Sunday 16 August 2015

The Toshiba Air wifi connected SD Card

Preamble

It takes me a very long while to acquire something - this is the case with the Toshiba Air SD Card - it's been several generations now that modern cameras have built-in wifi and I even have one of these but finally I got myself a wifi connected card for older camera. When I shoot now, I often want the instant gratification of uploading to social networks (G+ or Instagram) soon, without waiting for the journey home. The two market leaders for this type of card is the Toshiba Air and the Eye Fi. I knew that Olympus has an association with distributing Toshiba Air cards, so when I saw much reduced prices on eBay, I took down the local dealer's address and went in person to get one.

Things didn't look good when I inserted the card into either the Olympus E-PM2 or the Panasonic GF-3 - by what I could read from the brief documentation, I expected the card to broadcast a wifi SSID so that my phone or Windows PC could see it as a wifi source.

When you insert the card into any device, the wifi access point should start broadcasting and keep broadcasting for 5 minutes if it is on autostart. However in my case it was not on autostart and was on manual. I needed to set it to autostart.

To set up the card using the computer

  • Insert the card into the the sdcard slot of the computer
  • Run the FlashAir program - it was difficult to find, I found it at this Toshiba webpage.
    • Ensure the Wireless LAN is set to automatic startup
    • Change the connection password for the card to ensure that other cameras and device don't hijack your connection or data.

FlashAir.exe menus and screens

FlashAir Main Menu

FlashAir Network Settings

FlashAir Wireless LAN Startup Menu - ensure that this is set to automatic startup otherwise the card will not broadcast the SSID

FlashAir Drive Setting

FlashAir Initialise / Change - use this to set up the card to factory defaults and write missing or deleted folders and files

More Info

The Toshiba web pages / sites that came up in Google Search were not helpful - they were either describing product from the viewpoint of a manufacturer rather than from the viewpoint of a consumer. Often there were redirects to missing pages or pages written in Japanese. I finally found a Toshiba Singapore webpage that seemed readable. The details eluded me until I found a briefly written pdf hosted on an Olympus website. The document describes both the set up procedure using the FlashAir.exe computer program or the Flash Air mobile device app.

Here's what I discovered.

  1. The SD card appears to the camera or the computer (with SD Card slot) as a storage device.
  2. Certain folders and files are precious and should not be erased or formatted out during file deletion or formatting either in the camera or the computer. If these folders / files are deleted, you need to run FlashAir.exe (or in my case, FlashAir_v3.exe) - available in Windows or Mac variant, to replace these files on the inserted SD Card.
  3. Take care not to eject the SD Card without using the Windows Safely Remove procedure otherwise the special folders or file might be damaged by file system corruption. Of course they can be replaced by a card format but it's just more work.
The files and folders are in this structure


+---MISC
+---PRIVATE
|   |   FILEINFO.TBL
|   |   CACHE.DAT
|   \---AVCHD
|       +---BDMV
|       |   |   INDEX.BDM
|       |   |   MOVIEOBJ.BDM
|       |   |
|       |   +---PLAYLIST
|       |   +---CLIPINF
|       |   \---STREAM
|       \---AVCHDTN
|               THUMB.TID
|               THUMB.TDT
|
+---GUPIXINF
|   \---CARDICON
|          ICON_128.PNG|          ICON_32.PNG|          ICONINF.TXT
+---SD_WAN
|       CONFIG   
\---DCIM
    +---100__TSB
           FA000001.JPG


\DCIM\100__TSB\FA000001.JPG is an important static file that acts as a flag
Do not delete the folder and file, or you will be unable to change the automatic-manual operation for wireless LAN functionality. 
\SD_WAN\CONFIG is a vital text file containing settings

CONFIG contains text pairs like this:

[Vendor]

