

On Saturday I had a welcome unexpected chance to go to a Harlequins home game, and saw it as a chance to try some of the ideas that I’ve been picking up from Scott Kelby’s blog though just from the stands, rather than the privileged sideline access of the professional.

Kick-off was at 17:30 a quarter hour after sunset, so this was strictly a floodlight exercise.  I quickly found that the exposure on the field of play was fairly constant, but there was huge risk of variability if one let the camera “do it’s thing”so went fully manual, f2.8, 1/800th & ISO on H1 (12800).  The other half of this exercise was processing in LightRoom 4 beta, and the noise removal could only be better than the already good results one gets in Lr3. (continue reading…)

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The All Year Challenge

by on Jan.14, 2012, under Competitions, Learning, Off the wall

Lens Pro To Go, a US equipment rental company, have thrown down a challenge.

Joint them for a photo-per-week challenge on themes they set.  My photos will accumulate in this flickr set, and the  whole set of entries is in the Lens Pro To Go 52 week challenge.  The exercises are are as hard, or easy as you let them be, so it’s great fun.

Why not join in?

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Camera Club Fundraiser

by on Jul.09, 2011, under Camera Club, Equipment, On Site, Workflow

Three weekends ago, just before I went off for an op, we had a stand at Hatfield Heath Festival to try to raise awareness of the club, and raise some cash for the projector fund.  I havn’t quite got round to writing about it, having been slightly distracted, so it’s time to make amends

Hatfield Heath Public Photoshoot, © 2011 Paul Lambert

Photo given to sitter as 6×4 print

The Saturday session was in direct competition with Bishop’s Stortford Carnival, where we also had a stand, so each event had one of the two print stands, usually used for print competitions

We had a selection of member’s prints for sale, both ones that had been in competition, and some framed or mounted specially for this event.  Mainly though the exercise was to engage potential members, and enthuse them to come along for a trial club evening, and I think we were moderately successful in that.

We were also offering free “Hollywood Look” 4×6 portrait, retouched with “Portrait Professional”  (continue reading…)

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