Get Indexed by Google Quickly

In this video Matt Cutts points out a feature of Google Webmaster Tools that essentially allows you to manually update Google's record of your webpage. The fetch as google bot function used to simply show you how google would see your page but now it can be used to refresh, or create, Google's record of a page on your website. For established websites this is very useful if some important information needs to be changed, a common example being a change in the price of a product or service. For new websites this should enable webmasters to get their content indexed more quickly than waiting for a google bot to crawl their content naturally. Interestingly Matt also points out that this feature gives you the option of crawling the linked content on that page as well. This is an excellent way for new sites to get into the index especially if a main navigation page is submitted to the fetch as google bot feature.

Review - Peter Hurley - Art of the Headshot

Is Peter Hurley's Art of the Headshot worth the $300 pricetag?

To summarise what follows, probably. In fact if you're in a studio environment with more than one photographer shooting anything related to faces the answer is almost certainly yes.

Peter Hurley's art of the Headshot is 4 1/2 hours that you can spend with a top New York Photographer explaining his craft any time you like. While you might expect him to get bogged down in camera and lighting details or even stick to basic procedures he goes well beyond this. Instead he explains his complete approach and the trajectory of his career. From how he started out on his own as a natural light photographer to how he operates today charging $1100 per headshot shoot while working with a team including retouch and make-up artists.

Perhaps unexpectedly equipment and lighting set-ups end up taking a back seat to client-photographer interactions. In fact Peter makes the point that the reason he is a successful headshot photographer is that he is 10% photographer and 90% therapist. Rather than worrying about keeping his camera happy he focuses on making his clients comfortable.

While comfort is a key part of the therapy component of the shoot his therapy extends beyond this. Peter shares tips with his clients (and you the viewer) about how to create excellent photographs. For Peter this element of teaching is perhaps the most important aspect of his photographic therapy session.

Conveniently you are not required to take his word for this. As part of the DVD you are supplied with 6+ recorded headshot sessions. In these sessions you will see clients coached from average photos through to stunning photos as a result of the environment and education that Peter provides. Critically these sessions are not all performed with people who simply 'get' what Peter wants or how he wants them to behave. At times he encounters resistance and you the viewer get to see how he gets through that to reach the goals that he needs to achieve.

While this DVD has been marketed at photographers it could easily be marketed, perhaps in a condensed form, to models as well. The tips that Peter provides are the sort of things that models will be able to apply in most, if not all, of their photoshoots throughout their career. Check out the video at the bottom of this page for an example of one of the lessons.

However it's not all good news. Those who are taken aback by the pricetag might ask, isn't this the sort of information that I can get elsewhere for less than $300 or, in this modern age, for free? The answer to the question is yes... but. What Peter Hurley's DVD does is collect and assemble the information, that you will be able to find in pieces, in a way that not only works but has been shown to work. It's the difference between being able to find all the pieces necessary to make a car and having a fully functional vehicle. What is that difference worth to you?

While that point might be considered good news (in that you are getting some kind of value for your money if you do proceed with the purchase) the next point is cause for some concern. When Peter talks about equipment he stresses the importance of a pro-level dSLR as a minimum requirement. This is nonsense and probably stems from the fact that he is out of touch with the dSLR market (he admits to this but it is surprising that nobody on the F-stoppers team thought to question this point during the production of the video). Consumer level dSLRs would now be perfectly capable of performing the functions required for a headshot shoot and would be a much better investment for someone just starting out in photography than the pro-level equipment that will be outgunned by lower level cameras by the time the beginner has generated enough income to recoup the cost of their initial camera. As a reference point Peter shoots at a low shutter speed and at low ISO. Almost any decent consumer dSLR will perform well at these levels. If anything invest in a quality lens and a body that is good enough to get the job done.

Beyond this it is important to recognise that this DVD is about headshots. This means the techniques that you will learn will be useful for photographing people. Typically people on their own. Typically people from the shoulders up only. In fact the advice that Peter gives out during the DVD is all about the face and how to make it look its best. Now, don't get me wrong, faces are very important and these tips are extremely valuable but if you are expecting something more than this you won't get it. in this sense the DVD does what it says on the box - it tells you how to take a great headshot. While you can take some of the photographic lessons and apply them to other settings the headshot is where the focus stays. If you try some of the body positions Peter suggests in a full length shot you will end up with some very odd results.