CIPATH=/DCIM/100__TSB/FA000001.JPG
APPMODE=4
APPNETWORKKEY=*******
VERSION=FA9CAW3AW3.00.00
CID=long hex code
PRODUCT=FlashAir
VENDOR=TOSHIBA
LOCK=1
APPSSID=yourssid
WEBDAV=1
TIMEZONE=40
APPAUTOTIME=300000
DNSMODE=1

Information on these parameters is available at the FlashAir Developer's website

Factory Default Settings

SSID:  flashair_xxxxxxxxxxxx ( x represents MAC address of the Product) 
Security:  WPA2  security key: 12345678 
Encryption and authentification: WPA2-AES (access point mode) 
IP Address" 192.168.0.1 (access point mode)    

Wireless LAN functional specifications 

 Wireless LAN Standard: IEEE802.11b/g/n 
 Modulation: DSSS/CCK (1, 2, 5.5, 11 Mbps), OFDM (6 to 72.2 Mbps) 
 Wireless LAN Security: WEP, TKIP, AES (WPA/WPA2) 


Monday 6 April 2015

Why do we have Google Plus Photos repeated on Google Drive?

We're still trying to figure out WHY they created the Google Drive entry door to Google Photos (Google+ Photos).

At the moment, I suspect the designers wanted to offer a tree structure way of accessing your images. Neither the Picasa web interface nor Google Photos nor Picasa desktop client allow you to see a tree structured organisation of your image files.

Google Photos

This webapp has some logic on
a. albums
b. images from posts not in albums
c. autobackup images from phone or computer (guess)
d. images from other sources like hangouts (guess)
e. showing only the currently chosen version (there might be more than one version)
f. properties like date/time stamp and you could choose a timeline view.

You can create virtual copies of an image file between albums.

Google Drive

1. A default hierarchy tree of folders, in year/month naming e.g. Google Photos/2015/03
2. Every image file you produced from all the sources in that month is put in that month folder.
3. You can optionally see and find image files and move / make a different additional hierarchy within that base folder without breaking your G+ text post.
4. You can move image files out of that base folder into one of your own self made folders outside of the base Google Photos folder (does this count as a delete from G+ ? Not sure.
5. You can edit any of those image files with third party photo apps in the Drive menu without affecting your G+ Photos image and G+ text post. There will be Drive multiple versioning of your image file, not just the G+ Undo version.

In other words, you can carry out Drive actions and features that G+ Photos and Picasa Web webapps lack, all without breaking your G+ text posts, except image file deletion.
.
See:

Sunday 22 March 2015

The Olympus Photo Story

When I first got my OM-D E-M1, I looked at all the features that my previous and much loved Ruby PEN E-PM2 did not have. One of those was Photo Story – I was entranced by the way Olympus had progressed the Studio in the Field concept – as Liveview mirrorless cameras come of age. Freed from optical viewfinders, these cameras can carry out multiple aspect ratios, visual matting and composites dynamically as you aim.

What is a Photo Story? In essence, it is are live creation of Polyptch or  Collage Storyboards. You’ve seen two or three photos occupying one white matted frame in homes and exhibitions. Photo Storys are the digital, virtual equivalent of those – with the immediacy and adrenaline of creation at the point you shoot.

Olympus Cameras that I know have this Photo Story feature are:

  • OM-D E-M1
  • OM-D E-M10
  • OM-D E-M5 Mark 2
  • PEN E-P5
  • SH-1
  • SH-2
  • XZ-10

(if you know of any others, please comment).

On the E-M1, not only do you get the Photo Story image, you also get the individual image files – in case you want to create a the real thing – print out each photo and fix them to a physical frame.

Now, you might say, you normally don’t shoot like this, you prefer to be in full control – shoot your raw, process the JPEGs, run your favourite editor and paste the images onto a composite, high resolution composite image. If you do, please share what software you use and the procedure to create such composite images. For example, there could even be ready made Photoshop Actions scripted to do this.

If you do have one of these cameras, do have some fun, try making some image – have fun exercising your narrative, compositional and composite skills.

Wednesday 4 February 2015

Street Photography–Et tu Brute?

