masochismtango

Aperture, Light and Stops

// February 28th, 2010 // No Comments » // Photography

This is a diagram I drew to understand aperture numbers (the f numbers on a lens) and the concept of stops. In the graph, the gap between each bar is a stop (click to enlarge):

The most confusing thing was always the non-linear nature of stops – an increase of one stop of light means that the amount of light has doubled, a reduction by a stop means a halving of the light.

You can see the diaphragm of a lens here (the white circle in the centre, ie. the hole that lets the light through):

The Mechanics Behind the SLR

// February 17th, 2010 // No Comments » // Photography

A quick diagram I drew to explain the inners of an SLR, which is a mechanical setup that was developed to ensure the picture you see through the optical viewfinder matches the photo that will be taken:

This is how the mirror movement redirects the light to the sensor when a photo is actually taken:

Amusingly enough, you can view the complex mechanics that made the SLR so good for film as a drawback for the digital age – Live View, long a staple of point and shoot cameras, has been late in coming to SLRs because the whole mirror mechanism has to be bypassed.

Zenitar 16mm Fisheye on 5Dmk2 – First Impressions

// February 15th, 2010 // No Comments » // Photography

I shoot most of my photos with wide angle lenses, so it was inevitable that I’d eventually buy a fisheye.

Choosing

Given that ultrawide distortion is an easy thing to overuse though, I was looking for something in the £100-150 sweet spot – good enough to bother using, cheap enough to bother buying. Sigma and Canon models all come in over £400, so they were instantly out. That leaves two real contendors, with quite different characteristics:

1. Zenitar 16mm f2.8 – 180 degrees corner to corner on a full frame body like the 5Dmk2, but useless on a crop sensor body
2. Pelang 8mm f3.5 – projects a full circle on a full frame (ie. a circle in the middle of the exposure, with black all around)

As I have a full frame body, the 15mm was the obvious choice – it produces normal rectangular photos but with just enough distortion on the edges to be interesting. I am pretty certain that whilst the 8mm circle look can be cool, it would also get a lot less use than the more subtle 15mm.

Purchasing

I purchased my Zenitar for about £125 from MoscowPhoto on eBay. It arrived in under 2 weeks – a week faster than they suggested it would take.
The factory ships this lens with an old M42 mount, which usually requires an adapter but MoscowPhoto had fitted an EOS mount – this works perfectly and saves some hassle.

Quality

The lens looks very 70s, and it’s relatively lightweight, but for the money build quality is fine.

Picture quality is impressive for the money, as long as the lens is kept stopped down to f11 or f22. With such an enormous field of view that’s sensible anyway, as it would be hard to keep everything in focus at a wider aperture. There is a little vignetting, and in two of the four corners it is impossible to avoid small triangles of black, but it isn’t that noticable and can usually be hidden by the composition.

I don’t have the skills or the inclination to do any formal testing of the lens, but you can find my first batch of experiments on Picasa if you’d like to look. They were shot as S-RAW2, tidied a little in Lightroom and then shrunk to 1600px for Picasa, so not directly as the camera shot them, but a fair representation.

My subjective opinion is that at f11 and above the field was sharp enough to make me happy shooting handheld, a tripod would no doubt help – at which point the key issue for sharpness would be focussing, hard to do across the whole frame. There is noticable chromatic abberation, but it’s a fisheye so I won’t lose sleep over it. Colour saturation is disappointing compared to good glass, with colours coming out quite flat, but you can compensate in RAW and for an occasional use trick lens I don’t think it’s an issue.

Shooting Tips

Using such a narrow aperture obviously does make it hard to use the lens indoors. I found it could be used handheld in a dark room at ISO 2500-3200, which after some judicious editing in Lightroom produced acceptable pictures – I doubt you could use them as professional stock photos, but they’d be acceptable for small prints, web use etc. Your mileage with other bodies will vary, of course – the 5Dmk2 is spectacularly good at high ISO, so they work well together in this respect.