Ultimately then whether or not you should buy Peter Hurley's art of the headshot depends on what you expect  to be able to take away from it. If you are happy to take away photo related tips that focus on enhancing the faces of your subjects with little focus on any other body parts then this DVD is a no brainer. If you want to know how Peter Hurley runs his business, built his business, lights his studio, sets up his camera, selects clothes, guides make-up artists, or runs an individual session then this is well worth the money. But if you are looking for anything beyond this, such as how to take a great group portrait, and do not have the imagination or ability to take lessons learned in one area and apply them to another keep you money in your pocket. This is a DVD about taking great photos of individual faces that show a connection with the subject. While the rules can be applied to multiple subject shoots that application is left to you.

Google's 5 mistakes in SEO

1) Failure to provide value to the client
A website that has great SEO but no real value to it searchers will not reliably click through or refer friends.

2) A segmented approach to SEO
Focus on optimising your site through the whole customer experience. Align your marketing message with your SEO strategy.

3) Time Consuming Work Arounds
Stay up to date with current best practices to avoid wasting effort. One example is flagging content in such a way that causes google's spiders to disregard it completely.

4) Getting caught in SEO trends
The most dangerous trend to get caught up in is chasing the search engines rather than users. Search engines try to emulate users. If you chase users you and the search engines will be working towards the same goal meaning algorithm changes should help rather than hurt you.

5) Slow iteration
Update your site continually to provide maximal optimisation

Do these:
1) Do something cool
2) Include relevant keywords in your copy
3) Be smart about title and meta description tags
4) Sign up for e-mail forwarding in webmaster tools (it will send you information about problems etc.)
5) Attract Buzz, often referred to as creating link bait
6) Stay fresh and relevant

How to have a great career

Competence is no longer enough.
Laziness and procrastination are the enemy.
Madness is not a necessity.
Hard work is not enough.
Passion is important. It should be followed.
Passion is not the same as something you find interesting.
Passion is a great and consuming love.
Relationships have become a modern excuse. It is possible to be successful and be a good person.

Increase you Adwords ROI with Remarketing

Remarketing is an option that can be found in the Audience tab in Adwords. Remarketting allows you to target the same cutomers multiple times across the google display network by placing a cookie on their computer. This is how some ads can seem to follow you all over the internet.

In order for it to work you must include some tracking code on the relevant pages of your website. Adwords will generate this code for you while you set-up remarketing in the audience tab.

While attracting the same customer multiple times may seem counter intuitive at first there are sound reasons to implement such a practice.
1) It is rare for customers to purchase something after a single presentation
2) Remarketing helps you get found again
3) Remarketing targets customers who are likely to be interested in your product or service

Tips for Social Media Expansion

Use Social Media to accomplish a specific Goal
- Enhance branding awareness
- Protect your reputation
- Rank well in search
- Extend Customer Service
- Build Community
- Facilitate R&D
- Drive Sale and Leads
Note that these goals aren't necessarily about making more money directly. Use socail media for what it can do, not what you want it to do

Key Strategies

Customer Service
- Search for people mentioning your brand name
- When you find people who have an issue with your service reach out to them an dtry to solve the problem

Drive Sales
- Join the conversation, be present and engage with customers
- Don't just sell your product, provide something of value that helps cutomers see you as a resource
- Use clear calls to action

Fake Pro Photographer

Can you turn an amateur into a pro photographer in just 1 week? Here Kai and the Digital Rev team try to do just that putting the fake it till you make it addage to the test.

While it was ultimately unsuccessful in this case there are ways that such an outcome could be achieved. Chief among these would be prior knowledge of the final challenges. If you know exactly waht you are going to be required to produce you could work on that outcome with your mentors.

Critically while the above solution would only fulfil the brief in that limited scope that is actually all that would be required. Here they are trying to FAKE a pro photographer, not create one.