You’ve seen the photos of some famous street photographers and been impressed with their visual narrative. Or you’ve bought your camera and are close to urban areas – you could do landscapes and travel but those genres are so far away and so infrequent. You really find people in the street interesting, so you’re interested in street photography. But then it gets all difficult.  So let’s talk about a few things.

Knowing legal rights

In Australia, the most quoted source is the Arts Law information sheet available as a downloadable pdf. Briefly

  • taking photographs of people in public places is generally permitted.
  • if you are using your shots for a commercial purpose, such as for an advertising campaign or competition, you should obtain a model release form signed by the subjects you are photographing
  • There is no restriction on taking photographs of people on private property from public property.
  • Can taking photos be a criminal offence? Yes – read the document – case precedents and exclusions are cited.
  • Mark Davison has written an essay on photography in public in Victoria, Australia
  • For the UK, this is the advice.
  • Enjoying Yourself

  • You can’t enjoy yourself if you have to contend with expressed upset and anger from the people you take photos of. Regardless of whether  you have the right to take a photo of them or not. If you are argumentative and robust, yes, of course you can stand up to a scene in public but that is time and effort lost from the shooting. If you are faint hearted, it could spoil your day out to the extent that you pack it in.
  • A lot of enjoyment is in yourself – you’ve got to be at peace with yourself. And that’s before you aim the camera and press the shutter.
  • Emulating another photographer idol who euphemistically has balls of steel or adopting approaches that don’t suit you, might carry off one time, but progressively, won’t be sustainable.
  • You’ve got to develop your own mental state, your own approaches.

    Your Self Interview about your subject

    Of all the photography genres, Street insists on the most two way engagement. Landscape is one way. Have you ever had a rock talk back to you? Studio photography and Weddings – you do have to handle the client and the subject but there’s no doubt what your motives are. But in Street Photography – What are your motives? No, it’s not me you have to contend with – it’s the people you take a photo of and more importantly, it’s you, because you are the one who has to rationalise to yourself.
  • So, why actually, are you taking my photo?
  • Will my photo appear on the internet?
  • Will you make money from my photo?
  • Isn’t there a law about taking photos of me unawares?
  • What if I ask you to delete my photo?
  • Can I see all the photos you just took?
  • Why are you taking photos of my kids, sis, wife, gf? Are you some kind of pervert? Why don’t you play fair and take photos of your mother / wife / gf / yourself doing weird things and post them online?
  • Look, I’m not supposed to be here and you’ve taken a photo of me. I’m distressed, angry and upset. What are you going do about it?
  • ________________ over there doesn’t want you here. Could you go away now?
  • I’m calling the cops / reporting to the authorities. Does your employer / spouse / mother know you do this?
  • I’m bigger and tougher than you and I don’t like your face or how you’re carrying out your intrusive activities. Feel like making my day? These are not necessarily the questions you will be confronted with, but they could very well be things that people think about you. Be comfortable with your own answers – if you don’t believe your own answers, your photos are likely to show it.

    Seeing what others shoot

    Street Photography covers a multitude of styles. And although it’s about people, if you spend the time looking at various photographers’ photos, there are posed headshots (Robin Wong), there are full length posed portraits with interviews (HONY), there are environmental people and where they live / work (Yeow Chin Liang), there are general things that catch the eye – (Erwin Vindl, Thomas Leuthard), there are questions about why (Benizi Santamaria), viewpoints of the curious nanny (Vivian Maier), people in suits (Eric Kim) – there are heaps of different styles.

