Andrew Macpherson

Equipment

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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Photographing Charity Cycle Rides – lessons learned

by on Jul.28, 2013, under Equipment, Learning

Well it’s the 4th time I’ve had a go at photographing the participants in the London to Cambridge sponsored charity cycle ride. Each time I get a little closer to getting it right, a little more confident of getting a reasonable set of results.

So where have I got to?

  1. This may be a daytime event but I definitely want flash to get separation from a darker background
  2. If the aim is to get each participant there is not time to capture each and get AI servo lock, and definitely not time to focus so a big depth of field and manual pre-focus is crucial, especially as the riders are all over the road, which means
    • Strobe in high speed sync
    • or high power low ISO (recharging time is an issue)
    • This year I had a speed light with an external battery pack which both gave good recycle time and over 2000 discharges at 1/8 from the 12 AA cells, but in hindsight I could have done with being at 1/2 power (or 2 strobes at 1/4) but I’m not sure about charging being fast enough
  3. It may be worthwhile using a crop frame sensor and shorter (absolute) focal length lens to improve the effective depth of field for a given composition
  4. Get the other stuff right then shoot medium JPEG, there are several thousand riders, one really does not want 100G of raw to process
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Opportunistic lighting

by on Jun.20, 2013, under Equipment, Learning

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A neighbour’s daughter was being particularly cute, telling her aunt to pick up a book and read, then gazing into one herself.

Outside we had bright sunlight, with a slightly north facing window. The window light reflects ideally from the book into her face, so I sneaked a grab shot, holding the camera low (and failing to get the focus perfect- it’s on her arm rather than her eye) I thought I would share the shot for the lighting anyway

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Passport Photo? Certainly

by on Mar.27, 2013, under Equipment, Travel

Just got asked again to do a passport photo for a neighbour. As ever the problem is getting the photo cut out at the correct size, and so finally I bit the bullet and ordered a photo punch to do the job right

Konig Single Frame Passport Photo Cutting Machine

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Benefits of attending Trade Shows

by on Mar.16, 2013, under Equipment

Earlier this month I had 2 days at “Focus on Imaging” and saw some great presentations, met up with suppliers, and with a few friends. The big benefit though is being able to get help from experts on the smaller things that have caused one problems…

Top of this list for me was a visit to the Pixel stand. I’ve had good results with Pixel gear in general, particularly the low cost 3 way VM/VS 801 cat5 cable hotshoe extenders, and with Pixel’s excellent external battery packs to speed up recycling (and avoid melting) speedlites. I had however bought a set of Pixel King radio triggers and just could not get them to work in E-TTL mode with my Nissin DI866mkIi speedlites. They were fine in Manual mode, and I could adjust the power levels, use HSS etc but when it came to E-TTL the level setting preflash would trigger, but the shots would be dark.

I visited with Pixel and demonstrated my problem. No immediate solution, but careful notes… camera firmware release numbers, model numbers for the speed lights, and a promise to get back to me. I also was given a bonus – one of their very nice cable releases.

And of course Pixel have come back trumps with the solution. There are 2 current sets of firmware for the Pixel King Flash Triggers, and I had the highest numbered version (1031) loaded, which turns out to be for the Canon 1DX, whereas the other release (1030) is what is needed on the 5D3. I’ve re-flashed the firmware, and it’s all working. Thank You Pixel! While a radio trigger with manual control is very useful, the automation really helps at events.

The other thing I needed help with was printing on clear or highly reflective substrates, with my big Canon printer. Thanks due to RGB-UK on the Canon stand for helping me out here. One needs a narrow strip on the edge of the sheet to help the optical sensor in the printer detect the “paper.”

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5DIII after some weeks

by on Aug.02, 2012, under Equipment, Off the wall

I must say I’m loving it. The only major pain is how long the after-market ‘L’ bracket which fits round the BG-E11 took to appear. I noticed that Really Right Stuff had shipped some, even if they were on back order, so I ordered mine too, and now it has arrived to my great relief.

I’ve been getting questions on club outings about the L bracket, as the benefit isn’t immediately obvious to someone who hasn’t used one before. The quick switch from portrait to landscape, without having to re-adjust your tripod, and the way the weight stays centred are pretty conclusive, and of course the final benefit is the vendor neutrality of the Arca style fitting

A lot of thought has gone into the ergonomics on the 5D3. I initially set up my custom menu to copy that from my 5D2, and this got me going quickly. I’ve now almost completely deleted it, because everything is so quickly available on the shooting info back menu. Strangely after finding this on the 3, I discovered it had been there on the 5D2 as well (click the joystick on the back of the 2 to activate the selection, use the set button to select the setting to be adjusted). Presumably much the same is available on the 7D.

The new features I find myself using are:

  • All those focus points
  • built in level
  • 5 and 7 step bracketing
  • all those focus points
  • the second memory card for jpgs to copy onto my iPad for preview, and to tag using Photosmith
  • faster burst mode, particularly for panning and low light
  • did I mention all those focus points?

I nearly had a failed outing, as I left in a rush, only to discover that I had withdrawn my battery tray to put the Canon batteries on to charge and not picked it up again. Fortunately I had put the AA battery tray into my camera bag, along with a box of batteries. All goes to reinforce the need to carry spare memory cards and power at all times.

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