Peter Hurley - Art of the Headshot - Sample

I'm looking at purchasing Peter Hurley's Art Behind the headshot. It's a 4 hour course allegedly demonstrating everything that Peter Hurley has learnt over the past 8 years. If so it should be well worth the money. The above video is a sample from the 'DVD' (it's actually a download). What do you think? Worth spending a little bit to learn a lot or doesn't this look that useful?

My verdict on the Peter Hurley Art of the Headshot DVD can be found here

Taking better portraits - Defining the jawline

It's all about the Jaw from Peter Hurley on Vimeo.

In the above video Peter Hurley demonstrates the importance of, and techniques for, defining the jawline in photography. These techniques predominantly allow you to eliminate the appearance of double chins by preventing the key factors that cause them to appear in photographs.

On Page SEO for Photography Websites

One of the biggest challenges in optimising a photography website for google (or any other search engine) comes in creating quality on page content that search engines can read. Unlike you and I google's spiders don't see the internet with the human eye. They read it the same way that a computer reads it, as a set of instructions.

Unfortunately this means that google doesn't read your photo of a beautiful sunset as a photo of a beautiful sunset. Instead it reads the name of the file that contains the beautiful sunset, the written information on the rest of the page, and any other code that is built into your website. As such if you want your photography website to be found on google it isn't enough to load your page up with plenty of lovely photos, you must also load it up with plenty of words describing those lovely photos.

Filenames/Image Titles

At the simplest (and most overlooked level) you can rename your photo files (the .jpegs, .pngs or whatever you're using) to reflect their content. Instead of having a file called DSC00042.jpg use a file called Sunset.jpg. You can use underscores or dashes to break-up the words in your image file titles as well. For example you might like to call your file Auckland-Sunset.jpg if your photo shows a sunset in Auckland.

Alt Tags

The next level is the alt tag. the Alt tag is what is displayed to the user if the image cannot be displayed. Here you can include a description of what the photo is of. For example you might like to say something like "A golden sunset in Auckland New Zealand". As a side note this is also what will be read out to vision impaired people who visit your website.

Image Captions and On page text

With those out of the way we break into what people typically think of when you say on page content: image captions and on page text. Captions are spatially linked to images and this can be reflected in certain coding languages. It is likely that google will use image captions to identify what an image might be of for indexing in image search. As such image captions should describe the content of the image they are closest to. You may like to reword your alt tag and use it here.

On page text is less directly related to individual images. It is the written content on the page and often provides information related to some underlying theme between the photos on the page. For example if I post a gallery of property photography images like this one I include information about the property itself while mentioning that I am available for real estate photography in Auckland. In that body of text I signal to google and other search engines that the content on that page relates to property photography in Auckland increasing the odds of getting listed in google search for relevant search queries.

You may also notice that there are a few keywords on those pages. Those keywords are there because those are the words that I am interested in ranking for (property photography, real estate photography, and Auckland). You may also notice that those words are mentioned as naturally as possible. While they may be repeated from time to time I am not trying to ram them down google's throat. Why not? If google wants words and I know which ones I want to feed it surely more relevant food would be better right?

Wrong.

Remember that google is trying to simulate human search using computer algorithms. In order to do this they pay a lot of very clever people a lot of money to teach google to read like people do. If you stuff your page too full of keywords google will pick up on this now or in the future. Watch the Matt Cutts Google Webmaster Help video below for a clearer explanation.

Comments

The final option is comments. One of the key benefits of comments are that they can be generated by other people. As such you are essentially outsourcing your SEO work. One of the key downsides is that they are generated by other people and can actually do nothing for or damage your SEO if implemented and moderated incorrectly.

Recall that google can only read what is written on the page itself. This is important if you are using an external  method of generating and collecting comments. The Facebook comment box being the clearest example. If google is unable to see the comments they might as well not exist for SEO purposes.

Now also recall that google does read what is on the page and uses it to decide what your page is about. If you end up collecting a lot of comments that don't add to your page's content or accurately reflect or describe what is on the page they might as well not be there. To make matters worse if you get a lot of irrelevant comments than can lead google to believe that your page is less about what it would have thought your site was about than if the comments weren't there. For this reason it is good to be able to moderate your comments. This allows you to control the quality of the content that users are supplying and also helps stop any spam getting through.