    Various Perspectives

  • On how I approach strangers in the street | An Afternoon with Brandon Stanton | Humans of New York: Behind the Portraits | Brandon Stanton: The Good Story
  • Karlo de Leon: How to build confidence in photographing people 
  • B & H Video: How to Talk to Strangers: 7 Tips For Photographing People – Adam Marelli
  • Ming Thein's Thoughts on Portraiture
  • Joel Meyerowitz: Video: Milan 2013/10/28 | 1981 documentary
  • Henri Cartier-Bresson Video: 1998 “Pen, Brush and Camera”
  • Video: Street Photography Interview with Justin Vogel in NYC with Eric Kim | flickr: HCSP
  • Bruce Gilden Video: What Makes a Good Street Photograph?
  • Daido Moriyama Video: Near Equal
  • Garry Winograd Video: Visions and Images 1981
  • Video: The Many Lives of William Klein (2012)
  • Video: Leaving Home, Coming Home: A Portrait of Robert Frank (2005)
  • Ben Fewtrell: Taking Photos in Public
  • Monday 2 February 2015

    A list of third party photo editing software

    When newcomers to photography discuss whether to edit their photos on the computer and what to use, they ask various questions.
    • Are there any free ones?
    • Does the program have to be installed on the computer? (some people use work computers that don't allow installation
    • Does it run on their Windows / Mac / Linux / Android tablet / iPhone or iPad?
    I was thinking of what to say and then mentally crumpled that thought like a piece of paper. Made a grid so people can pick something. It's not comprehensive and may even be inaccurate.



    Sunday 1 February 2015

    Putting The Fun Back Into Photography

    (for those who found the deep, serious end and are stuck in a drought of interest)

    So what’s the point about this article?

    +Charles Strebor originally teased me about writing an article on Frivolous Photography – I’m turning it into a call-to-arms for those whose poor cameras languish on the pedestal of loneliness.

    Who this is for

    I’m using the mythical You for simplicity. If this is not you, rejoice. Try to help the sufferers amongst us.

    You own a Nikon D800 / Canon 5D3 / Leica M9. And the Holy Trinity of Lenses. Trouble is, the gear is sitting at home in the temperature and humidity controlled cabinet. Well, maybe that’s an over dramatization. Alternatively, you could as well be the owner of that nice interchangeable lens camera body with two lenses. You bought that for the once in a lifetime vacation to South America / Europe / Asia. Except that it’s still sitting at home in a camera bag.
    When was the last time you brought out the gear into the open. No, not into the lounge fondle fest, but out in the open, doing its thing, clicking the shutter, capturing images? Three months? Two months? Too long? When are you going to next use it? So and so’s wedding next year? When you’ll be the wedding uncle with the camera?

    Six Ways you can get the Fun back

    1. Make or break your genre

    Most people prefer to take photos in a particular genre. Travel, landscape scenery, architecture, the portraiture – categories like that. If you are still excited by your chosen genre, make some effort to shoot more. If your interest is waning, break out of your comfortable sofa and embrace the world. Open your eyes, look at all things not just the 9 to 5. There are heaps of things to take a photo of. There’s beauty in many things.
    Cables | Shoes | Things that look like Faces | Things that Steam – And there are heaps others

    2. Reduce the amount of gear you go out with

    I see lots of people go out with heavily padded camera backpacks, filled with gear when they go for a formal photo walk. Soon, every walk becomes a formal walk. There are no casual, grab-the-camera-get-out-the-door occasions anymore. And that’s the issue. Real, formal, pack-your-bag photo sessions happen as infrequently as once in three months for many people.
    There are more far more frequent happenings every day or every week as the world around you changes, as the people around you mature. That joie-de-vivre is worthy of capturing.

    3. If necessary, buy cheaper / smaller / weather resistant gear

    One thing I hear people say is “oh, I wouldn’t take my camera to __________” (fill in the blanks). That’s a signal that they have bought gear that is too precious. It does not have to be outrageously expensive – each one of us has a different definition to the minimum value for gear to be precious. And they’re afraid of the harm that will come to the gear so they don’t carry it out and use it.
    Many brands and models try to resolve this Strawman Fallacy – if we postulate that the gear is too big, we can sell you smaller gear. If we say that your gear is not weather resistant enough, we can sell you a camera that can take the sea and the beaches without breaking. And make big money selling supplemental gear.
    When what you really need is gear which is not precious. Get some.

