Monday, January 28, 2008

Winter Musings: January. From Camera to Computer. Part One

I thought some readers would be interested in learning about the technical details behind how I work. Some things were taught to me and others learned; nothing you read here is a secret per se but it is a result of experience. Originally planned as a single entry I decided to split it up due to length. So this month I will be describing my camera set up and rationale while next month I will discuss my preview and editing tools, and how it all comes together in my workflow.

I value consistency and process, Henry Ford would be proud. I am not as much a seat-of-the-pants photographer as others and believe my best results are achieved when I take more responsibility for how an image is exposed and processed. My own skills and experience are trusted over the exposure programs offered by the DSLR. This methodology helps streamline my RAW file workflow. Do you see of my engineering background peeking through? Yes, I like control!

My two Canon 5D DSLR's are configured identically and are fitted with aftermarket Haoda horizontal split prism focusing screens (SO missed these from my 1 series Canon's). I photograph using:
  • manual exposure - always
  • center focusing point - almost always
  • spot metering - almost always
  • evaluative metering when using ETTLII on the 580EX flash
  • "back button focusing" - almost always
  • normal focusing when dark and using 580EX flash's IR assist
  • RAW format - always
  • with lens hoods - always
I prefer manual exposure because it produces consistent results. I do not want my shutter speed or aperture to change just because I am pointed at a slightly different area of the scene. The light illuminating the scene has not changed. If I photograph a series, each exposure will be identical which makes post processing much simpler - assembly line is a good analogy. Tweaking each image to create a consistent looking result requires way too much effort. Manual exposure permits me to batch process exposure adjustments with a predictable outcome.

The center focusing point is used by many focus-and-recompose photographers like me. Letting the camera decide can be frustrating. Also, experience has shown that autofocus is great but the split prism is best for critical shooting when depth of field is at a premium. Just be careful when you are very close to the subject and shooting wide open. A slight recomposition may change the focal plane and something you thought was in focus will actually not be. Occasionally I will switch points when I want a particular framing. Despite how good the camera is at auto-selecting focusing points, I still like the control when manually selecting the point.

Spot metering gives the photographer control over highlights and shadows - here's that word again - consistency. I move the spot over areas of the frame and decide what I want to show; set the exposure (manually) and fire away. You will get rich and saturated images out of the camera without post processing. Weddings are easy because you generally contend with faces and dresses. I can always spot meter on the dress to prevent blown highlights. Something to think about: if you are going to use spot metering for backlit subjects, you might as well just use it all the time.

The one time I will not spot meter is when using flash. If you read about ETTL flash you will see why. Among other things, flash power algorithms are tied to exposure readings around the focus point.
When I focus and recompose, the focus point may not be on my subject when I am ready to shoot which will lead to errant exposure readings and flash output. Result? Annoying over and under exposures. I employ evaluative metering when using flash which averages over the entire scene. It is a much safer setting in this instance.

Ooooo, the legendary back button focus - a religion for some photographers, including me. This is when you set a "Custom Function" allowing you to use a button on the back of the camera to trigger auto focus. The shutter release is then decoupled from AF and serves one less function. There are a bevy of reasons to use this especially for manual-exposure-spot-metering-focus-and-recompose junkies!

First, you now get instant shutter release, on-demand. Before you would have to wait for the AF system to deliver a focus confirmation. The benefit is a reduced risk of missing your shot.

Second, this allows you to prefocus, meter, and recompose before firing.
This is commonly employed for predictably moving subjects. You focus on a spot then snap the photograph as they pass it. Higher probability of a sharp image. Before, the AF was triggered every time you press the shutter release thus changing what was in focus.

Third, you can use the full time manual (FT-M) feature of most pro lenses without flipping the AF/MF switch.
This is very convenient when shooting macro details. Before, the AF would always override what you manually set when you pressed the shutter release down. It works for moving subjects too when you choose not to use the AI-Servo mode.

Fourth, you decouple metering and focusing. You can focus on a subject and then move your spot meter over another area of the image to examine your exposure by pressing the shutter release down half way. Move the camera back to the subject and fire without ever changing what was in focus.

I disable back button focusing when I'm in a dark room. The flash's IR assist will make sure what I am pointing at is in focus and release the shutter at that instant. Not all images will be in focus but it is better than prefocusing and the split prism is useless when you can't really see your subject. This is used mostly at the end of the night when the dancing starts and the fairy godmother turns my camera into an expensive point and shoot.

I always shoot RAW. One dark church was all that was necessary to convert me. Aside from the 12-bit mathematical benefits over an 8-bit JPEG, it is a great time saver on many levels. Color correction is much simpler in Lightroom, under and over exposures are more recoverable, it appeals to my engineering nature, and it saves interim hard drive space for my workflow. That's right, you read it correctly. Stay tuned next month for the reason why.

There is a reason why your expensive $1100+ lens came with a hood. It wasn't an upsell. Hoods restrict incident light to whatever you are pointing at. This prevents flare at the extreme, but also improves the color saturation by controlling unwanted reflections and light pollution. One other benefit is that it protects your expensive glass from fingers and pointy things as you move around.

OMG, this is way too long already. Tune in next month for Part Two.

Winter Musings are monthly posts between November and February. They cover a range of topics related to wedding photography with couples and photographers in mind. I hope you will tune in next month. Comments and requests are appreciated!


Julian said...

Hi Karl,
Your photos are amazing! You are clearly an extremely talented photographer (who also really likes vignettes :) )

I have a question, however: I've heard a number of people preach the religion of the back focus button, but don't use it myself. I can't understand how it is so beneficial. However, with so many good photographers using this technique there must be something to it, so what am I missing here? Could you enlighten me? For example, you say:

> First, you now get instant shutter release
This is certainly useful in some situations. However what use is instant shutter release when the shot is not in focus. This would only work if you are shooting multiple shots focused on the same subject in the same spot. When shooting multiple (possibly moving) subjects wouldn't it be better to have the shutter button autofocus? That way you can quickly press, focus and release all in one action. Otherwise, fumbling with the back focus button and then pressing the shutter release is two steps, which would slow you down and might make use miss the shot.

> Second, this allows you to prefocus,
> meter, and recompose before firing.
Can't you just use the AE Lock button to do this? Sure, it's the other way around: meter first, then prefocus by half-pressing the shutter button; but it comes down to the same effect.

> Third, you can use the (FT-M) feature
> very convenient when shooting macro
Macro shoots don't occur that often and when they do you usually have plenty of time to compose, switch to manual focusing, and take the shot. I don't see how this justifies always shooting using the back focus button.

> Fourth, you decouple metering and focusing.
Again, you can use the AE-lock button for the same effect.

So, in my mind, that nullifies all your arguments for using the back focus button. What am I missing here?


Karl said...

Hi Julian,

Thank you for taking the time to read my blog! Sorry, looks like I should do blog maintenance a bit more frequently :) Yes, I might vignette a little too much ;)

You have some interesting arguments. I did call it a "religion" right? One cannot always explain faith. Many people do not use back-button and do so very successfully just as some people shoot Av mode or Program mode and make far more money than me. If something is working for you, definitely do not change what makes you successful!

Let me just say, I am a manual exposure, focus-and-recompose type photographer most of the time. I have found that back-button focusing works better for me in this operating paradigm.

We could poke holes in arguments several times over but in the end, I think it depends on the application, style, and familiarity. I do not personally use back button all of the time, or haven't quite figured out how to employ it advantageously in every situation but it is my preference given my current business focus. Also, it meshes well with my focus-recompose style.

Regarding instant shutter release with moving subjects. I do not generally use it for moving subjects in unpredictable situations. I also do not fire off a frame when I know it will be out of focus. There are better ways to handle it. For that, normal focus may be more appropriate as you noted; or perhaps AI-Servo on Canons (sorry, not familiar with Nikons). The example I have but failed to mention is photographing a processional. I prefocus on a spot and shoot as people pass that spot. This has worked better for me especially in the darker churches when AF tends to hunt as people walk beyond my frame. I tried other ways and didn't like my results. Framing and perspective are also more consistent from subject to subject. Panning is another situation when I would prefer back-button for prefocusing. Although I haven't tried this, I believe you can employ AI-Servo with the back-button and then hit the shutter release when ready.

Your second point about AE-lock or depressing the shutter half way down until your are ready. Well, I do not lock AE because I always use manual exposure so it would not work in my particular case. AE lock is useful in the other modes like Tv and Av. For the second half of the argument, you are right, the result is the same. Truth be told, I am a little lazy and prefer to do an initial setup and then wait without having to hold the button down. Nature photographers often do this too. Prefocus and meter then wait until the light is right or something appears.

About FT-M and macros. The frequency of macros is not so important, but I do use it often during a wedding. In my mode of shooting, it is just convenient to shoot with back-button and never need to flip the AF/MF switch. Back-button gets me close, the focusing ring allows me to fine tune using a split prism, shutter release to finally take the shot. Wanting to use the split prism is the reason I like FT-M.

Decoupling. Yup, AE lock decouples for people shooting Tv or Av; but unfortunately, I like shooting in manual.

Does that all make sense? Perhaps back-button doesn't fit into your methods but don't change what works for you. I just found that it works for me better than the alternative most of the time.

Thank you for sharing,


Julian said...

Yes, that makes a lot of sense. Back button focusing fits well with the manual style of photography you use.

Thanks for the reply,