The Standard on Page SEO tips

Beyond this the standard on-page SEO tips still hold true. Use page titles and headings sensibly. Use them to highlight your keywords but avoid using them for spam. Use the meta description to suggest a relevant snippet to google. While google might not use it many other search engines will and google will check it out in the same way that it looks at your page content, page titles, headings etc. Meta Keywords on the other hand are less useful for google but may still be useful for other search engines.

Quality Content

Finally (but arguably most importantly) focus on producing quality content. If you produce content that people will find useful they are likely to share it. If they share it they are likely to do so by linking to it. If they link to it someone has just created a backlink for you and backlinks are what will really bring google's spiders to your site. In terms of quality content for photography you may like to consider the following options

• How to articles
• Reviews
• Descriptive galleries of your personal work
• Blog posts detailing some aspect of your business (blogging of images from individual weddings is a popular example)
• Clear information for your clients (such as details around pricing - an often overlooked element)

If you aim for qaulity content the keywords should come fairly naturally meaning you won't need to worry about sending your content into spam land.

The Next Step

The next step is off page SEO. This revolves primarily around link building and can apply to different pages on your own website as well as pages built by other people. In most cases you will get the most bang for your buck by targetting inbound links from other people's pages. Off page SEO will be covered in more detail in a future post.

Impossible Photos - Discussing Digital Art

Digital Art is the art of creating photos that cannot be taken with a camera - the creation of impossible photos.

Erik Johannsen is interested in what you can do with a photograph after the shutter button is pressed. He felt that traditional photography was limited to essentially being in the right place at the right time. He felt that anyone could do that and he wanted to do more (arguably though anyone can do what he does as well, it will just involve more work in post than 'simply' taking a photograph).

So why not abandon photography completely and pick up a paintbrush instead? Photography portrays a level of realism that other mediums do not offer, or at least do not offer as readily. It is the subversion and manipulation of this realism that Johannsen enjoys and requires in his art.

Successful subversion primarily requires planning - knowing what you want the end product to look like before you begin so that you can collect the pieces necessary to complete the puzzle. Key considerations include perspective, lighting, colour, contrast, brightness, and how you will make the end product appear as a seamless solitary image despite the fact that it's made of many different images.

Becoming Successful in Photography - Art Streiber shares his thoughts

Here Art Streiber shares his opinion on what it takes to succeed and reach his level in photography. Key to this is the idea that the building of your brand and the building of your brand is not a sprint, it is a marathon. Part of this is the way in which you will develop. You can expect to develop in a stepwise fashion, going up in sudden bursts, rather than at a smoother constant rate.

YOU MUST BE COMMITTED TO THE CLIMB

You must shoot, maintain your archive, market yourself, and pay your bills in order to survive and, ultimately, thrive.

You must know your market. You must know your clients. You must put yourself in front of these people through marketing yourself and your skills to them. If you can identify people who will be your clients in the future and market to them before they are able to buy from you.

One way to do this is through your personal work. Personal unpaid work can demonstrate your skills to future clients but, more importantly, unpaid work can become paid work if the subject of your images becomes worthy of wider interest/publication.

A rational Discussion on the New Nikon D4

Dom Bower's photography videos are often worth a watch and this one is no exception. Here he outlines what many of us already know about Nikon's new flagship camera, the Nikon D4 - Essentially it will be a great camera but it is not for everyone. While there are plenty of people talking about most of them don't need it and can't afford it. While it can be fun to get caught up in the rumours and excitement surrounding a new camera's release it's also important to focus on keeping your feet on the ground.

From a practical standpoint the D4 looks to be a bit of a tank. It will be big and robust making it ideal for sports photographers (particularly those travelling to the 2012 Olympics) and event photographers but less convenient for wedding photographers (due to their large size).

Denis Reggie Seminar - Reflections

Yesterday I had the opportunity to attend a wedding photography workshop run by Denis Reggie and organised by Queensbury. Denis Reggie is an American Wedding Photojournalist catering to the very upper end of the wedding market. His lesson was broken into 2 parts. The first focussed on business and the market while the second part focussed on how he achieves the look of his photos. Below is a video showing how he achieves his look for group photos. Be warned, it is part of an ad for pocket wizard.