In good light, handheld shooting was easy – remembering to manually focus was the only real issue, and was easiest done by guesstimating using the distance markings on the dial. Speaking of manual dials, it’s worth noting that everything will have to be done manually with this lens – the camera cannot read the Aperture you have manually selected, so you have to work in Manual or Tv mode and do some test shots whenever the light changes. In practice this really isn’t challenging, and doesn’t require virtuoso knowledge of light metering. Obviously shooting RAW and using a body with good high ISO is very helpful here.

Overall, I’m really pleased with this lens and think it makes a great companion to a full frame SLR. The level of distortion can be subtle or extreme depending on composition and distance from subject, and works particularly well if you avoid aligning with strong horizontals and verticals. That said, it will take me a while to work out what sort of compositions it can usefully be used for, but it is light enough that you can carry it round just in case whatever the trip.

If you have a crop sensor body, however, you’ll need to look elsewhere…

Angles of View and Crop Factors

// February 5th, 2010 // No Comments » // Photography

Here are some more diagrams I drew to try and understand photography, specifically to understand crop factors and lens lengths.

Sensor Crop Factors

Every camera has a rectangular sensor which captures light. A “full frame” sensor is the same size as an old film negative – 35mm from bottom left to top right corner. Expensive SLRs use full frame sensors, but cheaper ones (such as any Canon in the x0D, xx0D and x000D ranges) use smaller sensors. The size of the sensor is described as its crop factor.

This diagram demonstrates the common crop factors found in digital SLRs (click to enlarge):

This explains why a larger crop factor will reduce vignetting (the darkening around the corners of a photo):

Note that we are talking here about conventional lenses designed for full frame cameras. Most manufacturers now also produce lenses which only work on crop factor sensors, such as Canon’s EF-S lens. These project a circle which does not reach the edge of a full frame sensor; understandably, these will vignette worse than the equivalent length lens designed for a full frame sensor.

Camera Lens Angles of View

The focal length of a lens is the number, quoted in mm, which indicates how close or far away things will look through it. This can be considered as an ‘angle of view’ – a larger focal length will produce a smaller angle of view – and a closer image. Think of it as the angle from the lens to the left edge across to the right edge of the frame.

Angles of view for a “full frame” sensor (click to enlarge):

In contrast, here are the angles of view for a 1.6x crop sensor:

For easier comparison, here they are side by side:

Saving a Dull Club Photo

// January 31st, 2010 // No Comments » // Photography

Often when taking a club photo you’ll just miss that cool background strobe, and end up with an underwhelming dark portrait that isn’t really usable. That’s fine if you have plenty of good ones in the bag, but sometimes you need a little help. That’s where Lightroom comes to the rescue!

Here’s an example of a picture straight out of the camera, that had potential but came out dull (click to enlarge):

Basic Brightness

If you are following the recommendations from my earlier post on club photography, you’ll be shooting in RAW. That’s essential to the recovery process!
Rule #1 of club photos is that you want colour and vibrancy, and no black space. To achieve this we can start with four basic tricks:

1. Bump up the ‘Exposure’ by a stop or so – keep an eye on the histogram, moving it as far right as you can without clipping the hilights (as this is a RAW photo, you should easily have an extra stop to spare without losing quality);
2. Reduce the ‘Blacks’ setting, which brings out more detail in the dark areas;
3. Increase the ‘Fill Light’ – this adds brightness to the dark areas, without compromising the well lit faces;
4. Crop the image to remove as much of the black border as possible – you might even consider turning a landscape orientation photograph into portrait, or vice versa.

You should now have something a little more like this (click to enlarge):

Bringing out the Background

That’s better, but there’s still a lot of dead black space. We can use one last trick to pull out more colour – use a Graduated Filter to increase the exposure on the black background another stop:

Note that whilst there is noise in the background, it’s relatively unimportant as the faces are the focus of the photo, and are still well balanced. The background is simply providing blurred colour to lift the picture.