    4. Carry the least amount of gear so that you have total upper body mobility

    I’m not that fit. Not young. My knees give me problems when I bend them. It gets worse even though I carry a light Lowe Passport thin fabric bag. Whether you’re fit or not, carrying a padded backpack with a bunch of large lenses restricts your inclination to lay the precious gear on the floor and get down low when you need to get down low. And quite a few shots work well below the waist. But what is the least amount of gear? How about one lens, one body?  Yes, I know you have an interchangeable lens camera but that doesn’t mean you have to change lenses constantly in the field.

    5. Let your hair down. Take it easy. Relax on that tender but excruciatingly meticulous pursuit of processing perfection

    So far, all cameras can produce JPEGs straight out of the camera. Some brands do it better than others. Even the ones that don’t do JPEGs as well, offer in-camera tweaks that improve over the defaults that camera review websites speak of. Find a good setting. Then shoot with it. Shoot JPEG + raw if you can’t avoid the obsessiveness of wanting to “work” raw one fine day. But for today, get to know and enjoy the JPEG. Celebrate it. Do as little post processing as possible - Straighten and Crop, Curves. Celebrate the SOOC JPEG. Celebrate you.

    6. Participate in a supportive, congenial, motivating community where you get inspiration and pings as often as hourly

    The joy of photography can be completely dampened by unenthusiastic, uncaring family and friends. You don’t have choice of family, that’s connection by birth. You do have a choice of friends but you often have made friends in you journey through life and not because they enthuse photography. Before the Web, life as a photo fan was indeed lonely – you could pore through glossy photo magazines but the photos weren’t yours and always looked better than whatever you could make.
    The Web has connected people who love photography and who enthuse, cross-inspire, cross-motivate. And across  distances and countries. Again, be wary of those old time formal galleries like 500px or even flickr. It’s easy to get a sense of inadequacy there, conversation is brief and admiring, seldom as frequent as daily or hourly. Give Google+ a try. Or at least Instagram.

    Follow Up Notes for People New to Serious Photography

    Prelims

    I had a fun time with some cool newcomers  to serious photography and two long time friends, arranged by Victor last evening. It's provided enough impetus to break my drought of writing on this blog - Google+ has been so absorbing that most times, that +Mike Elgan once predicted, it would sap away efforts to keep traditional blogs going.

    Fundamentals

    So, opening with fundamentals. But not so much about Photography as Stuff about Life.
    1. I use the phrase Serious Photography to mean photography where you take the time and effort to get set up the camera, control the photo result rather than let the modern camera or camera phone do its thang - I don't use it to mean Stuffed Shirt, Stiff Collar Photography or approaches to it. As I said to the group before the meeting, I've become quite irreverent these days.
    2. There's often more than one way to do a thing, There's often more than one technique, camera brand, camera, lens, software product. What matters is the result - viewers of your images often see the product, the result, not how you did it. There will always be some dude to can pick the spots off a white wall, but don't let that dude spoil your satisfaction. Put some distance between yourself and those dudes.
    3. Don't Sweat The Small Stuff - What matters is context and relative degrees of good and bad. For example, if someone tells you not to use f/22 because it loses sharpness and resolution, yes, that can be true but that doesn't mean you can't give it a burl or suck it and see yourself.
    4. You've got to go out into the field and do it yourself. Reading information only, can be boring but more importantly can bullshit brains.

    Camera Exposure Modes

    On most cameras, there are the following:
    • Green Auto or Auto or iAuto
    • Scene Modes - Like Landscape, Night Scenes, Fireworks
    • P / A / S / M or in Canon speak P / Av / Tv / M
    Some people deprecate the Green Auto or Scene Modes and some obsessives want to eradicate that from all cameras - or often say "I'd give X dollars for a camera that doesn't have automatic modes". Should you use them? Or more importantly, Can you use them without the terrible burden of guilt?