Of the two parts of his talk the most enlightening part was the first part, the part that focussed on the market. Here he suggested that the market can be split into two main groups of couples (each with two subgroups)  and two groups of photographers. To put it simply, adn to pull from the video above, couples either want to be themselves and have their photographer capture things as they actually happen or they want the photographer to tell them what to do. Similarly photographers either shoot things as they happen or try to control and orchestrate events.

Denis suggests that those who want the photographer to capture things as they happen are better clients as they are more likely to be high spend clients. While this is almost certainly true in his experience it is worth noting that his experience is skewed in two important ways:
1) He is a high end photographer with a high end price tag
As such he attracts high end, big spend clients.
2) He is a photojournalist
As such he attracts clients who want  their day captured as it occurs without direction from the photographer.

Notice that I have separated these two things. What Denis Reggie seems to suggest is that these two things go hand in hand. While this is true for his clients we must remember that his clients come from a specific subset of the population. Essentially his viewpoint, with or without his knowledge of it, is effected by sampling error.

Don't believe me? In order for Denis Reggie's assertion to be true high end wedding photographers would ALL need to be photojournalists as photojournalists would be the only ones who could survive at this end of the scale. This is not true. There are plenty of high end wedding photographers who are not photojournalists and they are doing just fine.

What then is the take home message? The take home message is, perhaps, that there is a market for high-end wedding photojournalism.

Side notes, the students

The people attending the seminar seemed to struggle with Denis Reggie's ideas and approach in the first section of the course. The main difficulty seemed to stem from treating the ideas as a presentation of how Denis sees the world rather than a presentation detailing how the world is. Those who got stuck in this second version, thinking his words were describing how the world is, had difficulty reconciling their experience of the world with the description he was given. What they missed was that here we are describing two completely different world views, as such they are never going to align themselves with each other as they are fundamentally different.
Here's how they differ:
Geographic Region
Denis' client base is world wide. For may of us our client base is restricted to the area that we live in. With a world wide client base you maximise the number of potential clients. Most importantly you maximise the number of potential big spend clients. As long as you're covering your travel costs you're away laughing.
Target Market 
Denis targets people who fit his way of photographing weddings. Consciously or not we also target clients who fit out way of shooting weddings as clients come to us because they like what we do. If we are shooting in fundamentally different ways to Denis then the clients we attract will also be fundamentally different. Many of the students felt that because they had never encountered the sorts of clients that Denis was talking about it was impossible for these clients to exist at all. Once again sampling bias is shaping opinions. As an illustration the fact that I have never met a US Senator does not mean that US Senators do not exist.

Mixed Lighting - Flash and tungsten (standard domestic lighting)

Colour temperature is measured in K and ranges from low blue temperatures to higher orange temperatures. Colour temperature varies by light source. Tungsten lights, standard domestic lights, appear warm and orange to most cameras. When shooting using a tungsten white balance the white point is moved higher meaning that things that would otherwise appear orange appear white and things that would otherwise appear white now appear blue.

In the example above the white balance has been set for the tungsten house lights in the kitchen and a flash without a gel has been used to light the foreground. Normally light from a flash is appears white in camera. However as the flash has a cooler colour temperature than the house lights (which the white balance has been set for) here the light from the flash appears blue.

The shot above is exactly the same as the first except this time the white balance has been set for the flash. Now the areas lit by the flash appear white and the areas lit by the tungsten house lights appear orange.

More Choice = Less Sales

It is fairly common for photographers to offer clients a few packages to choose from. Some photographers offer more choice, some less. Which is best?

Despite what you may initially think less choice is usually better than more choice. Fewer choices mean that fewer decisions must be made while more choices means more decisions must be made. More decisions = more fatigure = less enthusiasm = less sales.

Chase Jarvis - His Road to here and some extra guests

Backwards

Chase got where he is backwards. He didn't assist anyone. He didn't study photography formally.

Quitting

Chase quit medical school, a PhD program, and sport to do what he loved. He wanted to create things.

Transparency

- Information should be free
- Sharing trade secrets
- Blogging
- Youtube videos
- A rising tide (of knowledge) floats all boats

Villain

Sharing lead Chase to be vilified by his peers and the old guard. They were worried that what he was doing was taking money from their pockets and putting it in the hands of a 14 year old with a D40.

Now is the time for change

Content creators are now also distributors. That is what the internet has done for photography, video, and other sources. This is what makes the audience of hundreds of thousands possible.

Time for a new culture around creativity

Move from old art to social art, create content and context
interdisciplinary
participate
interact
symbiotic
everybody can win
incomplete without another person participating in some way

An opportunity for ecosystems

This collaboration requires a place to occur. In can be a physical location or one based online. If you provide a space for a community to thrive and a way to draw people in you can create a healthy creative environment like the Best Camera community.

Why do this?

It's good for you. It helps your soul, it can help your career. and it can help you develop your own creativity.
It's good for the world. Apparently creativity has been plummeting since the 1990s.

Jasmine Star
Top 10 wedding photographer in 4 years with no formal qualifications
Quit a law program to become a wedding photographer. Started with a simple Canon camera (20d) and a kit lens.
Zack Arias remembers her from a course he ran because she had excellent people skills, sent him cards, and had her brand in place before she even had a lens in her hand.

Joey Lawrence
Self taught pro Photoshopper and Photographer from 16
No formal training. Made home movies since childhood. Started photography with local bands. Crafted his portfolio to make it look like he had worked more jobs than he actually did.

Rob Haggart
Photo editor
The definition of photographer is changing. You are no longer restricted to being a shooter of still images. Create value with your images and your equipment in anyway that you can. Break out of the cog mode of thinking and working.

Zack Arias
Simple Gear for amazing photos
Also succeeded by doing things backwards, by not using the typical path in terms of gear etc.
Don't fear your clients. They are real people who are often under a lot of pressure, try to understand their needs and feel free to discuss your approach with them to reach a common understanding.
Jobs have 3 kinds of value - economic, creativity, opportunity

Vincent Laforet
dSLR filmmaker
Usually a late adopter but an early dSLR filmmaker, nothing makes him feel more alive than sharing.
The career paths that used to work often no longer exist.
Fear is the worst thing in life. It will freeze you up.
You aren't born with talent. You cultivate it.

Chase Jarvis
Photographer
You develop your look by taking a lot of photos.

Chase Jarvis - Lego Camera

The combination of Digital RevTV, Chase Jarvis, and a Lego Camera was always going to be a solid bit of fun. Rather unexpectedly though it is also a valuable learning experience. If you watch the video you will find that Chase inadvertantly, perhaps habitually, talks through his approach to each situation and explains how he will work around the limitations of the lego camera. He does this by anticipating the shutter delay, figuring out what the approcimate focal length is, and even building upon the basic system through the use of external flash and an ND filter.

For those unfamiliar with the triggering trick here's how it works. Most external flashes have a slave mode. When the external flash is in this mode it will fire whenever it detects that another flash has been fired. The other flash doesn't have to be particularly powerful either, it just has to be powerful enough for the external flash to see it. Here then the external flash (the SB-900) is triggered by the lego cameras flash giving Chase control over an external flash.

The ND filter is required because when the lego camera is in flash mode the settings lock to correctly expose the image for the lego camera flash. The external flash is stronger (brighter) than the lego cameras flash which then leads to the image being overexposed. The ND filter acts like a pair of sun glasses for the camera, cutting down the amount of light that enters the lens bringing the image back towards a correct exposure.

The Magic Numbers of Photography - How Focus works

Lately I've been getting interested in the principles behind photography (think physics). One key part of this is focal length and the idea that focal length is the distance from the front of the lens to the image sensor (for digital cameras) or film (for film cameras). The focal length is also the point at which light passing through the lens becomes focussed. This should mean that lenses of a given focal length should only be able to focus on objects at a particular distance. To put it another way lenses of a given focal length should not be able to have variable focus.

Yet we know this isn't true. All of our lenses have a focus ring and they all allow us to control where focus is without changing the focal length...

Or do they?

I decided to test this out by slapping my 50mm prime lens onto my camera then setting my camera up on a tripod in my lounge. I then took two pictures, 1 with the focus ring set to the furthest distance possible (infinity), the second with it set to the closest distance possible (in this case 45cm). The results were surprsing and gratifying at the same time.

Photo taken with focus set to infinity

Photo taken with focus set to 45cm

As you can see in the images above the field of view has shifted between the 2 photos. In the first case with focus set to infinity we have a wider angle of view than the second case with focus set to 45cm. The changing focus has changed the focal length.

This is surprising because:

We expect fixed focal length lenses to maintain a constant focal length. Clearly this is not the case

This is not surprising/is gratifying because:

It fits with the basic physical principles of how light can be focussed on a surface

It fits with what you SEE happening when you adjust focus on a lens (the lens moves away from the sensor when focussing on close objects (increased focal length and a narrower angle of view) and towards the sensor when focussing on distant objects (decreased focal length and a wider angle of view)).

The Magic Numbers of Photography - Calculating the F number

F numbers or F stops are an important concept to grasp in Photography. The F stop that you select will have important implications for your depth of field and the amount of light that enters the camera. But where does this value come from?

F numbers express the relationship between the focal length of a lens and the diameter of the opening through which light can pass (sometimes called a pupil or iris). The F number for any given lens is obtained by dividing the focal length by the diameter of the opening.

If they are equal the F number is 1.

If the focal length is smaller than the opening the F number is less than 1.

If the focal length is greater than the opening (the most common scenario) then the F number is greater than 1.

Now the truly interesting part about F numbers is the way that the relate to the amount of light that enters the lens. While doubling the shutter speed halves the amount of light that enters the camera doubling the f number more than halves the amount of light entering the camera. This is because the F number is related to the diameter of the opening while the amount of light that enters is determined by the area of the opening.

To illustrate this point we will compare the area and diameter of the opening for 3 F stop values in a 50mm lens: 1, 1.4, and 2.

F = 1

Diameter = 50/1 = 50mm

Area = 25 x 25 pi = 1964.29mm

F = 1.4

Diameter =  50/1.4 = 35.71...mm

Area = 17.86... x 17.86... x pi = 1002.19mm

F = 2

Diameter = 50/2 = 25mm

Area = 12.5 x 12.5 x pi = 491.07mm

NB:// This relationship holds for any focal length as F numbers take the focal length into account. 50mm simply used as a concrete example.

As it turns out in order to halve the amount of light that enters the camera you need to increase the f number by the sqaure root of 2 (1.4-ish). This is why the standard F stop scale goes:

1 - 1.4 - 2 - 2.8 - 4 - 5.6 - 8 - 11 - 16 - 22 - 32

Each value is an approximation to the preceding value multiplied by the square root of 2 (1.4-ish)

F = 1

Diameter = 50/1 = 50mm

Area = 25 x 25 pi = 1964.29mm

F= Square root of 2

Diameter = 35.53...

Area = 982.14

Now if you're super inquisitive you may be wondering why the square root of 2 is the magical number. If you're also super observant you may have noticed earlier that the change from an F number of 1 to an F number of 2 reduced the area by a factor of 4. If you extend that out to an F number of 4 the area is 16 times smaller than when you have an F number of 1.

F = 1

Diameter = 50/1 = 50mm

Area = 25 x 25 pi = 1964.29mm

F = 2

Diameter = 50/2 = 25mm

Area = 12.5 x 12.5 x pi = 491.07mm

F = 4

Diameter =  50/4 = 12.5.mm

Area = 6.25 x 6.25 x pi = 122.76mm

What's happening?

Every time you double the F number, by going from 1 to 2 or 2 to 4, the amount of light entering the camera reduces by 4 times (or 2 squared). 

If you quadruple the F number, by going from 1 to 4, the amount of light entering the camera reduces by 16 times (or 4 squared). Turning this around if you wanted to decrease the amount of light entering the lens by 16 times you could quadruple your f number (4 is the square root of 16). If you wanted to decrease the amount of light entering your camera by 4 times you could double your F number (2 is the square root of 4). Finally if you want to reduce the amount of light entering your camera by two times (i.e. if you wanted to halve the amount of light entering your camera) you could increase your F number by ~1.4 (~1.4 is the square root of 2).

In fact this concept pops up a lot in photography and is known as the inverse square law.