The Salvaged Image

After only a minute or two of processing, we now have our salvaged photo – a significant improvement, without any visible loss in quality thanks to the wonders of the RAW format:

Hard and Soft Light

// January 23rd, 2010 // No Comments » // Photography

Ages back I had a plan to create a new site which explained photography using primarily diagrams with illustrative photos, and minimal text – built up as I learnt new techniques. One day I’m sure I’ll get round to creating it, but until then I thought I’d post up some of the diagrams and notes here!

Light Hardness

The hardness of lighting has a huge impact on a photo – soft light means subtle wide edges to shadows on the subject, wheras hard light would give a very defined sharp border between lit and shaded areas.
As a basic rule of thumb, soft light is flattering in a portrait, hard light is dramatic:

Portrait with softer, flattering lighting

Portrait with harder, dramatic lighting

The Strobist 101 course explains the basic concept of hard vs. soft light in some detail, with some nice setup photos. I tried to boil the lessons down to their essence:

In a nutshell – the bigger the light relative to the subject, the softer the light.

In a nutshell – the further away a light gets from the subject, the smaller it becomes relative to the subject and the harder the light is.

Certainly not rocket science, but I like to reduce things to simple rules and present them visually!

DIY Soft Box

While we’re on the subject, I may as well present my quick instructions for making a very portable soft box from a shoe box – a flash modifier for producing softer light.  It’s small, so only suitable for a limited range of uses, but it slips nicely into a camera/laptop bag next to the laptop and weighs next to nothing so there’s no real harm in carrying it around!

Materials: one shoe box, some sticky backed velcro strips, a few sheets of shiny white printer paper and about an A4 sheet of tracing paper – plus duct tape, if you want to make it look nicer and be more durable.
Tools: glue (something like Pritt Stick), and either good scissors or a Stanley knife.

Step 1 – Open up the shoe box flat.

Step 2 – Mark out where to cut, which is driven by the size of your flash head – on the side flaps, put the head side on in the centre of the flap, and mark out diagonals to the top and bottom (it may be helpful to look at photo 5 to visualise how it will assemble in the end).

Step 3 – Cut out these diagonals, and most of the bottom of the box, with a Stanley knife. Fold the side flaps together, put the flash between them, and then fold the top and bottom flaps together; mark out diagonals on these top and bottom flaps so that you will be able to make a pyramid. Remember to leave tabs for the velcro (see next picture).

Step 4 – Cut the top and bottom flaps into shape, and then stick on the paper – white paper on all of the solid surfaces, and tracing paper across the big hole in the middle. If you have some duct tape, stick duct tape all across the back/outside of the box for strength. Add velcro to the tabs so that you can fold the box into a pyramid.

This photo shows the softbox assembled, with the flash firing and at rest. Note that the flash head also has velcro around it, for quickly attaching modifiers – see Strobist for thoughts on that.

Softbox flattened down for transport – it folds to about 1cm thick when it’s not under compression.

Art in Central London

// October 28th, 2009 // No Comments » // Photography

Last week I got to support some friends posing for the artist Richard Bagguley, dressed as a Roman soldier crucifying Jesus on Oxford St:

Richard was particularly looking for reactions from ordinary passers by, and has some genuinely interesting points to make. At the end of the video is a glimpse of André Camara, the photographer who’s story became the film City of God – who was just picked for the Brazilian 2012 paralympic rowing team, I discovered last night.

Jesus (SP Howarth) and my fellow Roman soldier (Andy) will be appearing in their play Baccus in Rehab at the end of November in Camden, which I strongly recommend – and not just because I designed the flyer and am taking the publicity shots!

One of André’s photos from the shoot was published in that weekend’s Independent on Saturday, and also appeared on the Express web site for a while but then got pulled down for mysterious reasons…

How To Take Club Photos

// September 28th, 2009 // 13 Comments » // Photography

I’ve been taking club photos for TillLate in London for half a year now, and I tried a few times at Club Illusion in Tartu, Estonia before that.  Early on, I remember struggling to find any good tutorials – as it turns out, the basics are pretty easy to understand.