    Look. You paid money for the camera. And the camera has those features. If you want to use it for whatever reason, go ahead - it's not a betrayal or cowardice.  Green Auto / Auto / iAuto is a brains off mode. You don't have to think. You could be on a blissful high and you don't want to spoil the moment with logical setup and thought. You could be real brain tired but still want to take the shot.

    Bear in mind though
    • some cameras automatically pop up that built in flash if the light is dim, making you look silly and spoiling the natural light nuances
    • you may not be able to tweak the brightness of the shot. If you can tweak the brightness, the camera does not remember your choice for long so that it's not stuck in a rut.
    • the camera saves only JPEG, not raw image files.
    • you can't tune the shot to a somewhat blurred background, emphasizing the person in the portrait.
    On some cameras, iAuto means the camera analyses the scene to figure out whether you're taking a photo of landscape or a person portrait or sports moving action. It's major innovation and it's getting better all the time as the cameras get more complex brains. But. If the scene light or  the camera and lens body capability can't make a good photo, sheer camera intelligence can't overcome that.

    Scene Modes

    When you use Scene Modes, you are telling the camera the type if scene it is. in targeting the type of scene. They're sets of camera settings biased towards for example, landscape (sharp distant scenery, lush greens), person portraits, night scenes (increased ISO, fastest shutter speed given the dim light, largest f/no). Some people have so much success with Scene Modes that they want to reverse engineer the Scene Mode settings so that they can use it in M (Manual) or P A S modes. And get upset that the manufacturer does not document the secret recipe to each mode. Shrug - they're a secret recipe.

    P / A / S / M Exposure Modes

    Symbol Canon Symbol Officially What it means Exposure Compensation Additional Remarks
    P P Programmed optimisation Camera chooses f/no and shutter speed You can darken/lighten the image brightness using the Exposure Compensation dial - the chosen pair of f/no and shutter speed will change. Ps - Program Shift is available - this allows the user to bias the Programmed choice towards a different recommendation of f/no and shutter speed, while keeping the image brightness the same. If using Auto ISO, this is one more factor the camera can adjust by itself
    A Av Aperture Priority You choose f/no, camera chooses shutter speed You can darken/lighten the image brightness using the Exposure Compensation dial - the camera cannot change the f/no so it changes the shutter speed If ISO is set to Auto, this is one more factor the camera can adjust by itself
    S Tv Shutter Priority You choose shutter speed, camera chooses f/no You can darken/lighten the image brightness using the Exposure Compensation dial - the camera cannot change the shutter speed so it changes the f/no If ISO is set to Auto, this is one more factor the camera can adjust by itself
    M M Manual Exposure You choose both f/no and shutter speed Usually not meaningful Be alert to the use of Auto ISO - on various cameras, this overrides full control image brightness since the camera can vary the ISO

    But which exposure mode one should you use? What do I use?

    Use P when you aren't too concerned about whether a shot has extreme background blur (subject isolation) or motion stopping. Fans of P often say they can twirl a dial and get Ps - Program Shift - that is, bias the choice towards a a certain f/no or a certain shutter speed.

    Use A when you tend to be concerned with landscapes, architecture, sunsets or person portraits. You directly set the f/no which controls Depth of Field.

    Use S when you tend to be concerned with freezing moving subjects (sports etc...) or when you want to nominate a shutter speed that is really slow for smooth blurred waterfalls.

    Use M with fixed ISO when you feel the camera's prediction is frequently confused. This could be that you're taking a photo of the moon and the camera doesn't understand. Or you taking photos of unevenly lit, dramatic scenes - as actor moves between spotlight and darkness, the camera doesn't get it either and always recommends wrong. One feature of modern cameras is that you have Liveview - either LCD on the back of the camera or Electronic View Finder. This makes M more easy to visualise - with emulation of scene brightness in Liveview, you can just point and twirl your f/no and/or shutter speed and/or ISO and you get a preview of the scene brightness before you click.

    Let's take an analogy. Let's say you drive to work and you take a certain route. How did you come to pick up the route? Was it because it is the shortest? Was it because it is the cheapest (no road tolls)? Was it because you could do a pickup of the your partner or child along the way?

    You can see that I'm heading the way that choice of Exposure Mode is a personal choice. For old timers choice depends on old habits. For example, in my days in the film era, the Minolta XE-1 only had A. There's also the facet that some have enough mindfulness to flex between Aperture Priority (when they want the emphasis on Depth of Field) and Shutter Priority (when they want to choose a shutter speed that is simply freezes motion). I don't enjoy that swapping and mostly stay on Aperture Priority because I don't have to deal with a different technique.

    Whether you use P A S or M in the end, doesn't really matter if you can spot the challenge and get the shot successfully - the image file does not care about P A S or M.  For most instances,  you can make the shot regardless of  whether you use P A S or M.

    Parameters, Constraints - Managing and controlling them

    P A S assist you in choosing parameters to achieve an image of relevant brightness - and clarity. Over time, you may want artistic renditions, conveying a sense of motion or subject isolation or sharpness or blur.

    1. The Shutter Speed Parameter

    Photography is about taking a moment in time, sampling the light from the scene and capturing it onto film or digital sensor. The moment in time is gated by the shutter speed. The shutter opens, light comes onto the sensor, then the shutter closes and the shot is captured. The Shutter Speed numbers run like 25 or 100 or 500 or 1000 - that's for simplicity of camera display - they are actually 1/25 or 1/1000 of a second. Each shutter speed, for example 1/100 sec, is designed to be the same across all cameras.

    The Shutter Speed range runs into several constraints:
    • There is a fastest speed limit each camera can do. For example 1/2000 of a second.
    • There is slowest speed limit each camera can do. Maybe a few seconds. You may choose B which stands for Bulb - an old term - meaning the shutter will only close when you release pressure on the Shutter Release Button.
    • For cameras with Focal Plane shutters there is a flash sync speed ceiling. Above that ceiling - called flash sync speed, photos with electronic flash will have parts blacked off.

    2. The F/no (mostly known as the f/stop) Parameter

    The f/no is a strange number. We often refer to this as Aperture. I prefer to call it f/no because people get confused with large aperture = small f/number  and small aperture / large f/number.
    (image "Aperture diagram" by Cbuckley at the English language Wikipedia.)

    Notice that the camera shows these numbers as 2 or 8 when it is actually f/2 or f/8. Unlike the Shutter Speed where you have the numbers progress in a doubling, the f/no scale is best committed to memory instead of doing arithmetic in your head. A certain f/no for example, f/8 is designed to be similar across all lenses. (If someone tells you about the t stop, don't obsess over it)

    The f/stop range hits the following constraints.
    • the smallest f/no is a optical, weight, size, cost limit. If your lens is not very expensive, it may have a brightest of f/4 - and for inexpensive zooms, as you zoom in, the brightest f/no will reduce in brightness to f/5.6 or darker.
    • the biggest f/no might be f/16 or f/22 - at this extreme, the aperture can be so small that edge diffraction effects happen - this reduces sharpness in the image. Don't obsess over this or anything else - sometimes you do want edge diffraction for sunburst effects in #chasingthesun. Know about it, but don't obsess about it. Try it once in a while.
    • In terms of detail and sharpness, there is a sweet spot for a certain lens (or several sweet spots if the lens zooms). It's worth bearing in mind but don't obsess over it and avoid the wide open f/no.

     3. The ISO parameter

    In photography we have abbreviated the term ISO 12232:2006 Photography -- Digital still cameras -- Determination of exposure index, ISO speed ratings, standard output sensitivity, and recommended exposure index to "ISO". By this, we mean we have a scale across all digital cameras (regardless of size) that we can refer to, as to how sensitive the sensor is to light.  For example, ISO 200 should be the same across all cameras so my camera, when set to ISO 200 will deliver the same image brightness as your camera for the same scene.

    Digital Sensors are designed with a native ISO - the one on my camera is ISO 200.  To allow the camera to offer a faster shutter speed and larger f/no even in dim light, the camera can amplify the sensitivity to 400, 800, 1600, 64000 and even higher. Extreme amplifications lead to increased digital noise (graininess in the image). Film, being based on photo chemistry was easy to make insensitive - we could have film that was ISO 25 or 32. Some digital sensors don't start so low, so manufacturers sometimes have a setting called Low which is a notch lower than the sensor's base sensitivity.

    4. The Scene Exposure Value - is it a Constraint or Parameter?

    You'll see references to the Exposure Triangle on the web. The three corners of the Triangle are of course Shutter Speed, F/No and ISO.  I tend to say that a Triangle is missing one more axis. I prefer to call it a pyramid - the fourth tip of the triangular pyramid is Scene Exposure Value.

    Normally, if we arrive at an outdoor scene, we have to accept the scene's actual brightness. So that's a constraint - i.e it could be a bright summer daylight scene (that's coded as EV 15 @ ISO 100) or an evening sunset scene (that's coded as EV 12 @ ISO 1OO).

    Scene Light is something  we accept as a Constraint. We could come back another time, or change our subject position relative to the sun - in which case it's a Parameter we can change. Some keen photographers carry strobe lights and fabric lighting modifiers to exercise control of light in person portrait shooting. Others carry graduated or full Neutral Density Filters. 2011 to 2014 showed a strong trend / fad to High Dynamic Range (HDR) techniques - taking a bracket of 3 or more shots of darker, middle, brighter shots and blending them on the computer in post process. Thankfully the fad of extreme toning is subsiding....

    Why it's a Constraint
    • If the scene is dark, (like EV 12 @ ISO 100) you can't attain the image brightness you want if you use f/8 and 1/1000 sec and  ISO 200
    • If the scene is bright (like EV 16 @ ISO 100) you can't attain the image brightness you want if you use f/8 10 secs  and ISO 200.
    How do you figure out these limits? Look at the  Table of Camera Settings for Scene Exposure Values and the Table of Exposure Values.

    Counting Stops / Twirling Dials

    In this day and age with the ability to chimp on the DSLR LCD after the shot, or to preview before the shot (particularly in compact system cameras a.k.a. mirrorless) - you don't have to walk around with sheets of tables, cardboard circular calculators or separate hand held exposure meters. You could, but you don't have to.

    What most people do is to use the power of being able to see the brightness and other characteristics of the image in the preview/review and twirl the dials in the right direction with confidence.

    What's the right direction?

    The most important thing to know is which end is low and which end is high. The second thing to know is how much to change - a third of a "stop" ? a full stop? more?  Let's look an example scene and the scales.

    1. The table below has several rows. Don't read any significance to the vertical arrangement of the cells - the table is to demonstrate the row wise adjustments.

    2. Assume we have a Scene EV of 14 - that's a daylight hazy scene with  soft shadows.

    How To Play

    • If we move the yellow box of the Scene EV to left by one cell, we have to move one of the yellow boxes on the other rows left one cell as well to maintain brightness.
    • If we want to darken the image (using fixed ISO), we can move the yellow cell in Exposure Compensation (the purple row) to the left, for P A S Exposure Modes. For M Exposure Mode, the purple row does not operate and we have to move the yellow cell to the left in one of the other white rows.
    As we adjust for image brightness, facets like clarity, motion blur, depth of field may also be affected.


    Scene EVdark111213141516bright









    Image / EV Compdarken-2.0-1.00.01.02.0
    lighten









    ISOclear10020040080016003200grainy









    Shutter Speedfreeze60125250500100030blur









    f/nodeep depth of field45.6811162.8shallow depth of field

    Further Topics to write about

    • JPEG vs raw or both
    • Should you / Do you need to post process your shots on the camera?

    Further Reading