What Are You Trying To Capture?

First up, consider why you’re taking the photo – to make the club look good:

For a straight club, make sure you are prioritising the following (in order):

1. Hot chicks;
2. Famous DJs (if any);
3. People having fun (mixed groups, couples, interesting blokes);
4. Cool venue.

What Kit Do You Need?

Very little, in SLR terms:

• D-SLR camera with M(anual) mode and RAW picture format;
• External flash with E-TTL (ie. an automatic mode);
• Something to soften the flash – maybe a Stofen Omnibounce, or just a DIY bounce card.

You can in theory take club photos with a built-in flash, but you’ll look amateur and so will the photos.  Your choice!

Note that good flashes have Infrared assisted focus – they fire a red beam at the subject to work out the focus, which would take forever to find without the flash.  This is invaluable.  Make sure the focus assist works in Manual mode – for some stupid reason the cheapest Canons will let you use Manual or IR assist, but not both.  Ridiculous.

What Settings Should You Use?

Steal settings – track down club photos you like and read the EXIF data!  On Flickr, you find a “More properties” link it below the picture on the right:

To get started, all of my example pictures in this article include an overlay showing the settings.

Settings for People Photos

The first thing to realise – the flash only lights the people in the foreground. It simply isn’t powerful enough to light the room, and you don’t want it to!

If you just use the camera’s automatic P mode, it will expose for the foreground and the background will go black. To get that colour, turn to Manual mode.  Set a relatively wide apperture (f2.8 – f5.1) and a relatively long exposure (1/6 – 1/13 second) with a fast ISO (round 400-800).  Turn off any Image Stabilizer your camera or lens has, it will slow down focussing and gets confused by background movement in the longer exposure.

Your flash will freeze the foreground, whilst the longer exposure allows the background lighting to soak in and add depth.  Where possible, position the subject(s) between you and the lights so you maximise the spread of that colour.  Smoke, low ceilings, decorations and people in the background all provide surfaces to maximise that colour.

Remember to always show the photos to your subjects – always appreciated!

Settings For Crowd Shots

Don’t take every photo with the flash. You want a smattering of longer exposure pictures without a brightly lit person in the foreground – either pick up something solid like the DJ booth or just blur the crowd:

The beauty of digital is that you can just chimp away with different exposure lengths until you find something that works.  If you’re uncertain use the Info view of the photo to see the image histogram, which will tell you when you have a reasonable exposure.

Settings for Bar Pictures

Relatively long flash-less exposures can also pick out the neon often lighting bars:

Processing The Photos

Always shoot in RAW instead of JPEG – correct exposures are hard to hit when in manual mode with variable club lighting going off at random, and RAW gives you a much larger safety margin. You’ll need good processing software as well – I find Adobe Lightroom is pretty quick and easy whilst having a lot of power.

Don’t be afraid to crop out black backgrounds, and use tricks like adding Fill Light to pull out extra background colour which isn’t initially visible.

Finally, below you can see examples of my club photography improving over time – from the first shoot in Estonia to some relatively recent ones in London (the latest are here).  Practice really makes a difference – good luck!

Photos Published in Eurail Magazine

// March 3rd, 2009 // No Comments » // Photography

I’ve just had some of my photos from a Masabi photoshoot in Waterloo station published in Eurail magazine (issue 19, PDF here), to accompany Ben’s mammoth article on reduced cap-ex mobile ticketing rollouts for UK trains.

Cynics might say it’s the kind of magazine that is likely to end up as a guest publication on Have I Got News For You, but it was a pretty important article for Masabi and it’s always nice to see your work in print!

At some point I will do a post on how to get usable shots of in-context mobile phone screens – it’s not quite as easy as it looks!

Photos From The Shoot

Some of the photos from the shoot are available on the Masabi Flickr stream: